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Proceedings of the 60th Conference of the California Weed Science Society Table of Contents

2008 Honorary Members – Mick Canevari and Tim Butler......................................…….… 6 2008 Award of Excellence Recipients – Dan Bryant and Will Crites......................................7 2008 Presidents Award for Lifetime Achievement in Weed Science Recipients Ken Dunster and Ron Vargas.....................................................................................................8 2008 Student Paper Contest Winners and Scholarship Recipients...............……...…...….10 In Memoriam.............................................................................................................................15 The Gadfly – a poem by David Haskell ………………….......……………...……..…………17 Oral Paper Summaries General Session: Everyone Benefits from Weed Control Chair: Stephen Colbert Presidential Address....................................................................................................................19 Carl Bell, UC Cooperative Extension, San Diego County Economic Considerations in Weed Control................................................................................21 Karen Klonsky, University of California, Davis Losses and Costs Imposed on California Ranchers by Yellow Starthistle.................................23 Mark Eiswerth, University of Wisconsin, Whitewater The Value of Herbicides in U.S. Crop Protection.......................................................................24 Leonard P. Gianessi, Crop Protection Research Institute, Washington, DC Weed School: Herbicides 101 Chair: Joseph DiTomaso Herbicide Mode of Action..........................................................................................................28 Joseph DiTomaso, University of California, Davis Herbicide Resistance Management.............................................................................................32 Tom Lanini, University of California, Davis Turf and Ornamental Sessions Chairs: Brad Hanson and Michael Kropp Residential Turf Weed Control...................................................................................................36

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Dennis Penner, Abate-A-Weed, Bakersfield, CA Application Temperature Impacts on Herbicide Effectiveness..................................................37 Jeffrey Derr, Virginia Polytechnic Institute and State University, Virginia Beach, VA Postemergence Nutsedge Management in Turf..........................................................................39 Jeffrey Derr, Virginia Polytechnic Institute and State University, Virginia Beach, VA Successful Control of English Lawn Daisy (Bellis perennis).....................................................41 Mark Mahady, Mark M. Mahady and Associates, Inc., Carmel Valley, CA Pendimethalin phytotoxicity and leaching in container media and field soil.............................44 Jeffrey Derr, Virginia Polytechnic Institute and State University, Virginia Beach, VA Japanese Dodder Detection and Treatment.................................................................................46 Terrance Lorick, California Department of Food and Agriculture, Sacramento Solarization and Steam Heat for Soil Disinfestation in Flower and Strawberry........................48 Celeste Gilbert, University of California, Davis Vegetable Crop Session Chairs: Steve Fennimore and Richard Smith Full Season Drip Irrigation in Lettuce – Impact on Weed Control.............................................49 Richard Smith, UC Cooperative Extension, Monterey County Vegetable Transplant Trends and Implications for Weed Control..............................................55 Sergio Silva, Growers Transplanting Incorporated, Salinas, CA Agronomic Crop Session Chair: Mick Canevari Sedge Biology and Control in California Rice...........................................................................56 Dave Cheetham, Helena Research and Development, Chico, CA Grass Weed Control In Small Grains..........................................................................................61 Steve Wright, UC Cooperative Extension, Tulare County, Visalia, CA Weed Management in Intermountain Alfalfa and Grass Hay.....................................................68 Steve Orloff, UC Cooperative Extension, Siskiyou County, Yreka, CA Factors Affecting Glyphosate Efficacy of Horseweed (Conyza canadensis) and Hairy Fleabane (Conyza bonariensis.....................................................................................................72 L. Scott Scheufele, California State University, Fresno, Ca

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Tree and Vine Session Chair: John Roncoroni Spatial Pattern of Glyphosate Resistance in Ryegrass in Yolo County......................................73 Anna Sherwood, University of California, Davis, CA Vines and Ovines: Using Sheep with a trained Aversion to Grape Leaves for Spring Vineyard Floor Management......................................................................................................74 Morgan P. Doran, UC Cooperative Extension, Solano County, Fairfield, CA Vineyard Weed Management Practices Influence Soil Nitrogen Retention...............................77 Kerri L. Steenwerth, USDA - Agricultural Research Service, Davis, CA Competitive Effects of Glyphosate-Resistant and Susceptible Horseweed with Young Grapevines and Established Vineyards.......................................................................................79 Marisa F. Alcorta, University of California, Davis, CA Non-Crop and Aquatic Sessions Chairs: Jennifer Malcolm and Frank Aulgur Biofuels and Invasive Species.....................................................................................................80 Joseph DiTomaso, University of California, Davis, CA The Effects of Puccinia jaceae on Yellow Starthistle Competition and Growth.......................81 Jon O’Brien, University of California, Davis, CA Assessing Research Priorities for Invasive Plants in California.................................................82 Ramona Robison, California Botany and Invasive Plant Council, Sacramento, CA Herbicide Control and Revegetation of Medusahead Sites in Northeastern California.............83 Rob Wilson, UC Cooperative Extension, Lassen County, Susanville, CA Out-Competing Roadside Weeds with Native Plants.................................................................85 Jeanette Wrysinski, Yolo County Resource Conservation District, Woodland, CA Biological Control of Russian Thistle (Tumbleweed)................................................................90 Lincoln Smith, USDA-Agricultural Research Service, Albany, CA Controlling Giant Reed (Arundo donax) Within the Tijuana River Valley................................94 Robert Hobbs, EcoSystems Restoration Associates, San Diego, CA Hydrilla Eradication Efforts in the Chowchilla River and Eastman Lake in Central California; a Success Story.........................................................................................................95 Florence Maly, California Department of Food and Agriculture, Fresno, CA

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Roadside Vegetation and Disaster Mitigation............................................................................99 Jennifer Malcolm, California Department of Transportation, Sacramento, CA Strawberry and Caneberry Session Chairs: Oleg Daugovish and Mark Bolda Weed Control in Caneberries......................................................................................................100 Mark Bolda, UC Cooperative Extension, Santa Cruz County, Watsonville, CA Integrated Weed Management in Strawberry.............................................................................102 Steven Fennimore, University of California, 1636 E. Alisal St., Salinas, CA, 93905 Control of Difficult Weeds in California Strawberry Production...............................................106 Oleg Daugovish, UC Cooperative Extension, Ventura County, Ventura, CA Laws and Regulations Session Chairs: Robert Leavitt and Richard Bireley Pesticide Enforcement in the Urban Environment......................................................................110 Christine Belden, Department of Agriculture, Los Angeles, CA California Department of Food and Agriculture’s Regulated Noxious Weed Programs...........111 Carri Pirosko, California Department of Food and Agriculture, Burney, CA Registration for Sales of Pesticides with Department of Pesticide Regulations.........................113 Richard Bireley, California Department of Pesticide Regulation, Sacramento, CA Volatile Organic Compounds Regulation Update......................................................................114 Randall Segawa, California Department of Pesticide Regulation, Sacramento, CA Research Authorization Program in California...........................................................................115 Maryam Khosravifard, California Department of Pesticide Regulation, Sacramento, CA Herbicide Efficacy and Phytotoxicity Requirement...................................................................117 Maryam Khosravifard, California Department of Pesticide Regulation, Sacramento, CA Student Poster Session Chairs: Tom Lanini and Rob Wilson Precision Guided Cultivation in Lettuce and Celery..................................................................118 Christina George, University of California, Davis, CA

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Research Poster Session Chair: David Haskell

Simazine, Diuron, and Atrazine Detections in California Surface Waters.................................119 Michael Ensminger, California Department of Pesticide Regulation, Sacramento, CA Milestone™ Herbicide: New Efficacy Research On Noxious And Invasive Weeds.................123 Celestine Duncan, Weed Management Services, Helena, MT Weed Management in Almonds for 2007...................................................................................124 Tome Martin-Duvall, UC Cooperative Extension, Madera County, Madera, CA Performance of a new organic herbicide based on d-limonene..................................................128 M.E. Koivunen, Marrone Organic Innovations, Inc., Davis, CA Field Evaluation Of Greenmatch Ex: A New Broad Spectrum Organic Herbicide....................129 C. Avila-Adame, Marrone Organic Innovations, Inc., Davis, CA Year End Financial Report......................................................................................................130 Honorary Members of the California Weed Science Society................................................132 Award of Excellence Recipients of the California Weed Science Society............................133 List of 2008 CWSS Conference Attendees..............................................................................134

2008 Honorary Members Mick Canaveri

Mick is the UC Farm Advisor in San Joaquin County with a primary focus in Agronomy. Mick has played a key role within CWSS serving on the Steering Committee, volunteering to be a Session Chair and speaker at numerous conference over the years, even as recent as this mourning where once again Mick served as Moderator of the Agronomic Crops Session. Through Mick’s career he as a Farm Advisor he has exhibited true diversification in that he has not only served as a crops advisors role but also worked with livestock production and the 4-H organization. At this time the CWSS would like to present Mick Canaveri with Honorary Membership

Tim Butler

A UC Davis graduate, starting his agricultural career with Uniroyal 36 years ago as a Development Representative. Tim became the Tech Service rep for the Pacoast Co followed by a stint as the wholesale rep before accepting a position with Shell Chemical in 1985. Tim's tenure at Shell was short lived as Shell was bought out by Dupont, Tim's current employer for the past 23 years. On March 1 of this year Tim will join the ranks of the retired, joining his wife Teress at their new home in Tucson, AZ. Tim is a third generation Californian who has dedicated 36 years to weed control in California Agriculture. He has served in many capacities as a member of CWSS most recently as a broad member and Director of the Steering Committee. Please join me in congratulating Tim Butler.

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Award of Excellence Will Crites Will is described by his peers as a "renaissance man." Will is a multi talented individual, who is accomplished in many creative areas arranging from the field of science to music, art and photography. Will has been known for his piano serenades since his college days at UC Davis and at last years conference was quick to make use of a Grand Piano at our meeting in La Jolla. At past conferences Will has work the camera angle capturing many candid moments which were share with the members in video loops which ran during evening and daytime functions Will started his career with Shell Chemical which became DuPont prior to his retirement. Dan Bryant Dan is a freelance Ag news writer who has covered various ag events and conferences for over 35 years. Dan received his degree in journalism from Humboldt State and except for a three year stint with Valley Nitrogen, Dan has spent his entire career writing for various farm publications including Ag Alert and Western Farm Press. Dan is now semi-retired, but still contributes two articles monthly to the Farm Press. Dan has six grandchildren, who keep him very busy, four in Fresno and two in Colorado Springs. I spoke to Dan last week just before his departure to Colorado Springs and he wanted me to share with you that he is honored to receive the Award of Excellence from CWSS.

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Presidential Lifetime Achievement Award Ken Dunster

As our sister organization, the Western Society of Weed Science (WSWS) said, “Ken was one of the giants of weed science in the western United States.” In addition to

being a past President of CWSS, Ken was also past President of WSWS, the Montana Weed Control Association, and the Western Plant Growth Regulator Conference. He was an honorary member of CWSS and received the Award ??. He was also a Fellow of WSWS and received their Outstanding Weed Scientist Award in 1992. His career in agriculture started in 1960 doing research and development for AmChem. He worked with James Dewlen on Brominal for grains, but also on herbicide and plant growth regulator development for alfalfa, grains, sugarbeets, and lots of vegetables. His work took him throughout the west, from Colorado to Hawaii. His value is evidenced by the fact that he survived and prospered during the mergers of AmChem into Union-Carbide, and then into Phone-Poulenc. But many of us remember Ken as a friend, adviser, and mentor. He started and guided the careers of several weed scientists working in California today. Colleagues like Ken Dunster are hard to replace. Ken was posthumously given the CWSS Presidential Lifetime Achievement Award (accepted above right by Wanda Graves) by a grateful society at this year’s 60th annual conference.

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Ron Vargas

The California Weed Science Society awarded the Presidential Lifetime Achievement Award to Ron Vargas, retired UC Cooperative Extension Farm Advisor and County Director. Ron has been one of the most active members in CWSS over the past 3 decades. He is a Past President, presiding over the 50th annual meeting of CWSS in 1998 and was selected by the society for an Award of Excellence in 1993 and as an Honorary Member in 2001. During his history with CWSS, Ron has given numerous (too numerous to count) presentations on weed control in cotton, alfalfa, small grains, and tree crops. He served on several committees, including the program

committee and the board of Directors. Ron received Bachelors and Masters Degrees in crop science and agriculture from Cal Poly San Luis Obispo. In Cooperative Extension, Ron started as a 4-H advisor in 1973, which, fortunately for us, included a part time assignment doing weed control research. Later he became agronomy and tree crop advisor, then acting Cotton Specialist for four years, then County Director for Madera County; but always keeping a strong focus on weed science. Ron retired in 2006 after 33 years with Cooperative Extension. In addition to our recognition, Ron has been honored by other groups; including being an inaugural inductee to the Farm Press magazine Researchers Hall of Fame in 2006, the National Cotton Council’s Extension Education Award in 1996, and Agriculturalist of the Year by the Cal Poly Crop Science Department in 2001. In retirement, Ron is attending to his 20 acre farm in Madera County, playing golf, riding his horses, and doing search and rescue in the Sierra mountains.

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2008 Conference Student Awards

Research Paper

1st place ($500) Jon O’Brien 2nd place ($300) L. Scott Scheufele

3rd place ($200) Marisa Alcorta

Pictured left to right Jon O’Brien, L. Scott Scheufele and Marisa Alcorta with Rob Wilson,

CWSS Director - Student and Commercial Liaison

Poster

1st place ($500) Christina George

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Undergraduate Scholarship Awards 1st- Bryce Borges- Fresno State University Plant Science Major- $2000 award Bryce Borges 5301 N. Valentine Ave. Apt. 134 Frenso, CA 93711 bborges@csufresno.edu 2nd (tie) Jessica May- Mendocino College Horticulture Major- $1000 award Jessica May 25234 Robinson Rd. #1 Willits, CA 95490 jessi_e_may@yahoo.com 2nd (tie) Matthew Linder- UC Davis Crop Science Major- $1000 award Matthew Linder 696 San Bruno Way Salinas, CA 93901 Phone: 831‐676‐5392 mlinder@ucdavis.edu  Graduate Scholarship Awards 1st (tie) John Jeremiah Mann- UC Davis PhD student in Weed Science- $2000 award John Jeremiah Mann Department of Plant Sciences Department of Plant Sciences, Mail Stop 4 One Shields Ave, Davis, CA 95616 E-mail: jjmann@ucdavis.edu 1st (tie) Kristen Weathers- UC Riverside PhD student in Plant Biology- $2000 award Kristin Weathers 192 E. Manfield St. Riverside, CA 92507 kristinweathers@mac.com 2nd (tie) Oli Bachie- UC Riverside PhD student in Plant Biology- $1000 award Oli Bachie 802 Grape Street Riverside, CA 92507 obach001@ucr.edu 2nd (tie) Celeste Gilbert- UC Davis PhD student in Horticulture Science- $1000 award Celeste Gilbert 1419 Wake Forest Dr. #3 Davis, CA 95616 cagilbert@ucd.edu 2nd (tie) Christina George- UC Davis Master student in Horticulture/Agronomy - $1000 award Christina George 675 Alvarado Ave. #35 Davis, CA 95616 cageorge@ucdavis.edu

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Jeremiah Mann Bio –graduate student

Jeremiah is a Ph.D. student at the University of California at Davis working with Dr. Joe DiTomaso. His dissertation work investigates the invasion potential of the biofuel crop Miscanthus x giganteus and to a lesser extent Panicum virgatum (switchgrass). This work focuses on understanding the plant’s ability to escape cultivation and establish in natural areas. In addition to his dissertation research, his is currently working on a project constructing an

invasive plant information database to be used by the California Department of Transportation for improved management of weeds and invasive plants located on roadsides and adjacent lands. He is also assisting Dr. DiTomaso with the compilation of an invasive plant management manual for western states. He intends to use his formal education and life experience to provide service to the community of natural resource partners that focus on terrestrial and aquatic weeds that occur in both wildland and agricultural areas. Kristen Weathers Bio- graduate student Kristen is a graduate student at UC Riverside, seeking her PhD in Plant Biology. She is jointly advised by Dr. Milt McGiffen and Dr. Edith Allen. Kristen’s thesis work focuses on the restoration of Coastal Sage Scrub communities, including managing invasive weeds through solarization and chemical techniques. After graduating, she plans to continue to conduct research on vegetation management and invasive weeds, as well as work closely with public and private land managers on community-based natural resource management and ecosystem management projects. Celeste Gilbert Bio- graduate student Celeste is a graduate student at UC Davis, seeking her PhD in Horticulture Science in the Plant Science Department. Her advisor is Dr. Steven Fennimore, an extension vegetable weed specialist for UC Davis in Salinas. Celeste’s thesis is studying the impact of solarization and steam heat to control weeds and soil-born pathogens in strawberry and cut flower cultivation. After graduating, she would like to pursue a career in weed science research.

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Oli Bachie Bio- graduate student Oli’s academic backgrounds include B.Sc (Plant Sciences), Masters in Agronomy (weed sciences), Forestry (seedling nutrition and vegetation management) and minor in soil sciences. He is currently enrolled in a PhD program with the Department of Botany and Plant Sciences (BPSC) at UC Riverside, majoring in Ecology with a minor in Nematology and Weed ecology. He’s a member of the Western Society of Weed

Science and the American Society of Horticultural Science. Beyond academics, he serves as a representative for BPSC Graduate Student Association and also volunteers at the Botanic Garden of the UCR. He’s current dissertation research, “Using Cover Crops to Build an Ecologically Based Pest Management Program for Vegetable Production” emphasizes the use of cover crops as a tool to manage weeds, nematodes and insects under the guidance of his advisor, Dr. Milt McGiffen. The research is being conducted at the University of California, South Coast Research Station and will last for three consecutive years. He’s also involved with a non-dissertation research project that attempts to investigate the best planting seasons for onion growers of the high desert areas of California. His intended area of specialization is in cropping and noxious weed and nematode management systems. His specific interest is in the study of survival, growth, characterization and management strategies on selected species of weedy, invasive species and nematodes under a sustainable farming system. Oli’s long-term career goal is to seek employment in an educational, research or both education and research based institution or governmental organization. Oli gives his sincere thanks and is appreciative to the society’s decision of awarding him a California Weed Science Society (CWSS) scholarship. Christina George Bio –graduate student

Christina is a graduate student at UC Davis, seeking her M.S. in Horticulture and Agronomy with a specialization in weed science. Her advisor is Dr. Steven Fennimore, an extension vegetable weed specialist for UC Davis in Salinas. Christina’s thesis work focuses on the use of precision cultivation for mechanical weed control in lettuce and celery. After graduating, she plans to seek an industry job at an organic company in vegetable production.

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Bryce Borges- undergraduate student Bryce is an undergraduate student at Fresno State with an emphasis in plant health. Agriculture was a big part of Bryce’s life growing up, and he was an active, award-winning FFA member at Hanford High School. He completed a summer internship with Western Farm Service, and he was as a research assistant at Fresno State for Dr. Lawson in 2007. Bryce plans to pursue a career as a Pest Control Advisor after graduation. Jessica May Bio- undergraduate student

Jessica is currently a full-time student at Mendocino College in Ukiah, CA. She is majoring in Natural Resources and Horticulture. In 2009, she will graduate from Mendocino College with an Associate Degree in Horticulture, an Associate Degree in Natural resources, and two Certificates in Landscaping and Nursery Production. She plans to transfer to Humboldt State University to major in natural Resources. After graduation, Jessica plans to open a California native plants nursery and specialize in habitat restoration. Jessica greatly thanks the society for the scholarship.

Matt Linder Bio- undergraduate student Matt is currently attending the University of California: Davis and obtaining a degree in Crop Science and Management. His academic advisor is Theresa Costa and current employer is Thomas Lanini. His future goals are to gain a Pesticide Control Applicators license and graduate from Davis with a Bachelor's in the degree listed above. From there he will pursue a job in agriculture, overseeing crop production and working on more effective and safe ways of controlling harmful pests in our environment.

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In Memoriam

The California Weed Science Society has lost three of its long time members this past year. They were remembered during the annual Business Lunch on January 29, 2008 with a few words by President Carl Bell and a Moment of Silence. These honored friends were:

James Dewlen James was the 17th President of CWSS, serving in that office in 1965. He spent most of his career working in Sales for AmChem, one of the principal manufacturers of pesticides at the time. His territory included much of northern California. One of his most important contributions to California agriculture was the development of Brominal (bromoxynil) for control of broadleaf weeds in small grains. This product is still in use throughout California and the west. For CWSS, James was responsible for starting the concurrent sessions; this allowed members to attend different sessions that provide information on subjects within their scope of interest. James Dewlen passed away in late 2007 at the age of 90. One of his friends, Harry Agamalian remembered James as someone that truly did not have an enemy in the world.

Neil Harold Phillips, Sr. October 31, 1933 – January 9, 2008

Neil passed away on January 9, 2008 at age 74. His tall figure was a fixture at CWSS meetings for decades. He was a third generation Californian and lived on a farm first owned by his grandparents in Patterson, near Modesto. Neil was a Korean War Veteran and a skilled marksman during his service to our country. When his service was finished, he started his agricultural career working for the USDA as a cannery inspector. Eventually he became a Pest Control Advisor and farmer. He had retired in September 2007 after spending his later years as an agricultural consultant and an expert witness. Neil is survived by his college sweetheart and wife of 51 years, Carolyn Goodhue Phillips, four children (including his son Neil, Jr. who is a PCA and attends the annual CWSS conference), and eleven grandchildren.

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Ken Dunster November 2, 1936 – January 18, 2007

As our sister organization, the Western Society of Weed Science (WSWS) said, “Ken was one of the giants of weed science in the western United States.” In addition to being a past President of CWSS, Ken was also past President of WSWS, the Montana Weed Control Association, and the Western Plant Growth Regulator Conference. He was an honorary member of CWSS and received the Award ??. He was also a Fellow of WSWS and received their Outstanding Weed Scientist Award in 1992. His career in agriculture started in 1960 doing research and development for AmChem. He worked with James Dewlen on Brominal for grains, but also on herbicide and plant growth regulator development for alfalfa, grains, sugarbeets, and lots of vegetables. His work took him throughout the west, from Colorado to Hawaii. His value is evidenced by the fact that he survived and prospered during the mergers of AmChem into Union-Carbide, and then into Phone-Poulenc. But many of us remember Ken as a friend, adviser, and mentor. He started and

guided the careers of several weed scientists working in California today. Colleagues like Ken Dunster are hard to replace. Ken was posthumously given the CWSS Presidential Lifetime Achievement Award by a grateful society at this year’s 60th annual conference.

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The Gadfly

The gadfly buzzes around the animal’s face, With an irritating sound hoping to be heard. But the beast just sits, completely content. To chew its cud with the rest of the herd.

The town’s people pull on the animal’s tether.

There’s work to be done in the fields. But it is used to the constant tugging, And their efforts fail to make it yield.

It’s ruminating on its mission statement.

It’s chewing on visions for its strategic plan. How can it keep its stakeholders promises?

And still get the governor to understand.

Its hide is marked with the bites from other flies, That made the animal turn his head and look around.

But they were only biting to feed on the animal’s blood. And it keeps resting on the same piece of ground.

The gadfly lands on the polished data volumes.

It detects decay under the skin. And it circles and rubs its wings together,

To warn of the “agenda science” that lies within.

Its mandibles cut through the layers of rhetoric. Its compound eyes see beyond the animal’s view. It asks the questions that no one wants to answer.

Why not follow the policies like they’re expected to do.

Its legs tickle the soft skin of the beast’s belly. The fly knows where the vulnerable spots are. But it won’t selfishly disclose this information.

It knows retaliation will not get it very far.

This fly’s bite can make the animal stand. Maybe see a better view from its upright position.

Observe the world beyond the pasture fence, And the town’s people that deserve more recognition.

This could be a symbiotic relationship.

If the advice is not viewed as a reprimand. Only to support the theory of responsible regulation,

That science and politics can walk hand-in-hand.

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The gadfly wants to become a team player.

It wants to gain the animal’s respect. But all flies are associated with filth.

And the fly’s motives are always suspect.

The gadfly is at risk from the swishing tail, That can sweep away promotions and travel per diems.

And memberships on policy committees. The fly could starve on the leftover crumbs.

The gadflies will come and these flies will go.

They will continue to rise out of all the manure. Most will bite just to feed on the animal’s blood,

But this fly could help the animal endure.

by

David Haskell

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CWSS, Weed Science, and the Short-Handled Hoe

Carl E. Bell President, California Weed Science Society

The theme of the 60th conference of the California Weed Science Society is

“Everyone benefits from weed control”. I applaud our Vice-President and Program Chair Stephen Colbert for coming up with this theme; in my opinion it is way past time we said this loud and clear. Our general session speakers are presenting the case quite well that there is an economic return on investing in weed control. One of our speakers, Leonard Gianessi, published an excellent paper in the journal Weed Technology in 2007 (volume 21, pages 559-566) that documents much of the information on this subject. I want to make the case, however, for the value of weed science as an important and essential contributor to the theme of the conference and I also want to expand the scope of the theme beyond economics.

At the third California Weed Conference (that used to be our name) in 1951, Paul Sharp, Director of the University of California Agricultural Experiment Station cited 20 years of UC research on weed control. Many of these studies were concerned with the development of selective herbicides; chemicals that could be used to kill weeds in crops without hurting the crop. This may seem routine today, but it was not then when the only truly selective herbicide was 2,4-D. By the 20th conference in 1968, 26 scientists from government, industry, and the universities discussed the use of a large variety of herbicides for weed control in field crops, vegetables, orchards and vineyards, rangeland, along utility corridors, and for noxious weed eradication. At the 30th conference, held here in Monterey and presided over by Floyd Colbert as President (our Program Chair’s father), 32 talks were presented by this mix of government, industry and university scientists and weed control practitioners. Every California Weed Conference, from the first one in 1949 to our 60th meeting today, has brought the audience the latest and the most reliable information on weed control. If you add it up, scientists have spoken to members of CWSS about 2500 times for 900 hours on how to control weeds in all of the variety of situations that weeds cause problems throughout this state. In addition, the third edition of our textbook, Principles of Weed Control has over 70 authors and contributors.

In addition to the value of the science benefiting weed control practices and the economic benefits of weed control for society, there is also an important social aspect to what we do, and it relates to the hoe. The ceremonial Robbins Short-Handled Hoe was presented to UC Davis Professor W.W. Robbins at the third conference in 1951 in recognition of his many contributions to CWSS. Walter Ball, with the CA Department of Agriculture, had been given the hoe by Dr. Robbins’ widow after his death and established the tradition of passing this hoe down to the current President. In his address to the conference, Walter Ball, speaking about Dr. Robbins said, “In his many talks before farmers he often would bring out the hoe and display it as the time honored tool; that even in his day of magic chemicals, was still the major weapon in the fight against weeds.”

From the 1900’s through the 1960’s, short-handled hoes were the most important tool used to weed vegetables and other row crops like cotton and sugarbeets. Farmers felt

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that the labor crews worked faster and more accurately if they were closer to the crop. But extended use of short-handled hoes caused permanent lower back injury and these hoes became a rallying cause for farmworkers, especially union members, of their mistreatment. Short handled hoes were banned in California in 1975 by the CA Industrial Safety Board; since then only long-handled hoes are allowed. Fortunately for California agriculture, selective weed control in crops with herbicides was well established by this time. Again, the weed scientists with industry, government, and universities had done the laboratory and field research to develop these herbicide practices. And they typically delivered their information at the California Weed Conference.

The short-handled hoe is still viewed negatively by farmworkers and the groups that support them. At the 59th conference the question was asked, “Why does CWSS have a short-handled hoe as its symbol?” As discussed earlier, it was given to Dr. Robbins to signify his work ethic and dedication to advancing weed control. It is passed on as a reminder of the importance of our endeavors. I personally feel that it is also a symbol of triumph for weed science and weed control in California that the short-handled hoe is no longer needed in our agricultural fields. It may be that we decide as an organization to drop the use of the short-handled hoe as our logo someday because it is no longer appropriate; but I doubt if it will ever be abandoned as our Presidential symbol. I feel honored to have had the hoe in my home for the past year and I feel privileged to pass it to Stephen Colbert.

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Economic Considerations in Weed Control

Karen Klonsky, Dept. of Agricultural and Resource Economics, University of California, Davis, California, 95616, klonsky@primal.ucdavis.edu

Economic considerations in weed control include efficacy (impact on yield and quality) and efficiency (cost per unit of production). Weed management costs at the farm level include labor for hand hoeing and tractor operation, materials, and equipment. Equipment costs include fuel and lube for tractors, repairs, insurance and property taxes, and capital recovery on ownership. Weed control alternatives can be compared based on costs per unit of production, resource use, risk, and environmental impacts.

Factors external to the farm impacting the efficiency of weed control practices include the prime interest rate; the cost of materials, equipment, and labor, availability of labor, and the cost of compliance with regulations impacting the use of herbicides. The low interest rates of the past 25 years has encouraged investment in farmland, farm equipment, and perennial crops. Over the last five years the cost of fuel has about tripled and the cost of fertilizer has doubled. In marked contrast the cost of herbicides and insecticides has only increased about ten percent over the past 10 years. Therefore, looking at the relative changes in input costs, the cost of cultivation using heaving equipment is the most highly impacted weed control method followed by herbicide applications and lastly hand hoeing.

When we look at specific crops, weed control represents between 1 and 20 percent of total production costs. For winegrape production weed control is between $50 and $100 per acre and only one percent of total costs. Control typically consists of winter strip spray along the vines, mowing the centers between the vines, and strip spot spray in the summer. The equipment used includes an ATV with a weed sprayer and a small tractor and mower. The difference in costs among vineyards is primarily due to the choice of herbicides used in the strip spray. The cost of vine row weed control for an organic vineyard unable to use herbicides is about $150 per acre using a small tractor and an in-row cultivator.

The cost of weed control in alfalfa in the Sacramento Valley is about $36 per acre. It consists of winter spray of herbicide. Weed control represents about seven percent of total costs and is extremely important to maintain quality hay.

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Weed control in high valued vegetables typically includes a combination of herbicide applications, cultivation, and hand weeding. For processing tomato weed control is about $400 per acre and represents 17 percent of total costs. The tomatoes are sprayed about five times, cultivated seven times and hoed by hand between one and three times depending on the weed pressure. The size of the tractors used will vary depending on the size of the fields. For broccoli on the coast, weed control is only about $100 per acre. There is typically only one herbicide application at planting, several cultivations, and one time over with hand hoeing. Organic broccoli cannot use the preplant herbicide and relies more on hand hoeing. Total weed control costs can jump to over $250 per acre, two and a half times the cost for a conventional grower.

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Losses and Costs Imposed on California Ranchers by Yellow Starthistle Alison J. Eagle,1 Mark E. Eiswerth,2 Wayne S Johnson,3 Steve E. Schoenig,4 and G. Cornelis van Kooten1, 1Dept. of Economics, University of Victoria, PO Box 1700, STN CSC, Victoria, BC, Canada V8W 2Y2; 2Dept. of Economics and University of Wisconsin Cooperative Extension, University of Wisconsin, Whitewater, WI 53190; 3Dept. of Resource Economics and University of Nevada Cooperative Extension, University of Nevada, Reno, NV 89557; 4California Department of Food and Agriculture, 1220 N Street, Sacramento, CA 95814, eiswertm@uww.edu This research was funded in part by a grant from the California Department of Food and Agriculture.

ABSTRACT

The substantial ecological damages caused by invasive weeds have been well documented. By comparison, the economic consequences of specific invasive weed species tend to be poorly understood to date. Yellow starthistle (Centaurea solstitialis L.) is the most widespread non-crop weed in California, yielding damage to forage on natural range and improved pasture. A survey was administered to California cattle ranchers to investigate infestation rates, loss of forage quantity and value, and control or eradication efforts related to this weed. The results were used to estimate county-wide losses and costs for three focus counties, as well as statewide losses/costs, due to yellow starthistle in California. Total losses of livestock forage value due to this weed on private land in the state of California are estimated at $7.65 million per year, with ranchers’ out-of-pocket expenditures on control amounting to $9.45 million per year. Together, these amount to the equivalent of 6-7% of the total annual harvested pasture value for the state. Therefore, while the impacts are relatively small within the statewide total agricultural production system, losses and costs due to yellow starthistle infestation do represent a constraint on California’s livestock grazing sector.

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The Value of Herbicides in U.S. Crop Protection Leonard P. Gianessi, Crop Protection Research Institute, CropLife Foundation, 1156 15th Street

NW, #400, Washington, DC 20005, lgianessi@croplifefoundation.org Widespread herbicide use is a relatively recent development in U.S. agriculture in comparison with insecticides and fungicides, which were routinely used in inorganic, naturally derived chemical formulations on U.S. fruit and vegetable crops beginning in the early 1900s. By contrast, widespread use of herbicides to kill weeds did not begin until the introduction of synthetic organic chemicals in the late 1940s. Currently, herbicides are routinely used on more than 90% of the area of most U.S. crops. The importance of herbicides to U.S. crop production can be understood through a historical perspective and examinations of the practices of organic growers. In the early years of crop production in the United States, human labor was used to remove weeds from fields. As late as 1850, 65% of the population lived on farms and removing weeds was one of the main farm chores. The historical record reveals that herbicides replaced or reduced the use of hand weeding and cultivation for weed control with an associated reduction in cost and increase in yield. The adoption of herbicides was spurred by a desire to reduce weed control costs as labor became scarce and more expensive in the years following World War II. Use of the short handled hoe was the primary weed control method for most vegetable crops in California from the early 1900s through the 1960s. Weeding of celery took 111 hours/hectare, carrot took 69 hours/hectare, strawberry required 69 hours/hectare. Numerous complaints were received from farm workers who stated that they suffered permanent back damage as a result of using the short handled hoe for extended periods of time. The California Industrial Safety Board issued a regulation that permanently banned the use of the short-handled hoe in 1975. Most growers switched to the use of herbicides which proved to be more economical than the use of workers wielding hoes. The cost of herbicides plus application was $25/hectare in comparison to hand weeding costs of $247/hectare for spinach, $198/hectare for celery, $309/hectare for onion, and $988/hectare for strawberry. The use of herbicides is credited with reducing the use of labor in California onion fields by 297 hours/hectare, which was equivalent to two million hours per year. For many crops, herbicides substituted for and reduced the practice of cultivation. For example, herbicides reduced the number of tillage trips in California almond orchards by 16 with grower savings of $52/hectare. For most crops, historical data indicate an increase in yields due to herbicide use .For two crops, corn and soybean, researchers have statistically determined the contribution of herbicides to improved yields. Herbicides accounted for 20% of the increase in corn yields 1964 through

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1979 and 62% of the yield increase in soybean 1965 through 1979.Better weed control with herbicides is credited as an important factor in doubling rice yields in the 1960s. For several crops, including carrot, cotton, and onion, dramatic improvements in yield did not occur following the adoption of herbicides. For these crops, an adequate amount of hand labor had been previously used to remove weeds and prevent yield loss prior to the introduction of herbicides. Organic crop growers do not use herbicides to control weed populations. The problem of controlling weeds without herbicides has been cited numerous times as the single biggest obstacle to crop production that organic crop growers encounter. Organic rice growers report that weed management is the most difficult part of organic production, and it is the major reason that organic rice yields are 50% lower than conventional yields. Lower yields and higher costs for weed control labor are two of the major reasons that organic cotton must sell with high price premiums. California organic crop growers rely extensively on hand weeding to control weed populations: almond (17h/ha), apple (50 h/ha), cotton (30 h/ha), cucumber (75 h/ha),grape (20 h/ha),lettuce (45 h/ha),onion (181 h/ha) and tomato (37 h/ha). The problem of farming without herbicides was recently highlighted in an exemption from a farm worker protection rule granted to California organic growers. The State of California banned the practice of using workers to pull weeds by hand in 2004. The California Occupational Safety and Health Standards Board determined that the practice of pulling weeds by hand was more destructive to workers backs than use of the short handled hoe, which had been banned in 1975. Organic crop interests sought and were granted an exemption from the ban on hand weeding, claiming they would incur tremendous yield and profit losses if they were required to use laborers with long handled hoes rather than hand weeders. Organic crop growers reported that workers with long-handled hoes would inadvertently damage or remove some of the vegetable plants while missing some of the weeds. References Adams, R. L. 1938. Seasonal Labor Requirements for California Crops. University of California Agricultural Experiment Station, Bulletin 623.

Asai, W., L. Hendricks, P. Verdegaal, K. Klonsky, C. Ingels, P. Livingston, and L. Tourte. 1992. Sample Costs to Produce Organic Almonds in the Northern San Joaquin Valley. University of California Cooperative Extension Service.

Ashton, F. M. 1960. The Major Problem in Vegetable Crop Production- Weed Control. Proceedings of the California Weed Science Society. 12: 72-74.

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Bolgenhom, V. 2004. The Use and Importance of Handweeding in Organic Farming, letter to Jose H. Millan, Deputy Secretary, Enforcement, California Labor and Workforce Development Agency. Available at- http://www.croplifefoundation.org.

Earthbound Organic. 2006. Organic Farming 101: Controlling Weeds Without Chemical Herbicides. Available at http://www.ebfarm.com/Organic/WeedControl.aspx.

Gianessi, Leonard. 2007. The Value of Herbicides in U.S. Crop Production. Weed Technology, 21: 559-566.

Gianessi, L. and N. Reigner. 2005. Why California Organic Growers Want an Exemption from a Farm Worker Protection Rule. CropLife Foundation. Available at-http://www.croplifefoundation.org.

Jourdane, Maurice “Mo.” The Struggle for Health and Legal Protection of Farm Workers: El Cortito. Houston, Texas: Arte Publico Press, 2004.

Klonsky, K., P. Livingston, R. Vargas, and B. Weir. 1995. Production Practices and Sample Costs for Organic Cotton – Northern San Joaquin Valley. U.S. Department of Agriculture, University of California Cooperative Extension.

Klonsky, K., L. Tourte, D. Chaney, P. Livingston, and R. Smith. 1994. Cultural Practices and Sample Costs for Organic Vegetable Production on the Central Coast of California. University of California, Giannini Foundation Information Series No. 94-2.

Klonsky, K., L. Tourte, and D. Chaney. 1993. Production Practices and Sample Costs for Organic Processing Tomatoes in the Sacramento Valley. University of California Cooperative Extension.

Klonsky, K., L. Tourte, and C. Ingels. 1992. Sample Costs to Produce Organic Wine Grapes in the North Coast. University of California Cooperative Extension.

Lange, A.H., and R.A. Brendler. 1965. Weed Control in Transplanted Celery. California Agriculture. 19 (2): 2-3. Meith, H. C., and P. S. Parsons 1965. Nontillage and Strip Weed Control: Cut Almond Production Costs in Butte County Test. California Agriculture. 19(6): 2-4. Mueller, K. E. and E. A. Oelke. 1965. Watergrass Control in Rice Fields with Propanil and Ordram. California Agriculture. 19(7): 10-12.

Nylund, R. E., D.C. Nelson, and D.H. Dinkel. 1958. Comparative Costs of Weeding Onions by Hand or with Monuron, CIPC, and CDAA. Weeds. 6:305-309.

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Peterson, G. E. 1967. The Discovery and Development of 2,4-D. Agricultural History. 41:243-253.

Rood, Mary Ann. 2002. Long-Haul Organic. Rice Journal. 105:12-17. Schneider, Paul. June 20, 1993. The Cotton Brief. New York Times. Schroder, D., J.C. Headley, and R.M. Finley. 1984. The Contribution of Herbicides and Other Technologies to Corn Production in the Corn Belt Region, 1964 to 1979. North Central Journal of Agricultural Economics, 6(1): 95-104. Schroder, D., J.C. Headley, and R.M. Finley. 1981. The Contribution of Herbicides and Other Technologies to Soybean Production in the Corn Belt Region, 1965-1979. University of Missouri, Agricultural Economics Paper 1981-33. Smith, N. J. 1956. How to Kill 20 Million Weeds an Hour! American Vegetable Grower. May: 12-13. Smith, R. J., W.T. Flinchum, and D.E. Seaman. 1977. Weed Control in U.S. Rice Production. U.S. Department of Agriculture, Agriculture Handbook 497.

Swezey, S. L., P. Vossen, J. Caprile, and W. Bentley. 2000. Organic Apple Production Manual, University of California Agriculture and Natural Resources, Publication 3403.

Watwood, R. P. 1959. Weed Control in Carrots and Celery. Proceedings 11th Annual Meeting California Weed Science Society. 11:21-22. Yarrick, B. E. 1946. Notes on Non-Tillage. The California Citrograph. 31: 318-319.

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Herbicide Mode of Action

Joseph M. DiTomaso Department of Plant Sciences, University of California, Davis, CA

The mode of action of an herbicide includes all aspects related to its uptake, movement, metabolism, and activity at the specific target site. Herbicides that reach their site of action can affect several biochemical responses. While most herbicides initially interfere with a single biochemical reaction, some may be relatively non-specific and interfere with several reactions simultaneously. Of the herbicides used in wildlands, the most common targeted biochemical reactions involve nucleic acid or amino acid metabolism. Most of these compounds fall into the category known as growth regulators, including 2,4-D, 2,4-DP, aminopyralid, dicamba, triclopyr, clopyralid, and picloram. These compounds mimic the naturally occurring auxins found in plants. A second common group of herbicides used in wildlands are the amino acid inhibitors which can either block the activity of the enzyme acetolactate synthase (ALS) or 5-enolpyruvylshikimate-3-phosphate synthase (EPSP synthase). The ALS inhibitors prevent the synthesis of branched chain amino acids and include chlorsulfuron, sulfometuron, metsulfuron, imazapyr, and imazapic, whereas glyphosate is the only EPSP synthase inhibitor and prevents the synthesis of aromatic amino acids. By disrupting any of these biochemical reactions, herbicides may injure or kill the plant. Growth Regulators

Growth regulator herbicides are compounds which mimic naturally occurring auxins. These can be divided into several groups; indole acids, phenoxy carboxylic acids, benzoic acids, and picolinic acid (also known as pyradines) derivatives. The indole acids include the naturally occurring growth regulator indole acetic acid (IAA). No compounds within this group are commercially available as herbicides. The latter three groups contain many herbicides registered for use in wildlands, including the phenoxy carboxylic acid 2,4-D, the benzoic acid dicamba, and the picolinic acids aminopyralid, triclopyr, clopyralid and picloram (not registered in California). These compounds are often called auxinic herbicides. All of these compounds are active as foliar applied herbicides, and some have excellent preemergence activity, particularly aminopyralid, clopyralid and picloram. They generally translocate through the phloem of the living plant and accumulate at the growing points or other carbohydrate sinks, such as roots and underground reproductive structures (Vencill 2002). One of the difficulties in studying the mechanism of auxin action is the multitude of different kinds of physiological processes that they appear to control. It has been suggested that there may be many target sites of IAA action or a single target site which unleashes a cascade of events. Auxins seem to be involved in a number of developmental functions, including phototropism, apical dominance, senescence, cell growth and differentiation, and root formation. Although they have been studied for a few decades, their specific mechanism of action is still not well understood. In general, however, the initial response of plants to auxin treatment can be categorized into two phases (DiTomaso 2002). Initially there is a fast response that occurs within minutes of exposure. This is characterized by rapid acidification and loosening of the cell wall. This is due to a

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weakening of the hydrogen bonds. The loosening of the bonds decreases the resistance of the wall to turgor pressure. More water would move into the cell causing an increase in cell volume and irreversibly stretching the cell wall. As a result, the petiole and stem internodes of treated plants often elongate within hours of treatment. The second phase of the response occurs 30-45 min after treatment, and involves the synthesis of nucleic acids.

Under natural growing conditions, plant tissues respond to auxin treatment by dramatically increasing nucleic acid and protein synthesis, and this effect is closely correlated to cell division and growth. The action of auxin appears to involve specific gene activation at the transcriptional level. Auxin may interact with a binding protein and the auxin-protein complex then interacts with chromatin (filamentous complex of DNA, histones and other proteins constituting chromosomes) to cause an increase in DNA template available for transcription. The result of this action could be altered DNA transcription and quantitative and qualitative changes in RNA synthesis. These RNAs would then serve as templates for the synthesis of the proteins required for the observed physiological responses. Auxinic herbicides, however, are applied at rates considerably higher than the concentration of IAA in plants. In meristematic tissues, high levels of auxins inhibit RNA synthesis and growth. In contrast, high auxin levels stimulate RNA and protein synthesis is mature tissues causing cells to divide. The abnormal stimulation of cell division by synthetic auxin treatment, in conjunction with the rapid cell wall loosening response, leads to uncontrolled growth and the production of callus tissue. Volume expansion of mature tissues is somewhat restricted by the presence of secondary cell walls and thickened cells, such as collenchyma and fibers. Consequently, excessive cell division in these tissues can cause stem swelling and eventually cellular collapse, particularly in the phloem tissues (DiTomaso 2002). The phytotoxic concentrations of growth regulator herbicides elicit a variety of symptoms in plants. Among these include leaf chlorosis (yellowing), stem tissue proliferation, root initiation in stem tissue, disintegration of root tissues, and abnormal apical growth. Many of these are secondary effects. The inhibition in cell division in meristematic regions, in conjunction with abnormal stimulation of cell division in mature tissues is the likely causes of plant death (Vencill 2002). Another characteristic symptom of growth regulator treated plants is a twisting response, known as epinasty. This response is the result of an auxin-induced stimulation in ethylene production. This symptom, in itself, is probably not responsible for the phytotoxic activity of these herbicides. Amino Acid Inhibitors Acetolactate Synthase (ALS) Inhibitors Although the sulfonylurea (chlorsulfuron, sulfometuron and metsulfuron) and imidazolinones (imazapyr and imazapic) herbicides are structurally quite different, they are highly active compounds that inhibit the activity of the same enzyme, acetolactate synthase (ALS), also called acetohydroxyacid synthase (AHAS). ALS catalyzes the first step in the synthesis of the branched-chain amino acids valine, leucine and isoleucine. ALS-inhibiting herbicides block the synthesis of branched-chain amino acids (DiTomaso 2002). The exact mechanism of plant death is unknown, and has been suggested to be either due to the

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buildup of a substrate of ALS, called α-ketobutarate (LaRossa and Van Dyk 1987), or to a depletion of the pool size of the essential amino acids. Although cell division and plant growth can he inhibited very soon after exposure to these herbicides, death occurs slowly. The rate of death is probably linked to the total pool size of the branched-chain amino acids available to the plant tissues. Thus, older plants and particularly woody species with large amino acid reserves will survive longer than younger plants. ALS inhibitors are typically applied preemergence, but can have excellent postemergence activity in some plants. Their symptomology includes the rapid inhibition of root and shoot growth, vein reddening, chlorosis, and meristematic necrosis (Vencill 2002). Young developing tissues can often appear disfigured. More weed species have developed resistance to the ALS inhibitors than to any other herbicide group. In most cases, this is due to selection of an altered ALS that is insensitive to these herbicides. In some cases, however, resistance in plants is due to an enhanced ability to metabolize or degrade the herbicide to non-phytotoxic components.

EPSP Synthase Inhibitor Glyphosate was identified in the late 1960’s in a Monsanto discovery program that initially produced the sugar cane ripener glyphosine. Glyphosate inhibits the activity of the enzyme 3-phospho-5-enoylpyruvateshikimate (EPSP) synthase in the shikimic acid pathway. This enzyme is essential to the synthesis of the aromatic amino acids phenylalanine, tyrosine, and tryptophan (Gresshoff 1979). These essential amino acids are important for protein synthesis and other biosynthetic pathways critical to growth. Inhibition of this biosynthetic pathway results in an unregulated accumulation of shikimate to very high levels in the plant. In fact, following glyphosate treatment, as much as 10 to 20% of the plant’s total soluble carbon can be found to accumulate in shikimate. Although not completely known, the apparent death of treated plants is the result of the unregulated accumulation of carbon in that intermediate. Like the ALS inhibitors, the rate of plant death depends on the amount of stored amino acids in the plant tissues. Thus, small plants may die within a week to a month, whereas larger plants, such as shrubs or trees, may require a year or more to be fully controlled. Glyphosate is a foliar applied herbicide that translocates in the living phloem of treated plants. Although it does not inhibit chlorophyll synthesis, symptoms can include interveinal chlorosis (Vencill 2002). This may be due to the high buildup of shikimate in the chloroplast. Accumulation of this organic acid can alter the pH balance of the chloroplast and cause loss of membrane integrity and chlorosis.

Glyphosate also interferes with normal carbohydrate translocation in plants. It has been shown to inhibit the import of sucrose to sink leaves, the export of sucrose from source leaves, and the net starch accumulation in source leaves. This disruption in carbon metabolism would eventually starve the plant of compounds required for growth. The appearance of a red coloration on leaves and stem of treated plants is due to the accumulation of the pigment anthocyanin. Anthocyanin accumulation is a typically symptom of an interference in carbon metabolism. Interestingly, anecdotal reports indicate that wildlife prefer to forage on glyphosate treated plants. This may be due to the increased levels of carbohydrates in the foliage. Literature Cited

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DiTomaso, J.M. 2002. Herbicides. Pages 189-219. In, Principles of Weed Control. 3rd Ed. Thomson Publ., Fresno, CA. Gresshoff, P.M. 1979. Growth inhibition by glyphosate and reversal of its action by phenylalanine and tyrosine. Aust. J. Plant Physiol. 6:177-182. LaRossa, R.A. and T.K. Van Dyk. 1987. Metabolic mayhem caused by 2-ketoacid imbalances. BioEssays 7(3):125-30. Vencill, W.K. (ed.). 2002. Herbicide Handbook. 8th Ed. Weed Science Society of America, Lawrence, KS.

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Herbicide Resistance Management

W. Thomas Lanini, University of California, Davis wtlanini@ucdavis.edu

Herbicide-resistant weeds generally occur where the same herbicide or herbicides

with the same site of action are used repeatedly. To prevent the appearance of herbicide-resistant weeds, you must know in which chemical family an herbicide belongs and which herbicides have the same site of action. Table 1 lists weeds resistant to herbicides in California, along with the site of action grouping, chemical name, and trade names. Herbicide families that have the same site of action are the same group number. An herbicide program to prevent resistance does not use herbicides from the same group more than once in 3 years. Management can prevent or delay the appearance of herbicide-resistant weeds. The following practices can be used with the information on herbicide families provided in the table to form an herbicide resistance management strategy. Prevention Herbicide rotation —Avoid year-after-year use of herbicides that have the same site of action. At one time this meant not using herbicides from the same chemical family, but this is no longer the case. For example, two chemically different groups of herbicides, the sulfonylureas and imidazolinones, have the same site of action, ALS inhibitors. For another example, Prism and Poast belong to different chemical families but kill susceptible grasses in the same way. Avoid repeated application of herbicides —Repeated applications within a growing season of an herbicide with no soil activity (e.g., glyphosate) has resulted in weeds resistant to the herbicide. Crop rotation —Because different crops may require different herbicides, rotating crops can increase herbicide rotation. But with glyphosate resistant crops, crop rotation alone may not be enough to avoid weed resistance. Cultivation/Hand weeding —In row crops, orchards, and vineyards cultivation can be an effective tool for eliminating weed escapes that may represent the resistant population. Tillage or hand weeding controls herbicide-resistant and herbicide-susceptible weeds equally as long as seedlings of the two biotypes emerge at the same time. Accurate record keeping — To have an effective herbicide rotation or tank-mix system to prevent resistance, you must know which herbicides have been used in the past, at what rate, and how often. Integrated weed management —This concept is important for all weed control, not just management of herbicide-resistant weeds. Integrated weed management uses all the tools available to control weeds, including cultural, mechanical, and chemical methods. An integrated approach to weed management, whether it is in crop or noncrop land, is an important environmental and economic consideration. Monitor fields for weed escapes —Weed escapes are not necessarily resistant, but they may be. A resistance problem may not be visible until 30 percent or more of the weeds are no longer controlled. See whether escapes are only one species or a mixture. If only one species, the problem is more apt to be resistance, especially if the herbicide controlled the species in the past and if the same herbicide has been used repeatedly in the field. Keep weeds from spreading —Prevent known resistant weeds from flowering and producing seed. After using machinery in fields or areas with known or suspected

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Table 1. Weeds resistant to herbicides in California Group Type and Site of Action1

Weed Chemical Trade names

Group A/1 Acetyl CoA carboxylase

Late Watergrass (Echinochloa phyllopogon)

fenoxaprop-p-ethyl Puma, Whip, Acclaim

(ACCase) inhibitors

Barnyardgrass (Echinochloa crus-galli)

cyhalofop-butyl, fenoxaprop-p-ethyl, molinate, thiobencarb

Clincher, Whip, Ordram, Bolero

Early Watergrass (Echinochloa oryzicola)

cyhalofop-butyl, fenoxaprop-p-ethyl, molinate, thiobencarb

Clincher, Whip, Ordram, Bolero

Little Seed Canary Grass (Phalaris minor)

Fluazifop, fenoxaprop-p-ethyl, sethoxydim, clethodim

Fusilade, Whip, Poast, Prism, Select

Group B/2 Acetolactate

Perennial Ryegrass (Lolium perenne)

sulfometuron-methyl Oust

synthase (ALS) Smallflower Umbrella Sedge (Cyperus difformis)

bensulfuron-methyl Londax

inhibitors California Arrowhead (Sagittaria montevidensis)

bensulfuron-methyl Londax

Redstem (Ammania auriculata)

bensulfuron-methyl Londax

Ricefield Bulrush (Scirpus mucronatus)

bensulfuron-methyl Londax

Group B/2 Acetolactate

Long-Leaved loosestrife (Ammania coccinea)

bensulfuron-methyl Londax

synthase (ALS) inhibitors

Russian Thistle (Salsola iberica)

chlorsulfuron, sulfometuron-methyl

Telar, Oust

Group O/4 Synthetic auxins

Smooth Crabgrass (Digitaria ischaemum)

quinclorac Facet

Group N/8 Lipid

Wild Oat (Avena fatua)

difenzoquat Avenge

synthesis inhibitors

Late Watergrass (Echinochloa phyllopogon)

thiobencarb Bolero

but not ACCase

Early Watergrass (Echinochloa oryzicola)

thiobencarb Bolero

inhibitors Barnyardgrass (Echinochloa crus-galli)

thiobencarb Bolero

Group G/9 EPSP

Rigid Ryegrass (Lolium rigidum)

glyphosate Roundup, Touchdown, etc

synthase inhibitors

Horseweed (Conyza canadensis)

glyphosate Roundup, Touchdown, etc

Hairy Fleabane (Conyza bonariensis)

glyphosate Roundup, Touchdown, etc

Junglerice (Echinochloa colona)

glyphosate Roundup, Touchdown, etc

1 Mode of action classification based on Herbicide Resistance Action Committee (HRAC) and Weed Science Society of America systems.

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infestations of herbicide-resistant weeds, thoroughly clean the equipment to reduce the spread of resistant weeds from one field or area to another. Change crops and tillage systems —Crop rotation and altered tillage practices can affect the weed populations. Alternating spring and winter crops means that the field will be tilled at different times each year. During one of the field preparation operations, resistant as well as susceptible weeds will be killed. Change herbicide program —If weed resistance occurs, herbicides with other sites of action and other weed management practices must be used. Control of Roundup Resistant Ryegrass in Almonds Ryegrass (Lolium multiflorum or rigidum) has been reported to be resistant to glyphosate (Roundup) in Sacramento Valley of California. An experiment was conducted in a mature almond orchard, located on the Pante Farm, near Durham, California, (N39º38.545, W121 º46.027) to assess ryegrass control. Experimental plots were arranged in a randomized complete block and replicated 6 times. Individual plots were 10 ft. wide by 27ft. long, with a single almond tree in the center of each plot. Treatments were applied on November 22, 2006, using a CO2 powered backpack sprayer. Visual evaluations of ryegrass control were made at 1, 2, 3, 4, 6, 12, and 20 weeks after application. Additionally, overall weed control was assessed at 20 weeks and 30 weeks after treatment. At one week after treatment, ryegrass control was over 90% if Gramoxone was included in the treatment (Table 2). The addition of other herbicides with Gramoxone did not influence ryegrass control. Weather was relatively cool during the week after application and activity of the systemic herbicides was much slower. By two weeks after treatment, the Gramoxone treatments were still providing the best control, but other treatments were starting to show more activity, particularly the Chateau treatments. By three weeks after treatment, Roundup plus Poast treatments were also providing 90% control, with the exception of the Roundup plus Poast plus Princep treatment. The addition of Princep, a wettable powder, may have caused some binding of the active herbicide molecules, and thus a reduction in activity of both the Roundup and Poast, as has been reported previously. By 12 weeks after application, all treatments except Roundup alone, were providing 90 percent or better ryegrass control. Roundup alone provided about 50% control, which probably represents the portion of the ryegrass population which was sensitive to glyphosate. The addition of Poast, Surflan, Princep, or Chateau, to Roundup, resulted in about 50% better ryegrass control. In summary, Roundup alone would not be an effective treatment in situations where glyphosate resistant ryegrass was present. The addition of Poast can help to control the ryegrass. Gramoxone was effective against established ryegrass, but a residual material would help to improve residual weed control. Princep should not be added to Roundup treatments as antagonism would likely reduce activity.

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Table 2. Ryegrass control (%) relative to herbicide treatment and evaluation date. Treatment 11/29 12/6 12/13 12/20 1/2 2/12 4/13

Roundup 1.5 lb/A 3 22 42 48 53 51 48 Roundup 1.5 lb/A + Poast 0.375 lb/A 7 38 90 91 94 97 97 Poast 0.375 lb/A 1 13 26 42 79 97 94 Roundup 1.5 lb/A + Poast 0.375 lb/A + Surflan 4 lb/A

4 31 90 92 99 99 100

Poast 0.28 lb/A + Surflan 4 lb/A 2 10 25 48 88 99 98 Roundup 1.5 lb/A + Poast 0.375 lb/A + Princep 2 lb/A

2 12 53 70 90 97 92

Poast 0.375 lb/A + Princep 2 lb/A 4 10 22 37 75 98 97 Roundup 1.5 lb/A + Chateau 5.1 oz/A 6 52 72 82 97 96 96 Roundup 1.5 lb/A + Poast 0.375 lb/A + Chateau 5.1 oz/A

39 62 94 96 99 99 99

Gramoxone 1.0 lb/A 93 94 94 95 93 90 90 Gramoxone 1.0 lb/A + Surflan 4 lb/A 96 97 96 96 99 99 99 Gramoxone 1.0 lb/A + Poast 0.375 lb/A + Surflan 4 lb/A

94 98 96 98 99 99 99

Gramoxone 0.75 lb/A + Princep 2 lb/A 96 99 98 99 100 99 99 Gramoxone 0.75lb/A + Poast 0.375 lb/A + Princep 2 lb/A

93 96 99 99 99 99 99

Untreated 0 0 0 0 0 0 0 LSD .05 13 13 16 18 15 10 11

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Residential Turf Weed Control

Dennis Penner Abate-A-Weed, Bakersfield, CA

Weeds compete for the following in turf: water, nutrients, light, carbon dioxide, space. The best defense for weed control in turf is to build a healthy turf stand. Identifying weeds correctly in turf is required in order to select the proper herbicide. Applying the herbicide properly is essential for good weed control. The pre emergent herbicides (Dimension, Pendulum, Gallery) and post emergent herbicides (Trimec Turf, Weedhoe, Sedgehammer, Turflon) are chosen based on the type of existing weeds. Weed control is an environmental craft. As professional pesticide applicators, we are improving the beneficial state of the environment. We help protect infrastructure, human health, safety, and natural resources.

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Application Temperature Impacts on Herbicide Effectiveness

Jeffrey Derr, Professor of Weed Science, Virginia Tech, Hampton Roads AREC, 1444 Diamond Springs Rd, Virginia Beach, VA 23455-3315, jderr@vt.edu

Winter annual broadleaf weeds are common problems in turfgrass. Application of

herbicides in cool weather is generally thought to be less effective than treatments applied during warmer conditions. It has been suggested that products containing carfentrazone may be effective for broadleaf weed control in winter or early spring. Carfentrazone is a contact broadleaf herbicide sold by itself as QuickSilver. It can be added to systemic herbicides and is also available in the prepackaged mixes Powerzone and Speedzone.

The objective of this research was to compare the effectiveness of carfentrazone applied alone or in combination with systemic broadleaf herbicides for turf weed control. A combination product containing sulfentrazone was also included in the research conducted.

Two identical trials were conducted in order to determine the efficacy of carfentrazone

applied alone (0.016 lb ai/A), Speedzone (carfentrazone plus 2,4-D plus MCPP plus dicamba at 0.020, 0.67, 0.2 and 0.06 lb ai/A, respectively), Speedzone Southern (carfentrazone plus 2,4-D plus MCPP plus dicamba at 0.020, 0.26. 0.10, and 0.025 lb ai/a, respectively), Powerzone (carfentrazone plus MCPA plus MCPP plus dicamba at 0.018, 0.97, 0.19, and 0.10 lb ai/A respectively), Surge (sulfentrazone plus 2,4-D plus MCPP plus dicamba at 0.024, 0.57, 0.20, and 0.09 lb ai/A, respectively) compared to Trimec Classic (2,4-D plus MCPP plus dicamba at 0.80, 0.22, 0.22, and 0.09 lb ai/A, respectively ) on winter broadleaf weeds.

The first trial was conducted in well-maintained tall fescue (Festuca arundinacea

Schreb.). The cool weather treatment was applied at 46 F and the warm weather application was made at 67 F. Control of ivyleaf speedwell [Veronica hederifolia L.], common chickweed [Stellaria media L. Vill.], and henbit [Lamium amplexicaule L.] was determined. The second trial was conducted in a stand of dormant common bermudagrass. The cool temperature treatment was applied at 44 F while the warm temperature application was made at 64 F. Along with ivyleaf speedwell and common chickweed, control of purple deadnettle [Lamium purpureum L.] and wild garlic [Allium vineale L.] was determined.

In trial one, warm weather applications resulted in greater initial control at 5 days after

treatment (DAT) than cold weather application. However, by approximately 17 DAT, similar results were seen between cool and warm temperature applications of each herbicide. At this time, all herbicides applied in both weather conditions with the exception of Trimec Classic provided 92% or greater control of ivyleaf speedwell and 82% or greater control of henbit. Trimec Classic provided less than 50% control of both ivyleaf speedwell and henbit. At both temperature regimes, Trimec Classic and carfentrazone controlled common chickweed about 55% at this time. Common chickweed control with Surge, Speedzone, Speedzone Southern, and Powerzone at both application timings was similar, ranging from 68% to 78%.

At 34 DAT in both temperature regimes, all herbicides provided 96% or greater control

of ivyleaf speedwell and 84% or greater control of henbit, with the exception of Trimec Classic

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(approximately 58% control of ivyleaf speedwell at both temperatures and 34 and 68% henbit control for warm and cold temperature applications, respectively). Common chickweed control with a given herbicide was similar at both temperature regimes. All treatments except carfentrazone provided good to excellent control of common chickweed.

At approximately 2 months after treatment, all treatments at both temperatures gave 97% or greater control of ivleaf speedwell and henbit, except for Trimec Classic, which gave about 85% control of ivyleaf speedwell and about 60% henbit control. All treatments except carfentrazone gave excellent common chickweed control.

In trial two, similar control trends were observed, although overall weed control was

lower than in the first trial. At 7 DAT, warm weather treatments resulted in generally greater weed control. At 14 DAT, control of ivyleaf speedwell was similar between warm and cold temperature applications for a given herbicide. Control of common chickweed and purple deadnettle tended to higher with warm applications compared to cold applications for all treatments except Surge. By approximately 37 DAT, generally similar control was seen when comparing the effectiveness of a given herbicide applied at cold versus warm temperature application. Powerzone and Speedzone were the overall most effective treatments in the second study.

Application of these herbicides under warm conditions resulted in faster symptom development in broadleaf weeds, but long term control was generally similar between warm and cold temperature applications for a given herbicide. Better weed control in the first trial may be the result of younger plants (treated in mid-December) and competition from tall fescue. Trial two was in an area not regularly mowed and weeds were older and more mature (trial treated in early March). In general, Speedzone and Powerzone were more effective than Trimec Classic, which could be due to the presence of carfentrazone and/or due to the use of an ester form of 2,4-D and MCPA in Speedzone and Powerzone, respectively, compared to an amine form of 2,4-D in Trimec Classic. The addition of carfentrazone may provide an additive or synergistic effect. Using ester forms of 2,4-D (Speedzone) and MCPA (Powerzone) should improve effectiveness over an amine form of 2,4-D (Trimec Classic). Carfentrazone combinations with systemic broadleaf herbicides are effective for winter broadleaf weed control under cold weather conditions.

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Postemergence Nutsedge Management in Turf Jeffrey Derr, Professor of Weed Science, Virginia Tech, Hampton Roads AREC, 1444 Diamond

Springs Rd, Virginia Beach, VA 23455-3315, jderr@vt.edu

Yellow nutsedge is a common turf weed throughout the 48 contiguous states. Purple nutsedge is an occasional turf weed in the southern half of the US. Both species primarily spread vegetatively by rhizomes and tubers but both do produce seed. Several new herbicides have been introduced to the turf industry for control of sedges, among other weeds. Mesotrione is an herbicide that causes bleaching in susceptible species. Sulfentrazone is a contact herbicide that is available alone and in combination with prodiamine.

In the first trial, sulfentrazone was applied post for yellow nutsedge control at 0.25, 0.3125, 0.375 lb ai/A (0.28, 0.35, 0.42 kg ai/ha) to established perennial ryegrass, for comparison, halosulfuron was applied at 0.047 lb ai/A + X-77 nonionic surfactant. Injury symptoms following sulfentrazone application was observed 1 day after treatment (DAT) while injury symptom development was much slower with halosulfuron. By 20 DAT, sulfentrazone controlled yellow nutsedge 74, 80 and 90% at 0.25, 0.3125, 0.375 lb ai/A, respectively while halosulfuron provided 97% control. Repeat applications of sulfentrazone were evaluated for purple nutsedge control. Sulfentrazone was applied once at 0.125, 0.188, 0.25, or 0.375 lb ai/A. An additional set of plots were treated with sulfentrazone at 0.25 lb ai/A followed by 0.125 lb ai/A at 28, 35, or 42 days after the first application. Sulfentrazone caused a rapid burn in purple nutsedge but control never exceeded 55% with single or repeat applications. Halosulfuron controlled purple nutsedge 100% at 21 DAT, although control decreased to 71% at 41 DAT. Mesotrione was applied at 0.125 or 0.25 lb ai/a (0.14 or 0.28 kg ai/ha) once or repeated 14 days later for postemergence control of yellow nutsedge. At 9 DAT, mesotrione controlled yellow nutsedge 78 and 98%, respectively, at 0.125 and 0.25 lb ai/A. Yellow nutsedge regrew when mesotrione was only applied once but two applications at 0.125 lb ai/A gave good control with excellent control seen with two applications at 0.25 lb ai/A 41 DAT.

Sulfentrazone and mesotrione were compared to halosulfuron and trifloxysulfuron in another trial for postemergence control of yellow and purple nutsedge. Sulfentrazone injured both sedge species approximately 20% at 3 DAT. AT 17 and 32 DAT, yellow control with sulfentrazone increased to approximately 60%, depending on rate, but decreased at later rating dates. Sulfentrazone provided no control of purple nutsedge at 32 DAT. A single application of mesotrione at 0.25 lb ai/A controlled yellow nutsedge 50% at 39 DAT, with lower injury seen in purple nutsedge. Halosulfuron and trifloxysulfuron provided approximately 75% control of both sedge species at 39 DAT. Sulfentrazone was compared to the sulfonylureas foramsulfuron, halosulfuron, trifloxysulfuron, flazasulfuron, and sulfosulfuron for postemergence yellow and purple nutsedge control. Sulfentrazone caused approximately 15 to 20% injury in both sedge species at 1 DAT while injury symptom development was much slower with the sulfonylurea herbicides. By 49

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DAT, sulfentrazone caused 35 to 71% reduction in yellow nutsedge shoot fresh weight and 14 to 28% reduction in purple nutsedge shoot weight, depending on application rate. Foramsulfuron did not provide acceptable control of either sedge species. Halosulfuron, trifloxysulfuron, flazasulfuron, and sulfosulfuron all provided excellent control of both yellow and purple nutsedge.

Sulfentrazone provides rapid burning of yellow and purple nutsedge but provides much better control of yellow compared to purple nutsedge. Thus, repeat applications are needed to maintain control. It can cause temporary injury to bermudagrass, tall fescue, perennial ryegrass but injury disappeared by 2 weeks after application. Mesotrione was slower acting than sulfentrazone and also provided better control of yellow compared to purple nutsedge. Two applications of mesotrione provided much better yellow nutsedge control than a single application. The sulfonylureas halosulfuron, trifloxysulfuron, flazasulfuron, and sulfosulfuron are effective on both yellow and purple nutsedge.

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Successful Control of English Lawn Daisy (Bellis perennis)

Mark M. Mahady, President, Mark M. Mahady and Associates, Inc., 531 Country Club Dr, Carmel Valley, CA 93924-9542, markmahady@aol.com

Introduction English lawn daisy or English daisy (Bellis perennis) is the most troublesome and difficult to control broadleaf turfgrass weed in California. English daisy continues to flourish in turf stands and frustrate turf managers due to its ability to adapt to a wide range of cultural practices, and to resist and tolerate many of the presently registered broadleaf herbicides. English daisy is a fibrous rooted perennial with basal leaves and a prostrate, spreading growth habit. The leaves are nearly smooth or loosely hairy, entire margined or variably toothed, broad above, and narrowed at the base to a long stalk. Flower heads are white or pinkish with yellow centers. Flower stalks generally exceed the leaves in length. This aggressive and troublesome weed spreads through a rapidly advancing rhizome system, and exhibits the potential to root and produce new plants at each node along individual rhizomes. English daisy also appears to be a prolific seed producer. Germinating seedlings have been observed in Northern California from April until late September. Once established in turf this dual propagation system contributes to the rapid spread and invasion of English daisy in adjacent turfgrass areas. English lawn daisy was introduced from Europe as a garden plant and today there are thought to be at least six known biotypes in California. Field Research 1992-2008 Applications of chloro-phenoxy herbicides have historically exhibited poor control of English lawn daisy. In the past when English daisy populations were extreme, golf course superintendents would often make three to five applications per year of 2,4-D and related products with poor results. The greatest benefit of chloro-phenoxy applications was short-term flower removal and suppression. With the registration of quinclorac (Drive 75DF: BASF) in California the potential to control English daisy improved. Although quinclorac alone never exhibited high levels of English daisy control in our field trials when used as a stand-alone application, it did appear to enhance the performance of other products when used in tank mix combinations. Three-way tank mix combinations of SpeedZone Southern (2,4-D, MCPP, dicamba, carfentrazone: PBI Gordon), Drive 75DF (quinclorac: BASF) and Vanquish (dicamba: Syngenta) exhibited improved activity on English daisy. In rough areas three applications of this three-way tank mix showed 75-80% English daisy control and in fairways 50-60% control. Over the last 16 years Mark M. Mahady & Associates, Inc. has conducted 15 replicated field research trials for the control of English daisy in cool season grass fairway and roughs areas. To date 31 products and 90 different product combinations have been evaluated. Those products

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screened for English daisy suppression and control include Trimec Classic, Trimec Amine, Confront, Gallery, Turflon, Drive, SpeedZone, Vanquish, 2,4-D, 2,4-DP, Lontrel, Greenor, Roundup Pro, Scythe, Prograss, Dissolve, Triplet, TriPower, Triamine II, Lesco 3-Way, MSMA, MCPP, MCPA, Momentum, Millenium, Chaser, Carfentrazone, Spotlight, XDE-565, Mesotrione and Penoxsulam. To date the best performing product reviewed for selective postemergent control of English daisy in cool season grasses has been Penoxsulam. Penoxsulam is manufactured by Dow AgroSciences and exhibits the following classifications and characteristics:

• Sulfonamide herbicide classification • Postemergence herbicide, ALS (acetolactase synthase) inhibitor • Mobile, but not persistent • Low volatility • Reduced risk pesticide due to its favorable human health risk profile

Since 2004 five replicated field research trials and two superintendent applied split fairway demonstration trials have been conducted on golf courses in the Monterey Peninsula in order to evaluate the performance of Penoxsulam for English daisy control. The key take home messages from these trials are as follows:

• Late summer/early fall is the best time period for efficacious applications of Penoxsulam. Apply the first application on approximately September 25 with a second application 21 days later.

• At application rates of 0.02 lb. ai/A no injury to cool season grasses has been

observed in our trials. Some golf course superintendents have reported slight and short term yellowing on Poa annua. No long-term reduction in surface quality has been observed. At very high rates (0.08 lb. ai/A) injury to some varieties of perennial ryegrass has been observed.

• A minimum of two sequential applications at 0.02 lb (9 grams) ai/A is required for

high levels of control. Single applications are much less effective with dynamic regrowth of English daisy often appearing.

• With late summer/fall timing two sequential treatments applied at a 21-day interval

will provide high levels of control (95%+). In a replicated field trial conducted on a golf course fairway in 2006-2007, two late summer treatments of Penoxsulam applied at 0.02 lb (9 grams) ai/A resulted in 96% English daisy control 345 days after the second application. In a replicated field trial conducted on a golf course fairway in 2007-2008, two late summer treatments of Penoxsulam applied at 0.02 lb (9 grams) ai/A resulted in 100% English daisy control 70 days after the second application.

• If spring applications are planned a third sequential application will be required for

high levels of control.

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• Use a non-ionic surfactant at standard label rates with all applications. Penoxsulam is an exceptional new tool for English daisy control in cool season turfgrasses. California registration is expected during the summer of 2008. Acknowledgements Over the last 16 years many product development companies have graciously provided funding to support English daisy field research. We would like to thank Dow AgroSciences, The Northern California Golf Course Association, BASF, LESCO, PBI Gordon, DuPont, Syngenta, Rancho Canada Golf Club and Mark M. Mahady & Associates, Inc. for their generous financial support.

* * * * *

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Pendimethalin phytotoxicity and leaching in container media and field soil Jeffrey Derr, Professor of Weed Science, Virginia Tech, Hampton Roads AREC, 1444 Diamond

Springs Rd, Virginia Beach, VA 23455-3315, jderr@vt.edu Weed management in container nursery production relies primarily on hand weeding and

preemergence herbicide application. Dinitroaniline herbicides are commonly-applied to container-grown plants for preemergence weed control. Previous research has shown these herbicides can affect root development of container-grown nursery crops.

Container trials were conducted to determine the importance of leaf versus root uptake of pendimethalin by azalea. The emulsifiable concentrate form of pendimethalin was applied at 3.34 kg ai/ha to ‘Tradition’ azalea shoots, the growing medium (pine bark), or shoots plus the growing medium. Initial plant height and root volume were recorded. Plant height was recorded 2, 4 and 8 weeks after treatment (WAT). Azalea root and shoot growth was evaluated at 4 and 8 WAT. After 4 WAT, azalea height in shoot-only and shoot plus growing medium exposure treatments increased by 17% and 25%, respectively, while height in growing-medium only exposure and in the untreated control increased by 34%. All treatments reduced azalea shoot fresh weight when compared to the untreated control. At 4 WAT, azalea root development in the shoot only exposure was similar to that seen in the untreated plants, while root growth was reduced in the growing medium and growing medium plus shoot exposures.

Experiments were conducted to evaluate depth of pendimethalin movement in container

media and field soil at two different irrigation volumes, as indicated by a large crabgrass bioassay. Soil columns were constructed from polyvinyl chloride pipe, with a 5 cm internal diameter and a 35 cm length. A Tetotum silt loam soil was compared to 100% pine bark. An emulsifiable concentrate form of pendimethalin was applied at 3.4 kg ai/ha. Media in the soil columns were separated into 0 to 3 cm, 3 to 6 cm, 6 to 9 cm, 9 to12 cm, 12 to 18, and 18 to 24 cm depths after completion of the simulated irrigation events and seeded with large crabgrass. Large crabgrass root weight and root length were recorded 2 weeks later. After 18 cm of irrigation, pendimethalin leached into the 6 to 9 cm depth in pine bark, while the silt loam field soil displayed no detectable herbicide movement past the 0 to 3 cm depth. Doubling the irrigation volume did not increase the depth to which pendimethalin leached in pine bark or field soil. Large crabgrass root weights significantly increased as pine bark depth increased from the 0 to 3 cm, 3 to 6 cm, 6 to 9 cm and 9 to 12 cm depths, indicating most of the herbicide remained near the medium surface. There was no significant difference in large crabgrass root weights among the 9 to 12 cm, 12 to 18 cm and 18 to 24 cm depths in pine bark. By mass, approximately one half of the particle size of pine bark was 2 mm or greater, while none of the field soil particles were 2 mm or greater. Pine bark had a drastically greater volume of air space (41%) compared to the silt loam soil (4%). The bulk density of pine bark was much less than that of field soil, while water percolation rates were much higher for pine bark than field soil.

Sprayed applications of pendimethalin can directly reduce azalea shoot growth, while

exposure of root systems to pendimethalin results in reduced root growth. Root suppression is due to pendimethalin leaching into the 6 to 9 cm zone below the pine bark surface. Pendimethalin moves downward in pine bark much more readily than in field soil as

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pendimethalin did not leach below 3 cm in field soil.. The differences in physical properties between pine bark and field soil may account for the greater leaching depth in a soil-less growing medium. The greater leaching in pine bark is probably due to the higher percolation rate and higher amount of air space in this growing medium compared to field soil. Growers need to ensure adequate root development prior to application of a dinitroaniline herbicide to containers.

4645

Japanese Dodder Detection and Treatment

Terrance Lorick, Japanese Dodder Program Manager, California Department of Food and Agriculture, 1220 N Street Sacramento, California, U.S.A. 95814-560

Japanese dodder, Cuscuta japonica is listed as both a California and federal noxious weed, and as such is subject to eradication when found in the state. In California, C. japonica seed was initially detected at a retail business in Redding, in 2004. The confiscated seed was not sterile and was destroyed under USDA, (United States Department of Agriculture) authority. Subsequent to this interception, in June 2004, a specimen of dodder from Shasta County was submitted to the California Department of Food and Agriculture (CDFA), Botany Laboratory. This specimen was tentatively identified as C. relfexa, giant dodder, a closely related noxious weed, also from the eastern Asian seaboard. Each of these weeds belongs to a group of dodders known as ‘giant dodder’ because of their robust stems, unlike other dodders that are thin stemmed. In October 2005 a specimen from Shasta County, growing on citrus was submitted to the CDFA Botany Laboratory. This specimen had well-developed flowers and was positively identified as C. japonica. Subsequent surveys found no other infested properties. The infested citrus tree was removed and disposed at an approved landfill. In the spring of 2005, the initial residential site was re-inspected for evidence of any return of the dodder. As no evidence of the plant was found, it is thought that it succumbed to winter temperatures since this is not a cold tolerant species. In its native range, Japanese dodder is an annual parasitic plant that uses specialized roots called haustoria that allow the plant to obtain water and nutrients from its host. C. japonica can infect a wide variety of hosts. In its native tropical range it grows, sets seed, and dies in a single season. Japanese dodder plants are robust, rapidly growing plants that can survive for prolonged periods without a host. In addition to its wide host range, some cultivation by certain ethnic groups is possible. Flowering of C. japonica has been observed in California, but seed production has not. Seeds pose an extreme threat to California as they can live in excess of 20 years. In California it is unknown if the plant will adapt and establish in the varying climates found in the state. In late 2005, the CDFA decided to survey areas in the state where Japanese dodder was likely to occur. These surveys detected one site in Los Angeles County. In 2006, a sharp increase of C. japonica sites were detected throughout. Emergency funds were made available and the Japanese Dodder Survey and Eradication Protocol was developed. The six components of the protocol are detection, eradication, post-treatment monitoring, outreach and education, and regulatory. Annual detection surveys begin in spring and last through late fall. Each of the fifty-eight counties in California is assigned a ‘Tier’ based on likelihood of harboring infestations of C. japonica. Tier I is “highest risk,” Tier II is “moderate risk,” and the remaining counties are either infested or determined to be unsuitable for establishment of C. japonica. Each of the Tier I counties and a majority of the moderate risk counties were surveyed by CDFA crews in 2007. Over 20,000 net miles comprising 4.8 million primarily urban and some rural residential properties were surveyed for the presence of Japanese dodder in 2007, only one site was found infested. In January 2007, almost the entirety of the state experienced a prolonged period of below freezing temperatures. This event appears to have decimated existing infestations of

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Japanese dodder in most areas and, decreased the viability of other infested sites, except in some coastal environments. Currently 206 infested sites in 14 counties have been detected and treated. The primary method of ‘treating’ infested sites is total host removal or severe pruning to eliminate infested material. Post-treatment monitoring occurs on a regular basis, with eradication declared after two years. CDFA will continue its outreach and education efforts and enlist the public’s assistance in locating previously undetected sites.

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Solarization And Steam Heat For Soil Disinfestation In Flower And Strawberry Celeste A. Gilbert, Steven A. Fennimore, Krishna Subbarao, Rachael Goodue, and J. Ben Weber, University of California, Davis, Department of Plant Sciences, One Shields Ave.,

Davis, CA. 95616-8780, calgilbert@ucdavis.edu Abstract

The objective of this research is to develop an economically feasible combined solarization and steam heat, soil disinfestation system for field-grown flowers and strawberry. Soil solarization performance in cool coastal areas of California is often inconsistent due to fog and cool summer temperatures that do not allow soil to reach high temperatures required to reliably kill soil pests. Coastal California is also the principal strawberry fruit and cut flower production region, and solarization has displaced virtually no methyl bromide (MB) use in these crops. Soil disinfestation with steam has a long and proven track record for control of soil pests including weeds and pathogens in greenhouse and nursery settings. However, use of steam at the field level has been limited due to difficulty in treating large areas with existing steam applicators and high energy costs for steam disinfestation. A steam blanket prefabricated to fit the bed widths and plot lengths was used for the injection of steam into finished planting beds with a mobile steam generator. Each plot required about 1-1.5 hours to apply steam and raise soil temperatures to 70°C at a depth of 6 inches. We do expect large increases in efficiencies by treating larger areas. Results to date indicate that weed control with steam plus solarization was comparable to MB.

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Full Season Drip Irrigation in Lettuce – Impact on Weed Control

Richard Smith1, Michael Cahn1 and Steve Fennimore2, 1 - University of California Cooperative Extension, Monterey County, 1432 Abbott Street,

Salinas, CA 93901, rifsmith@ucdavis.edu; 2 – UC, Davis, Dept. of Plant Sciences INTRODUCTION The acreage of lettuce under drip irrigation in the Salinas Valley has noticeably increased during the past 10 years; in 2005, 31% of the vegetable acreage was drip irrigated compared with 3% of the acreage in 1993 (Thomasberg et al. 2007). Despite the increased acreage under drip, overhead sprinklers are used on most of the vegetable acreage from planting until thinning. After thinning and side-dressing of fertilizer, drip tape is usually installed on top of the beds and used to irrigate the crop until harvest. Growers have justified the costs of using surface-placed drip after sprinklers by such advantages as reducing water use, minimizing foliar diseases, and increasing fertilizer-use efficiency. Growers in the Salinas Valley have experimented with irrigating lettuce with drip tape from planting to harvest. Full season use of drip maximizes the benefits of drip irrigation and eliminates some of the disadvantages of sprinklers. For full season use, the tape is buried a few inches below ground so that the crop can be planted and thinned without damaging the tape. Besides eliminating the costs of using overhead sprinklers, using only drip can improve access to the field by keeping the furrows dry, prevent the formation of soil crusts which reduces emergence, and permits growers to irrigate with a high uniformity during windy conditions. Obtaining uniform germination with shallowly buried drip tape can be a significant limitation to using full-season drip: particularly, obtaining uniform wetting of the bed tops. Where as overhead sprinklers apply water directly to the seed line, water from the buried drip tape must move both upward and horizontally to the seed. In some cases, growers have needed to irrigate for as much as 24 hours during a single set to obtain a satisfactory level of moisture in the seedline, and on some soil types, such as well-aggregated clays, the drip system was unable to move moisture to the seedline if the soil was initially too dry. Weed control can be another challenge to germinating lettuce with drip tape. Where overhead sprinklers are used they effectively activate the commonly applied preemergent herbicides, Kerb and Prefar. Sprinkler applied water is considered necessary to obtain full efficacy from these herbicides, because the overhead application of water moves the herbicide from the soil surface to the depth where germinating weed seed are located. Questions arise about the efficacy of activating surface applications of Kerb and Prefar with drip irrigation due to differences in the movement of the germination water from the drip tape. Water from the drip tape is moving laterally as well as downward and the question is, can water from the drip system effectively activate the preemergent herbicides and provide good weed control.

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METHODS We conducted two field trials: Trial No. 1: In 2006 we compared sprinkler and drip germinated lettuce. The trial was conducted at the USDA Spence research farm on a sandy loam soil. Three application methods of Kerb: 1) bedtop spray, 2) injection into the drip tape, and 3) no Kerb. Three irrigation methods were tested: 1) one line of drip tape in the bed middle on the bed surface, 2) one line of drip tape in the bed middle buried at 2 inch depth; and 3) sprinkler irrigation. Kerb was applied at 1.2 lbs a.i./A. Each treatment was replicated four times and each plot was one bed wide by 135 feet long. The sprinkler plots were separated from the from the drip plot to prevent contamination between plots. Trial No. 2: 2007 trial was conducted with a cooperating grower on a site with Salinas Clay Loam Soil. The drip tape buried drip at 2-3” depth. The herbicides were sprayed 14 hours after the initiation of the germination water and the water was run for 4 hours following the application. All materials were applied with a CO2 backpack sprayer at 30 psi applying 72 gallons of water per acre. Each plot was one 40 inch bed wide by 30 feet long. RESULTS Trial No. 1: The primary weed species at the trial site were shepherd’s-purse and common groundsel. Plots treated by Kerb Chemigation had less common groundsel than plots treated with Kerb on the bed top. Drip germinated treatments had significantly fewer weeds that sprinkler irrigated treatments (Table 1). Kerb had no effect on the lettuce stand whether applied by spray or chemigation. Lettuce stand in the drip irrigated treatments were higher than in the sprinkler irrigation treatments. Kerb application method did not affect lettuce yield, but lettuce yields in drip irrigated plots were higher than in sprinkler irrigated plots (data not shown). Trial No. 2: On August 3 the weeds were small and there were fewer purslane plants in the Prefar treatments than in the Kerb treatments (Table 2); however, by August 31 there were no difference in the number of purslane plants per plot between the Kerb and Prefar treatments indicating mortality of purslane seedlings in the Kerb treatment. Prefar provided better control of burning nettle on the August 3 evaluation date; on August 31 the high rates of both Prefar and Kerb provided better control of this weed than the lower rates. Prefar provided better weed control of total weeds than Kerb on the August 3 evaluation date but there were no significant differences among the herbicide treatments on the August 31 evaluation date with both herbicides providing greatly improved weed control than the untreated. An evaluation of the movement of Kerb in the soil was conducted to better understand the movement of Kerb in a situation where it is activated by water coming from drip tape as opposed to sprinklers which is the common method currently used in the Salinas Valley. The evaluation showed that about 75% of the 2.0 lb a.i. application of Kerb remained in the top 2.0 inches of soil (Table 2); 62.5% of the material was in the top 0.5 inch of soil which is the zone of active weed seed germination. These results help us to better understand the movement of Kerb in soils

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under this irrigation scheme and will need to be built upon in the future to better understand the movement of Kerb and how best to optimize its use in lettuce production. CONCLUSIONS The irrigation system used for germinating lettuce impacted weed pressure; drip germinated lettuce had less initial weed pressure than sprinkler germinated lettuce. The movement of water from drip tape differs from the pattern of movement from sprinkler irrigation; however, Kerb and Prefar were successfully activated and provided good weed control in the two trials conducted in these studies. LITERATURE CITED Thomasberg, K., J. Barreras, C. James and T. Campa. 2007. 2005 Groundwater summary report. Monterey County Water Resources Agency. http://www.mcwra.co.monterey.ca.us/Agency_data/GEMS_Reports/2005%20Summary%20Report.pdf ACKNOWLEDGEMENTS We would like to thank Boutonnet Farms and the USDA for their cooperation in conducting the field trials, the California Lettuce Research Board for financial support for this project, and staff research associates Miriam Silva Ruiz and John Rachuy.

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Table 1. Effect of Kerb application method (spray, chemigation or untreated) and irrigation method (surface tape, buried tape or sprinkler) on weed densities, lettuce stand and visual injury. Kerb application

Irrigation Weed densities (no. / species / 10ft2)

Lettuce stand

Visual Injury

Shepherd's Purse

Common groundsel

Total Weeds

No./ 10ft1

Rating 2

(0-10)

Spray Surface 1.9 b 12.0 c 21.4 c 60.3 a 0.0 Spray Buried 4.1 b 13. 1c 24.0 c 60.5 a 0.0Spray Sprinkler 86.4 b 52.1 a 145.3 b 42.6 b 0.0Chemigation Surface 8.3 b 10.8 c 26.9 c 56.6 a 0.0Chemigation Buried 5.8 b 10.1 c 24.4 c 52.1 ab 0.0Untreated Surface 16.6 b 11.3c 41.1c 59.1 a 0.0Untreated Buried 16.5 b 14.1 c 46.1 bc 51.9 ab 0.0 Untreated Sprinkler 243.4 a 38.4 b 297.6 a 42.3 b 0.0

LSD (P=0.05) 90.6 10.6 102.6 10.1 ---Treatment Prob (F) 0.0002 0.0001 0.0001 0.0029 ---

Main effects of Kerb application 0.0 Spray 30.8 b 25.8 328.9 54.5 0.0Chemigation 7.0 b 10.4 300.1 54.4 0.0Untreated 92.2 a 21.3 347.7 51.1 0.0

Anova ---Kerb application 0.0177 0.2589 0.6925 0.3343 ---

Main effects of Irrigation method Surface 8.9 b 11.3b 286.5 b 58.7 a 0.0 Buried 8.8 b 12.5 b 290.7 b 54.8 a 0.0 Sprinkler 164.9 a 45.3 a 449.1 a 42.4 b 0.0

Anova ---Irrigation method <.0001 <.0001 <.0001 <.0001 ---

1 Number of seedlings in 10 feet of a single plant line 2 Rating scale: 0 = no injury; ≤2 = commercially acceptable; 10 = dead plants

5352

Table 2. Number of weeds per 45 ft2 on two dates Material Material/A a.i./A Purslane

8/3 8/31

Shepherd’s Purse

8/3 8/31

Burning Nettle

8/3 8/31

Total Weeds

8/3 8/31 Kerb 50W 2.0 lbs 1.0 12.0 2.5 2.3 1.0 6.3 1.3 23.7 7.3 Kerb 50W 4.0 lbs 2.0 11.0 2.3 1.0 0.8 6.5 0.3 22.2 6.5 Prefar 4E 3.0 quarts 3.0 1.5 5.8 1.8 0.5 2.5 0.8 9.0 8.5 Prefar 4E 6.0 quarts 6.0 0.3 3.8 1.5 0.3 1.0 0.0 6.0 4.5 Kerb 50W Prefar 4E

4.0 lbs 6.0 quarts

2.0 6.0

0.3 1.8 1.8 0.0 1.0 0.3 7.3 3.5

Untreated --- --- 25.5 43.5 1.0 0.3 7.3 1.5 37.8 45.8 LSD (0.05)

7.7 13.4 n.s. n.s. 3.7 0.9 8.6 13.2

Table 3. Analyses of Kerb in soil on August 1. Soil Depth 2.0 lbs a.i./A Kerb

Treatment

ppm Kerb

Percent of 2.0 lbs a.i./A Kerb

application at each soil depth2

Untreated1 Treatment

ppm Kerb

0.0 – 0.5 inch 7.53 a 62.5 0.0 0.5 – 1.0 inch 0.70 b 5.5 0.0 1.0 – 1.5 inch 0.48 b 4.0 0.8 1.5 – 2.0 inch 0.30 b 2.5 0.0 LSD (0.05) 2.71 --- --- 1 – One replication sampled; 2 – a total of 74.5% of the 2.0 lb a.i./A application was recovered in the top 2.0 inches of soil.

5453

Vegetable Transplant Trends and Implications for Weed Control

Sergio Silva, President of Growers Transplanting Incorporated 360 Espinosa Road, Salinas, CA, 93907

Growers Transplanting Incorporated (GTI) has been in business for 26 and produces vegetable transplants for commercial growers. Crops grown include tomatoes, peppers, broccoli, romaine and mixed lettuces. Crops are grown in greenhouse facilities in Salinas, Watsonville, Santa Maria and Gustine with over 3 million square feet of greenhouse space. Crops are produced both conventionally and organically. Crops are seeded into planting trays and moved to the greenhouse where they are allowed to grow to maturity; they are then moved outside to harden off. Once plants are ready for transplanting, they are packed into special boxes that protect them as they are transported to the field. Transplanting is carried out by transplanting machinery. Both hand and automated systems are employed, and GTI developed one of the first mechanical transplanters. GTI is able to accommodate transplanting double lines on forty inch beds as well as multiple lines on eighty inch beds. Transplanting provides advantages for weed control because the plants are in the ground for fewer days and there are no thinning/weeding and fewer hand hoeing costs. The benefits apply to both conventional and organic production, but are particularly beneficial to organic production where there are no available herbicides. Transplanting has other advantages such as less susceptibility to bird damage, may have less need for fungicides and insecticides (i.e. fewer issues with maggots), and lower seed costs. Transplants can increase the number of crop rotations in a year and lend themselves to efficient use of drip irrigation. Aside from the benefits of transplanting in the field, the use of transplants are more efficient in the establishment of the crop; for instance, only 263 ft2 of greenhouse space is required to produce an acre worth of broccoli transplants. This amount of space requires less water, fertilizer and pesticides to establish the crop than is needed in the field. In this regard, vegetable transplants help to make vegetable production more environmentally friendly and help provide a “greener planet”.

5554

Sedge Biology and Control in California Rice

Dave Cheetham, Helena Research and Development, 3155 Southgate Lane, Chico, CA 95928, dcheetham@helenaresearch.com

Rice in California is typically grown in monoculture with water seeded rice being the main method for establishing the crop. Weeds are the main yield inhibiting pest to the crop. Weed control in California rice is largely dependant on selective herbicides. There are three types of weeds that infest California rice fields, grasses, sedges, and broadleaves. Ricefield Bulrush (Schenoplectus mucronatus) and Smallflower Umbrella Plant (Cyperus difformis) are the main sedge weeds in California rice. Both of these weeds are monocot, water obligates of the Cyperaceae family. Both weeds reproduce via seed and are self pollinated. Ricefield Bulrush seeds are black in color and can remain viable in the soil for as many as 10-years. Smallflower seeds are brown in color and can remain viable in the soil for as many as 5-years. When in the seedling stage, Ricefield Bulrush can be identified by its 180 degree or linear leaf arrangement. Mature plants can be 2 to 3-feet tall with a single leaf like bract that subtends the inflorescence or nutlet. Smallflower Umbrella Plant can be identified in the seedling stage by its glasslike, 120 degree leaf arrangement. Mature plants can be 18 to 24-inches tall and produces several pithy stems. Each stem has secondary leaves that subtend the umble arranged flower clusters. Both weeds flower within 60 to 70 days after germination. Their seed are spread via irrigation, dirty rice seed, and equipment. These weeds are prolific seed producers with each plant producing as many 20,000 seed. When uncontrolled these weeds are known to inhibit yield by as much as 22 to 43%. Ricefield Bulrush and Smallflower Umbrella Plant are hard to control as their narrow, vertical and waxy leaves hard to get good coverage with foliar herbicides. California Rice Farmers are almost completely dependant on herbicides for weed control. Unfortunately the arsenal of herbicides for California rice farmers is small with ALS inhibiting herbicides being key in their programs. That being said, these sedge weeds are known to be highly resistant to the affects of ALS inhibitors. For example, Londax (bensulfuron methyl) was introduced into California rice in 1989. Resistance to Londax was first determined in smallflower in 1992 and ricefield bulrush in 1993. By 1994, ALS herbicide resistance was estimated to be present in 96% of the California Rice acreage (Hill, JE., et al 1998). Cross resistance expressed by Smallflower and Bulrush to ALS inhibitors is likely due to several genes responsible for a target site mutation in the ALS loci. There are five families of ALS inhibitors: sulfonylureas (SU), imidazolinones (IMI), triazolopyrimidines (TP), pyrimidinylbenzoates (PB), and sulfonylamino carbonyltriazolinones (SCT). ALS herbicides currently used in rice include members of the first four groups, all of which have some known resistance by Smallflower and Bulrush (Busi et al. 2006), (Merotto et al. 2007). Control Strategies The critical first step in managing ALS resistant/tolerant weeds is to recognize that they occur in your field, than limit their spread. Control options should be implemented with the understanding that limiting the weeds production of new seed is the top priority. This

5655

will likely be attained by managing the weeds both culturally and through well timed herbicide applications with multiple modes of action that work on the target weeds.

Cultural – Increasing competition on the weeds by increasing the amount of rice seeded at planting is a good means for reducing weed pressure. Typical seed rates in California water seeded rice is around 150 pounds per acre; increasing to 200 pounds per acre can dramatically decrease competition by weeds. The use of high early vigor varieties such as M-104 and M-202 can also help with competition on weeds as compared to slower growing varieties such as M-206 and M-401. Changing the method by which you establish and or rear your crop can also make a tremendous difference on the diversity and vigor of the weeds expressed in rice fields. The use of a continuous flood culture can result in the reduction of sedge weeds (figure 1). Establishing rice in a dry seeded culture instead of a water seeded culture can also result in the reduction of sedge weeds (figure 2).

Herbicides- There are eight different modes of action available to California rice farmers (see table 1). Of these ALS inhibitors, Lipid Synthesis Inhibitors, Micro Tubule Synthesis Inhibitors, Photosynthesis Inhibitors, PPO Inhibitors, and Synthetic Auxins can be used for sedge control in California rice. It is important that applications be made according to directions on the herbicide label. Post emergent herbicides always work better on juvenile weeds than large wolfy weeds. The use of tank mixes with multiple modes of action often times result in an increase in control and offer a good means of resistance management and preserving good herbicides for future use (figures 3 and 4). Table 1. Herbicidal modes of action for rice herbicides in California.

M o d e o f A c tio n T ra d e N a m e A c tive In g re d ie n tA C C a s e In h ib ito r C lin c h e r* c yh a lo fo p b u ty l

W h ip * fe n o xa p ro p e th y l

A L S In h ib ito r G ra n ite * p e n o xs u la mL o n d a x* b e n s u lfu ro n

R e g im e n t* b is p y rib a cS tra d a * o rth o s u lfa m u ro n

S a n d e a * h a lo s u lfu ro n

C a ro te n o id S yn th e s is In h ib ito r C e ra n o * c lo m a zo n e

L ip id S yn th e s is In h ib ito r O rd ra m m o lin a teB o le ro /A b o lis h th io b e n c a rb

M ic ro tu b u le S yn th e s is In h ib ito r P ro w l/P ro w l H 2 O ** p e n d im e th a lin

P h o to s yn th e s is In h ib ito r S u p e r W h a m /W h a m /S ta m p ro p a n il

P ro to x (P P O ) In h ib ito r S h a rk c a rfe n tra zo n e

S yn th e tic A u x in G ra n d s ta n d tr ic h lo p y rU n is o n 2 ,4 -D

*- H e rb ic id e s k n o w n to h a ve re s is ta n c e d e ve lo p e d .** -N o t ye t re g is te re d fo r w a te r s e e d e d r ic e .

5756

Figure 1. Weed association to water management.

Figure 2. Weed dynamics associated to method of establishment.

Dry seeded (conventional) ECHINOCHLOA

SPRANGLETOP

SMALLFLOWER

Water seeded (conventional) ECHINOCHLOA

SMALLFLOWER

RICEFIELD BULR.

DUCKSALAD

REDSTEM

Weeds Associated With Water Management

0

5

10

15

20

25

30

35

40

45

50

Late Watergrass Sprangletop Bulrush Smallflower Redstem

Weed Species

Percen

t Co

ver Aerobic 12 Days

Continuous Flood

5857

Figure 3. Shark (carfentrazone) plus ALS inhibitors for the control of sedges in California rice.

Figure 4. Small Flower Umbrella Plant (CYPDI) and Ricefield Bulrush (SCPMU) control in Pin-point (treatments 1-5) and Continuous (6-11) cultures in California rice.

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

1 2 3 4 5 6 7 8 9 1 0 1 1

Per

cent

Con

trol

C Y P D IS C P M U

T re a tm e n t # T re a tm e n t R a te T im in g1 G ra n ite S C 2 o z/A 3 L F2 G ra n ite S C fb . S ta m 2 o z/A fb . 5 lb /A 3 L F fb . 2 T il3 G ra n ite S C 2 o z/A 2 T il4 G ra n ite S C + S ta m 2 o z/A + 5 lb /A 2 T il5 G ra n ite S C + G ra n d s ta n d 2 o z/A + 4 o z/A 2 T il6 C e ra n o fb . G ra n ite G R 8 lb /A fb . 1 5 lb /A D O S fb . 2 .5 L F7 B o le ro M a x fb . G ra n ite G R 2 7 lb /A fb . 1 5 lb /A 1 -2 L F fb . 2 .5 L F8 G ra n ite G R fb . S ta m 1 5 lb /A fb . 5 lb /A 2 .5 L F fb . 2 T il9 C e ra n o fb . G ra n ite S C 8 lb /A fb . 2 o z/A D O S fb . 2 T il

1 0 B o le rM a x fb . G ra n it S C 2 7 lb /A fb . 2 o z/A 1 -2 L F fb . 2 T il1 1 S h a rk H 2 O fb . G ra n ite S C 8 o z/A + 2 o z/A 2 -3 L F fb . 2 T il

0

10

20

30

40

50

60

70

80

90

100

Shark (8

oz/A)

Londax (1.67 oz/A

)

Shark (8

oz/A)+

Londax (1.67 oz/A

)

Sandea (1.67 oz/A

)

Shark (8

oz/A) +

Sandea (1

.67 oz/A

)

Granite

GR (1

5 lb/A

)

Shark (8

oz/A) +

Gra

nite G

R (15 lb

/A

Perc

ent C

ontr

ol

C Y P D IS C P M U

5958

References Cited

Busi, R., Vidotto, F., Fischer, A., Osuna, M., De Prado, R., and Ferrero, A. (2006) Patterns of Resistance to ALS Herbicides in Smallflower Umbrella Sedge (Cyperus difformis) and Ricefield Bulrush (Schenoplectus mucronatus). Weed Technology. 20: 1004-1014. Fischer, A., Eckert, J., Boddy, L., Marchesi, C., Merroto, A., Osuna, M., Yasuor., Schaal, B., (2007) Comprehensive Rice Research. Weed Control in Rice. Annual Report to California Rice Research Board. Project No. RP-1. Fischer, A., Eckert, J., Boddy, L., Marchesi, C., Merroto, A., Osuna, M., Perez de Vida, F., Yasuor., (2006) Comprehensive Rice Research. Weed Control in Rice. Annual Report to California Rice Research Board. Project No. RP-1. Hill, JE., et al., (1998) Crop Profile for Rice in California. Integrated Pest Management for Rice. Univ. of California Statewide Integrated Pest Management Project – Division of Agricultural Sciences. 11-14. Merroto, A., et al., (2007) Cross-Reistance to all ALS-inhibiting herbicide groups and phylogenetic relationship of ALS gene in Cyperus difformis L. Post Doctoral Thesis. Publication Pending. 35-66.

6059

Grass Weed Control In Small Grains

Steve Wright1, Mick Canevari2, Lalo Banuelos1

1University of California Cooperative Extension, Tulare & Kings Counties 4437B S Laspina St, Tulare, CA 93274, sdwright@ucdavis.edu

²420 South Wilson Way, Stockton CA 95205 wmcanevari@ucdavis.edu Cereals are grown for grain, hay silage, or covercrop. Wheat, barley, oats and triticale were

planted to approximately 750,000 acres in 2007. Durum wheat was planted to 100,000 acres. Wheat, the most important of the cereals, is predominantly of the hard red winter type and is planted in the fall of the year. Approximately 25 percent of the cereal acreage is grown under dryland conditions. Barley is mostly utilized as grain. Triticale is planted on approximately 100,000 acres for silage. Since grains are grown under a wide range of conditions, a wide spectrum of week species may be present in any given field that has the potential to affect both yield and quality.

The major grass weeds in small grains are canarygrass and wild oats (Table 1.). Other weeds

include Italian Ryegrass, annual bluegrass, ripgut brome, foxtail barley, and rabbitsfoot grass.

Table 1. Grass Weed Survey for California Wheat Weed Wheat Acres %Canarygrass 158,952 31Wild Oats 126,427 24Italian Ryegrass 60,897 12Ripgut Brome 24,053 5 Johnsongrass 15,500 3 Foxtail Barley 7,750 2 Others 1,784 <1

Even light infestations can reduce yields. They can clog up screens in a harvester and can

result in a 5 percent loss due to dockage at the elevator. Italian ryegrass, little seed canarygrass, hooded canarygrass, and ripgut brome can cause serious yield losses in some fields (Fig. 1, Fig. 2, Table 2.).

Grass weeds are most often found in areas with continuous grain. Dryland grain growers for

years have waited for rain to bring up a flush of wild oats before planting. After several dry years, most growers have had to plant dry and wait for rains. This practice is less risky as far as getting a good stand and taking full advantage of the rainfall, but it increases weed competition and is only partially effective because wild oats have a long germination period.

Most competition studies in cereals have been limited to wild oats. One study conducted by

Jim Hill in 1977 showed that wild oats reduced yields at 2 oats/square foot. However, an herbicide treatment was not cost effective until wild oat populations reach 4 per square foot. Wild oats populations commonly exceed 10-20 oats per foot. It is interesting to note that even

Survey conducted 1998, UC Grain Workgroup

6160

the herbicide treatment did not restore Yecora Rojo yields to where no wild oats were present. (Table 3.)

29.4

63

33.3

92

36.7

100

24.8

86

10.6

0

Puma (.045) Puma (.067) Puma (.089) Hoelon (1.0) Control

Figure 1. Hood Canarygrass Control & Yields in Wheat with PumaMick Canevari, UCCE San Joaquin

Wheat Yield(lbs/ac)

CanarygrassControl (%)

Table 2. Yield Summary

Treatment Number

Treatment Name

Rate

Yield Lbs/A

Bushel Weight

6 Buctril .04+.375 7857 A 63.0 4 Olympus+2,4D .04+.15 7202 AB 63.0 9 Puma+Buctril .083+.375 7167 AB 62.7 5 Olympus+2,4D .04+.71 6952 AB 63.0 3 *Olympus 0.04 6929 AB 62.7 2 Olympus 0.04 6417 B 62.7 7 Clarity .04+.25 6262 B 63.0 9 Olympus+Aim .04+.017 6155 B 63.1 1 Untreated 4036 C 62.5 CV: 9.5 LSD@5% 1089 *0.5%NIS

Activator-90

6261

51

97 94

0

10

20

30

40

50

60

70

80

90

100

Canarygrass % Control Timing 1-3 lf

Figure 2. Arizona Canarygrass ControlBarry Tickes, U of A

Hoelon @ 2.4 pts/A Puma @ 14 fl. oz/A Achieve @ 9.2 fl. oz/A

Table 3. Effect of Wild Oats on Wheat Yield (lbs/A)

Wild Oats (#/sq ft) Untreated Avenge Treated 0 7325 7610 2 7005 6938 4 6165 6810 16 3645 6880

In another trial in 1984, several inputs were studied as to their effect on dryland wheat. The

application of Avenge was not economical when wild oat populations averaged 6-8 per square foot. There was a slight decrease in oats with additional nitrogen. In this case, money was better spent on nitrogen for increasing yields. The year 1984 was dry, with less than five inches of rain. It appeared that this treatment had a greater effect and perhaps became economical in 1986 when it was planted again and the treated plots were still visible and free of oats. (Table 4.)

J. Hill – Tulare County – 1977

6362

Table 4. Effect of N and Wild Oat Control on Wheat Yield and Weed Population N (lb/A) Oat Control Wild Oats (#/sq ft) Yield (lbs/A) 0 No 8 2130 0 Yes 0 2275 40 No 6 2759 40 Yes 0 2888 60 No 6 2928 60 Yes 0 2928

Carlson and Hill (1985) demonstrated that yield losses to wild oats depend on the wheat population and wild out density. Higher wheat population (38-67 plants/ft.) minimized the effect of increasing wild oat populations compared to 10 wild oats/sq. ft. (Figure 3).

Figure 3. Effect of Increasing Wild Oat Density at Three Wheat SFigure 3. Effect of Increasing Wild Oat Density at Three Wheat Stand Densitiestand Densities

0

20

40

60

80

100

1 2 3 4 5 6 7 8 9

Wild oat density (plants/ft')

Rel

ativ

e Y

ield

%

A = 67 wheat plants/ft' B = 38 wheat plants/ft'C = 10 wheat plants/ft'

Wild oat competition studies in Manitoba (1988) demonstrated that when the wild oat

emerged it had the largest impact on yields. If the wild oat emerged behind the wheat emergence, the impact on yield was less. (Figure 4.)

Deciding whether a weed control application is economical will depend largely on the price of grain and the cost of treatment. Sound economical weed control practices must be followed to maintain California’s present high standing in crop production.

Broadleaf weeds in irrigated cereals can be controlled for as little as 2-4 percent of cash

costs. When grass weeds are controlled, costs go up to about 10 percent of the total. In dryland grain, where cash costs are about half and yields are about half of irrigated grains, weed control becomes a major input with grass control representing up to 20 percent of cash costs (Table 5.)

Wright, Munier – Tulare/Kern County

6463

05

101520253035

1 5 10 14Wild Oat Density (plants/sq m)

Figure 4. Yield Losses of Wheat at Different Densities of Oats

1-lf stage ahead Same lf stage 1-lf stage behind

Cultural Practices for Grass Control Practiced primarily for moisture conservation in dryland cereals, fallowing is important in

keeping weeds somewhat in check. Wild oat populations in dryland grains would be considerably higher if this was not practiced. Weeds should then be controlled by tillage and/or chemically.

Fields not under a good crop rotation system have the worst weed problems. Small grains

fields planted behind cotton in which good weed control practices were employed are usually clean and often don’t require herbicides.

Pre-irrigation or waiting for the first rain can be useful some years in germinating weeds that

are then removed by tillage prior to planting. However, this is not usually possible following cotton or corn in the San Joaquin Valley. On heavier soils, it may not be possible for fields to dry in time for planting. This practice is most useful in germinating annual grasses. Weeds should then be controlled by tillage and/or chemically. Usually annual broadleaves germinate later, January through March.

Price Yield (Ton/A)($/Ton) 1.5 2.0 2.5 3.0 3.5 4.0 4.5

130 -98 -38 22 82 142 203 264200 7 102 197 292 387 483 579250 82 202 322 442 562 683 804300 157 302 447 592 737 883 1029

Table 5. Net Returns/A Above Total Costs for Dryland Wheat

6564

When heavy populations of wild oats show up after heading, it is often more advantageous

yield-wise and economically to the grower, to cut wheat and barley for silage or hay. This practice also reduces the weed population considerably for the following crop.

Herbicides for Grass Control-Wheat, Barley

Fenoxaprop (Puma) controls wild oat canarygrass and several Setaria spp... It also suppresses

mustards. It has a wide window of application, providing effective control when applied between the 1-leaf and 6th leaf grass stage. For best control of wild oat, delay application until most wild oat plants have emerged. A tank mixture with bromoxynil allows for a wide range of weed control at an early timing. Fenoxaprop cannot be tank-mixed with phenoxy herbicides because it may reduce grass control when tank mixed. Most growers are applying a carfentrazone application and then coming back 7-10 days with Puma to keep up with early weed competition.

Mesosulfuron (Osprey) is especially effective on Italian ryegrass, wild oat, little seed and

hood canarygrass, and annual bluegrass. It controls ripgut brome and other brome species depending on weed size at application. It also controls many broadleaf weeds such as mustard, w.radish, and chickweed in wheat. Most California wheat cultivars have good tolerance to the herbicide. However, wheat often turns a lighter green color for a couple weeks following application. It also provides partial control of many other broadleaf weeds including common groundsel, common malva, fiddleneck, yellowstar thistle and milk thistle. Mesosulfuron can be tank mixed with bromoxynil and MCPA and may be applied from the 1-leaf to 1-tiller wheat stage and up to the 2-tiller stage of grass weed development. A methylated seed oil or a non-ionic surfactant is required; ammonium sulfate or low rates of UN-32 added will enhance weed control on difficult to control weeds. Restrictions on crop rotations are greater than with Fenoxaprop.

“Achieve” a fairly new herbicide in California controls wild oats, Italian Ryegrass, and

provides suppression of canarygrass at the 1-6 leaf stage. “Treflan” provides suppression of wild oats and canarygrass applied preimmergent at 2” in depth, incorporated, then planted below the herbicide zone. “Prowl H20” provides suppression of wild oats applied postplant after the 2-leaf stage of wheat. It then controls later emerging grasses so long as there is moisture to activate the herbicide. It is expected to have California registration in spring of 2008. “Axial” is a new grass control herbicide expecting registration in the near future.

During 2004-2007, several herbicides were evaluated for wild oat control. In addition non

label combinations of UN-32 were included. Treatments giving the highest control of Puma and secondly Osprey gave excellent control of wild oat (Table 6.). Additions of 5 gallons of UN-32 or Shark to Puma or Osprey did not reduce weed control. Additions of 5 gallons of UN-32 or Shark to Puma caused only a temporary stunting which quickly grew out of it. Additions of 5 gallons of UN-32 or Shark to Osprey caused severe stunting but eventually grew out of it by harvest time.

6665

TABLE 6. Grass Herbicide Evalutations Tulare County, 1 – May 2007

Treatments

Rates/A Wild Oats

Chickweed Shepherd’s Purse 1. Axial + Adigor 8.2 oz + 9.6 oz

(.75% v/v) 99 0 0

2. Osprey + COC 4.75 oz + 9.6 oz 88 100 100 3. Puma + COC 10.6 oz + 9.6 oz 99 0 0 4. Puma + UN32 10.6 oz + 5 gal 98 0 0 5. Puma + UN32 + 10-34-0

10.6 oz + 5 gal + 2 qt/100 gal 97 7 0

6. Puma + Shark + UN32

10.6 oz + .75 oz + 5 gal . 90 20 100

7. Puma + Shark + UN32 + 10-34-0

10.6 oz + .75 oz + 5 gal + 2 qt/100 gal

94 20 100

8. Puma + ET + UN32

10.6 oz + .75 oz + 5 gal 96 88 100

9. Puma + ET + UN32 + 10-34-0

10.6 oz + .75 oz + 5 gal + 2 qt/100 gal

96 73 100

10. Puma + Prowl H20 + Clarity + UN32

10.6 oz + 1.5 pt + 4 oz + 5 gal 94 100 100

11. Puma + Prowl H20 + Clarity + UN33

10.6 oz + 3 pt + 4 oz + 5 gal 99 100 100

12. UTC ---- 0 0 0

6766

References

Canaveri, M., Vargas, H. Carlson, S. Wright. 2007. Weed Control in Small Grains. UC IPM Pest Management Guidelines Publication.

Wright S., M. Canevari, L. Banuelos. 2007. New Weed Control Approaches in Small Grains

and Off–Target Movement Challenges. California Weed Science Society Proceedings. Wright, S. D. 1993. Weed Control in Small Grains. California Weed Conference

Proceedings. pp. 88-92. Wright, S. D. 1992. Benefits of Weed Control in Field Crops. California Weed Conference

Proceedings. Vol. 44, pp. 142-145. Wright, S. January 1987. Cost Effective Weed Management in Cereals. California Weed

Conference Proceedings. Hills, J. E., and J. Prato. 1977. Wild Oat and Broadleaf Weed Competition and Control

Studies. Cereal Trials Publication. 77:27-40. Hills, J. E. 1978. Weed Control in Winter Cereals. Cereal Trials Publication. 78:3-11. Munier, D. J., S. D. Wright, and L. W. Mitich. 1983. Effect of Seeding Rate, Variety,

Phosphorus, and Nitrogen on Yield, Bushel Weight and Wild Oats and Dryland Wheat. San Joaquin Valley Cereal Trials. 83:28-29.

Wright, S. D., and D. J. Munier. 1982. Preemergence Wild Oat Control in Dryland Barley

Cereal Trials. San Joaquin Valley Cereal Trials. 82:31.

6867

Weed Management in Intermountain Alfalfa and Grass Hay

Steve Orloff and Rob Wilson University of California Cooperative Extension, Siskiyou and Lassen Counties

1655 S. Main St. Yreka, CA 96097 and 707 Nevada Street Susanville, CA 96130 email: sborloff@ucdavis.edu and rgwilson@ucdavis.edu

Forages, primarily alfalfa, grasses and mixed planting of alfalfa and grasses, are

important crops in the intermountain area of Northern California occupying the majority of the irrigated acreage in the region. The intermountain alfalfa and grass hay production area is unique compared with other production areas in California. The growing season is shorter and cooler and the winter is much colder than in the Central Valley and desert areas of California. Therefore, alfalfa is typically only harvested three to four times per season and grass hay crops are cut three times. Hay destined for the dairy and horse markets must be nearly weed-free—a difficult accomplishment given the broad spectrum of weeds encountered in many fields.

The intermountain environment creates some unique weed control issues and challenges. The primary issues are the following: timing of herbicide application timing for winter annual weed control in established alfalfa, summer annual weed control, weed control in mixed stands of alfalfa and orchardgrass, and weed control in grass hay fields. Trials were conducted over the past several years in Siskiyou and Lassen Counties to address these issues. Application Timing for Winter Annual Weed Control in Established Alfalfa

Unlike other areas of California, alfalfa in the intermountain area goes completely dormant over the winter and visible growth ceases for several months. During mid winter, frozen soil and/or snow can preclude herbicide applications. In late winter, inclement weather and windy conditions make herbicide applications difficult often delaying applications into early spring, mid- to late-March. The question arises as to whether it is better then to make applications in late fall, late winter or early spring. To evaluate which of the three timings is superior, a series of trials were established where herbicides were applied in November, January-February, or mid March. The herbicides evaluated in the fall timing included hexazinone (Velpar), diuron (Karmex), and metribuzin (Sencor). Those same herbicides plus a Karmex and Gramoxone tank mix were applied in late winter. The same herbicide applied in late winter were applied in early spring except an imazamox (Raptor) treatment replaced the Karmex alone treatment.

The late winter (late January-February) treatment timing generally provided the best weed control. Figure 1 shows the results for shepherdspurse, but other weeds responded similarly. The fall application may be less effective because at the rates tested the herbicides may not have enough soil residual to control late-emerging weeds, especially with the amount of

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rainfall received in the years we conducted the study. Weed control with a March application was generally less than the late-winter application timing because by this time the weeds were larger and more difficult to control. Another problem with mid to late March applications is that oftentimes there is insufficient rainfall after application to incorporate the herbicides.

0 10 20 30 40 50 60 70 80 90 100

Raptor 5.0 oz + MSO

Sencor 0.6 lb + GramoxoneMax 0.8 pt + NIS

Karmex 1.75 lb + GramoxoneMax 0.8 pt + NIS

GramoxoneMax 1.67 pt + NIS

Karmex 1.75 lb + NIS

Sencor 0.67 lb + NIS

Velpar 0.67 lb + NIS

untreated

% shepherdspurse control

November application January application Mid-March application

Figure 1. The effect of application timing on shepherdspurse control in established alfalfa.

Another major drawback of spring applications is that they are more injurious to the alfalfa. These studies demonstrated that late winter is the preferred herbicide application timing to maximize weed control while minimizing alfalfa injury. Summer Annual Weed Control

Summer annual weeds (such as summer foxtails, lovegrass, and pigweed) can be problematic in established alfalfa fields in some areas of the Intermountain Region. This is especially the case in older fields where the alfalfa stand is less competitive with weeds. Alfalfa stand life in the intermountain area is longer than other areas in California—typically 5 to 7 years—due to the environment and lack of profitable rotation crops.

Trifluralin (Treflan) is often used to control summer annual grasses in established alfalfa. However, in the Intermountain area summer annual weeds only infest the second and third cuttings making it more difficult to justify the cost especially since Treflan granules require a separate application. Research was conducted during the 2007 growing season to evaluate the effectiveness of pendimethalin (Prowl H2o) for summer annual weed control. As a liquid, Prowl can be tank mixed with the standard herbicides used for winter annual weed control. A trial was

7069

established where Prowl was tank mixed with Velpar, Sencor or Gramoxone at 1.9 or 3.8 pounds active ingredient per acre. Combining Prowl with the dormant herbicides resulted in a slight increase in the control of the winter annual weeds. This was surprising because the weeds were already emerged at the time of application and Prowl is generally not effective on the winter weed spectrum. Prowl provided effective control of the summer annual weeds (both green foxtail and pigweed). The higher rate was needed for near perfect control but this may have been due to the low alfalfa stand density in the trial affording little competition to the weeds. The overall most effective treatment for the control of both winter and summer annual weeds was a tank mix of Velpar and Prowl. These results are promising because they demonstrate that season-long control of both winter and summer annual weeds may be feasible with a single application of herbicides. Weed Control in Mixed Stands of Alfalfa and Orchardgrass

Alfalfa/grass mixtures have become very popular in the Western U.S. due to a strong horse-hay market that often prefers mixed hay over pure alfalfa. Excellent weed control is needed to produce the quality of hay desired by horse owners. A dense vigorous stand competes well with weeds so in many cases weed problems in alfalfa/grass mixtures are the result of poor stand and/or improper irrigation, fertility, or harvest management. Alfalfa density thins in an aging stand and the grass component, typically orchardgrass, becomes more dominant. While a 50:50 mixture of alfalfa was considered optimum in the past, a higher proportion of grass has become acceptable, or even preferred, by some horse owners allowing growers to keep the stand in production longer. Weeds have become more of a problem in these older stands.

Weed control in mixed alfalfa/grass stands is challenging, as the herbicides must be safe to both species. Several herbicides including Velpar, Sencor, Gramoxone, Pursuit, Raptor and MCPA were evaluated in the Intermountain Region with two treatment timings (late-November to early December and early March). The most effective treatment was Sencor DF at 0.5- 1.0 lb/A plus non-ionic surfactant applied in late fall. This treatment provided excellent weed control and very little injury to either the alfalfa or the orchardgrass. Prior to conducting this research, it was thought that Gramoxone would be an effective treatment thinking that Gramoxone would only cause temporary “burn-back” of the orchardgrass and alfalfa foliage. However, it was found that Gramoxone alone or in combination with other herbicides was much more injurious to the orchardgrass than expected and caused yield reduction and even stand loss. In contrast to the results with pure alfalfa, a fall application to alfalfa/orchardgrass was preferred. The herbicides were more effective for grass control when applied pre-emergence and long soil residual was not as important as with pure alfalfa because the orchardgrass resumes growth earlier in the spring and shades the soil. Pursuit plus methlyated seed oil applied shortly after green-up provided good control of emerged mustards and excellent selectivity to both alfalfa and orchardgrass. Currently, Sencor is the only one of these herbicides with specific label instructions for use in mixed alfalfa/grass stands.

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Figure 2. Shepherdspurse and downy brome control in alfalfa/orchardgrass with fall or early March herbicide applications (data combined over years and sites). Weed Control in Grass Hay Fields

Pure grass hay has become very popular for the horse market. A dense vigorous stand of grass is an outstanding competitor with weeds. Adequate nitrogen fertilizer throughout the growing season improves grass vigor helping to reduce weed problems. Besides dramatically increasing yield and forage quality, nitrogen speeds growth in the spring and after cutting minimizing the chance for weed encroachment. If grass stands become patchy and depleted, reseed to thicken the stand because weeds quickly invade bare areas in the field.

Even with a good stand, herbicides are sometimes needed and they offer an effective and undisruptive weed control option. Several herbicides are labeled for use in grass hay for broadleaf weed control. These herbicides are best applied in spring, fall, or between cuttings when annual weeds are in the seedling stage. For control of most perennial weeds, target herbicide applications in late spring when they are flowering or in fall to new re-growth. Controlling grassy weeds in grass hay is far more problematic and current research is underway to evaluate potential herbicides and to determine their safety to different grass hay species.

0 10 20 30 40 50 60 70 80 90 100

Untreated

MCPA 0.5 pt + NIS

Gramoxone Max 1.3 pt + NIS

Velpar 0.5 lb + NIS

Sencor 0.6 lb + NIS

Velpar 0.3 lb + Gramoxone Max 1.3 pt + NIS

Sencor 0.6 lb + Gramoxone Max 1.3 pt + NIS

Pursuit 1.44 oz + MSO

Raptor 5 oz + MSO

Velpar 0.5 lb + NIS (Fall)

Velpar 0.67lb + NIS (Fall)

Sencor 0.6 lb + NIS (Fall)

Sencor 1.0 lb + NIS (Fall)

% Control

shepherdspurse downy brome

NIS= non-ionic surfactant at 0.25% v/v MSO= methlyated seed oil at 2 pt/A Herbicide Rates= product rate/acre Error bars= 95% confidence interval

7271

Factors Affecting Glyphosate Efficacy of Horseweed (Conyza canadensis) and Hairy Fleabane (Conyza bonariensis)

L. Scott Scheufele, Graduate Student, Plant Science Department, CSU-Fresno, 2415 E. San

Ramon, Fresno, CA 93740

Abstract: Horseweed (Conyza canadensis) and hairy fleabane (Conyza bonariensis) are troublesome weeds in many agricultural settings. Herbicides applied postemergence are often ineffective due to its woody-like stalks and lack of leaf surface area. Previous research has indicated that fall applications of postemergence herbicides provide the best control. In this study Roundup WeatherMAX® (glyphosate) was evaluated for controlling hairy fleabane at four growth stages and four rates. Horseweed was evaluated at three different growth stages and three application rates. Trials were conducted in 2006 at the CSU-Fresno Farm and in 2007 at commercial peach and plum orchards located in south Fresno and central Tulare counties. In conjunction with rate and growth factors, a nozzle and spray volume study was conducted for each species to compare efficacy of glyphosate. Glyphosate was applied at a single rate of 1.0 lbai acre-1, targeting a single growth stage (bolting >6 inches) and applied at three spray volumes (10, 20 and 30 gpa). Three nozzle types were evaluated: TwinJets (TJ60-8001 and TJ60-8003) and XR TeeJets (11001, 11002 and 11003) from Spraying Systems, Inc., and Air-Bubble Jets (11001, 11002 and 11003) from Billericay Farm Systems. Hairy fleabane and horseweed control was evaluated visually for all experiments. Glyphosate applied at 0.5. 1.0, 1.5 and 2.0 lbai acre-1 provided similar control of hairy fleabane at the early and late rosette stages. Hairy fleabane control decreased significantly after bolting, especially at the lower rates (0.5 and 1.0 lbai acre-1). Control measures are best applied at the early growth stages for horseweed. Horseweed control by glyphosate decreased significantly as growth increased from early rosette to bolting >6 inches. Glyphosate applied in low spray volumes (10 gpa) provided greater control of horseweed and hairy fleabane as compared to higher spray volumes (20 and 30 gpa). Comparison of nozzle types suggested that control of horseweed and hair fleabane was superior using TwinJet nozzles at low spray volumes (10 gpa). Key Words: AMS, Ammonium Sulfate, carrier, Conyza bonariensis, Conyza canadensis, glyphosate, hairy fleabane, horseweed, lbs ai acre-1 (pounds active ingredient per acre), marestail, replicate, Roundup WeatherMAX, Touchdown.

7372

Spatial Pattern of Glyphosate Resistance in Ryegrass in Yolo County

Anna Sherwood, University of California, Davis, Department of Plant Sciences, One Shields Ave., Davis, CA. 95616-8780

Abstract

In 1996, approximately 20 years after the introduction of the herbicide glyphosate, the

first glyphosate-resistant weed, rigid ryegrass, was identified in Australia. Today, glyphosate-resistant weed populations have been identified in 12 species and 11 countries. The proliferation of glyphosate-resistant weeds is impacting both agriculture and the environment by increasing the concentration and number of herbicides required to control weeds. Preventing both the evolution of new glyphosate-resistant weed populations and preventing the spread of currently resistant populations is now an important task for weed scientists. Annual ryegrasses (both rigid and Italian) are the most notorious glyphosate-resistant weeds with populations on 5 continents evolving glyphosate resistance. The first ryegrass population with glyphosate resistance in North America was identified in 1998 in an almond orchard near Chico CA. Today, many weedy ryegrass populations throughout the Central Valley are reported to contain glyphosate-resistant plants. Identifying which populations are most resistant relative to land and weed management practices may help farmers and managers design control strategies for resistant weeds and prevent further evolution and spread of glyphosate resistance. We worked on identifying which environments have the highest concentration of herbicide resistant individuals. In the summer of 2006, we surveyed weedy ryegrass populations within Yolo County for glyphosate resistance. We found, unsurprisingly, that ryegrass populations in environments with glyphosate application had higher frequencies of glyphosate-resistant individuals. We also found that in those environments where glyphosate was applied, roadsides had populations with higher frequencies of glyphosate-resistant individuals than agricultural fields. We also found that populations in fields adjacent to roads had higher frequencies of resistant individuals than their more secluded counterparts. Our results suggest that roadsides in Yolo County may often be reservoirs of glyphosate-resistant ryegrass. Thus, controlling glyphosate-resistant ryegrass populations along public roads may limit the spread of glyphosate resistance in agricultural fields.

7473

Vines and Ovines: Using SHEEP with a trained AVERSION to grape leaves for spring VINEYARD floor management.

Morgan P. Doran, University of California Cooperative Extension, 501 Texas Street, Fairfield,

CA 94533, mpdoran@ucdavis.edu Melvin R. George, Department of Plant Sciences, One Shields Ave., University of California,

Davis, CA 95616 John M. Harper, University of California Cooperative Extension, 890 N. Bush Street, Ukiah, CA

95482-3734 Roger S. Ingram, University of California, Cooperative Extension, 11477 E Ave., Auburn, CA

95602 Emilio A. Laca, Department of Plant Sciences, One Shields Ave., University of California, Davis,

CA 95616 Stephanie Larson, University of California Cooperative Extension, 133 Aviation Blvd., Suite 109,

Santa Rosa, CA 95403-2894 Glenn T. McGourty, University of California Cooperative Extension, 890 N. Bush Street, Ukiah,

CA 95482-3734 Ed A. Weber (deceased), University of California Cooperative Extension, 1710 Soscol Ave., #4,

Napa, CA 94559

Traditional vineyard floor management practices have limitations and potentially undesirable consequences. Herbicide applications can reduce surface and ground water quality, especially when applications are made during the rainy season. Volatilization and drift can damage developing grape buds and shoots if applications are made after bud emergence. Mowing and tillage are commonly utilized in late winter or early spring, but can be delayed if excessive rain prevents tractor access into the vineyard. Such delays can affect vine development by allowing vegetation to compete with the vines for soil nutrients and by increasing the risk of frost damage.

Sheep grazing is a cultural practice to manage the vineyard floor that is growing in use and

acceptability. Several vineyards in California’s wine growing regions have been experimenting with sheep grazing and have adopted the practice to supplement other floor management practices. Sheep can eliminate the need for herbicides, and they can be used in vineyards rain or shine. Currently, the biggest impediment to their use is the fact that sheep like to browse the spring growth of grapevines. Some vineyards work around this problem by using Babydoll Southdown sheep, which are too short to reach the vines. Vineyard managers are pleased with the results, but the use of these miniature sheep is very limited due to their rarity and consequent high price. Other vineyards are using normal commercial sheep, but only by placing electric fencing around each vine row or by limiting grazing to times of the year when the vines are not susceptible to sheep damage, such as between the time of harvest and the emergence of new spring growth.

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Training sheep to have a dietary aversion to grape leaves will extend the time sheep can

graze in vineyards through the spring months when weed and cover crop vegetation grow most vigorously. Expanding the time during which sheep can graze in vineyards should make this practice attractive to more growers. Sheep grazing is a reduced risk alternative to herbicide applications and is an attractive option for sustainable, organic and biodynamic grape production programs, which are becoming more popular among wine grape producers and consumers.

Our project team conducted two research trials from June 2006 through June 2007 at the

University of California Hopland Research and Extension Center. The first trial tested the persistence of a grape leaf aversion induced by two different methods of orally administering lithium chloride (LiCl) to sheep. In the second trial we grazed vineyard plots with the trained and untrained sheep in the spring of 2007 and compared the browsing impacts on the vines.

Aversion Trial

The aversion training was conducted in barn corrals and followed the procedures and

recommendations obtained from Dr. Fred Provenza and his colleagues at Utah State University and their BEHAVE program. In June 2006, sixty ewe lambs were divided into three groups of twenty. Sheep in each group were presented with fresh grape leaves for ten minutes, which was sufficient time to consume an average of 135 bites per sheep. Immediately following the grape leaf consumption, one group of sheep was orally administered LiCl (150 mg/kg body weight) in gelatin capsules (Capsule group), the other group was orally administered the same dose of LiCl in a liquid solution (Drench group), and sheep in the third group were orally administered either an empty gelatin capsule or water (Control group).

We tested the aversion at intervals of one day, one week, one month, two months and nine

months after the initial aversion training. The one-day test revealed a very weak aversion in the trained groups. We then allowed the “trained” sheep to consume more grape leaves, followed by a second and larger dose of LiCl (175 mg/kg body weight). All the subsequent aversion tests indicated a very strong aversion in both the capsule and drench groups and normal grape leaf consumption in the control group.

Vineyard Grazing Trial

The vineyard grazing trial occurred between the months of March, April and May of 2007,

with one grazing event per month. The trial was structured as a complete randomized block design with four treatments and four replicates per treatment.

Treatment 1: No vine row or middle management. Treatment 2: Normal vine row and middle management (chemical and mechanical).

7675

Treatment 3: Vine row and middle grazed by untrained sheep. Treatment 4: Vine row and middle grazed by trained sheep.

Each replicate plot was approximately 0.05 acres and included 16 or 17 grape vines. Sheep from the capsule and drench groups in the aversion trial were comingled and randomly assigned into two equal groups of trained sheep and used for the vineyard grazing treatments along with the control group as the untrained sheep.

A strategy of high density and short duration grazing was used to quickly graze the

vineyard floor. Approximately 16 ewes (100 lb. average weight) grazed each plot for a 10 to 12 hour period, equaling a stocking density of 53 animal units (AU) per acre. The stocking period did vary according to the amount of floor vegetation. Sheep were removed once they appeared to have consumed all the palatable forages.

Although the data analysis for the grazing trial is not complete, we do have some

preliminary results and anecdotal observations to present in this paper. An important finding we learned with the March grazing event is that the trained sheep were not averted to developed grape buds. Damage to the very small buds was minimal, but increased as the size and maturity of the buds increased. We suspect that the buds have a different flavor than mature grape leaves, to which the sheep were averted, leaving the buds vulnerable to damage by trained and untrained sheep. This can be avoided by grazing the sheep well before bud emergence and not returning the sheep to the vineyard until mature leaves are present on the vines.

The April and May grazing events demonstrated that the trained sheep had almost no

impact on the grape vines while the untrained sheep removed much of the foliage within reach. We estimated that an average of 50% of the combined length of all vine shoot material was damaged by the untrained sheep. This trial also showed that the amount of vineyard floor vegetation in the grazed treatments at the end of the May grazing event was comparable to the treatment with normal floor management.

This project demonstrates that sheep with a trained aversion to grape leaves can be used for

spring vineyard floor vegetation management without damaging the grape vines. Also revealed are many factors that must be addressed in future research before developing a complete set of recommendations to commercial practitioners. Some of the more salient topics that deserve future investigation include the determination of forage conditions that cause sheep to lose the aversion, regulations on the use of LiCl in livestock consumed by humans, a cost analysis on the use of sheep for vineyard floor vegetation management, the long-term effect of sheep grazing on soil quality and on grape vine health.

This project was funded by a Core Issue Grant from the University of California, Division

of Agriculture and Natural Resources.

7776

Vineyard Weed Management Practices Influence Soil Nitrogen Retention

Kerri L. Steenwerth*1 and Kelley M. Belina1, 1USDA - Agricultural Research Service, Crops Pathology and Genetics Research Unit, Davis, CA 95616, *ksteenwerth@ucdavis.edu

Cultivation has been shown to reduce soil organic matter content and labile carbon pools,

which are important factors in soil nitrogen (N) retention. Cultivation also causes changes in soil bulk density, effecting changes in soil porosity which can influence soil water and nutrient movement. Using herbicides for weed control instead of cultivation avoids the soil disturbance caused by cultivation. Therefore, we hypothesized that soil N dynamics would differ between these weed management practices. We also investigated the effects of the two weed management practices (i.e., cultivation and herbicide) on soil N dynamics during a fertigation event.

We tested this hypothesis in a Chardonnay vineyard planted on Teleki 5C rootstock in

Greenfield, Monterey Co., CA. In the cultivated treatment (‘Clemens’), the Clemens® vineyard cultivator was used to mechanically cultivate the vineyard rows as needed during the season (i.e. 4-6x). In the herbicide treatment (‘Standard’), simazine (2.0 lbs a.i./A) + oxyfluorfen (1.5 lbs a.i./A) was applied in the winter. In summer, post emergence applications of 2% glyphosate + 0.25% oxyfluorfen were applied as needed. These treatments had been established and repeated annually four years prior to the current study as part of a separate experiment. Thus, the current study occurred during the fifth year of this original study. In November 2005, emitters on one side of each grapevines (4 total in each treatment) were plugged, leaving one emitter open on the opposite side of the grapevine. At this time, soil characteristics were characterized to a depth of approximately 1-1.5 meters. These included cation exchange capacity, exchangeable cations (X-cation) (i.e., X-Mg, X-Ca, X-K), total carbon (C) and N, bulk density, inorganic N pools [i.e., ammonium (NH4

+-N) and nitrate (NO3--N)], and soil texture. Anionic resin bags were inserted at

1 m depth to determine the amount of inorganic N moving through the soil profile from November 2005 to November 2006. At the conclusion of the experiment in November 2006, soil bulk density, dissolved organic C, potential soil respiration as a measure of labile C pools and inorganic N pools were measured in the soil profile. During the main fertigation event in July 2006, soil inorganic N pools, nitrous oxide (N2O) efflux, and soil moisture were documented in the upper 20 cm of the soil profile. The vineyard was fertigated at a rate of 28.32 lbs. N per acre (UN32: 32% total N, of which was 44.3% NH4NO3 and 35.4% Urea). The soil type was the Elder loam with gravelly substratum (Coarse-loamy, mixed, superactive, thermic Cumulic Haploxeroll).

We found that most soil characteristics varied with soil depth, but few differences

occurred between the ‘Clemens’ and ‘Standard’ treatments. Cation exchange capacity ranged between 15.1 – 17.2 cmolc kg-1. Exchangeable Mg ranged between 3.4 cmolc kg-1 and soil pH ranged from 7.6 – 7.7. The only noted difference was in total soil C, which was approximately 0.8% g C g-1 in ‘Clemens’ and only 0.7% in ‘Standard’ in the upper 20 cm. Exchangeable K was greater in the upper 30 cm (ca. 0.44 cmolc kg-1) than the lower depths (ca. 0.21-0.28 cmolc kg-1, 30-105 cm). Also, total soil N decreased with depth, ranging from 0.063-0.078% g N g-1 in the upper 30 cm, and 0.051-0.056% g N g-1 in the lower depths (30-105 cm). Bulk density decreased with increasing depth, but did not differ between treatments. Soil texture among all depths and treatments was approximately 60% sand, 25% silt, and 15% clay.

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During the fertigation event, soil gravimetric water content in the upper 20 cm decreased

from 30% to 15% over three days, remaining at a similar value for the subsequent two weeks. Soil ammonium concentrations increased to 80-100 μg NH4

+-N during the first three days after irrigation, decreasing over the next two weeks to pre-fertigation levels, and no difference between treatments was observed. Soil nitrate concentrations were greater in ‘Standard’ than ‘Clemens’ three days after irrigation, increasing to approximately 75 μg NO3

--N g-1 in ‘Standard’ and 40 μg NO3

--N g-1 in ‘Clemens’. In both treatments, these values decreased to pre-irrigation concentrations after approximately 10 days, and then showed small increases to approximately 20 μg NO3

--N g-1, potentially due to upward movement of soil nitrate during soil drying or mineralization of urea. Nitrous oxide efflux was greater in the ‘Standard’ than ‘Clemens’. At its greatest efflux rate after fertigation, which occurred one day after fertigation, N2O efflux from ‘Standard’ was approximately 4.3 μg N2O-N m-2 s-1 while it was about 2 μg N2O-N m-2 s-1 in ‘Clemens’. Nitrous oxide efflux decreased thereafter, reaching pre-irrigation values ten days after fertigation in both treatments. There were no noted changes in soil N pools and water content in soils where the emitter had been plugged.

When soil resin bags were removed in November 2006, inorganic N concentrations were

greater in the ‘Standard’ than ‘Clemens’. The resin bags in ‘Standard’ had collected approximately 1300 μg NO3

--N while in ‘Clemens’ they had <1 μg NO3--N, indicating that less

NO3--N had reached that soil depth. This suggests that the ‘Clemens’ treatment had increased

soil N retention than the ‘Standard’. Preliminary estimates suggest that approximately 4-10% of the total N added to the vineyard soil during the growing season was captured by the resin in ‘Standard’.

These preliminary findings suggest that weed management practices had impacts on N2O

efflux as well as soil N retention. Few differences in soil characteristics that are often linked to movement (i.e., bulk density) and retention (i.e., soil C content, DOC, labile C by respiration) of soil N were detected in the two treatments. We suggest that the increased weed biomass (K. Steenwerth, personal observation) and weed frequency (R. Smith, personal communication) underneath the grapevines in ‘Clemens’ captured some fraction of the fertilizer-derived N. Interestingly, it appears that the grapevines did not show any clear response to these respective weed treatments in the four years prior to this experiment (L. Bettiga and R. Smith, personal communication). In addition, total C was greater in the ‘Clemens’ than ‘Standard’, suggesting that the ‘Clemens’ soil may support greater soil microbial biomass, which could then immobilize relatively greater soil N within their biomass than in ‘Standard’. In conclusion, the ‘Clemens’ treatment provided an unexpected service of increased soil nitrogen retention. Further study is required to quantify the role that weeds play in N retention, the temporal dynamics of decomposition and N release, and potential long-term effects on grapevines in the ‘Clemens’ system.

7978

Competitive Effects of Glyphosate-Resistant and Susceptible Horseweed with Young Grapevines and Established Vineyards

Marisa F. Alcorta*, Department of Viticulture & Enology, University of California, Davis, One Shields Ave, Davis CA 95616. Matthew W. Fidelibus, Department of Viticulture & Enology,

University of California, Davis, and University of California Cooperative Extension, Kearney Agricultural Center, 9240 S. Riverbend, Parlier, CA 93648. Anil Shrestha, University of California Integrated Pest Management Program, Kearney Agricultural Center, 9240 S. Riverbend, Parlier, CA 93648. Kurt J. Hembree, University of California Cooperative

Extension, Fresno County, 1720 S. Maple Ave. Fresno, CA 93702. *corresponding author: malcorta@ucdavis.edu

Horseweed (Conyza canadensis) is an annual weed in the Asteraceae family that has recently became a major pest in San Joaquin Valley vineyards. A glyphosate-resistant (GR) biotype of horseweed was confirmed in California in 2005, from the banks along an irrigation canal in the central San Joaquin Valley. Studies have shown that the GR biotype flowers earlier and accumulates more biomass than the glyphosate-susceptible (GS) biotype of horseweed. This disparity in phenology and growth led us to hypothesize that the GR biotype may be more competitive than the GS biotype. To evaluate the competitive effects of both GR & GS biotypes of horseweed on grapevine, we conducted two experiments in 2006 and 2007. The goal of the first experiment was to compare the respective competitive abilities of GR and GS horseweed biotypes on one-year old grapevine in a greenhouse setting. Among the response variables measured were grapevine shoot length, dry vegetative biomass, chlorophyll levels, leaf number and leaf area. The goal of the second experiment was to examine the effects of increasing density of GS horseweed on grapevine growth, yield, and fruit quality in an established vineyard. Grape yield and time to harvest were measured. Soluble sugars, titratable acidity and the number of clean clusters per vine were also measured as indicators of fruit quality. Results from the greenhouse experiment showed that young grapevines were significantly affected by competition from either horseweed biotype. Both the GS & GR horseweed reduced grape aboveground dry mass significantly, as well as decreased leaf number, canopy leaf area, and chlorophyll levels in grapevines. However, contrary to our hypothesis, the two biotypes did not differ in their ability to suppress grapevine growth. Both biotypes compete equally with grapevine. Results from the density experiment showed that increasing horseweed densities did not affect grape yield, quality, or the time required to harvest the grapes. There was, however, a negative correlation between weed dry mass and pruning weights which suggests that high densities of annual weeds may reduce vegetative growth of established vines.

8079

Biofuels and Invasive Species

Joseph M. DiTomaso and Jacob N. Barney. Department of Plant Sciences, University of California, One Shields Ave., Davis, CA. 95616-8780, jmditomaso@ucdavis.edu

In response to growing energy demands and climate change awareness,

alternative energy sources are being sought. Biomass-derived energy from dedicated biofuel crops is under active research by many nations with exotic rhizomatous perennial grasses as the leading candidates. To be economically viable, biofuel crops are being selected/breed/engineered that are highly efficient (e.g., water, nutrients), tolerate poor growing conditions (e.g., drought, saline and infertile soils), possess few resident pests, and produce highly competitive monospecific stands. These desired agronomic traits, however, typify much of our invasive flora, and pose a potential threat of some biofuel crops becoming invasive pests. To test the potential invasiveness of leading biofuel candidate crops, including switchgrass, giant reed, and miscanthus, we used the standard Weed Risk Assessment protocol to qualify their risk potential under various assumptions. In addition, we are conducting ecological studies of fitness responses to various environmental and disturbance scenarios, which will provide data in climate-matching models to predict the potential invasiveness of biofuel species in a variety of ecosystems. Breeding and genetic engineering for enhanced environmental tolerance (e.g., drought tolerance), increased harvestable biomass production (e.g., lower root-to-shoot ratio), and enhanced energy conversion through fermentation (e.g., lower lignin content) may have unexpected ecological consequences outside the agronomic framework. For example, using the WRA protocol, switchgrass was found to have a high invasive potential (‘reject’) in California, unless sterility was introduced (‘accept’). The potential societal benefits of a biologically-based energy supply are great, but the introduction and development of biofuel crops should be conducted to minimize the risk of these proposed feedstock species escaping cultivation and causing economic or environmental damage.

8180

The Effects of Puccinia jaceae on Yellow Starthistle Competition and Growth

Jon M. O’Brien, Joseph M. DiTomaso, and Guy B. Kyser, Weed Science Program, Department of Plant Sciences, University of California, Davis, CA, and Dale M. Woods, California

Department of Food and Agriculture, Sacramento, CA Corresponding author: jonobrien@ucdavis.edu

A new bio-control rust, Puccinia jaceae var. solstitialis, was introduced to control yellow starthistle (Centaurea solstitialis) in 2003. To test the effects of the rust on the weed under field conditions, we performed two experiments in 2006 and 2007. The objective of the first experiment was to examine the effects of the pathogen on the above ground biomass production of yellow starthistle (YST) using both an additive and replacement series design. As part of this experiment, we also evaluated the effect of the rust on the competitive ability of YST with the common rangeland annual grass wild oat (Avena fatua). The objective of the second experiment was to test the interaction of the rust with two common insect bio-control agents (Eustenopus villosus and Chaetorellia succinea). In both experiments, we measured infection rates over time, YST chlorophyll levels, seedhead production, and vegetative biomass. Insect attack rates were also determined on a subset of mature seedheads. On a per leaf basis, chlorophyll levels were significantly reduced by increased infection with the rust. In YST monocultures, the rust had no effect on any of the growth or reproductive variables measured. However, in the competition experiment with wild oat, there were several rust-induced reductions in YST performance. Infected plants had fewer leaves overall than non-infected plants. The rust decreased overall YST biomass/m2 over both years of the experiment, and seedling diameters in 2007. Seedheads in inoculated plots developed earlier in the season than those in non-inoculated plots. No interaction effect was found between the rust and the insect bio-control agents. The results indicate that the rust had minor negative affects on yellow starthistle growth, especially under conditions of interspecific competition. However, these effects do not appear to be biologically significant and the presence of the rust is unlikely to lead to large-scale declines in the YST populations statewide.

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Assessing Research Priorities for Invasive Plants in California

Ramona Robison, California Botany and California Invasive Plant Council, 1925 Meer Way, Sacramento, CA 95822, Mona@calbotany.com

California has over a thousand introduced plant species, many of which are invasive in

wildlands. In 2006, the California Invasive Plant Council rated the most invasive plants in the “California Invasive Plant Inventory.” During the research compilation process for the list it became evident that information was lacking on many species. However, the limited availability of funding for management and control programs makes it important to know where research should be focused. The Research Needs Assessment project was formed in 2005 at UC Davis. The project will summarize existing research pertaining to invasive plants in California through literature review and interviews with researchers, and identify high-priority areas for future research. It will address 12 topics including biology, effects of human alterations (i.e. climate change, nitrogen deposition), weeds of horticultural origin, and policy. Through this effort, we seek to further energize the academic and land management communities by: (1) facilitating connections between disciplines by increasing awareness of the range of ongoing research on invasive plants; (2) creating a forum for assessing high-priority research needs; and (3) guiding future research (especially graduate student projects) toward these high-priority needs. Our talk summarizes the research areas where we would like to see efforts continue and provides sample projects for each area. A directory of invasive plant researchers is also available.

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Herbicide Control and Revegetation of Medusahead Sites in Northeastern California

Rob Wilson, UCCE Lassen County, 707 Nevada St. Susanville, CA 96130, rgwilson@ucdavis.edu

The invasion of non-native annual grasses is considered by many private and public

range managers to be one of the most serious pest problems in the West. These species dominate more than 130 million acres throughout California, Idaho, Oregon, Nevada, Washington, and Utah and continue to rapidly spread. Medusahead dramatically reduces plant diversity and richness, shrinks wildlife habitat, decreases livestock forage by 50-80%, and promotes out-of-control wildfires. Annual grass invasion is also a major obstacle for successful implementation of several Great Basin range projects including sage grouse habitat restoration, juniper removal, wildfire rehabilitation, and improving rangeland carry capacity. This project evaluated herbicide efficacy for medusahead control in big sagebrush rangeland. It also examined when native and introduced perennial grasses common to Northeastern California can be re-seeded following herbicide application. Herbicide Efficacy for Medusahead Control

Fall applications of Matrix at rates ≥ 4 oz/A, Landmark XP at 1 oz/A, Oust at 1 oz/A, and Plateau at 6 oz/A gave >95% control of medusahead and Japanese brome. Fall (pre-emergence) application of Matrix provided better medusahead control compared to early spring (post-emergence) application. Low rates of glyphosate (Roundup Original 4L) at rates ≤ 16 oz/A applied in early spring (post-emergence) failed to give > 80% control of medusahead, but in other trials where the site was tilled before herbicide application, 1 qt/A of Roundup Original applied in early spring gave 100% control. Matrix at rates ≤ 6 oz/A and Plateau at 6 oz/A were safe on established squirreltail and California brome. Landmark XP, Oust, and Roundup at 16 oz/A caused > 50% injury to these perennial grasses. Perennial Grass Plant-Black Safety Following Herbicide Application

Matrix, Landmark XP, and Plateau reduced perennial grass cover and yield compared to the untreated control when grasses were spring-seeded 4 months after winter herbicide application. The herbicides’ reduction in spring-seeded grass yield differed between grass species and ranged from 34 to 84% for Matrix at 4 oz/A, 65 to 98% for Matrix at 8 oz/A, and 50% to 97% for Plateau at 6 oz/A five months after planting. None of the spring-seeded grass species established in plots treated with Landmark XP at 1.5 oz/A. Delaying perennial grass seeding a full growing season after herbicide treatment increased herbicide safety. When grasses were fall-seeded 8 months after herbicide application, Matrix at 4 and 8 oz/A and Plateau at 6 oz/A did not decrease seedling grass cover compared to the untreated control. Landmark XP at 1.5 oz/A reduced fall-seeded grass cover compared to the untreated control for all grass species,

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but Landmark’s injury to fall-seeded perennial grasses was less compared to the earlier spring seeding. It is important to note that Landmark XP at 1.5 oz/A is a high rate, and Landmark XP rates between 0.75 and 1.0 oz/A gave effective annual grass control in previous trials.

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Out-Competing Roadside Weeds with Native Plants

Jeanette E. Wrysinski, Yolo County Resource Conservation District (RCD), 221 West Court St., Ste. 1, Woodland, CA 9569, wrysinski@yolorcd.org

Rural roadsides in every part of the state are predictable nurseries and reservoirs for a

broad array of invasive weeds and seeds. Typical roadside management programs, whether sponsored by county road departments or managed by adjacent landowners commonly involve spraying, scraping and/or discing. If county road departments are tasked with doing this, there is typically a significant investment in equipment such as scrapers, the personnel to operate them, and in keeping those personnel busy cycling through the county from one road to the next and back again. This investment in equipment and the personnel to operate it can be a significant barrier to different approaches.

Current water quality improvement requirements throughout the state are forcing a new look at how to manage roadside weeds with reduced chemical input. The Yolo County RCD has more than a decade of experience with managing rural roadsides using California native grasses for multiple benefits. Detailed methods are explained in the RCD publication “Bring Farm Edges Back to Life,” which can be viewed on-line at the above-listed website, publication page 19. Tables below have been excerpted from this publication.

The battle against recurrent roadside weeds is un-winnable, given the current approach. Continuing with current methods promotes replanting of weed seeds and repeating the same measures the following year. It produces herbicide-resistant weeds over time and releases pesticide runoff into regional waterways. Wherever soil is left bare, something will try to grow. A more effective approach involves planting something on those roadsides that is desirable, that will compete effectively with annual weeds, something that will not require extensive annual spraying, discing or scraping and will not be invasive to neighboring areas.

California native perennial grasses are excellent candidates for use in this kind of system and can provide additional benefits beyond weed management. Native perennials are long-lived. Once established individual plants can live ten years or more and can re-seed themselves in the interim. They can provide dense soil coverage, competing with annuals for sunlight and soil nutrients. Their roots are deep – sometimes four to six feet – compared with annual weeds whose roots can be only inches deep, and can assist with greater storm water penetration and reduced runoff. Native grasses can provide habitat for native wildlife and insects that can benefit the neighboring land.

Establishing a native roadside is very similar to planting a new alfalfa field, pasture or lawn and does not require any new tools. Begin in spring by eliminating as many of the existing weeds as possible through a combination of approaches such as repeated discing,

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burning, spraying and/or mowing, with a focus on preventing new weed seed from being set. If possible, re-grade the slope of the roadside ditch from that shown in Figure 1 to improve safety and to promote ease of maintenance.

Figure 1

In the fall, after the first good seed-germinating rain, disc under the new weed

seedlings. Prepare a fine seedbed and broadcast a native grass seed mix that is designed for your area. Lightly harrow the seed in. Example mixes for different strips are shown in figure 2, below. If there is no roadside ditch, a single seed mix could be used.

Figure 2 Pavement edge: California barley (Hordeum californicum), Pine bluegrass (Poa secunda), Purple needlegrass (Nassella pulchra), Nodding needlegrass (Nassella cernua), California oniongrass (Melica californica). Roadside berm and inner ditchbank: California barley, California oniongrass, Meadow barley (Hordeum brachyantherum), Nodding needlegrass, Pine bluegrass, Purple Needlegrass, and Squirreltail (Elymus elymoides). Ditch bed: Meadow barley, Purple needlegrass, and sedges and rushes. Outer ditchbank and fieldside berm: Deep, Good Soils: Blue wildrye (Elymus glaucus), Purple needlegrass, Slender wheatgrass (Elymus trachycaulus ssp. trachycaulus), California barley, and Deergrass (Muhlenbergia rigens). Poor Soils: Purple needlegrass, Nodding needlegrass, California barley, and Pine bluegrass. Field edge: Creeping wildrye (Leymus triticoides).

Native roadsides need attention to maintenance during the first two to three years, just as if you were managing a crop. Thereafter, maintenance should be minimal. The most important maintenance measure is reduction of weed competition while the perennials are getting established. During the first year or two perennials develop a deep root system rather than top-growth, so reducing early competition for sunlight is critical to their survival.

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The following three tables provide guidelines and costs for successfully establishing native grasses along a rural roadside. Once the grasses are well established and broadleaf weeds have been reduced to a minimum, native wildflower seed can be scattered among the grasses to enhance the roadside’s appearance and diversity. It is advised to consult someone who has had experience with native grass establishment to ensure success. Although initial costs may be high, the pro-rated costs over ten years or more, coupled with the associated improvements in water quality, reduction of pesticide applications, appearance improvement, and wildlife habitat make the benefits clear. Cost-share options are available through the USDA Natural Resources Conservation Service, conservation organizations and local RCD’s.

Native Grass Establishment Schedule Year 1 Month Project Description March-September Prepare Seed Bed • disking in spring and/or burning in fall

removes weeds and prepares the soil for planting September-March Seeding &

First Weed Control • drill or broadcast and harrow seed • spray glyphosphate on 1st flush of weeds before native grasses emerge

February-March Broadleaf Weed Control • spray phenoxy herbicides to eliminate broadleaf weeds in planted area

March-June Late Grass Weed Control • mow, hay, or lightly graze planted area to remove annual grasses before they go to seed

Year 2 October-December Fall Weed Control • pre-emergent herbicides (consult Ag

Extension) or a broadleaf herbicide after weed emergence

April-June Spring Weed Control • broad-leaf herbicides, mowing, burning, or grazing can be used, depending on the weeds that are present

Year 3 and Beyond October-November Fall Weed Control • pre-emergent herbicide or burning April-July Spring or Summer • mowing, burning, or grazing (grass lands are

Management of Grasses healthiest when these management practices are alternated from year to year)

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Native Grass Establishment Program Checklist (reproduce for project reference)

Project/Location_____________________________ Date________________ ___ Choose a site that will not be awkward to protect and that can be accessed with equipment for maintenance ___ Minimize weed generation and seed production on proposed site for at least one year ___ Order seed (see vendor list) Year 1 (Summer/1st Fall-2nd Fall) ___ Prepare seed bed by disking in spring and/or burning in fall ___ Kill first flush of fall weeds after early rains ___ Drill or broadcast seed (preferably before December, but sometimes OK as late as March) ___ Spray out weed seedlings that germinate within two weeks of seeding ___ In mid-to-late winter, spray phenoxy herbicides to eliminate broadleaf weeds in planted area (use only herbicides such as MCPA that won’t burn perennial grass seedlings) ___ In spring, mow, hay, or lightly graze planted area to remove annual grasses before they produce viable seed (in a wet spring, this may need to be repeated) ___ Late-spring/summer weed control by hoeing, mowing, or with chemicals (as needed) Year 2 (2nd Fall-3rd Fall) ___ (Optional) Apply pre-emergent herbicides (consult Ag Extension) or a broadleaf herbicide after weed emergence in fall ___ In late winter, spot spray phenoxy herbicides or hoe to eliminate broadleaf weeds in planted area ___ Mow, hay, or lightly graze planted area to remove annual grasses before they produce viable seed (in a wet spring, this may need to be repeated) ___ Late-spring/summer weed control by hoeing or with chemicals (as needed) ___ (Optional) Late spring/summer/fall burn to reduce weed seed production and thatch; timing depends on the available fuel (dry matter to carry a fire) and type of weeds present Year 3 and Beyond ___ Fall weed control with pre-emergent herbicide or fire ___ Selective hoeing and spot spraying for winter broadleaf and grass weeds ___ Spring mowing, burning, or grazing (grasslands are healthiest when these management practices are alternated from year-to-year) ___ Selective hoeing and spot spraying for summer broadleaf and grass weeds

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Grassed Roadside Installation and Maintenance Cost Estimate (1999) For one mile of roadside, 15 feet wide (approx. 1.8 acres)

Cost/hr. Time Total Cost Low High Low High Low High Range Range Range Range Range Range

Installation Earthwork* $70.00 $70.00 2 8 hrs. $140.00 $560.00 Bed preparation 50.00 50.00 2 4 hrs. 100.00 200.00 Pre-plant Herbicide 60.00 0 0.5 gal. 30.00 Labor 10.00 0 2 hrs. 20.00 Spray rig 25.00 0 2 hrs. 50.00 Seeding: 20-40 lbs./acre for 1.8 ac. 10.00 35.00 36 72 lbs. 360.00 2,520.00 Broadcast/Harrowing Seed 35.00 35.00 2 8 hrs. 70.00 280.00 Total Installation Cost $670.00 $3,660.00 Maintenance Costs (first three years): Mowing 40.00 40.00 2 2 hrs. 80.00 80.00 Spot spray broadleaf weeds 10.00 10.00 1 3 hrs. 10.00 30.00 Herbicide 22.00 60.00 0.125 0.25 gal. 2.75 15.00 Second mowing 40.00 0 2 hrs. 80.00 Controlled Burn (once in 3 yrs) 10.00 0 7 hrs. 70.00 Annual Cost $92.75 $275.00 Perpetual Costs:** Mowing 40.00 40.00 2 4 hrs. 80.00 160.00 Spot spraying 10.00 0 4 hrs. 40.00 Herbicide 60.00 0 0.25 gal. 15.00 Controlled burn (ea. 2nd yr. max.) 10.00 0 10 hrs. 100.00 Annual Cost $80.00 $315.00 Average annual maintenance cost over 10 years $83.83 $303.00 For comparison, standard roadside management in Yolo County (a combination of “blading,” spraying, and/or mowing) costs between $140 and $490 per year depending on the roadside and management system. This does not include the secondary weed control costs to landowners or downstream water quality problems. * Depending on your roadside’s existing configuration, there may be minimal or extensive re-grading required. This grading estimate assumes work done by a county roadside blade operator (in which case, the cost is theirs). ** The degree of long-term maintenance can depend on the individual landowner’s tolerance for some weeds or no weeds

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Biological Control of Russian Thistle (Tumbleweed)

Lincoln Smith, USDA-Agricultural Research Service, Albany, CA 94710, lsmith@pw.usda.gov

Abstract

Russian thistle (Salsola tragus) is an important alien weed that first appeared in the 1870s

and has invaded about 100 million acres in the western U.S. Tumbleweeds invade fallow fields, clog irrigation systems, are hazardous to automobile traffic, spread wildfires and harbor insect pests that transmit viruses to many vegetable crops. Two moth biological control agents that were introduced in the 1970s have became widely established, but they are not providing sufficient control. We have evaluated several prospective new agents of this weed and have rejected two of them because they are not sufficiently host specific. A petition was submitted to the USDA-APHIS Technical Advisory Group (TAG) in Dec. 2004 requesting permission to release the blister mite (Aceria salsolae) to control Russian thistle. A seed-feeding and stem-boring caterpillar, Gymnancyla canella, is undergoing a third year of host-specificity evaluation in Albany. Two interesting weevils (Anthypurinus biimpressus and Baris przewalskyi) have been discovered during foreign exploration in Tunisia and Kazakhstan. These new biological control agents should help reduce the populations of this weed to innocuous levels over extensive regions. Successful biological control would provide self-perpetuating long-term management of this weed, reduce the need to apply pesticides, and increase the productivity and utility of millions of acres in the western U.S.

Russian thistle (tumbleweed, Salsola tragus, Chenopodiaceae) is an alien weed that first

appeared in North America in Bonhomme county, South Dakota in 1874, and has invaded about 100 million acres in the western U.S. Because it is alien and is not closely related to any native North American species, it has been targeted for classical biological control (Goeden and Pemberton 1995, Pitcairn 2004). The plant is native to central Asia and historically has been called S. australis, S. iberica, S. kali, and S. pestifer (Mosyakin 1996, 2003). Similar weedy species in North America include S. paulsenii (barbwire thistle), which occurs primarily in desert habitat, and S. collina (slender Russian thistle), which occurs east of the Rocky Mountains. Recent botanical studies using morphological characters and molecular genetics have revealed the existence of two newly described species. Salsola australis (sometimes called "type B") apparently originates from Australia and occurs in the San Joaquin Valley and southern coastal zone of California. Salsola x ryanii is a hybrid between S. tragus and S. australis (F. Hrusa unpubl. data). Salsola tragus, paulsenii and collina all originate from Eurasia.

Two species of moths (Coleophora klimeschiella and C. parthenica) were evaluated and

introduced in the 1970s for biological control of S. tragus (Goeden 1973). Coleophora klimeschiella is a case-forming caterpillar that feeds on leaves, and C. parthenica larvae mine the stems. Both moths became widespread, but predators and parasites prevent them from being abundant enough to control the weed (Goeden et al. 1987, Müller et al. 1990). Further foreign exploration in the Mediterranean Region by R. Sobhian led to the discovery of several prospective new biological control agents (Table 1). Evaluations conducted by R. Sobhian (USDA-ARS, European Biological Control Laboratory) demonstrated that two of these are

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specific enough to warrant further evaluation, and that two should be eliminated from further consideration.

The blister mite (Aceria salsolae) is an eriophyid mite that destroys the young growing tips

of the plant, stunting its growth and preventing development of flowers. The blister mite has been evaluated for host plant specificity, and its ability to damage the plant in quarantine experiments at the USDA-ARS quarantine laboratory in Albany, CA. These studies demonstrated that the mite attacks only a few closely related species of Salsola, all of which are invasive alien weeds. A petition was submitted to the USDA-APHIS Technical Advisory Group (TAG) in Dec. 2004 (Smith 2005), and TAG recommended approval of release in Aug. 2005. An application for a release permit was submitted to USDA-APHIS-PPQ in Nov. 2005. APHIS has not yet completed review of the permit application. Both AHIS and the California Department of Food and Agriculture must approve the permit before the mite can be released.

Caterpillars of the moth, Gymnancyla canella, commonly attack Russian thistle on beaches

of southern France. Larvae feed on developing seeds and stems, causing extensive damage. Host specificity tests have been conducted for several years at Montpellier France and in the Albany quarantine laboratory and are expected to be finished in another year.

Foreign cooperators are exploring new regions in Central Asia (Turkey, Kazakhstan and

Uzbekistan) and have discovered many species of beetles attacking Russian thistle. Several of these are thought likely to be host-specific (Table 1). Initial experiments to evaluate host plant specificity are being conducted by cooperators in Italy. Access to Central Asia greatly improves our chances of finding safe, effective biological control agents because this appears to be the region of highest biodiversity of this plant.

These new biological control agents should help reduce the populations of this weed to

innocuous levels over extensive regions. Successful biological control would provide self-perpetuating long-term management of this weed, reduce the need to apply pesticides, and increase the productivity and utility of millions of acres in the western U.S.

In anticipation of obtaining permission to release the blister mite. We have begun to select

sites in a variety of climatic zones in California and collect baseline data on Salsola abundance.

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Table 1. Status of prospective biological control agents of Russian thistle. Taxonomic name Common name Current information

Evaluated species

Aceria salsolae (Acari: Eriophyidae)

blister mite The mite attacks developing tips. Petition "approved" by TAG, release permit submitted to APHIS (Smith 2005).

Gymnancyla canella (Lepidoptera: Pyralidae)

seed and stem moth

Caterpillar feeds on seeds and young branch tips. Host specificity testing almost completed.

Colletotrichum gloeosporioides rust More damaging to Russian thistle type A than to type B (Bruckart et al. 2004). Being evaluated by W. Bruckart USDA-ARS, Maryland.

Uromyces salsolae rust Damages Russian thistle type A (Hasan et al. 2001). Being evaluated by W. Bruckart USDA-ARS, Maryland.

Kochiomyia [=Desertovelum] stackelbergi (Diptera: Cecidomyiidae)

gall midge Uzbekistan strain attacks Salsola type A more than type B. Apparently requires a yet unidentified fungal symbiont to reproduce (Sobhian et al. 2003b). Research suspended.

Lixus incanescens [=salsolae] (Coleoptera: Curculionidae)

stem weevil Adults feed on many plants in choice test at Montpellier, France (Sobhian et al. 2003a). Rejected.

Piesma salsolae (Hemiptera: Piesmatidae)

plant bug Develops on beets in no choice lab test at Montpellier, France (R. Sobhian pers. com.). Rejected.

New species

Anthypurinus biimpressus (Coleoptera: Curculionidae)

jumping weevil Found in Tunisia in 2004. Larvae and adults feed on leaves. Biology is unknown.

Baris przewalskyi (Coleoptera: Curculionidae)

weevil Abundant on Salsola in Kazakhstan in 2004. Biology is unknown.

Salsolia morgei (Coleoptera: Curculionidae)

weevil Found in Kazakhstan in 2004. Reported to be monophagous.

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References Bruckart, W., Cavin, C., Vajna, L., Schwarczinger, I., and Ryan, F. J. 2004. Differential

susceptibility of Russian thistle accessions to Colletotrichum gloeosporoides. Biological Control. 30(2): 306-311.

Goeden, R. D. 1973. Phytophagous insects found on Salsola in Turkey during exploration for biological weed control agents for California. Entomophaga. 18(4): 439-448.

Goeden, R. D. and R. W. Pemberton. 1995. Russian thistle, pp. 276-280. In J.R. Nechols, L.A. Andres, J.W. Beardsley, R.D. Goeden and C.G. Jackson (editors), Biological Control in the Western United States: Accomplishments and benefits of regional research project W-84, 1964-1989. University of California, Division of Agriculture and Natural Resources, Oakland. Publ. 3361.

Goeden, R. D., D. W. Ricker, and H. Müller. 1987. Introduction, recovery, and limited establishment of Coleophora klimeschiella (Lepidoptera: Coleophoridae) on Russian thistles, Salsola australis, in southern California. Environ. Entomol 16: 1027-1029.

Hasan, S., R. Sobhian and F. Herard. 2001. Biology, impact and preliminary host-specificity testing of the rust fungus, Uromyces salsolae, a potential biological control agent for Salsola kali in the USA. Biocontrol Science and Technology 11: 677-689.

Mosyakin, S. L. 1996. A taxonomic synopsis of the genus Salsola (Chenopodiaceae) in North America. Ann. Missouri Bot. Gard. 83:387-395.

Mosyakin, S. L. 2003. Salsola Linnaeus. Flora of North America, vol. 4. Magnoliophyta: Caryophyllidae, Part 1: 398-403. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=129079

Müller, H., Nuessly, G.S., and Goeden, R.D. 1990. Natural enemies and host-plant asynchrony contributing to the failure of the introduced moth, Coleophora parthenica Meyerick (Lepidoptera: Coleophoridae), to control Russian thistle. Agric., Ecosystems, and Environ. 32:133-142.

Pitcairn, M. J. 2004. Russian thistle, pp. 304-310. In E. M. Coombs, J. K. Clark, G. L. Piper, and A. F. Cofrancesco, Jr. (eds.). Biological Control of Invasive Plants in the United States. Oregon State University Press.

Smith, L. 2005. Host plant specificity and potential impact of Aceria salsolae (Acari: Eriophyidae), an agent proposed for biological control of Russian thistle (Salsola tragus). Biological Control 34(1): 83-92.

Sobhian, R., Fumanal, B., and Pitcairn, M. 2003a. Observations on the host specificity and biology of Lixus salsolae (Coleoptera: Curculionidae), a potential biological control agent of Russian thistle, Salsola tragus (Chenopodiaceae) in North America. J. of Appl. Entomol. 127: 322-324.

Sobhian, R., F. J. Ryan, A. Khamraev, M. J. Pitcairn, and D. E. Bell. 2003b. DNA phenotyping to find a natural enemy in Uzbekistan for California biotypes of Salsola tragus L. Biological Control. 28: 222-228.

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Controlling giant reed (Arundo donax) within the Tijuana River Valley.

Robert W. Hobbs1*, Julie Simonsen-Marchant1, Tito Marchant1, and John Boland2, 1EcoSystems Restoration Associates, San Diego, CA, 2Southwest Wetlands Interpretative Association,

Imperial Beach, CA. (robert.hobbs@tcb.aecom.com or 619-291-1475 ext 240).

EcoSystems Restoration Associates (ERA), in cooperation with Southwest Wetlands Interpretive Association (SWIA), has been conducting chemical and physical control of giant reed (arundo donax) as well as habitat restoration throughout the Tijuana River Valley Regional Complex for the last three years. In the Tijuana River Valley, giant reed occurs in a patchy distribution in comparison to the large, dense stands that are more typical in San Diego County. Since the habitat surrounding infestation areas was primarily composed of riparian woodland, riparian scrub, and open water, project specifications required that ERA avoid substantial impacts to sensitive biological resources such as the federally listed least Bell’s vireo, while cost-effectively controlling this highly invasive species. The control techniques utilized included foliar treatment on intact and trampled stands of giant reed, as well as cut-stump treatment. The foliar herbicide treatments included the application of 4%, 6%, and 7.5% glyphosate over a three-year period. The most effective means of control was achieved thorough foliar application of 7.5% glyphosate, which resulted in complete eradication within four weeks. The 4% and 6% glyphosate application rates resulted in approximately 60-80% suppression of the stands. The cut-stump treatment was overall unsuccessful with nearly 100% re-growth, although these results varied by year. From a cost perspective, using a 7.5% treatment was equivalent to using the cut-stump method. The results ran contrary to original beliefs, but confirmation from the third year of experimentation showed that the cost benefit and effective means were maintained by the using 7.5% application rates.

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Hydrilla Eradication Efforts in the Chowchilla River and Eastman Lake in Central California; a Success Story

Florence C. Maly, California Department of Food and Agriculture, 2889 N. Larkin, Suite

106, Fresno, CA 93727, fmaly@cdfa.ca.gov

Hydrilla is an invasive, non-native aquatic plant that is a serious threat to the water resources of the State. It reduces the storage capacity of lakes and ponds, impedes movement in streams and canals; clogs pumps and hydroelectric generators; degrades fish and wildlife habitat; and can even endanger public health by creating mosquito breeding habitat. Hydrilla can reproduce by stem fragments that root and form mature plants; turions that form in the leaf axils; and most troubling, tubers that form on the end of underground rhizomes in the spring and again in late summer through fall. These tubers can survive in the hydrosoil for several years or more. Following the first introduction of hydrilla into California, in 1977 the California Legislature mandated that the CDFA Secretary initiate a detection program for hydrilla and to eradicate it wherever “feasible”. This mandate is stated in the California Code of Regulations.

The discovery of hydrilla in Eastman Lake and the Chowchilla River presented new challenges to the CDFA. Previous infestations had occurred primarily in locations that were easily accessible and where the water could be controlled. This infestation was the first to be seen in a free flowing seasonal river. The Chowchilla River originates in the Sierra Nevada foothills in Mariposa County. The three forks of the Chowchilla fill Eastman Lake, an 1800-acre reservoir owned by the U.S. Army Corps of Engineers. Eastman is used primarily for flood control, irrigation, recreation and wildlife preservation.

Hydrilla was first detected in Eastman Lake on June 20, 1989, during a routine survey by CDFA and Madera County Department of Agriculture personnel. Plant samples were collected, sent to the CDFA Diagnostics Lab and confirmed as dioecious hydrilla. Initially the infestation appeared to cover approximately 100 gross acres in the northern section of the lake. CDFA acted immediately to prevent hydrilla spreading to other local lakes or into the irrigation canals by requesting that the U.S. Army Corps of Engineers close off the northern portion of the lake to recreational activities on June 23. Just 5 days later the entire lake was placed under quarantine as many more plant sites were found along the eastern shore line.

While Eastman was being inspected, additional teams of Biologists were starting a delimitation survey to discover the full extent of the problem. When they discovered hydrilla in the Chowchilla River in a few easily accessible places upstream of Eastman Lake it was clear that personnel needed to follow the river upstream to find the source of the infestation. This was not as simple as it sounds. Since the Chowchilla flows completely through private land, property owners had to be contacted in order to gain access to the river. Most owners granted permission immediately but others had to be persuaded to allow people on their property. Government types aren’t exactly welcomed in many of the foothill and mountain areas of California, especially when questions are being raised about precious water resources. When the most upstream site of the

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infestation was located in the West Fork of the Chowchilla River, 26 miles upstream from Eastman Lake, the entire West Fork of the river was closed, restricting all water related activities.

Right at the beginning of this project there were many who questioned the “feasibility” of eradicating hydrilla from the Chowchilla River. It flows through some extremely rugged terrain, with steep hills and deep canyons. Just getting to the water in many places involves driving on a rugged 4-wheel drive road, then hiking for a half mile or more on cattle trails through oak grassland or chaparral, sometimes through stands of poison oak. Biting and stinging insects, rattlesnakes, the occasional mountain lion or bear, the not so occasional wild pig, and even people with guns, add to the adventure of just getting to the water! Once in the river personnel are faced with the daunting task of staying upright on slippery rocks, or hacking through thick stands of cattails or willows. In the early years of the project, all of this was done while carrying a backpack sprayer with 40 pounds of liquid herbicide sloshing around! Weather is another big challenge. Summer temperatures in these foothill canyons can easily reach 105 degrees Fahrenheit and beyond, with hot afternoon winds that feel like they are right out of a blast furnace; winter days can be just as miserable with thick fog and wind chill down into the 20’s. In spite of these logistical environmental roadblocks, a Scientific Advisory Panel, convened in July 1989, concluded, “anything less than an eradication effort is unacceptable”. It was therefore deemed “feasible” to eradicate hydrilla from the Chowchilla River and Eastman Lake.

Work began immediately. Within a month after the initial detection, seasonal staff was hired to work with CDFA Biologists. The first step was mapping the river and lake. This was before we had GPS so the primary tools were a topo map, a compass and a good sense of direction. The river system was divided into 38 management units for ease of record keeping. While the river was mapped, several crews of three to four people surveyed foot by foot, looking at every pool and puddle. Hydrilla was found in every management unit, ranging from single plants to large masses filling entire ponded areas.

Chemical control was an essential tool early in the project, so any plants found were treated with Komeen, a copper based contact herbicide used to control the top growth of hydrilla plants. Crewmembers had to learn the terrain and river access points, and also how to use the herbicide, and how much to carry each day. By the second season crews were surveying the entire river every two weeks, treating as necessary. A number of heavily infested ponded sites were measured and treated a number of times with predetermined amounts of Komeen. During 1989, 1990 and 1991 an average of 450 gallons of Komeen per year were applied to ponded and slow moving water in the river.

In the meantime, work at Eastman Lake was progressing. In 1989 mats and individual plants of hydrilla were detected, marked with bamboo stakes, and removed by hand. Plant site areas were netted to catch any fragments that might break off. Project officials also started a chemical treatment program. Komeen was applied to pre-measured sections of the lake using a custom boom sprayer system with weighted down dragger hoses to get the material down into deep water, and a spray gun for the more shallow areas along the shoreline. In the years 1990 through 1992, 1000 to 2000 gallons of

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Komeen were applied to the lake per year, during regularly scheduled treatments. In addition to the Komeen treatments, in 1990 the upper lake delta area was fumigated with Vapam. This area was heavily infested with hydrilla and held a massive reserve of tubers. Vapam is a soil fumigant that kills tubers, roots and stems of plants in the soil. The lake water level was drawn down to dry the sandy soil of the delta. Private contractors brought in sprinkler irrigation pipes to apply the Vapam to the area. This treatment was highly successful, as very few plants were later found in the treated area.

Along with the herbicide treatments, personnel were hand-removing plants. The herbicides eliminated the huge mats, so by 1990 individual plants could be counted. Crewmembers literally waded, swam and even snorkeled in the water of the river and lake to look for plants. And not only did we have to find hydrilla plants, but find and identify them among many other aquatic plants, often in deplorable water conditions. When plants were found they were gently pulled out of the soil, often still attached to the tuber from which they grew. When tubers broke off they were removed by sifting the soil material through hardware cloth welded inside a metal ring. This became known as the “shovel and sift” method. When large numbers of plants were found in one area, we would shovel and sift, then use suction dredges to remove more tubers from the soil. Dredging requires a lot of manpower, not only to get the equipment to the site, but also to simply look through the material to find the tubers. Use of our four-inch intake dredge was highly successful at the site of the source of the infestation, where in the span of five weeks in 1991, approximately 35,000 tubers were removed.

Up through 1996, this routine continued: survey, pull plants, shovel and sift, treat and dredge, and survey again. Plant numbers declined dramatically. In 1993 over 6,000 plants were removed; by 1997 we saw a major drop to 562. In 1997 we were given a new weapon – Sonar. Sonar is a selective systemic aquatic herbicide that causes the breakdown of chlorophyll. At the end of 1998 we saw another major drop in plant numbers – down to 49! We frankly did not expect that dramatic a reduction in one season. We ascribe this to several factors: effective use of Sonar, hand removing plants, which prevented the production of new tubers, and the fact that the existing tuber bank was being exhausted. Hand removal became our primary tool and only two plants were found in 2002!

While all this work was conducted in the lake and river, additional detection work was done in a corridor two miles wide on both sides of the river. All stock ponds, fire ponds, and creeks within that corridor were thoroughly checked. The Middle and East Forks of the Chowchilla River, and the outflow from Eastman Lake were also surveyed. No hydrilla was ever found in any other body of water in the area.

A bio-control agent, a weevil called Bagous affinis, was released in the river, but unpredictable water flows made the attempt impractical. Besides, as a tool for this project the very nature of bio-control is inconsistent with the mandate to eradicate all hydrilla plants.

Mother Nature did help us, however. Several periods of drought during the project years left many sections of the river dry for much of the season. Even if hydrilla plants

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sprouted they did not have the opportunity to grow and produce new tubers before the water evaporated or disappeared underground.

The dry years also helped to reopen Eastman Lake by leaving dormant tubers high and dry above the water level. Even after a small number of plants appeared in July 1992, CDFA officials were so confident that the hydrilla was well under control they worked with officials from the U.S. Army Corps of Engineers and the State Department of Fish and Game to open the west shoreline for fishing in August 1992. Hundreds of happy anglers lined up elbow to elbow along the shoreline to catch those bass that had been growing undisturbed for three years. In 1995 almost the entire lake was opened to all forms of water activities. A small portion of the lake remains closed today to protect nesting bald eagles that moved in when the lake was closed.

We are excited that zero hydrilla plants have been found in the Chowchilla River and Eastman Lake system since 2002. Native aquatic vegetation is thriving in the river, enticing wildlife in the region. However, because the plants found in 2002 were located approximately 20 miles upstream from Eastman Lake, the entire system must still be considered infested, and the river remains under quarantine. In 2004 and 2005 each management unit of the river was surveyed at least two times and Eastman Lake was thoroughly checked four times. Sonar herbicide treatments were completed in 2005. In 2006 and again last summer the river system was surveyed once and we are cautiously optimistic that our hard work will be rewarded by one more year of negative hydrilla finds, the minimum required before eradication can be declared.

The first key element to successfully eradicating hydrilla is early detection and rapid response. The Chowchilla River/Eastman Lake infestation was estimated to be about four years old, and while portions of the river were thickly infested, the amount found in the lake was not yet completely out of control. Irrigation and recreational activities would have been severely impacted if CDFA had not acted immediately. Another key element in eradication is a complete commitment to the project by all parties involved. And in this respect the Chowchilla project really stands out. CDFA made a full time commitment to attacking this problem, supplying not only financial resources, but a dedicated staff as well. The U. S. Army Corps of Engineers, Madera and Mariposa County Departments of Agriculture and other agencies continue to supply financial and logistical support. But it is not only the financial resources that made this project a success; it is the legion of dedicated people who have made the difference. People who were willing to immerse themselves in algae covered water that was pretty disgusting; willing to encounter dead animals, fish, and smelly rotting vegetation and endure being literally covered in hydrilla plants! People who used every tool - swimming, snorkeling, using herbicides, hand pulling, dredging, and surveying again and again - to eliminate hydrilla. And that is the final key point – hydrilla cannot be ignored, it requires constant attention. To be successful, we cannot afford to turn our backs on current projects and we must be vigilant, always looking for new infestations, finding them early, and acting on them quickly. Only by doing so can we keep the vital water resources of the State of California free of this noxious pest.

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Roadside Vegetation and Disaster Mitigation Jennifer A. Malcolm, California Department of Transportation, Headquarters, Division

of Maintenance, Office of Roadsides, 1120 N Street, MS 31, Sacramento, CA 95814, jennifer_malcolm@dot.ca.gov

This discussion focuses on roadside vegetation and how disasters affect our work.

Roadside vegetation managers can assist others (such as engineers) during major disasters in many ways which can lessen future noxious and invasive weed invasions and help to reestablish native plants.

This presentation shows how the 2005 winter storms devastated southern

California. Many areas in California received over 300% of their normal annual rainfall from January through March of 2005. Governor Schwarzenegger declared an emergency in eight counties (Los Angeles, Ventura, Santa Barbara, Riverside, San Bernardino, Orange, San Diego and Kern) on January 15, 2005.

There are many types of failures that affect roadways and roadsides. These

photographs illustrate the variety of types of failures which occur during disasters. It is important to correctly identify the specific type of failure, since money and resources are tied to such repairs. Some of the most common roadside disaster failures include:

Bridge failures - when excessive water scours out bridge supports, causing failure or collapse.

Roadbed failures occur due to excess saturation. Culvert failures occur when water volumes greater than the culvert can handle

either blowout, topple or separate. Failures normally occur at culvert entrances and detention basins when they fill up with mud and debris.

Mudslides - when water and dirt combine to overtop roadways. Rockslides and landslides occur when saturated hillsides can no longer support

their own weight, falling down onto the roadways below. Slipouts occur when saturated hills fail below the roadways, taking the roadway

with it. Washouts - a violent form of flooding that takes the entire roadway with it. Flooding - when runoff overtops roadways. Roadside vegetation managers should suggest appropriate repair strategies. By

acknowledging drainage patterns and nearby site features, roadside vegetation managers can suggest: appropriate seed mixes (including pioneer species, forbs, wildflowers and native grasses); planting options (such as broadcast seeding, no-till drilling, imprinting, hydroseeding, and plug planting); drainage options (such as rock-lined swales, geocells, different size and tonnage of boulders); erosion control options (including bonded fiber matrixes, erosion control blankets and stabilizing mats); and grading options (such as slope steepness, berms next to roadsides to channelize water, and slope rounding/contour grading). By helping others during a disaster, we can help to make our roadsides better in the future!

10099

Weed Control in Caneberries

Mark Bolda, UC Cooperative Extension, Santa Cruz County, 1432 Freedom Boulevard, Cooperative Extension Santa Cruz County, Watsonville, CA 95076-2796, mpbolda@ucdavis.edu

and Chris Matthews, Manager, Garroutte Farms

Weed control in caneberries is done for many of the same reasons as other crops; weeds compete with the crop for light and water, and contaminate the crop and soil with seeds and debris. There are several additional matters with weed and vegetation management in caneberries however. One particular problem is that caneberries are usually grown over multiple years and canes for next year are produced vegetatively in the cropping year. First year, non-bearing canes are called primocanes, while flowering and fruiting canes are called floricanes. However, while the primocane is next year’s crop, it also competes with the current crop for nutrients, so it is vital that this vegetative cane be managed properly to minimize the potential for yield loss brought about by competition for nutrients. There are several options available to growers to manage the vegetative cane. Growers generally remove the first flush of vegetative cane, or all cane when in the last year of production. Cane can be removed by hand, but this is very expensive and time consuming. ... In California, herbicides are playing a larger and larger role in the management of primocane. The use of herbicides is of twofold utility, one to control weeds and the other to control primocane. Paraquat (Gramoxone), while very effective in burning down primocane and weeds, has very little residual effect. Oxyfluorfen (Goal), which is not registered in California, appears to have a longer residual effect in suppressing primocane and weeds. Some growers in the Pacific Northwest, where this material is registered, do caution that this material can be deleterious to a weakened caneberry stand. Finally, carfentrazone (Shark) is effective in suppressing primocane and has a small residual effect, as well as being registered in California. Tillage is effective for weed control in caneberries, outside of the hedgerows which are generally too thick to work with tractor drawn implements. Caneberry roots do not generally grow into furrows and row middles, since there is very little water there in the summer, so tillage does very little harm there. ... Cover cropping is also an important tool in suppressing weeds, especially during the winter months when it can be difficult to get into the field with a tractor because the soil is so wet. Still, cover crops should be low growing and not interfere with air circulation through the caneberry hedgerow. Cover crops should be seeded after completion of harvest in the fall, and tilled back into the ground in the spring. The loss of methyl bromide, controlling methyl bromide and glyphosate resistant weed species, primocane control, hardships of hand weeding and organic production methods are all challenges facing strawberry and caneberry growers in California.

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The impending loss of methyl bromide as a pre-plant soil fumigant has brought about the use of several alternative fumigants, such as 1,3-D, chloropicrin and metam sodium. Since many of these alternative fumigants are applied through the drip system with the bed mulch already in place, strawberry growers are working with fuller and longer duration bed coverage, better water management, and planting through the mulch. Additionally methyl bromide tolerant weed species, such as little mallow, Malva parviflora, and glyphosate resistant weeds such as burning nettle, Utrica urens, will be less of a problem with the application of alternative fumigants. The use of the herbicides flumioxazin (Chateau) in the furrows and oxyfluorfen (Goaltender) over the top of the bed has gone hand in hand with the bed applications of the alternative fumigants. Management of vegetative primocanes in is an important part of caneberry cultivation. Growers can burn these canes with a propane burner, cut them out by hand or use herbicides. Herbicide use and flaming is most advantageous in raspberries, where the floricane is woody and resistant to burning. Most of the cane of blackberries is green, and more susceptible to herbicide and flaming damage. One trail done on our farm tested the efficacy and length of control of applications of paraquat (Gramoxone), oxfluorfen (Goal- not registered in California) and carfentrazone (Shark) in suppressing primocanes. Oxyfluorfen appeared to have a little longer effect than carfentrazone, and significantly longer than paraquat. Organic production of caneberries presents more challenges in terms of weed control. A promising herbicide for organic use, pelargonic acid, is yet to be registered, so organic caneberry growers continue to use hand weeding as their main weed management strategy in organic caneberries.

102101

Integrated Weed Management in Strawberry

Steven A. Fennimore, J. Ben Weber, and John Rachuy; U.C. Davis,1636 E. Alisal St., Salinas, CA, 93905, safennimore@ucdavis.edu

Summary. Field studies were conducted to further develop the use pattern of oxyfluorfen herbicide (GoalTender) which is used to control weeds such as little mallow and filaree in strawberry. Oxyfluorfen herbicide is labeled for application on strawberry beds at least 30 days before transplanting. Oxyfluorfen treated soil must be tarped prior to strawberry transplanting to avoid injury to strawberry. Studies were conducted to determine if oxyfluorfen must be activated with sprinkler irrigation prior to tarp installation or if fallow beds can be tarped as soon as the oxyfluorfen has been applied. We found that when oxyfluorfen was applied and tarped right away without sprinkler irrigation activation that weed control was as good as when oxyfluorfen was irrigated before tarp installation. Introduction. Oxyfluorfen is applied at least 30 days before transplanting, and is often watered in with sprinkler irrigation to activate the herbicide prior to tarp installation on the planting beds. Eliminating the irrigation activation step would allow installation of the tarp directly after the herbicide application and would both reduce costs and simplify the process. The primary objective was to verify whether or not the irrigation activation step is necessary for effective weed control with oxyfluorfen. A second objective was to evaluate oxyfluorfen in combination with napropamide (Devrinol), pendimethalin (Prowl H20) and dazomet (Basamid). Materials and methods. Two field studies were conducted to evaluate the effect of irrigation activation of several herbicide treatments on weed control and crop tolerance. The treatments were arranged in a randomized complete block with four replicates. Each plot was 20-ft long by 52-in wide with a 26-in bed top. The first herbicide trial was conducted at Monterey Bay Academy at Watsonville, CA on soil previously fumigated with methyl bromide/chlorpicrin (MBPic) at 350 lbs/A. Black medic and little mallow were seeded throughout the trial on Oct. 6, 2005. On Oct. 7 herbicide treatments were applied to the bed top using a single nozzle backpack type CO2 sprayer at a volume of 40 GPA. Treatments included oxyfluorfen at 0.125, 0.25, 0.375 and 0.5 lb ai/A plus an untreated control. One-half of the plots were then directly tarped without sprinkler irrigation, while the other half of the plots received 0.5-in irrigation and were not tarped until just before transplanting. Strawberry ‘Albion’ was transplanted on Nov. 7, 2005. The second trial was initiated at the USDA-ARS/UCCE Spence research farm near Salinas, CA on soil previously fumigated with MBPic at 350 lbs/A. As in the previous trial, black medic and little mallow were planted on the bed tops prior to herbicide application. At Salinas, oxyfluorfen at 0.125 lb ai/A, 0.25 lb ai/A, 0.375 lb ai/A, and 0.5 lb ai/A and flumioxazin (Chateau) at 0.063 lb ai/A were applied on Oct. 28, 2005 (30 days pre transplant). Other treatments included: pendimethalin at 1.0 lb/A, napropamide at 2.0 lb/A, pendimethalin plus oxyfluorfen at 1.0 plus

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0.125 lb ai/A, and napropamide plus oxyfluorfen at 2.0 plus 0.125 lb ai/A. A sequential application of dazomet at 150 lb followed by 0.125 lb ai/A oxyfluorfen was also evaluated. Untreated control treatments were also included. One-half of the plots were then immediately tarped without sprinkler irrigation, while the other half of the plots received 0.55 in sprinkler irrigation on Nov. 2 and were not tarped until just before transplanting. On Nov. 29, 2005 strawberry ‘Diamante’ was transplanted. At Watsonville, crop injury ratings, 0 = safe, 10= dead, were taken on Dec. 15, 2005, Jan. 16, and Feb. 9, 2006. Weed densities were measured on: Nov. 16, and Dec. 15, 2005 and Feb. 23, 2006. Planted weeds were counted separately from native weed species. Fruit was harvested twice weekly from April 6, to Sept. 14, 2006. At Salinas, crop injury ratings were taken on: Jan. 9, Feb. 7, and Mar. 8, 2006. Weed densities were measured Nov. 28, 2005, Jan. 12, and Mar. 1, 2006. Fruit was harvested May 9, to Sept. 22, 2006. Analysis of variance was performed on the data and mean separation was performed using LSD’s. Analysis was also conducted to determine the main effect of irrigation activation of the herbicides on weed control. Results. Oxyfluorfen caused little crop injury at Watsonville, but at Salinas the 0.375 and 0.50 lb ai/A rates caused moderate crop injury (Tables 1 and 2). The data also shows that irrigation activation had no effect on fruit production at either Watsonville or Salinas. Weed control in the no irrigation activation treatments was essentially the same as the treatments that received irrigation activation and delayed tarping. At Watsonville and Salinas, oxyfluorfen at 0.375 ai/A and above controlled little mallow and black medic (Tables 3 and 4). Control of little mallow and black medic was excellent with the combination of pendimethalin plus oxyfluorfen at 1.0 plus 0.125 ai/A. The napropamide plus oxyfluorfen 2 plus 0.125 lb ai/A combination gave good control of little mallow and black medic, much better than napropamide alone. The sequential application of dazomet (150 lb ai/A) followed by oxyfluorfen (0.125 lb ai/A) gave excellent control of planted black medic and little mallow. Overall weed control results at Watsonville and Spence suggests that sprinkler irrigation activation of oxyfluorfen on fallow beds is not required for effective weed control.

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Table 1. Strawberry injury ratings and fruit yields at Watsonville, CA. Treatment Rate lb ai/A Irrigation

Activation Crop injury

0 = safe, 10 = dead Mkt.yield

12.15.05 1.12.06 gr./plant 1 Untreated 0 Yes 0.0 d 0.0 d 651 2 Untreated 0 No 0.0 d 0.0 d 668 3 Oxyfluorfen 0.125 Yes 0.4 cd 0.1 cd 640 4 Oxyfluorfen 0.125 No 0.0 d 0.7 abc 652 5Oxyfluorfen 0.25 Yes 0.5 bc 0.8 abc 710 6 Oxyfluorfen 0.25 No 0.3 cd 0.5 bcd 643 7 Oxyfluorfen 0.375 Yes 0.9 ab 1.3 a 667 8 Oxyfluorfen 0.375 No 0.6 bc 1.0 ab 621 9 Oxyfluorfen 0.5 Yes 1.1 a 1.3 a 674 10 Oxyfluorfen 0.5 No 0.6 bc 1.3 a 656 Main effects GoalTender 0.0001 0.0001 0.7340 Activation 0.0157 0.9449 0.3212 Table 2. Strawberry injury ratings, and fruit yields at Salinas, CA.

Treatment Rate lb ai/A Irrigation Activation

Crop injury 0 = safe, 10 = dead

Mkt.yield

1-9-06 2-7-06 gr./plant 1 Untreated 0 Yes 0.0 g 0.0 h 633 2 Untreated 0 No 0.0 g 0.0 h 679 3 Oxyfluorfen 0.125 Yes 0.3 g 0.5 e-h 712 4 Oxyfluorfen 0.125 No 0.4 fg 0.1 gh 696 5 Oxyfluorfen 0.25 Yes 0.5 efg 0.6 d-g 706 6 Oxyfluorfen 0.25 No 1.3 cd 1.1 cd 761 7 Oxyfluorfen 0.375 Yes 1.1 cde 1.5 bc 789 8 Oxyfluorfen 0.375 No 1.5 bc 2.0 ab 677 9 Oxyfluorfen 0.5 Yes 2.3 a 2.4 a 696 10 Oxyfluorfen 0.5 No 2.0 ab 2.1 a 661 11 flumioxazin 0.063 Yes 0.1 g 0.1 gh 659 12 flumioxazin 0.063 No 0.4 fg 0.8 def 685 13Oxyfluorfen/pendimethalin 0.125/1.0 Yes 0.6 d-g 0.8 def 658 14Oxyfluorfen/pendimethalin 0.125/1.0 No 1.0 c-f 1.5 bc 742 15 pendimethalin 1.0 Yes 0.3 g 0.5 e-h 624 16 pendimethalin 1.0 No 0.6 d-g 0.4 fgh 710 17 Oxyfluorfen/napropamide 0.125/2.0 Yes 0.4 fg 0.4 fgh 673 18 Oxyfluorfen/napropamide 0.125/2.0 No 1.0 c-f 1.0 cde 669 19 napropamide 2.0 Yes 0.1 g 0.3 fgh 644 20 napropamide 2.0 No 0.3 g 0.4 fgh 685 21 dazomet 150 Yes 0.4 fg 0.4 fgh 696 22 dazomet /Oxyfluorfen 150/0.125 Yes 1.1 cde 1.1 cd 784 LSD 0.56 0.72 164 Treatment probability 0.0001 0.0001 0.584

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Table 3. Season total weed densities at Watsonville, CA. Treatment Rate lb ai/A Irrigation

Activation Blk.Medic

Planted L.Mallow Planted

Total resident weeds

------------- No./20 ft. -------- No. 41.7 ft2 1 Untreated 0 Yes 139.0 ab 25.8 b 28.0 a 2 Untreated 0 No 150.3 a 71.0 a 19.3 ab 3 Oxyfluorfen 0.125 Yes 78.8 bc 5.0 c 11.5 bc 4 Oxyfluorfen 0.125 No 34.0 cd 9.0 bc 11.0 bc 5Oxyfluorfen 0.25 Yes 30.3 cd 1.0 c 1.8 c 6 Oxyfluorfen 0.25 No 11.0 d 3.5 c 4.0 c 7 Oxyfluorfen 0.375 Yes 15.8 d 0.3 c 2.0 c 8 Oxyfluorfen 0.375 No 3.5 d 0.0 c 0.8 c 9 Oxyfluorfen 0.5 Yes 16.3 d 0.3 c 1.3 c 10 Oxyfluorfen 0.5 No 2.0 d 0.0 c 1.0 c LSD 61.15 19.72 11.31 Main effects GoalTender 0.0001 0.0001 0.0002 Activation 0.25 0.0244 0.5 Table 4. Season total weed densities at Salinas, CA.

Treatment Rate lb ai/A Irrigation Activation

Blk.Medic Planted

Mallow Planted

Total Weeds

--------No. /20 linear feet------ No./ 41.6 ft2 1 Untreated 0 Yes 310.5 a 99.8 a 10.3 a 2 Untreated 0 No 174.5 b 86.8 a 6.5 b 3 Oxyfluorfen 0.125 Yes 21.5 de 24.0 bc 1.4de 4 Oxyfluorfen 0.125 No 29.3 de 13.3 cd 1.4 de 5 Oxyfluorfen 0.25 Yes 10.0 de 5.0 cd 0.5 de 6 Oxyfluorfen 0.25 No 9.0 de 3.8 cd 0.4 de 7 Oxyfluorfen 0.375 Yes 4.3 e 0.0 d 0.2 e 8 Oxyfluorfen 0.375 No 9.8 de 0.8 cd 0.4 e 9 Oxyfluorfen 0.5 Yes 3.3 e 0.8 cd 0.1 e 10 Oxyfluorfen 0.5 No 8.3 e 0.3 d 0.4 e 11 flumioxazin 0.063 Yes 4.0 e 1.0 cd 0.2 e 12 flumioxazin 0.063 No 16.5 de 4.0 cd 0.6 de 13Oxyfluorfen/pendimethalin 0.125/1.0 Yes 5.8 e 1.0 cd 0.3 e 14Oxyfluorfen/pendimethalin 0.125/1.0 No 3.3 e 0.3 d 0.1 e 15 pendimethalin 1.0 Yes 110.3 c 47.3 b 4.2 c 16 pendimethalin 1.0 No 62.8 cd 16.5 cd 2.0 d 17 Oxyfluorfen/ napropamide 0.125/2.0 Yes 11.5 de 2.8 cd 0.4 de 18 Oxyfluorfen/ napropamide 0.125/2.0 No 17.0 de 0.8 d 0.5 de 19 napropamide 2.0 Yes 185.5 b 101.8 a 7.3 b 20 napropamide 2.0 No 200.0 b 105.5 a 7.7 b 21 dazomet 150 Yes 12.3 de 16.8 cd 1.0 de 22 dazomet/Oxyfluorfen 150/0.125 Yes 2.0 e 1.5 cd 0.2 e LSD 54.399 23.620 1.623 Treatment probability 0.0001 0.0001 0.0001

106105

Control of Difficult Weeds in California Strawberry Production.

Oleg Daugovish and Maren Mochizuki, Farm Advisor and Staff Research Associate, UCCE-Ventura, 669 County Square Drive #100, Ventura, CA 93003, odaugovish@ucdavis.edu

INTRODUCTION

Strawberries for fresh market and processing were grown on 21,200 ha in the United States in 2005, a crop valued at $1.4 billion (USDA ERS 2007). Nearly 90% of U.S. strawberries were grown in the California coastal areas around Watsonville (36% of California production area), Oxnard (33%), and Santa Maria (18%) (USDA ERS 2007); fruit is harvested from January to June in the southern region of the state and from March to October in the northern region.

Strawberry transplants are particularly sensitive to competition with weeds early in the

season (Fennimore et al. 2005). Soil fumigation and opaque plastic mulch are standard practices costing $1,750-5,000 per ha that provide some initial weed control (Daugovish et al. 2004), however weeds with hard seed coats such as little mallow and clovers escape fumigation and germinate during production season. Oxyfluorfen and flumioxazin herbicides were effective against broadleaf weeds when tested in vegetable production (Daugovish et al. 2006, Hatterman-Valenti and Auwarter 2007, Shrefler and Webber 2004) and are registered for strawberry in California but their use has been limited. Flumioxazin is new to strawberry industry in California, while oxyfluorfen applications raised concerns due to potential crop injury. Oxyfluorfen moves with water vapor from the soil surface to strawberry foliage, a process known as “lift off” or codistillation (Fennimore et al. 2005) and can injure the plants. Alternative fumigants are less effective than methyl bromide in controlling yellow nutsedge. Shoots of nutsedge penetrate opaque mulch and rapidly establish in strawberry beds. When applied via drip fumigants do strawberry beds, the furrows remain non-fumigated, allowing weed growth. Yet another increasing problem is with weeds with wind dispersed seed which establish in strawberry planting holes and furrows throughout the season. One of the common wind dispersed species – horseweed has been recently reported to be resistant to glyphosate.

Our studies focused in four areas: pre-plant application of oxyfluorfen to beds, control of yellow nutsedge in non-fumigated strawberry, furrow weed control, and control of wind-dispersed weeds.

MATERIALS AND METHODS Pre-plant application of oxyfluorfen to beds

Eight randomized complete block (RCB) experiments (2002-2006) with four replications each evaluated weed control and crop injury with 0.6 or 0.3 kg· a. i. ha-1 of oxyfluorfen applied 30 days before strawberry transplanting. Individual plots were 1.5 m wide and 30 m long at Oxnard, California and 1.3 m wide and 6.1 m long at Salinas, California. Following application,

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beds were either immediately covered with PVC mulch or remained bare until 4-5 weeks after planting.

Yellow nutsedge control.

An RCB experiment with five replications was conducted at Oxnard, California (2006-2007) to compare emergence of yellow nutsedge and crop performance in beds covered with black PVC mulch alone and beds were Novovita paper (recycled newspapers, gypsum) was laid under mulch. In 2007-2008 this experiment was repeated but Novovita paper was installed between the two layers of plastic mulch, and, as additional treatments, weed barrier matt and water resistant Tyvek (DuPont) home wrap paper were tested under black PVC mulch. All plots were 1.5 by 8 m.

Furrow weed control.

An RCB experiment with three replication at Camarillo, CA compared weed control with flumioxazin at 0.1 kg a. i.·ha-1 and oxyfluorfen 0.3 kg a. i. ·ha-1 applied to furrows 30 days pre-transplant. Individual plots were 12 by 35 m. In an additional RCB experiment with four replications at Santa Paula, CA we evaluated weed control and crop safety of flumioxazin applied at 0.1 kg·a. i. ha-1 to furrows or over the bed top during strawberry fruiting in March 2007.

Herbicide evaluation for control of fleabane and sowthistle.

This RCB experiment at Santa Paula, California with four replications evaluated flumioxazin at 0.1 kg·a. i. ha-1 and oxyfluorfen at 0.3 kg a. i.·ha-1 for fleabane and sowthistle control at Santa Paula, CA. Weed seed were collected locally, mixed with sand and dispersed manually on moist bed tops to simulate natural deposition. Herbicides were applied the next day, the beds were immediately covered by clear mulch and strawberry was transplanted 30 days later.

In all studies weeds were counted by species, injury evaluated in percent and weeding time recorded for two persons per plot at Oxnard, Camarillo and Santa Paula. Analyses of variance for weed numbers, percent injury and weeding times were performed with the GLM Procedure in SAS (SAS Systems, Cary, NC) with the overall error rate controlled by Tukey-Kramer adjustment.

RESULTS AND DISCUSSION

Pre-plant application of oxyfluorfen to beds.

Averaged over the eight studies, oxyfluorfen at 0.3 kg a. i.·ha-1 provided 89-100% control of little mallow and most other broadleaf weeds, but only 0.6 kg a. i.·ha-1 rate controlled of yellow sweetclover 45-95%. Weeding times in oxyfluorfen treated plots were, on average, 37-

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63% less that in untreated controls. Oxyfluorfen did not control yellow nutsedge and injured strawberry when plastic mulch was not present before transplanting. However, when mulch was laid prior to crop transplanting the co-distillation of herbicide was greatly reduced and no injury occurred. This indicated that with proper application, oxyfluorfen is an effective, economical and safe herbicide that especially valuable in controlling hard-seed weeds that survive fumigation.

Yellow nutsedge control.

In fall and winter the combination of paper under plastic completely eliminated yellow nutsedge germination that otherwise germinated through plastic at a density of 5 plants m²-1 per week. However, in spring when the paper disintegrated due to contact with wet soil and when soil temperature increased above 16ºC the nutsedge resumed germination at a rate of 3 to16 plants m²-1 per week in all treatments. This indicated that paper with greater water resistance or/and protected from contact with wet soil may be needed for a season- long control. In 2007-2008 the weed barrier matt, paper layered between two plastic mulch layers and water resistant Tyvek (Du Pont) paper all provided 100% control of nutsedge shoots that otherwise germinated through plastic at a density of 0.6 plants m²-1 per week. This study suggests that persistent mechanical barriers prevent nutsedge germination and are especially valuable in non-fumigated and organic production in the absence of other nutsedge control tools.

Furrow weed control

At Camarillo, both oxyfluorfen and flumioxazin treatments reduced weed densities (primarily wind-dispersed weeds) 84-95% at 4 weeks after application, about 68% at 8 weeks, and reduced weeding time 50% or more compared to untreated control. This study showed that pre-plant furrow application of oxyfluorfen and flumioxazin to furrows were safe and effective, however, additional in-season weed control in furrows is needed. At Santa Paula, flumioxazin provided complete (100%) control of burning nettle (Urtica urens), little mallow and nettleleaf goosefoot (Chenopodium murale) in furrows and did not injure strawberry. However, when applied over the bed top, flumioxazin damaged strawberry fruit and foliage resulting in significant fruit losses for 3 weeks after application. This indicates that flumioxazin may be useful for in-season weed control but caution should be exercised to prevent herbicide drift to strawberry plants during furrow application.

Herbicide evaluation for control of fleabane and sowthistle

Both, oxyfluorfen and flumioxazin controlled sowthistle near 100% and did not injure strawberry. Fleabane failed to germinate until 12 weeks after strawberry transplanting and was not controlled by either herbicide at that time. In this and in previous studies we have observed that wind-blown weeds continuously reinfest the strawberry planting holes and furrows as they blow in from the surrounding areas. Thus, destruction of seed sources in and outside the production field is essential in minimizing weeding expenses associated with this wind-dispersed weeds.

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Overall, this weed management program identified cost-effective management tools for difficult to control weeds in California strawberries. We continue investigation of mechanical barriers and herbicides to control difficult weeds.

LITERATURE CITED

Daugovish, O., S. A. Fennimore, R. Smith, J. Rachuy, M. Mochizuki. 2006. Weed control for broccoli in coastal California. Calif. Weed Sci. Soc. Annu. Mtg., Ventura, 16-18 Jan. 2006.

Daugovish O., E. Takele. K. M. Klonsky and R. M. DeMoura. 2004. Sample costs to produce strawberries- South coast region-Ventura County. Available at: http://coststudies.ucdavis.edu/files/strawscvent2004.pdf. Accessed Oct. 11, 2007

Fennimore S. A., R. F. Smith, and W. E. Bendixen. 2005. Strawberry integrated weed management. In: University of California Integrated Pest Management Guidelines: Strawberry. UC Agriculture and Natural Resources Publication 3468. Available at: http://www.ipm.ucdavis.edu/PMG/r734700111.html. Accessed Aug. 2, 2007.

Hatterman-Valenti, H.M. and C.P. Auwarter. 2007. Broadleaf weed control in transplanted cabbage. Abs. HortScience 42:872.

Shrefler, J. and C.L. Webber III. 2004. Transplanted onion weed control. Abs. Available at:http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=163851. Accessed on: 9 Oct., 2007.

[USDA ERS] United States Department of Agriculture Economic Research Service. 2007. U.S.

Strawberry Industry. Table 1, 4, 5. Available at:http://usda.mannlib.cornell.edu/MannUsda/viewDocumentInfo.do?documentID=1381. Accessed Aug. 2, 2007.

110109

Pesticide Enforcement in the Urban Environment

Christine Belden, Agricultural/ Wts. & Meas. Inspector III Pesticide Division, CBelden@acwm.lacounty.gov

Los Angeles County is approximately 4,000 square miles and has a population of over 10 million people. Agriculture is still prevalent in the outlying areas of Los Angeles County. In the L.A. basin, wholesale nurseries grow plants under power lines and Edison right of ways. Nursery stock is one of Los Angeles County’s top grossing commodities. However, urbanization has dramatically increased over the last several years, and the use of pesticides has been under understandable scrutiny. No matter where pesticides are used, it is vital that the application be done safely, with consideration for the applicator, the neighbors, and the environment. The perception of pesticide usage is generally not a favorable one with the public. A well planned pest control program makes use of the cultural, physical, chemical methods. Using the pesticide permitting program, inspectors can verify that a safe material handling program is in place. By performing pesticide use inspections we can ensure that potentially dangerous materials are being used in a safe and effective manner.

111110

California Department of Food and Agriculture’s Regulated Noxious Weed Programs

Carri Pirosko1 and Courtney Albrecht

2, California Department of Food and Agriculture

1Associate Agricultural Biologist, Integrated Pest Control Branch, 37490 Toronto Ave., Burney

CA 96013, cpirosko@cdfa.ca.gov 2Senior Agricultural Biologist, Pest Exclusion Branch, 1220 N Street, Sacramento CA 95814,

calbrecht@cdfa.ca.gov

The Mission of the California Department of Food and Agriculture is to promote and protect California agriculture. This includes the prevention, introduction and spread of injurious insects or animal pests, plant diseases, and noxious weeds. The Noxious Weeds Program is authorized by the California Food and Agricultural Code, Section 403 where it states, “The Department shall prevent the introduction and spread of … noxious weeds.” The term “noxious weed” is defined in the code, Section 5004 as “any species of plant which is, or is liable to be, detrimental or destructive and difficult to control or eradicate.” USDA/APHIS, CDFA Exterior (border stations), and CDFA Interior (CDFA biologists) and County Agricultural Commissioners share responsibility in regulating noxious weeds at California’s borders, as well as within the state. An Action-Oriented Pest Rating System provides guidance from the California Department of Food and Agriculture to county and state agricultural inspectors on regulatory actions to take when a plant pest is detected or intercepted in trade or in the environment. Under the system, plant pests are assigned a rating (A, B, C, D, or Q). The rating designates the recommended regulatory action, ranging from eradication and containment to release at the discretion of the county agricultural commissioner. Although not codified as a law, the Plant Pest Rating System is a policy that enables the Department to carry out laws intended to protect California’s agriculture against pests. A procedure is in place to change a pest rating and includes the following steps and guidelines: (1) “Q” pests to be reviewed every year, (2) a request can come from any interested person to change an existing “A”, “B”, “C” or “D”, (3) a Pest Study Team is convened to review new requests, (4) supporting documentation is review by the team, (5) other affected agencies are consulted, (6) A new rating is proposed to County Agricultural Commissioner’s and a 30-day comment period follows, and lastly (7) a final rating is published. The Department has a proven track record with A-rated statewide noxious weed eradications. Thirteen A-rated weeds have been eradicated from the state entirely: whitestem distaff thistle (Carthamus leucocaulos), dudaim melon (Cucumis melo L. var. dudaim), giant dodder (Cuscuta reflexa), serrate spurge (Euphorbia serrata), Russian salt tree (Halimodendron halodendron), blueweed (Helianthus ciliaris), tanglehead (Heteropogon contortus), creeping mesquite (Prosopis strombulifera), southern meadow sage (Salvia virgata), heartleaf nightshade (Solanum cardiophyllum), Austrian peaweed (Sphaerophysa salsula), wild marigold (Tagetes minuta ), and Syrian beancaper (Zygophyllum fabago). In addition, several A-rated noxious weeds are approaching statewide eradication: golden thistle, Scolymus hispanicus (zer o-few plants in Alameda County), perennial sowthistle, Sonchus arvensis (small sites in Modoc and Santa Barbara Counties), long-leaf groundcherry, Physalis longifolia (small sites in Siskiyou County), Taurian thistle, Onopordum tauricum (small sites in Siskiyou and Monterey Counties), Illyrian

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thistle, Onopordum illyricum (zero-few plants in Santa Clara County), and camelthorn, Alhagi maurorum (only 1 site in Inyo County). Examples of County/Regional Eradications of A-rated noxious weeds include: hydrilla, hydrilla verticillata from eleven Counties and Scotch thistle, Onopordum acanthium from twelve Counties. California has a unique and coordinated noxious weed program/system with a long history. District Biologist and County Agricultural Commissioner’s Offices are out there working A-rated Noxious Weed populations to eradication. Eradication of incipient populations of A-rated Noxious Weeds is possible. Continued successes are tallied each year.

113112

Registration for Sales of Pesticides with Department of Pesticide Regulations

Richard Bireley, Associate Environmental Research Scientist, California Department of Pesticide Regulation, 1001 I Street, Sacramento, CA 95812, rbireley@cdpr.ca.gov

Before a company can sell a pesticide in California, the product must first be registered by the Department of Pesticide Regulation (DPR). As part of the registration process, the company must submit certain supporting data to DPR. Scientists in a variety of disciplines review these data to determine the accuracy of the data, the results of the studies, the potential impacts to humans and the environment, and whether the pesticide (herbicide) works according to the label claims. A significant portion of these required data represent the pesticide’s potential impact on fish, wildlife and the natural environment. The submitted data include acute, subacute, and chronic studies on the impacts of the active ingredient on various species of freshwater and estuarine fish and invertebrates, birds, mammals, sediment dwelling aquatic invertebrates and honeybees. The species tested are intended to represent other similar species. For example, the results of the bluegill sunfish toxicity study are extrapolated to represent the effects of the pesticide on all warm water fish species. In addition, scientists review environmental fate data to determine what the pesticide does in the environment. These data tell us how long a pesticide lasts in the environment under a variety of conditions, what the metabolites are, how long the metabolites last in the environment, the solubility of the pesticide in water, and whether the pesticide will move in soil. The results of all the data reviews are then used to build a picture of what the pesticide will do in the environment when used according to label directions. This picture is the basis for the recommendation of whether the pesticide should be registered as submitted by the registrant.

114113

Volatile Organic Compounds Regulation Update

Randall Segawa, Department of Pesticide Regulation, 1001 I Street Sacramento, CA 95812, rsegawa@cdpr.ca.gov

The State Implementation Plan (SIP) for ozone requires the Department of Pesticide Regulation (DPR) to track and reduce volatile organic compound (VOC) emissions from pesticides in five non-attainment areas. DPR estimates and tracks VOC emissions based on pesticide use report data, lab data on the VOC content of pesticide products, and field emission data for fumigants. Three of the five non-attainment areas currently do not meet the reduction obligations in the SIP. DPR has developed regulations to obtain the needed reductions by controlling fumigant emissions. The regulations contain five major elements. First, pest control businesses must have at least one person certified in the new licensing sub-category for fumigation. Second, only "low-emission" fumigation methods can be used during May - October in the three non-attainment areas that need additional reductions. Third, pesticide use reports for fumigations in the five non-attainment areas must include the specific method of fumigation. Fourth, DPR must implement a fumigant limit for a non-attainment area if emissions exceed a trigger level. DPR will implement a fumigant limit for the Ventura non-attainment area in 2008, and likely in the San Joaquin Valley and Southeast Desert non-attainment areas in 2009. The fumigant limits are enforced through "emission allowances" included as a condition on restricted materials permits for each grower. Fifth, DPR must publish an annual report containing the latest emission estimates and any needed fumigant limits.

115114

Research Authorization Program in California

Maryam Khosravifard, Staff Environmental Scientist, California Department of Pesticide Regulation, 1220 N Street Sacramento, Ca 95814, mkhosrav@cdfa.ca.gov

The Research Authorization (RA) program governs the experimental application of pesticides in California. The permits are requested by, and granted to researcher personnel working for registrants, contract researchers, commodity groups, and individuals seeking to test pesticides to study efficacy, residues, environmental fate and other aspects of pesticide use. The purpose of these tests is to gather information to eventually support the registration and use of a product in California and with the USEPA. The oversight of the RA program resides in the Department of Pesticide Regulation (DPR), Pesticide Registration Branch, in the Plant Physiology station. Authorization for Research (CCR Section 6260) Authorization for research shall be obtained from DPR prior to any experimental, unregistered use of pesticide. The authorization may specify conditions under which the research shall be conducted. The condition may include handling of the treated commodity, safety equipment, reentry intervals, medical monitoring, and field posting. Research requiring an approved human exposure protocol pursuant to Section 6710, shall be conducted in accordance with that protocol. DPR may terminate, amend, or refuse to issue a RA whenever it is determined that 1) the research may involve a hazard to handlers and/or field workers, the public health or the environment; 2) the research is used for purposes unrelated to pesticide data development; or 3) violation of the authorization, a previous authorization, or Division 6 or 7 of the Food and Agriculture Code, or regulations adopted pursuant to them, have occurred in connection with such research. Application for Research Authorization (CCR Section 6262) Application for a RA may be obtained from DPR at www.DPR.CA.gov/docs/regforms/ra/ramenu.htm. The application requires applicants to provide the following information: 1) Name, mailing address and telephone number of applicant; 2) pesticide to be applied; 3) type of site or commodity and stage of growth at which pesticide will be applied; 4) size, number, and total area of trials; 5) date of first and last applications; 6) type of data sought; 7) planned disposition of treated commodity; 8) signature and title of persons responsible for the trials. Additional data may be required if necessary to assess the potential adverse effects to workers, the public, and/or the environment.

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Notification and Use of Research Authorization (CCR Section 6264) At least 24 hours prior to beginning application of a pesticide, the researcher shall submit to the agricultural commissioner of the county where the proposed trial site is located a copy of the RA. In addition a notice of intent as provided in Section 6434(b) specifying the location of each trial. If not submitted with the notice of intent, the research shall submit a plot map of the exact location of each trial within seven days after initial application of the pesticide. If no application of pesticide is made following the notice of intent, the researcher shall notify the agricultural commissioner within two weeks by submitting an Experimental Trial Report as required in Section 6266 (a). Reports of Research Authorization Use (CCR Section 6266) The researcher shall submit an Experimental Trial Report to California agricultural commissioner following the final application of a pesticide requiring an RA, and at least 24 hours prior to either harvest or crop destruction the following information: 1) firm name; 2) RA number;3) commodity or site treated; 4) date of report; 5) trial location; 6) date and method of planned disposition of treated commodity; and 7) name and telephone number of researcher or representative responsible for crop disposition. The researcher shall submit to the DPR an Experimental Pesticide Use Report within two weeks following the expiration date of the RA. The report shall include the following information: 1) RA number; 2) pesticide product applied; 3) commodity or site treated; 4) rate of active ingredient per acre or unit; 5) Total amount of active ingredient used 6) total acres or units treated; 7) counties where trials were conducted; 8) name, address, and phone number of researcher; 9) certification that the commodity was harvested/disposed of as required by RA. Exemption from Authorization for Research (CCR Section 6268) A pesticide registrant is exempt from these requirements when the registrant is the operator of the property upon which the research is to be conducted and continues to be the operator until the treated commodity is destroyed or harvested. Also, personnel employed by colleges and universities and engaged in pesticide research are exempt if they are operating according to the current established policy of the college or university, which covers pesticide use and experimentation. Position of Authorization (CCR Section 6272) Each person making an application of a pesticide under a RA shall have a copy of the RA available at the use site at the time of application.

117116

Herbicide Efficacy and Phytotoxicity Requirement

Maryam Khosravifard, Staff Environmental Scientist, California Department of Pesticide Regulation,1220 N Street Sacramento, CA 95814, mkhosrav@cdfa.ca.gov

Efficacy data is required for herbicide registration to support label claims and uses. Data must demonstrate consistent product efficacy whether the product is used according to label directions. The user of the product must be assured that there is significant benefit from the use of product. Efficacy data development generally follows USEPA Guidelines Subdivision G, Product Performance, series 94. Herbicide registrants develop data, which they submit, or data from the public literature. Field trials shall be designed to allow for appropriate statistical analysis such as randomized complete block design. P retreatment and post treatment of trials shall be documented. Treatments shall include untreated controls, standard products, and several rates to demonstrate that selected label rates are appropriate. Statistical analysis of data is required to demonstrate significance at 95 percent confidence. Efficacy trials shall be conducted in California or under California like conditions. Trials shall be conducted over two growing seasons and at several locations based on where crops are grown in California. Phytotoxicity data are required to demonstrate safety of formulated products to crops/plants being treated and crops located off-site or adjacent. Usually use injury ratings or other parameters such as yield, vigor, necrosis, chlorosis is documented. At a minimum, documentation or lack of phytotoxicity as part of efficacy trials and residue studies are acceptable. Margins of safety may be established by using twice label rate or higher rates. Data presentation is very important part of reports for efficacy and phytotoxicity studies. Reports should include product overview, summary of results of field trials with the use of tables, charts, and graphs. Individual trial results should include trial summary, raw data, statistical analysis, terms definitions, and any abbreviations.

118117

Precision Guided Cultivation in Lettuce and Celery

Christina A. George Graduate Student Researcher, University of California Davis John S. Rachuy Staff Research Associate III Cooperative Extension UC Davis

Steven A. Fennimore Extension Vegetable Weed Specialist UC Davis 1636 East Alisal St. Salinas, CA 93905; 831-755-2896; safennimore@ucdavis.edu

Abstract

In 2007, three trials were conducted to evaluate the efficiency of the Robocrop vision-guided system with various cultivation tools in conjunction with post-emergent and pre-emergent herbicides. The lettuce trials were arranged as a split plot with pronamide as the main plot and cultivator tool or directed herbicide as the subplot. Half of the main plots were treated with a pre-emergent application of pronamide at 1.2 ai/Ac in 40 GPA, the other half of the plots received no pronamide. The cultivator tools included in the comparison were: sweep knives, bezzerides, and coulters with sweep knives. The post-emergent directed herbicides included Scythe 4.2EC and Shark 2E. Scythe was applied at 3 and 6% v/v in the first trial and second trials respectively, while Shark was applied at 0.032 lb/ai/Ac in both trials. Data gathered were the number of marketable heads, weed densities and hand-weeding times. In the celery trial, the Robocrop was used to guide an application of Scythe herbicide at 3% v/v in a volume of 100 GPA directed between the plant lines and to guide a close cultivation with sweep knives. Data gathered in the celery study were crop injury, and yield, weed densities and hand weeding times. The first lettuce trial showed that the pronamide application significantly reduced hand weeding times, produced larger marketable heads, and increased yield. The bezzerides gave the highest yield when the pronamide was applied. The best weed control in both trials was found in the plots that used knives, coulters with knives, and Shark. However Shark caused crop injury and lowered yields. In the second trial, the bezzerides and the Scythe treatments produced the largest heads; Shark again injured the crop. In the celery trial, the knives and directed Scythe spray significantly reduced weeds, and no crop injury was observed. The Scythe treatment produced the greatest number, weight, and size of marketable celery stalks.

119118

Simazine, Diuron, and Atrazine Detections in California Surface Waters

Michael P. Ensminger, Keith Starner, and Kevin Kelley, California Department of Pesticide Regulation, Environmental Monitoring Branch, 1001 I Street, Sacramento, CA 95812,

mensminger@cdpr.ca.gov

Introduction A wide variety of herbicides are applied annually in high amounts throughout California. In 2006, 65 herbicide active ingredients were each applied in amounts over 1,000 kg active ingredient; this amounted to about 8.8 million kg herbicides applied. For many of these herbicides, recent surface water monitoring data from areas of high use are lacking; such data are needed in order to assess their potential impacts on aquatic systems. Simazine and atrazine, both triazine herbicides used to control broadleaf weeds and annual grasses, are toxic to non-target aquatic plants. Simazine is used in several agricultural regions of California and is applied to wine grapes in the Sonoma/Napa area during California’s wet season. Almost half of California’s atrazine use occurs in the Imperial Valley. No recent triazine surface water monitoring data are available for these regions of high use. In 2006, DPR initiated a monitoring study designed to begin assessing pesticide contamination of surface waters in high-use regions of the state. As part of that study, surface water samples were collected from Napa, Sonoma, Monterey, and Imperial Counties in early 2007 and analyzed for a suite of seven herbicide active ingredients. Materials And Methods Twenty-eight monitoring sites were chosen in three regions of California: Napa/Sonoma, Imperial, and Monterey Counties. From the 28 sites, a total of 35 samples were collected in January, February, or March 2007. In two regions of California, sampling was timed to coincide with historic periods of high triazine herbicide use; simazine in Napa/Sonoma Counties, and atrazine in Imperial County. For one sampling interval in Napa/Sonoma, storm run-off samples were collected during a winter storm. All other sampling occurred during dry weather. Surface water samples were collected as close as possible to the center channel by using an extendable pole, collecting the water sample directly into a 1 L amber bottle. After collecting the samples, bottles were sealed with Teflon®-lined lids and transported on wet ice or refrigerated at 4°C until extracted for chemical analysis. At each site, dissolved oxygen, pH, specific conductance and water temperature were measured in situ. The California Department of Food and Agriculture’s Center for Analytical Chemistry (CDFA) analyzed the surface water samples for the following herbicides: atrazine, simazine, diuron, prometon, bromacil, hexazinone, and norflurazon. Reporting limits (RL) for all herbicides are 0.05 μg L-1. Detections above the RL were reported in μg L-1; detections below the RL but above the method detection limit were reported as trace detections but were not quantified.

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Results And Discussion Several herbicides were detected in the water samples from the three regions (Table 1). Simazine was detected only in the Napa/Sonoma region; all storm samples had detections above the RL. Samples collected during dry weather in Napa/Sonoma had two trace detections of simazine. Atrazine was detected only in Imperial County; two samples were detectioned above the RL and two additional samples were trace detections. An additional sample from Imperial County had a trace detection of deethyl-atrazine (DEA), a degradate of atrazine. Diuron was detected above the RL in all three regions. The overall detection frequency of diuron, including trace detections, was over 30%; this is especially significant considering that diuron use is relatively low in these regions at the times sampled. The detected concentrations of simazine, atrazine and diuron did not exceed the US EPA Aquatic Life Benchmarks. However, triazine herbicides, as well as diuron, have been shown to potentiate the effects of organophosphate (OP) insecticides. As such, concentrations of these herbicides that are not themselves toxic to aquatic organisms can increase the toxicity of OP insecticides that are present in the aquatic system. OP insecticides were co-detected with diuron in two samples from Monterey County and one sample from Imperial County. Additionally, both atrazine and simazine are suspected endocrine disruptors and the US EPA has recommended additional monitoring for these compounds. For diuron, monitoring results available elsewhere indicate that, in over 1200 samples collected throughout California between 2000 and 2005, the diuron benchmark of 2.4 μg L-1 was exceeded in about 5% of samples. The mass loading of herbicides during storm samples can also be substantial, as shown in Table 2. Mass loading calculations for simazine, diuron, and prometon indicate that large amounts of these herbicides can enter water bodies during storm events. Perhaps the most interesting data are for atrazine in the Salton Sea. The Salton Sea contains ca. 9.25 trillion L of water; it represents a large reservoir for potential dilution of incoming water. While the number of samples were limited, atrazine concentrations in the Salton Sea were greater than those in the primary input waters (Alamo and New Rivers). In addition, atrazine was detected in the Salton Sea ca. 42 km from the primary agricultural drainage inflows. Because the Salton Sea is a sensitive aquatic habitat, further sampling is warranted to better define the temporal and spatial extent of atrazine concentrations, evaluate those concentrations relative to aquatic toxicology benchmarks, and investigate the mass budgets of atrazine and other herbicides in the Salton Sea. The results from this study indicate that atrazine, simazine, and diuron are contaminants in surface water. Based on these results, additional monitoring for these herbicides is warranted. Monitoring for other herbicides with low aquatic toxicity benchmarks and high use, especially those with high use during California’s wet season, is also recommended. Herbicides that fit this profile include oxyfluorfen and several of the dinitroaniline herbicides (trifluralin, pendamethalin, and oryzalin). Where indicated, simultaneous monitoring for OP insecticides should also be considered.

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Table 1. Summary of 2007 herbicide monitoring results.

Detections (trace detections2) Region Date

Number of Samples Simazine Atrazine Diuron Other

Napa/Sonoma Jan 2007 14 0 (2) 0 2 (3) none Napa/Sonoma Feb 20071 7 7 0 2 prometon: 1 Imperial Mar 2007 10 0 2 (2) 1 DEA: 0 (1) Monterey Mar 2007 4 0 0 2 (1) none 1 Storm samples 2 First number is the number of detections (> RL); the number in parentheses, when present, is the number of trace detections (< RL).

Table 2. Mass loading of water bodies from detected herbicides using flow data from USGS gauging stations.

Water Body (flow rate, L sec-1)

Herbicide detected (μg L-1)

Mass loading (mg sec-1)

Mass loading (g day-1)

Napa River (14,385) diuron (0.095) 1.4 118 Napa River (14,385) simazine (0.556) 8.0 691 Russian River (291,664) diuron (0.077) 22.5 1,940 Russian River (291,664) simazine (0.842) 245.6 21,218 Russian River (235,879) simazine (0.096) 22.6 1,957 Mark West Creek (42,192) simazine (1.94) 81.9 7,072 Mark West Creek(42,192) prometon (0.092) 3.9 335 Sonoma Creek (15,065) simazine (0.227) 3.4 296

Acknowledgements Many people have generously given their time and talents to help this study succeed. We would like to thank Kean S. Goh for his overall support of this study and to Frank C. Spurlock and Marshall Lee for their swift and succinct review of the poster. We would like to thank Carissa Ganapathy for sample coordination and organization between DPR and CDFA and we would like to thank Jessie Ybarra for his help in maintaining DPR’s West Sacramento’s facility. Furthermore, we would like to thank the staff at DPR, Environmental Monitoring Branch, for assisting in field sampling. Finally, we extend gratitude to Steven Siegel, Jane White, Jean Hsu, and the staff at CDFA for sample analysis. Disclaimer The mention of commercial products, their source, or use in connection with material reported herein is not be construed as either an actual or implied endorsement of such products.

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References Banks, K.E, P.K. Turner, S.H. Wood, and C. Matthews. 2005. Increased toxicity to Ceriodaphnia dubia in mixtures of atrazine and diazinon at environmentally realistic concentrations. Ecotoxicology and Environmental Safety 60: 28-26. CA DPR 2007a. California Department of Pesticide Regulation, California pesticide information portal, pesticide use report (PUR) [Online]. Available at http://calpip.cdpr.ca.gov/cfdocs/calpip/prod/main.cfm (accessed on November 8, 2007). CA DPR 2007b. California Department of Pesticide Regulation, California surface water database [Online]. Available at http://www.cdpr.ca.gov/docs/sw/surfdata.htm (accessed on November 8, 2007). Starner, K. 2006. Preliminary assessment of pesticide contamination of surface waters in high use regions of California: malathion, methomyl, simazine, atrazine, and thiram. DPR study protocol [Online]. Available at http://www.cdpr.ca.gov/docs/emon/pubs/protocol/study238protocol.pdf (accessed on December 17, 2007). US EPA 2003b. October 31, 2003 revised atrazine IRED [Online]. Available at http://www.epa.gov/oppsrrd1/reregistration/atrazine/ (accessed on December 17, 2007). US EPA 2006. Reregistration eligibility decision for simazine. EPA 738-R-06-008 [Online]. Available at http://www.epa.gov/oppsrrd1/REDs/simazine_red.pdf (accessed on December 17, 2007).

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vedt

, Bru

ce K

idd,

Van

elle

Pet

erso

n, B

yron

Sle

ugh,

and

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dy S

mith

, Dow

Agr

oSci

ence

s LLC

, Ind

iana

polis

, IN

Mat

eria

ls a

nd M

etho

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ultip

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esea

rch

trial

s w

ere

initi

ated

in 2

005

and

2006

on

non-

crop

land

site

s in

C

alifo

rnia

, Id

aho,

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onta

na,

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rask

a,

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gon,

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uth

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ashi

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sm

all,

repl

icat

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ials

with

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ston

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3, 5

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l oz

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duct

/A, 3

to

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plic

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n a

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omiz

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sign

, app

lied

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usin

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GPA

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reat

men

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ere

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t 0.

25%

v/v

. Pl

ots

wer

e ev

alua

ted

at 4

7 to

379

day

s af

ter

appl

icat

ion

for p

erce

nt v

isua

l con

trol.

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ls w

ere

esta

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to a

sses

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lein

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n (C

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arth

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,

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aca

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ch

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pord

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ium

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pons

es to

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inop

yral

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mar

yM

ilest

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reg

iste

red

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he U

S EP

A i

n O

ctob

er 2

005.

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rty-e

ight

wee

d sp

ecie

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clud

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ada

this

tle (

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sium

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ense

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otte

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ussi

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llow

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k (C

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d bu

ll (C

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this

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nd y

ello

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awkw

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cium

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cum

and

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ere

liste

d on

the

labe

l. Fi

eld

trial

s ha

ve b

een

cond

ucte

d si

nce

the

regi

stra

tion

of M

ilest

one

to d

eter

min

e ef

ficac

y on

oth

er w

eeds

. Th

e ne

w

wee

ds c

ontro

lled

by M

ilest

one

incl

ude

mea

dow

kna

pwee

d, w

oolly

dis

taff

and

Ital

ian

this

tle,

tall

butte

rcup

, St

. Jo

hnsw

ort,

rush

ske

leto

nwee

d, S

cotc

h an

d ar

ticho

ke t

hist

les,

purp

le

star

this

tle, a

nd m

ulle

in.

A to

tal o

f 24

new

wee

d sp

ecie

s w

ere

adde

d to

the

late

st re

visi

on o

f th

e M

ilest

one

labe

l tha

t was

acc

epte

d by

EPA

in Ja

nuar

y 20

07.

Intr

oduc

tion

Am

inop

yral

id is

a n

ew p

yrid

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carb

oxyl

ic a

cid

herb

icid

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tend

ed fo

r use

in

rang

elan

ds, p

astu

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Con

serv

atio

n R

eser

ve P

rogr

am (C

RP)

, and

indu

stria

l ve

geta

tion

man

agem

ent a

reas

, inc

ludi

ng ri

ghts

-of-

way

for r

oads

, rai

lroad

s and

el

ectri

c ut

ility

line

s. T

his D

ow A

groS

cien

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igne

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d de

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spec

ifica

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con

trol o

f nox

ious

and

inva

sive

wee

d sp

ecie

s on

non

-cro

plan

d si

tes.

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inop

yral

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a n

ew g

ener

atio

n ac

tive

ingr

edie

nt

that

is e

ffec

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at v

ery

low

rate

s as c

ompa

red

to c

urre

ntly

regi

ster

ed

herb

icid

es w

ith th

e sa

me

mod

e of

act

ion,

incl

udin

g 2,

4-D

, clo

pyra

lid,

tricl

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, pic

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m a

nd d

icam

ba.

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inop

yral

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road

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rbic

ide

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vide

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ic, p

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mer

genc

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vasi

ve

annu

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ienn

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nd p

eren

nial

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rono

mic

ally

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mi-w

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inop

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an p

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sidu

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ontro

l, th

us re

duci

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e ne

ed fo

r re-

treat

men

t, de

pend

ing

on th

e ra

te a

pplie

d an

d th

e ta

rget

wee

ds.

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rent

ly a

min

opyr

alid

is re

gist

ered

as M

ilest

oneTM

, Mile

ston

e V

M, a

nd F

oreF

ront

™R

&P

(pre

mix

with

2,4

-D).

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ults

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5 a

nd 7

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celle

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l of

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lly

dist

aff

this

tle (

100/

100%

), ru

sh s

kele

tonw

eed

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95%

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Joh

nsw

ort

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d ta

ll bu

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ear a

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pplic

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able

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), ar

ticho

ke t

hist

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), an

d Ita

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80%

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1 y

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plic

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in t

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row

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f ap

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otch

th

istle

at 3

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trad

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124123

Weed Management in Almonds for 2007

Tome Martin-Duvall, Brent Holtz, Ron Vargas, University of California Cooperative Extension, 328 Madera Avenue, Madera CA 93637, tmmartinduvall@ucdavis.edu

Weed management in both young and established almonds (Prunus dulcis) is important to ensure proper growth and seasonal development. Many growers have reduced or eliminated weed management to conserve their financial resources. However, this is a mistake, as weeds will compete for water, nutrients, sunlight and space, interfere with effective harvest and physically reduce yield. New materials and new formulations of established materials have been evaluated in 2007 research trials. Materials and Methods All tests were applied with CO2 backpack sprayers delivering a spray volume of 20 GPA at 40 psi thru 8002 flat fan nozzles. 4 Year Almond Trial 2007: A four year old almond orchard planted to a 14 x 22 ft spacing was divided into 2 reps of Nonpariel and 2 reps of Fritz for a total of 4 replications of 14 treatments in RCBD. Evaluations in Jan and Feb showed no effects due to the lack of weeds believed to be from the severe cold weather during much of that time. Evaluations were conducted on April 13 (127 Days after the initial treatment - DAT), May 29 (173 DAT), September 11 (278 DAT), 2007. Harvest samples were collected on August 10 & Sept 19, 2007 1 Year Almond Trial 2007: An almond orchard planted March 1, 2006 on a 17 by 20 ft spacing was divided into two tree plots of 22 treatments with four replications in a randomized complete block design. Treatments were applied on Jan 3, 2007. Certain treatment were not applied at this time. The second application which included treatments not previously applied and sequentially timed treatments was April 16, 2007. Trunk diameters were taken on January 16, March 19, and June 5, 2007. Due to extremely cold weather, there were no weeds present to evaluate at 30 and 60 days after the initial treatment. Weed and crop injury evaluations were conducted on April 13 (127 DAT) and August 10 (219 DAT), 2007. Four year old trial site At 127 DAT only Matrix @ 4 oz tank mixed with Glyphosate (RU) at 1 qt and Induce (NIS) at 6.4 oz indicated significantly lower control that the best treatments. However this treatment still exhibited excellent control at 92% for hairy fleabane, foxtail barley, rattail fescue, mayweed, pineapple weed, whitestem filaree, panicle willowweed, shepherd’s purse, and white clover. There were no significant differences for brass buttons by any treatment. At 173 DAT, all treatments still provided excellent control of hairy fleabane, foxtail barley, and rattail fescue with only Matrix SC at 4 oz tank mixed with NIS or RU tank mixed with Rely and AMS exhibiting significantly less control than the other treatments. Mayweed, pineappleweed and whitestem filaree were completely controlled by all treatments. At 278 DAT, excellent control was exhibited for the following weeds by all treatments: barnyardgrass, junglerice - 100%, and cheeseweed - 95 to 100%. Fleabane exhibited 87 to 100% control, white clover exhibited 86 to 100 % control, and sowthistle exhibited 91 to 100% control with no significant differences between treatments. Acceptable control of spotted spurge was only exhibited by the following: Goal 2XL 2 pt mixed with Surflan 1 gal, RU 1 qt and NIS 6.4 fl oz; Matrix SG 4 oz mixed with

125124

NIS 6.4 oz, Chateau 8 oz mixed with Matrix SG 4 oz, Prowl H2O 4 qt and RU 1 qt; Chateau 8 oz mixed with Matrix SG 4 oz, Prowl H2O 3 qt, RU 1 qt and NIS 6.4 oz (2X); or RU 2 qt mixed with Rely 4 qt and AMS 10 lb. There was no indication of crop injury at any evaluation throughout the year.

4 Year Almond Weed Study 2007

0

10

20

30

40

50

60

70

80

90

100

Hairy Fleabane

127 DAT MatrixWG +NIS

MatrixWG+RU+NIS

Goal 2XL+Surflan+RU+NIS

MatrixSG+NIS

MatrixSG+RU+NIS

Chateau+MatrixSG+Prowl H2O+RU

MatrixSG+Surflan+RU

MatrixSG+Goal+RU+NIS

Chateau 6/8 +Prowl + RU+NIS

Chateau8+MatrixSG+Prowl+RU+NIS (2X)

RU+Rely+AMS

Gallery+GoalTender+Surflan+RU+NIS

Gallery+SurflanAS+RU+NIS

UTC

4 Year Almond Weed Study 2007

0

10

20

30

40

50

60

70

80

90

100

Hairy Fleabane Spotted Spurge

278 DAT MatrixWG +NIS

MatrixWG+RU+NIS

Goal 2XL+Surflan+RU+NIS

MatrixSG+NIS

MatrixSG+RU+NIS

Chateau+MatrixSG+Prowl H2O+RU

MatrixSG+Surflan+RU

MatrixSG+Goal+RU+NIS

Chateau 6/8 +Prowl + RU+NIS

Chateau8+MatrixSG+Prowl+RU+NIS (2X)

RU+Rely+AMS

Gallery+GoalTender+Surflan+RU+NIS

Gallery+SurflanAS+RU+NIS

UTC

126125

One year old trial site At 85 DAT, the greatest control of ryegrass was exhibited by Matrix SG tank mixed with Goal, Roundup WeatherMax (RU) and Induce (NIS) and was not significantly different from any treatment but the following: Chateau at 6 oz mixed with Prowl H2O, RU and NIS followed by Chateau at 8 oz mixed with Prowl H2O, RU and NIS (which still provided acceptable control); Gallery T&V at 0.67 lb mixed with Prowl H2O, RU and NIS or the UTC. There were no significant differences in chickweed control for any treatment with all treatments providing excellent control and significantly greater control than the UTC. There was no indication of crop injury by any treatment at this evaluation. At 219 DAT, paraquat had been uniformly sprayed over the entire trial site. There were no significant differences in sowthistle or spiny clotbur control. The greatest control of junglerice was exhibited by Gallery T&V at 1 lb mixed with Prowl H2O, RU and NIS at 94 percent. Although other treatments provided significantly similar control, control levels below 80 percent are considered adequate rather than good or excellent and anything less than 70 percent is considered unacceptable. There was no indication of crop injury at this evaluation.

Young Almond Weed Management 200785 DAT

3 pt + 3 qt + 25.6 fl oz + 6.4 fl ozGoalTender + Surflan + RU + NISb

6 qt + 6 ozRely + Chateaub

4 qt + 1 qt + 3 qtRely + GoalTender + Surflanb

6 qt + 1 qt + 3 qtRely + GoalTender + Surflanb

4 qt + 6 ozRely + Chateaub

7 b0 eUTC

100 a99 a4 oz + 1 gal + 1qtMatrix SG + Surflan + RUa

98 a100 a4 oz + 1 pt + 1 qt + 6.4 ozMatrix SG + Goal + RU + NISa

2 qt + 1 gal + 10 lbRU + Rely + AMSb

100 a96 ab8 oz + 4 oz +3 qt + 1 qt + 6.4 fl ozChateau + Matrix SG + Prowl H2O + RUab

53 d

94 abc

89 bc

94 abc

85 c

92 abc

96 ab

98 ab

96 ab

95 ab

99 a

Ryegrass

1 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISb

100 a0.67 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

100 a1.33 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

100 a1 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

100 a2 qt + 1 gal + 25.6 fl oz + 6.4 fl ozGoalTender + Prowl H2O+RU+NISa

100 a6 oz + 3 qt + 1 qt/8 oz + 3 qt + 1 qt + 6.4 fl ozChateau + Prowl H2O + RU/Chateau + Prowl H2O + RUab

100 a8 oz + 4 oz + 1 gal + 1 qtChateau + Matrix SG + Prowl H2O + RUa

100 a4 oz + 1 qt + 6.4 fl ozMatrix SG + RU + NISa

100 a4 oz + 6.4 fl ozMatrix SG + NISa

100 a2 qt + 1 Gal + 1 qt + 6.4 fl ozGoal 2XL + Surflan + RU + NISa

98 a4 oz + 1 qt + 6.4 fl ozMatrix WG + RU + NISa

100 a4 oz + 6.4 fl ozMatrix WG + NISa

ChickweedRateTreatment

127126

Young Almond Weed Management 2007

85 DAT

3 pt + 3 qt + 25.6 fl oz + 6.4 fl ozGoalTender + Surflan + RU + NISb

6 qt + 6 ozRely + Chateaub

4 qt + 1 qt + 3 qtRely + GoalTender + Surflanb

6 qt + 1 qt + 3 qtRely + GoalTender + Surflanb

4 qt + 6 ozRely + Chateaub

7 b0 eUTC

100 a99 a4 oz + 1 gal + 1qtMatrix SG + Surflan + RUa

98 a100 a4 oz + 1 pt + 1 qt + 6.4 ozMatrix SG + Goal + RU + NISa

2 qt + 1 gal + 10 lbRU + Rely + AMSb

100 a96 ab8 oz + 4 oz +3 qt + 1 qt + 6.4 fl ozChateau + Matrix SG + Prowl H2O + RUab

53 d

94 abc

89 bc

94 abc

85 c

92 abc

96 ab

98 ab

96 ab

95 ab

99 a

Ryegrass

1 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISb

100 a0.67 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

100 a1.33 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

100 a1 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

100 a2 qt + 1 gal + 25.6 fl oz + 6.4 fl ozGoalTender + Prowl H2O+RU+NISa

100 a6 oz + 3 qt + 1 qt/8 oz + 3 qt + 1 qt + 6.4 fl ozChateau + Prowl H2O + RU/Chateau + Prowl H2O + RUab

100 a8 oz + 4 oz + 1 gal + 1 qtChateau + Matrix SG + Prowl H2O + RUa

100 a4 oz + 1 qt + 6.4 fl ozMatrix SG + RU + NISa

100 a4 oz + 6.4 fl ozMatrix SG + NISa

100 a2 qt + 1 Gal + 1 qt + 6.4 fl ozGoal 2XL + Surflan + RU + NISa

98 a4 oz + 1 qt + 6.4 fl ozMatrix WG + RU + NISa

100 a4 oz + 6.4 fl ozMatrix WG + NISa

ChickweedRateTreatment

Young Almond Weed Management 2007 219 DAT August 10 2007

100

98

96

99

99

99

100

92

100

100

100

99

100

99

95

92

98

94

89

100

91

98

Sowthistle

10070 bcd3 pt + 3 qt + 25.6 fl oz + 6.4 fl ozGoalTender + Surflan + RU + NISb

9666 bcde6 qt + 6 ozRely + Chateaub

10055 cdefg4 qt + 1 qt + 3 qtRely + GoalTender + Surflanb

10080 ab6 qt + 1 qt + 3 qtRely + GoalTender + Surflanb

9855 cdefg4 qt + 6 ozRely + Chateaub

10080 abUTC

9545 fgh4 oz + 1 gal + 1qtMatrix SG + Surflan + RUa

10068 bcde4 oz + 1 pt + 1 qt + 6.4 ozMatrix SG + Goal + RU + NISa

10050 efg2 qt + 1 gal + 10 lbRU + Rely + AMSb

10079 ab8 oz + 4 oz +3 qt + 1 qt + 6.4 fl ozChateau + Matrix SG + Prowl H2O + RUab

94 a

74 bc

75 ab

64 bcdef

76 ab

82 ab

79 ab

51 def

26 hi

75 ab

36 ghi

25 i

Junglerice

981 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISb

1000.67 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

991.33 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

941 lb + 1 gal + 25.6 fl oz + 6.4 fl ozGallery T&V + Prowl H2O+RU+NISa

982 qt + 1 gal + 25.6 fl oz + 6.4 fl ozGoalTender + Prowl H2O+RU+NISa

926 oz/ 8oz + 3 qt + 1 qtChateau + Prowl H2O + RU/Chateau

988 oz + 4 oz + 1 gal + 1 qtChateau + Matrix SG + Prowl H2O + RUa

884 oz + 1 qt + 6.4 fl ozMatrix SG + RU + NISa

1004 oz + 6.4 fl ozMatrix SG + NISa

1002 qt + 1 Gal + 1 qt + 6.4 fl ozGoal 2XL + Surflan + RU + NISa

984 oz + 1 qt + 6.4 fl ozMatrix WG + RU + NISa

1004 oz + 6.4 fl ozMatrix WG + NISa

Spiny ClotburRateTreatment

128127

Perf

orm

ance

of a

new

org

anic

her

bici

de b

ased

on

d-lim

onen

eM

.E. K

oivu

nen,

L.E.

Fer

nánd

ez, B

.J. C

ampb

ell,

J. V

ersm

an, a

nd P

.G. M

arro

neM

arro

ne O

rgan

ic In

nova

tions

, Inc

., D

avis

, Cal

iforn

ia; m

koiv

unen

@m

arro

neor

gani

cs.c

om

Nat

ural

pro

duct

her

bici

des h

ave

the

pote

ntia

l to

play

an

impo

rtant

role

in

cont

rolli

ng w

eeds

on

orga

nic

farm

s by

redu

cing

relia

nce

on ti

llage

and

cul

tivat

ion

and

repl

acin

g ex

pens

ive

hand

hoe

ing

prac

tices

. In

addi

tion,

cos

teff

ectiv

e na

tura

l pr

oduc

ts w

ith h

igh

effic

acy

coul

d re

plac

e m

ore

toxi

c pe

stic

ides

cur

rent

ly in

use

on

con

vent

iona

l far

ms.

Nat

ural

her

bici

des c

onta

inin

g ei

ther

vin

egar

(ace

tic a

cid)

or c

love

oil

(eug

enol

) ar

e co

mm

erci

ally

ava

ilabl

e to

org

anic

gro

wer

s, bu

t onl

y lim

ited

info

rmat

ion

is

avai

labl

e on

thei

r eff

ectiv

e us

e. G

reen

hous

e an

d fie

ld tr

ials

hav

e sh

own

that

vi

nega

r app

lied

in c

once

ntra

tions

bet

wee

n 10

and

30%

can

eff

ectiv

ely

supp

ress

m

ultip

le b

road

leaf

wee

d sp

ecie

s, bu

t can

not c

onsi

sten

tly c

ontro

lgra

sses

(F

ergu

son

and

Cha

se 2

005)

. Clo

ve o

il at

con

cent

ratio

ns o

f 1 to

10

% h

as a

lso

been

dem

onst

rate

d to

pro

vide

goo

d co

ntro

l of s

ever

al b

road

leaf

wee

d sp

ecie

s in

som

e st

udie

s (B

aina

rdet

al.

2006

; Tw

orko

ski,

2002

) but

inco

nsis

tent

con

trol i

n ot

hers

(e.g

. Fer

guso

n an

d C

hase

200

5).

A n

ew O

MR

I-lis

ted

orga

nic

herb

icid

e ba

sed

on d

-lim

onen

e (G

reen

Mat

ch™

O,

EPA

Reg

. No.

820

52-1

) has

rece

ntly

bee

n in

trodu

ced

to th

e m

arke

t by

Mar

rone

O

rgan

ic In

nova

tions

, and

a se

ries o

f lab

orat

ory

bioa

ssay

s and

fiel

d st

udie

s hav

e be

en c

ondu

cted

to d

emon

stra

te it

s eff

icac

y on

som

e of

the

mos

t com

mon

wee

ds in

or

gani

c fa

rmin

g sy

stem

s.

Intr

oduc

tion

Intr

oduc

tion

Abs

trac

tA

bstr

act

In o

rgan

ic fa

rmin

g, b

iolo

gica

l con

trol

of w

eeds

usi

ng h

erbi

cide

sbas

ed

on n

atur

al p

rodu

cts o

r ph

ytot

oxic

mic

robi

al m

etab

olite

sis a

pot

entia

l al

tern

ativ

e fo

r ha

nd h

oein

g an

d fla

min

g. T

he h

erbi

cida

l eff

ects

of p

lant

ex

trac

ts a

nd e

ssen

tial o

ils h

ave

been

ack

now

ledg

ed fo

r de

cade

s but

onl

y re

cent

ly h

ave

thes

e pr

oduc

ts b

ecom

e co

mm

erci

ally

ava

ilabl

e fo

r gr

ower

s. O

ne o

f the

mos

t pro

mis

ing

orga

nic

herb

icid

es is

d-li

mon

ene,

a m

onot

erpe

neex

trac

ted

from

ora

nge

peel

s. It

has

pre

viou

sly

been

use

d as

an

inse

ctic

ide

in

orga

nic

farm

ing

but r

ecen

t fie

ld st

udie

s hav

e sh

own

that

a

d-lim

onen

e-pr

oduc

t, G

reen

Mat

ch™

O (7

0 %

d-li

mon

ene)

, at 1

:3 d

ilutio

n co

ntro

ls m

ost o

f the

com

mon

bro

adle

aved

and

gra

ss w

eeds

. The

non

-sy

stem

ic b

urn-

dow

n ef

fect

is b

ased

on

fast

dis

rupt

ion

of th

e le

af c

utic

le,

whi

ch le

ads t

o w

iltin

g. T

he e

ffec

t is d

epen

dent

on

tem

pera

ture

as w

ell a

s the

pl

ant a

ge a

nd le

af st

ruct

ure

but i

n m

ost c

ases

, one

app

licat

ion

of d

-lim

onen

e co

ntro

ls m

ore

than

80

% o

f wee

ds fo

r 3-

4 w

eeks

.

Fiel

d st

udie

sFi

eld

stud

ies

•d-li

mon

ene

((4R)

-1-m

ethy

l-4-(

1-m

ethy

leth

enyl

)cyc

lohe

xene

or (

R)-4

-is

opro

peny

l-1-m

ethy

lcyc

lohe

xene

) is a

rela

tivel

y st

able

mon

oter

pene

from

ora

nge

peel

s and

wid

ely

used

as a

cle

anin

g ag

ent.

•the

fast

, non

-sel

ectiv

e he

rbic

idal

eff

ect o

f d-li

mon

ene

is b

ased

on

the

disr

uptio

n of

the

leaf

cut

icle

whi

ch le

ads t

o fa

st w

iltin

g of

pla

nts d

ue to

re

duce

d ch

loro

phyl

l flu

ores

cenc

e an

d st

omat

alfu

nctio

ning

(Im

rahi

met

al.

2004

)

•the

phy

toto

xic

effe

ct o

fGre

enM

atch

was

test

ed in

a la

bora

tory

bio

assa

y on

a 6

-w

ell p

late

usi

ngin

tact

leav

es o

f chi

ckw

eed

(Ste

llaria

med

ia) a

s a te

st su

bjec

t

•t

he c

omm

erci

al p

rodu

ct c

onta

inin

g 70

% o

f d-li

mon

ene

was

dilu

ted

with

DI

wat

er to

the

follo

win

g co

ncen

tratio

ns: 0

.5, 2

.5, 5

.0, 1

0.0

%. D

Iwat

er a

nd

Rou

ndup

®R

TU w

ere

used

as c

ontro

l tre

atm

ents

•a 0

.5-m

L al

iquo

t of e

ach

solu

tion

was

pip

ette

don

a fi

lter p

aper

, and

one

leaf

of

chic

kwee

d w

as p

lace

d on

the

top

of th

e fil

ter p

aper

•the

leav

es w

ere

incu

bate

d fo

r 2 d

ays i

n a

gree

nhou

se w

ith a

12-

hr li

ght/d

ark

cycl

e, a

fter w

hich

the

leav

es w

ere

eval

uate

d fo

r col

or c

hang

e

40.0

a32

.5 c

21.3

b50

.0 b

41.7

b30

.0 c

4 qt

/AR

ound

up®

19.7

18.7

6.6

10.5

18.5

8.5

LSD

(p≤

0.05

)

63.8

a

50.0

b

0.0

d

1 D

ATW

eed

cont

rol (

%)

Com

mon

lam

bsqu

arte

rs(C

heno

podi

umal

bum

)

98.0

a

87.5

a

0.0

c

8 D

AT

97.8

a

98.3

a

0.0

d

15 D

AT

15 D

AT

8 D

AT

1 D

AT

56.3

a68

.8 a

28.8

a17

.5G

reen

Mat

ch™

O

45.0

a47

.5 b

c30

.0 a

10.0

Gre

enM

atch

™O

0.0

b0.

0 d

0.0

c0.

0 U

ntre

ated

Wee

d co

ntro

l (%

)A

nnua

l blu

egra

ss

(Poa

annu

a)

App

licat

ion

rate

(%

A.I.

)

Trea

tmen

t

dd --lim

onen

elim

onen

e

Bio

assa

y se

tB

ioas

say

set --

upup

Bio

assa

yB

ioas

say

resu

ltsre

sults

The

resu

lts (o

n th

e rig

ht) s

how

that

:•

with

in 2

-day

s, a

dire

ct c

onta

ct w

ith d

-lim

onen

e at

a c

once

ntra

tion

2.5

% re

sults

in

fast

des

truct

ion

of th

e ch

loro

phyl

l whi

ch c

an

be se

en a

s a to

tal b

leac

hing

of l

eave

s. •

the

effe

ct o

f d-

limon

ene,

as a

bur

ndow

n,

non-

sele

ctiv

e, n

on-s

yste

mic

her

bici

de, i

s fa

ster

than

that

of s

yste

mic

Rou

ndup

®.

Tab

le 1

Tab

le 1

Stud

y co

nduc

ted

by B

ioR

esea

rch,

Fre

sno,

CA

; D

ecem

ber

2006

, spr

ay v

olum

e 40

gpa

;R

ound

up®

is a

reg

iste

red

trad

emar

k of

Mon

sant

o C

ompa

ny

Tab

le 2

T

able

2

357070701400

Spr

ay

volu

me

(gpa

)

7.5

c13

.8 d

8.8

c10

% d

ilutio

nA

cetic

aci

d

25.0

bc

36.2

c17

.5 b

10 %

dilu

tion

Mat

ran®

EC

28.3

15.5

6.6

LSD

(p≤

0.05

)

25.0

bc

52.5

b28

.8 a

17.5

Gre

enM

atch

™O

37.5

ab

38.8

c17

.5 b

10.0

Gre

enM

atch

™O

57.5

a85

.0 a

16.2

b10

.0G

reen

Mat

ch™

O

0.0

c 0.

0 d

0.

0 d

0.0

Unt

reat

ed

34 D

AT

13 D

AT

1 D

AT

Wee

d co

ntro

l (%

)M

usta

rd a

t 4-5

leaf

sta

ge(B

rass

ica

junc

ea)

App

licat

ion

rate

(% A

.I.)

Trea

tmen

t

Con

clus

ions

Con

clus

ions

•an

orga

nic

herb

icid

e ba

sed

on d

-lim

onen

e (G

reen

Mat

ch™

O)

prov

ides

fast

and

eff

ectiv

e co

ntro

l of b

oth

broa

dlea

ved

and

gras

s wee

ds•t

he h

erbi

cida

l eff

ect o

f d-li

mon

ene

decr

ease

s with

dec

reas

ing

tem

pera

ture

and

incr

easi

ng le

af c

utic

le th

ickn

ess

•for

opt

imal

per

form

ance

, Gre

enM

atch

™O

shou

ld b

e di

lute

d 4–

7x (

17.5

–10

% A

.I.) d

epen

ding

on

tem

pera

ture

and

the

size

of w

eeds

•g

ood

cove

rage

(spr

ayin

g vo

lum

e of

60

gpa

or h

ighe

r) is

re

quir

ed fo

r be

st w

eed

cont

rol e

spec

ially

at l

ow te

mpe

ratu

res

and

for

larg

e w

eeds

Ref

eren

ces

Ref

eren

ces

Uni

vers

ity o

f Cal

iforn

ia, D

avis

, Jan

200

7; M

atra

n®an

d ac

etic

aci

d w

ere

appl

ied

acco

rdin

g to

m

anuf

actu

rer’

s rec

omm

enda

tions

. Mat

ran®

is a

regi

ster

ed tr

adem

ark

of E

coSm

artT

echn

olog

ies,

Inc.

Bai

nard

, L.D

., Is

man

, M.B

. and

Upa

dhya

ya, M

.K. 2

006.

Wee

d Sc

i. 54

: 833

-837

Ferg

uson

J.J.

and

Cha

se, C

.A. 2

005.

Uni

vers

ity o

f Flo

rida,

IFA

S Ex

tens

ion

HS1

003;

ht

tp://

edis

.ifas

.ufl.

edu/

HS2

47

Imbr

ahim

, M.A

., O

ksan

en, E

.J. a

nd H

olop

aine

n, J.

K. 2

004.

J. S

ci. F

ood

Agr

ic. 8

4: 1

319-

1326

Twor

kosk

i, T.

200

2. W

eed

Sci.

50:4

25-4

31

A se

ries o

f fie

ld st

udie

s hav

e be

en c

ondu

cted

to te

st th

e ef

ficac

y of

Gre

enM

atch

™O

on

both

bro

adle

af a

nd g

rass

wee

ds (s

ee p

ictu

res b

elow

).Se

lect

ed fi

eld

stud

y re

sults

are

pre

sent

ed in

Tab

les 1

and

2.

129128

FIELD EVALUATION OF GreenMatch EX:A NEW BROAD SPECTRUM ORGANIC HERBICIDE

Avila-Adame C, Fernández L, Campbell B, Tan E, Koivunen M, Marrone P. Marrone Organic Innovations, Inc., 2121 Second Street, Suite B-107, Davis, CA 95618

ABSTRACTGreenMatch EX is a new contact, non-selective, broad spectrum, foliar herbicide. It is exempt from EPA registration and is approved

for use in organic farming. This biological product controls both annual and perennial broadleaf and grassy weeds. GreenMatch EX has been tested in California against various broadleaf and grassy weed species to obtain efficacy and weed spectrum data. Studies with three dilution rates (7.5, 10, and 15%) and three spraying volumes (35, 60, and 100 gallons per acre) showed a significant correlation between concentration/water volume and percent weed control. The best efficacy was achieved at 10 to 15% dilution rate (v/v) employing 100 gallons of water per acre, which indicates that complete tissue coverage is required to achieve full efficacy. GreenMatch EX performance was dependent upon the age of the weeds, and the best weed control was obtained when plants were young and actively growing. GreenMatch EX at 15% was more effective than GreenMatch (d-limonene) and Matran EC (clove leaf oil) at the recommended commercial application rates of 18% and 5%, respectively.

INTRODUCTIONInterest in incorporating natural-based pesticides in “green” integrated pest management programs has increased dramatically

during the past few years (2, 3). Currently, biopesticides represent 2.4% of the global pesticide market, and is projected to increase to 4.2% by 2010(3). Weeds constitute the main problem in agricultural systems by reducing crop yields up to 12%(4), and various kinds of herbicides are employed worldwide to control weed pests. During 2005, the estimated global pesticide market was 33.6 billion dollars with herbicide use accounting for 45.8% of this market(3). At present, the number of biological herbicides with potential to control weeds is limited. Corn gluten meal, a by-product in the manufacture of cornstarch, is available as Bioweed™ and has efficacy as a pre-emergence herbicide. Other commercially available post-emergence herbicides include fatty acid (pelargonic acid) sold under the trade name Scythe™, essential oil (clove) sold as Matran™, and monoterpene (d-limonene) from citrus oil sold as Nature’s Avenger™ and GreenMatch™ O(1, 2). The present study discusses the effectiveness of GreenMatch EX as a new non-selective biopesticide with potential to control a broad spectrum of grassy and broadleaf weeds.

MATERIALS AND METHODSEfficacy of GreenMatch EX was evaluated in three locations in California. The first trial

was established in two locations in Davis, CA: inside a peach orchard and in an open field. The second trial was located in Wasco, CA inside an almond orchard. A third trial was performed in Fresno, CA in a golf course. The treatments in all field experiments were arranged under a randomized complete block experimental design with 3 or 4 repetitions. In the trials performed in Wasco and Fresno, Matran® EC and GreenMatch were used as the commercial controls at the rate specified in the label. Treatments in the Wasco and Fresno trials were applied using a hand-held CO2 sprayer, while all treatments in Davis were applied with a hand-held sprayer. Water was used as a carrier during the treatment application. When indicated, Nu Film P at 0.05% was used as a surfactant.

RESULTSGreenMatch EX showed non-selectivity in controlling

weeds. Both broadleaf and grassy weeds were burned in the presence of herbicide. In the trial performed inside the peach orchard in Davis, eight weed species were commonly found during the evaluation. Excellent control was observed against spurge and thistle; good control against bindweed, clover, and crabgrass; and satisfactory control against bermuda grass. Poor efficacy was detected in controlling henbit and dandelion. Table1 shows the overall control estimated during this trial. Herbicidal effect was increased in the presence of surfactant. Control was greater than 86% at 10% dilution of GreenMatchEX at 100 gpa in the presence of 0.05% NuFilm P.

Redstem filaree, little mallow, shepherd’s purse, londonrocket, hairy fleabane, and annual bluegrass were the most common weeds found in the almond orchard in Wasco (Table 2). Data in table 2 shows that weed control depended upon GreenMatch EX concentration and volume of water employed (Figs 1, 2). All six weeds were controlled at the 15% concentration at 100 gpa. It was interesting to note that efficacy on shepherd’s purse, london rocket, and hairy fleabane was higher than 92% at 10% concentration in 70 gpa. At these concentrations, GreenMatch EX performance was better than Matran EC applied at the recommended label rate.

Seven weed species were selected for the trial performed in the golf course in Fresno (Table 3). Smooth crabgrass was highly sensitive to GreenMatch EX followed by prickly lettuce and postrate spurge. Lower efficacy was detected against annual sowthistle, horse weed and flax fleabane. Interestingly, purple cudweed was not affected by GreenMatch EX, GreenMatch, and Matran EC.

CONCLUSIONSGreenMatch EX shows good control of a wide variety ofbroadleaf and grassy weed.

For best efficacy, GreenMatch EX should be used at 10-15% dilution and 100 gal/acre.

Good coverage (high gpa) is important for best performance.

Surfactant improves efficacy at high application volumes.

Excellent control can be obtained for the following weedspecies: spurge, sowthistle, shepherd’s purse, clover, mustard, London rocket, hairy fleabane, annualbluegrass, smooth crabgrass.

REFERENCES1.Chase, C. A., J. M. Scholberg, et al. 2004. Preliminary evaluation of non-synthetic herbicides for weed management in organic orange production. Proc. Fla. State Hort. Soc. 117: 135-138.2.Copping L. G. and Duke S. O. 2007. Natural products that have been used commercially as crop protection agents. Pest Manag Sci 63:524–554.3.Marrone P. G. 2007. Barriers to adoption of biological control agents and biological pesticides. In: CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources. CABI: published online, ISSN 1749-8848, 2, No. 051.4.Yandoc-Ables, C. B., Rosskopf, E. N., and Charudattan, R. 2007. Plant Pathogens at Work:Progress and possibilities for weed biocontrol classical versus bioherbicidal approach. Online. Plant Health Progress doi:10.1094/PHP-2007-0822-01-RV.

FIG. 1. GreenMatch EX EFFICACY 20 DAYS AFTER TREATMENT(WASCO, CA)

FIG. 2. GreenMatch EX EFFICACY AT 100 GPA 20 DAYS AFTERTREATMENT (WASCO, CA)

130129

California Weed Science Society Financials

Income and Expenses July 1, 2007 - May 28, 2008

Ordinary Income/Expense Income 4000 · Registration Income 73,215.00 4001 · Membership Income 175.00 4010 · Proceedings Income 3,251.25 4020 · Exhibit Income 17,195.00 4030 · Sponsor Income 10,750.00 4040 · CWSS Textbook Income 3,360.00 4060 · Promotional Items Income 8.00 4065 · Orchid Fundraiser 475.00 4290 · Refunds -810.00 Total Income 107,619.25

Expense 4300 · Conference Accreditation 135.00 4320 · Conference Catering Expense 27,144.22 4330 · Conference Equipment Expense 5,750.00 4340 · Conference Labor 87.50 4360 · Student Awards/Poster Expense 1,500.00 4361 · Awards-Board/Special Recog. 339.33 4370 · Scholarship Expense 11,000.00 4375 · Speaker Lodging/Travel Expense 1,217.66 4380 · Conference Supplies 1,360.94 6090 · Advertising 750.00 6120 · Bank Service Charges 1,724.60 6130 · Board Meeting Expenses 819.80 6240 · Insurance - General 4,300.00 6280 · Mail Box Rental Expense 56.00 6300 · Office Expense 70.03 6307 · Outside Services - PAPA 23,398.54 6340 · Postage/Shipping Expense 3,047.31 6345 · Printing Expense - Newsletter 7,736.85 6350 · Promotional Item Expense 4,109.46 6355 · Website Expense 1,318.25 6360 · Storage Rental Expense 522.00 6500 · Taxes - Other 30.00 6520 · Telephone/Internet Expense 855.48 6530 · Travel - Transport/Lodging 1,078.01 6540 · Travel - Meals/Entertainment 139.26 Total Expense 98,490.24

131130

Net Ordinary Income 9,129.01

Net Income 9,129.01

Reserve Account (April 30, 2008)

Cash & Money Market $27,726.99US equities $83,079.33International equities $69,610.99Taxable fixed income $56,274.80Mixed assets $41,010.25Current account value $277,702.36

132131

CWSS HONORARY MEMBERS LISTING

Harry Agamalian (1983) Norman Akesson (1998) Floyd Ashton (1990) Alvin Baber (1995) Walter Ball * Dave Bayer (1986) Lester Berry Tim Butler (2008) Mick Canevari (2008) Don Colbert (2002) Floyd Colbert (1987) Alden Crafts * Marcus Cravens * Dave Cudney (1998) Richard Dana Boysie Day * Nate Dechoretz (2003) Jim Dewlen (1979)* Paul Dresher * Ken Dunster (1993)* Matt Elhardt (2005) Clyde Elmore (1994) Bill Fischer Dick Fosse * Tad Gantenbein (2004) Rick Geddes (2006) George Gowgani Bill Harvey * F. Dan Hess (2001)* Floyd Holmes (1979) Nelroy Jackson (1997) Warren Johnson (1977)* Jim Koehler Harold Kempen (1988) Don Koehler (2003) *Deceased

Butch Kreps (1987) Edward Kurtz (1992) Art Lange (1986) Oliver Leonard * Jim McHenry Bob Meeks Bob Mullen (1996) Robert Norris (2002) Ralph Offutt Jack Orr (1999) Ruben Pahl (1990) Martin Pruett Murray Pryor * Richard Raynor Howard Rhoads * Jesse Richardson (2000) Ed Rose (1991) Conrad Schilling * Jack Schlesselman (1999) Vince Schweers (2003) Conrad Skimina (2003) Leslie Sonder * Stan Strew Huey Sykes (1989) Tom Thomson (1999) Robert Underhill Lee VanDeren (1983) * Ron Vargas (2001) Stan Walton (1988) Bryant Washburn (1988) Steve Wright (2007)

133132

CWSS AWARD OF EXCELLENCE MEMBERS LISTING

1985 June McCaskell, Jack Schlesselman & Tom Yutani 1986 Harry Agamalian, Floyd Colbert & Ed Rose 1987 Bruce Ames, Pam Jones, & Steve Orloff 1988 Bill Clark & Linda Romander 1989 Earl Suber 1990 Ron Hanson & Phil Larson 1991 John Arvik & Elin Miller 1992 Don Colbert & Ron Kelley 1993 Ron Vargas 1994 Jim Cook & Robert Norris 1995 Mick Canevari & Rich Waegner 1996 Galen Hiett & Bill Tidwell 1997 David Haskell & Louis Hearn 1998 Jim Helmer & Jim Hill 1999 Joe DiTomaso 2000 Kurt Hembree 2001 Steven Fennimore, Wanda Graves & Scott Steinmaus 2002 Carl Bell & Harry Kline 2003 Dave Cudney & Clyde Elmore* 2004 Michelle LeStrange & Mark Mahady 2005 Scott Johnson & Richard Smith 2006 Bruce. Kidd, Judy Letterman & Celeste Elliott 2007 Barry Tickes & Cheryl Wilen 2008 Dan Bryant & Will Crites 2008 Ken Dunster* & Ron Vargas*

*President’s Award for Lifetime Achievement in Weed Science

134133

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

12300 LOWER AZUSA RDARCADIA, 91006 91006

MARK ADAMSCOUNTY OF LOS ANGELES AG

1.

626-575-5462mark@acwm.co.la.ca.us

6 SAN CARLOS DRSALINAS, CA 93901-3008

HARRY S AGAMALIANUNIVERSITY OF CALIFORNIA EXT.

2.

831-758-0300

P O BOX 127CLOVIS, CA 93613

CARL AHRENDESALLIED WEED CONTROL

3.

559-285-8671rma21@csufresno.edu

1001 I ST.SACRAMENTO, CA 95812

RAIS AKANDACAL/EPA-DPR

4.

916-445-4270rakanda@cdpr.ca.gov

284 POST AVE.SANGER, CA 93657-3805

EDDIE ALLENALBAUGH INC

5.

559-281-1125eallen125@comcast.net

1203 CORBETT CYN RD.ARROYO GRANDE, CA 93420

TONY ALVAREZGO GREEN ENVIRONMENTAL

6.

805-440-4811GoGreenTA@aol.com

PO BOX 1548GRASS VALLEY, CA 95945

CATHERINE ANSOLABEHEREALL SEASONS WEED CONTROL

7.

530-273-2323allseasonswc@sbcglobal.net

1170 WEST SHAW AVE #103FRESNO, CA 93711-3703

MIKE ANSOLABEHEREVALENT USA

8.

559-281-5994MANSO@VALENT.COM

P.O. BOX 2157LOS BANOS, CA 93635

GENE ARMONDSAN LUIS & DELTA MENDOTA

9.

209-826-4778

2121 FERN CANYONUKIAH, CA 95482

JOHN ATTAWAYATTAWAY FIELD RESEARCH

10.

707-463-2169att52@saber.net

135134

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

PO BOX 92DUNNIGAN, CA 95937

FRANK AULGURDUPONT CROP PROTECTION

11.

916-765-6308L-FRANK.AULGUR@USA.DUPONT.CO

5063 COMMERCIAL CIR. STE. CCONCORD, CA 94520

ANDREA AUSTELCYGNET ENTERPRISES WEST

12.

925-685-8081aaustel@cygnetwest.com

2121 2ND ST. STE. B-107DAVIS, CA 95618

CRUZ AVILA-ADAMEMARRONE ORGANIC INNOVATIONS

13.

530-750-2800cavila@marroneorganics.com

1323 CLUB DR.VALLEJO, CA 94592

DAVID BAKKEUSDA FOREST SERVICE

14.

707-562-8916dbakke@fs.fed.us

4437-B S. LASPINA STTULARE, CA 93274

GERARDO BANUELOSU.C.C.E.

15.

559-685-3309gbanuelos@ucdavis.edu

P.O. BOX 1971NEVADA CITY, CA 95959

DON BARTELSIERRA CONSULTING & INTEGRATED

16.

530-432-7845donald.bartel@sbcglobal.net

PO BOX 2634MINDEN, NV 89423

JOHN BATISTICHNOR-CAL WEED CONTROL

17.

775-782-6759JOANBAT@HOTMAIL.COM

50 E. REILLY RDMERCED, CA 95340

MATT BEENEHELENA RESEARCH &

18.

559-408-4112mbeene@helenaresearch.com

4141 N VINELANDKERMAN, CA 93630

MICHAEL BEEVERSCAL AG RESEARCH, INC.

19.

559-843-2997calag@kermantel.net

5555 OVERLAND AVE STE 4101SAN DIEGO, CA 92123-1219

CARL E BELLU.C.C.E. - SAN DIEGO

20.

858-694-3386cebell@ucdavis.edu

136135

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

PO BOX 33632SAN DIEGO, CA 92103

JUDY BELLZOOLOGICAL SOCIETY OF SAN

21.

619-298-3609judyann-bell@hotmail.com

PO BOX 3186MARTINEZ, CA 94553

THOMAS BENNEYCLEAN LAKES, INC

22.

925-957-1905TBENNEY@CLEANLAKE.COM

16003 TRADITION CTBAKERSFIELD, CA 93314

MICHAEL BLAINEWEST COAST GRAPE FARMING

23.

661-201-1020mpblaine@hughes.net

7201 SCHIRRA COURT STE. HBAKERSFIELD, CA 93313

DAVE C BLODGETBAKER PETROLITE

24.

661-834-5109david.blodget@bakerpetrolite.com

703 B ST.MARYSVILLE, CA 95901

JEFF BODDESTATE OF CALIFORNIA

25.

530-218-3682jeffrey_bodde@dot.ca.gov

5145 BOYLAN STBAKERSFIELD, CA 93308

BONNIE M BONNIVIERBAKER PETROLITE

26.

661-325-4138bonnie.bonnivier@bakerpetrolite.com

1050 E. HOLTON RDHOLTVILLE, 92250 92250

BRENT E BOUTWELLU.C.C.E. IMPERIAL COUNTY

27.

760-352-9474beboutwell@ucdavis.edu

827 7TH ST. RM. 301SACRAMENTO, CA 95814

JAMES W BRADLEYSACRAMENTO COUNTY WATER

28.

916-874-8684BRADLEYJ@SACCOUNTY.NET

P.O. BOX 937IMPERIAL, CA 92251

VIKKI DEE BRADSHAWIMPERIAL IRRIGATION DISTRICT

29.

760-482-3610vdbradshaw@iid.com

578 CONESTOGA RDSAN DIMAS, CA 91773

JACK BRAMKAMPUAP DISTRIBUTION, INC.

30.

909-802-4114jack.bramkamp@uap.com

137136

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

8071 LANGDALE CT.SACRAMENTO, CA 95829

JAMES BRAZZLEGOWAN CO.

31.

916-801-2892jbrazzle@gowanco.com

1155 MABURY RDSAN JOSE, CA 95133

CASEY BRIERLEYTARGET SPECIALTY PRODUCTS

32.

800-767-0719casey.brierley@target-specialty.com

501 TAFT HWYBAKERSFIELD, CA 93307

CHRIS BROOKSKERN DELTA WATER DISTRICT

33.

661-834-4656

15415 MARQUARDT AVE.SANTA FE SPRINGS, CA 90274

DONNA BROWNETARGET SPECIALTY PRODUCTS

34.

800-352-3870donna.browne@target-specialty.com

2950 PERALTA OAKS CT.WALNUT CREEK, CA 94605

NANCY T BROWNFIELDEAST BAY REGIONAL PARKS

35.

510-544-2343nbrownfield@ebparks.org

1476 ANITA ST.CARPINTERIA, CA 93013

TIM BUFFALOCARPINTERIA VALLEY GROWERS

36.

805-896-1526tbuff3@msn.com

5201 STRONG CIRCLEWATSONVILLE, CA 95076

KEITH BUNGOWELL PICT, INC.

37.

831-475-1327

PO BOX 6654VISALIA, CA 93290

TODD BURKDOLLBASF

38.

559-635-8902

12300 LOWER AZUSA RDARCADIA, 91006 91006

CONRAD BURTONCOUNTY OF LOS ANGELES AG COMM

39.

626-575-5462

420 S WILSON WAYSTOCKTON, CA 95205

MICK CANEVARIU.C.C.E.-SAN JOAQUIN COUNTY

40.

209-468-9493wmcanevari@ucdavis.edu

138137

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

2000 EVERGREEN ST. STE. 100SACRAMENTO, CA 95815

MARCIA CARLOCKSTATE OF CALIFORNIA

41.

916-263-8142mcarlock@dbw.ca.gov

2175 AIRPORT BLVDSANTA ROSA, CA 95403

VINCE CARVALHOCOUNTY OF SONOMA PUBLIC WORKS

42.

707-565-7579

PO BOX 1700MARIPOSA, CA 95338

BERNARD CASNERYOSEMITE PEST CONTROL

43.

209-966-5745YOSEMITEPEST@STI.NET

5247 TIP TOP RDMARIPOSA, CA 95338

DAVID CASNERYOSEMITE PEST CONTROL

44.

209-742-7755YOSEMITEPEST@STI.NET

28777 AVE 13MADERA, CA 93638

JOHN M CHAVEZKALIFORNIA GOLD AG SERVICE, INC.

45.

559-674-9015

3155 SOUTHGATE LN.CHICO, CA 95928

DAVE CHEETHAMHELENA CHEMICAL CO.

46.

530-345-6140dcheetham@helenaresearch.com

2175 AIRPORT BLVDSANTA ROSA, CA 95403

GREG CHIOSSICOUNTY OF SONOMA PUBLIC WORKS

47.

707-565-7579

1951 CHATEAU CTWALNUT CREEK, CA 94598-1219

DALE CHRISTENSEN48.

925-689-8991MPCCC@ASTOUND. NET

11279 S. GLENWOOD AVE. #11051YUMA, AZ 85367

CHARLES CHUMLEYHELENA CHEMICAL CO.

49.

602-418-9587charlie.chumley@runbox.com

4000 SHIPROCK DR.MODESTO, CA 95355

KIM CLARKMODESTO IRRIGATION DISTRICT

50.

209-526-7631kimc@mid.org

139138

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

37860 W. SMITH-ENKE RDMARICOPA, AZ 85238

PATRICK CLAYVALENT USA

51.

520-381-2220pat.clay@valent.com

2787 W. BULLARD AVE STE 101FRESNO, CA 93711

JAMES COBURNWESTERN FARM SERVICE

52.

559-436-2800

P.O. BOX 1256LUCERNE, CA 95458

JOHN COCHRANECITY OF SAN RAFAEL

53.

415-485-3375

1060 MARTIN LUTHER KING BLVDRIVERSIDE, CA 92507

STEPHEN T COCKERHAMU.C. RIVERSIDE

54.

951-827-5906stephen.cockerham@ucr.edu

228 E. ACACIA ST.SALINAS, CA 93901

PATRICK COLLINSDOLE FRESH VEGETABLES, INC.

55.

831-229-5767patrick_j_collins@na.dole.com

1536 E. PRINCETON CT.VISALIA, CA 93292

MICHAEL COXBASF

56.

559-625-9106michael.cox@basf.com

1108 PASO ROBLES STPASO ROBLES, CA 93446

PAUL CROUTSAN LUIS OBISPO FARM SUPPLY

57.

805-238-1177prpca@farmsupplycompany.com

PO BOX 1175MADERA, CA 93639

WES CROXENBAKER PETROLITE

58.

559-661-1845wesley.croxen@bakerpetrolite.com

P.O. BOX 1580CARMICHAEL, CA 95609

KEM CUNNINGHAMAMVAC

59.

916-484-3456kemc@amvac.net

3027 BUENA VISTA AVELEMON GROVE, CA 91945

STEVEN DAVIDSONCALTRANS

60.

619-460-6224steven.davidson@att.net

140139

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

6709 SADDLEBACK DRIVEBAKERSFIELD, CA 93309

DONALD D DAVISKERN WATER BANK AUTHORITY

61.

661-333-1952ddavis@kwb.org

35124 QUALLS PRATHER RD.AUBERRY, CA 93602

BRIAN D DEETERGOWAN CO.

62.

559-779-3624bdeeter@gowanco.com

P.O. BOX 314WOODLAKE, CA 93286

STEVE S DEITZSAWTOOTH AG RESEARCH

63.

559-564-3209sdeitz@wildblue.net

2068 W FIR AVEFRESNO, CA 93711

SIMON DEMIRJIANWILBUR-ELLIS CO. - HELM WESTERN

64.

559-435-5354

1170 WEST SHAW AVE STE 103FRESNO, CA 93720

TOM DEWITTVALENT

65.

559-269-1754tom.dewitt@valent.com

2364 E. SOUTHWOOD RDQUEEN CREEK, AZ 85242

MICHAEL DINNMONSANTO

66.

480-507-2204michael.j.dinn@monsanto.com

3700 E. ROUSAY DRQUEEN CREEK, AZ 85242

TOM DINNNUFARM TURF & SPECIALTY

67.

480-987-6404tom.dinn@us.nufarm.com

U.C.D.-DEPT. OF PLANT SCIENCEDAVIS, CA 95616

JOE DITOMASOU.C. DAVIS

68.

530-754-8715jmditomaso@ucdavis.edu

1618 DOOLITTLE DRSAN LEANDRO, CA 94577

RICHARD DUBEYAMERICAN CLEANWAY

69.

510-719-9009rdubey@sbcglobal.net

427 E. MICHIGANFRESNO, CA 93704

DANIEL DUNHAMTESSENDERLO KERLEY

70.

559-250-1264

141140

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

P.O. BOX 2157LOS BANOS, CA 93635

JESS DURANSAN LUIS & DELTA MENDOTA

71.

209-826-4778

3604 PINE AVE.MANHATTAN BEACH, CA 90266

FRED ECKERTBASF TURF & ORNAMENTAL

72.

310-220-9159fred.eckert@basf.com

7619 E GREENWAY RDSCOTTSDALE, AZ 85260

ANDY EGGENEGGEN WEED CONTROL,INC.

73.

602-996-1000eggens@qwest.net

1001 I ST. P.O. BOX 4015SACRAMENTO, CA 95812

MIKE ENSMINGERCDPR

74.

916-324-4186mensminger@cdpr.ca.gov

5199 W HOLLY HILL DRBOISE, ID 83703

PAUL J ESCOBARSSI MAXIM CO.

75.

208-331-3189PESCOBAR@SSIMAXIM.COM

7455 CASEY DRIVESAN MIGUEL, CA 93451

DALE A EVENSONSLO FARM SUPPLY

76.

805-712-2589

1812 OLVERA DR.WOODLAND, CA 95776

DUANE EWINGEWING & ASSOCIATES

77.

530-662-8414duane@ewing-associates.com

P.O. BOX 7043SPRECKELS, CA 93962

BUDDY FALLONBUDSCO, INC.

78.

831-424-8001

123 E. ANAPAMU ST.SANTA BARBARA, CA 93101

LARRY L FAUSETTSANTA BARBARA CO. FLOOD

79.

805-568-3437LFAUSET@COSBPW.NET

1636 E ALISAL STSALINAS, CA 93905

STEVE FENNIMOREUNIVERSITY OF CALIFORNIA

80.

831-755-2896safennimore@ucdavis.edu

142141

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

1701 NIMBUS RDRANCHO CORDOVA, CA 95670

BRIAN J FINLAYSONCALIFORNIA FISH & GAME

81.

916-358-2950bfinlays@ospr.dfg.ca.gov

12608 ROAD 35 1/2MADERA, CA 93638

DARYL FLETCHERMILLER CHEMICAL & FERTILIZER

82.

559-479-6224

249 SOUTH PACIFIC AVEVENTURA, CA 93001

KIT FLOMCAL TRANS

83.

805-383-8844kit_flom@dot.ca.gov

1889 E. 9TH ST.STOCKTON, CA 95206

JIMMY FLORESCALTRANS

84.

209-948-7109jimmy_flores@dot.ca.gov

501 TAFT HWYBAKERSFIELD, CA 93307

LOUIS FONTESKERN DELTA WATER DISTRICT

85.

661-834-4656

3766 BILSTED WAYSACRAMENTO, CA 95834

HAYAT FORDCDPR

86.

916-445-0179hford@cdpr.ca.gov

4821 ADOHR LN.CAMARILLO, CA 93012

JAMES FOWLERCALTRANS

87.

805-389-1565james_fowler@dot.ca.gov

PO BOX 3186MARTINEZ, CA 94553

TYLER FOWLERCLEAN LAKES, INC

88.

925-766-5256TFOWLER@CLEANLAKES.COM

P.O. BOX 488CERES, CA 95307

BRIAN FRANZIAWEST COAST GRAPE FARMING

89.

209-993-9201b.franzia@sbcglobal.net

12360 S. INDUSTRIAL DR. EASTPLAINFIELD, IL 60585

REBECCA FRYSPECTRUM TECHNOLOGIES, INC.

90.

815-436-4460

143142

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

1211 GARDEN AVE.ST HELENA, CA 94574

DEWITT GARLOCKDGVCS, INC.

91.

707-486-6118litefoot@napanet.net

1800 PACIFICA DRYUBA CITY, CA 95991-6927

RICK GEDDESDOW AGRO SCIENCES

92.

530-673-2628rdgeddes@dow.com

1860 BAGWELL STFLINT, MI 48503

JOHN GOIDOSIKCYGNET ENTERPRISES WEST

93.

810-744-0540jgoidosik@cygnetenterprises.com

1428 ABBOTT STSALINAS, CA 93901

HENRY GONZALESCOUNTY OF MONTEREY

94.

831-759-7325

4477 KENAI CT.SANTA MARIA, CA 93455

DAVID M GOODRICHWESTERN FARM SERVICE

95.

805-260-3158dgoodrich@agriumretail.com

37185 SANTA ROSA GLEN DR.MURRIETA, CA 92562

STEVEN GOULDMONSANTO

96.

951-894-2006steven.d.gould@monsanto.com

171 EDYTHE STLIVERMORE, CA 94550

JOHN W GOUVAIACOUNTY OF ALAMEDA

97.

925-373-9010jwgouvaia@comcast.net

5375 EASTLAKE BLVDWASHOE VALLEY, NV 89704

JIM GREILROCKY MOUNTAIN AGRONOMICS

98.

775-771-5510jimgreil@clearwire.net

1408 IVAN AVEBAKERSFIELD, CA 93304

JOE GUERRASTATE OF CALIFORNIA - DWR

99.

661-858-5534jguerra@water.ca.gov

2570 18TH AVE.KINGSBURG, CA 93631

DAVID HAASNICHINO AMERICA, INC.

100.

559-238-3911dhaas@nichino.net

144143

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

PO BOX 463DIXON, CA 95620

MICHAEL L HAILELINWOOD SUPPLY, INC.

101.

707-678-5087michael@linwoodsupply.com

PO BOX 877CORCORAN, CA 93212

DAVID HANSEJ.G. BOSWELL COMPANY

102.

559-992-5011DHANSE@JGBOSWELL.COM

328 7TH AVESEASIDE, OR 97138

MARK HANSENUAP DISTRIBUTION, INC.

103.

503-703-6315mark.hansen@uap.com

9611 S. RIVERBEND AVE.PARLIER, CA 93648

BRAD HANSONUSDA-ARS

104.

559-596-2860brad.hanson@ars.usda.gov

20101 N.E. 104TH AVE.BATTLE GROUND, WA 98604

JACK HARDYMONSANTO

105.

360-666-5691john.o.hardy@monsanto.com

PO BOX 877CORCORAN, CA 93212

CINDY HARRISJ.G. BOSWELL COMPANY

106.

559-992-5011charris@jgboswell.com

15415 MARQUARDT AVESANTA FE SPRINGS, CA 90670

WILL HARRISONTARGET SPECIALTY PRODUCTS

107.

800-352-3870will.harrison@target-specialty.com

9407 SHUMWAY DRORANGEVALE, CA 95662

DAVID E HASKELLCAL/EPA-DPR

108.

916-445-4207dhaskell@cdpr.ca.gov

1315 JACOBS PLACEDIXON, CA 95620

CLIFF HEDBERGGROWERS AG SERVICE

109.

707-678-9668chedberg@tremontag.com

3586 N. DEL REY AVE.SANGER, CA 93657

JOHN HELMWILBUR-ELLIS CO.

110.

559-788-9673jhelm@wilbur-ellis.com

145144

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

1720 S MAPLEFRESNO, CA 93702

KURT HEMBREEU.C.C.E., FRESNO

111.

559-456-7556kjhembree@ucdavis.edu

8954 RIO SAN DIEGO DR. #610SAN DIEGO, CA 92108

ROBERT W HOBBSECO SYSTEMS RESTORATION

112.

619-291-1475

9211 E. JACKSON ST.SELMA, IN 47383

NICK HOFFMANECO-PAK LLC

113.

765-228-9243NHOFFMAN@ECOPAKLLC.COM

8290 SAN DIMAS RDATASCADERO, CA 93422

MICHAEL HOLLARMANWESTERN FARM SERVICE

114.

805-441-3124

PO BOX 2484FAYETTEVILLE, NC 28302

RICK HOUSTONU-TECK

115.

910-483-5016info@uteck.com

PO BOX 877CORCORAN, CA 93212

BEAU HOWARDJ.G. BOSWELL COMPANY

116.

559-992-5011bhoward@jgboswell.com

2760 FLOWER ST.WASCO, CA 93280

DANNY W HOWARDLOST HILLS WATER DISTRICT

117.

661-333-0077

PO BOX 175ARVIN, CA 93203

TED HUCKABY ARVIN-EDISON WSD

118.

661-854-5573ssmith@aewsd.org

97 BERKELEY AVESAN RAFAEL, CA 94960

EDWARD P HULMECOUNTY OF MARIN PARKS

119.

415-499-6531ehulme@co.marin.ca.us

47560 N. COURTLAND RDCLARKSBURG, CA 95612

LAWRENCE HUNNHUNN, MERWIN, MERWIN

120.

916-775-1254

146145

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

321 APPALOOSA DRPASO ROBLES, CA 93446

RICHARD HURSTAKCROP SCIENCE SERVICES

121.

805-459-6400cropscienceservices@gmail.com

3280 WESTERDOLL AVELOVELAND, CO 80538

SCOTT INMANNOVOZYMES BIOLOGICAL

122.

970-663-0860scin@novozymes.com

P O BOX 183KINGSBURG, CA 93631

LYNDON INOUYEVALENT USA

123.

559-269-0324lyndon.inouye@valent.com

400 CASSERLY RDWATSONVILLE, CA 95076

STAN IVERSENSUNCREST NURSERIES

124.

831-728-2595siversen@cruzio.com

PO BOX 2484FAYETTEVILLE, NC 28302

NANETTE JACKSONU-TECK

125.

910-483-5016njackson@uteck.com

9543 ROBLIN COURTELK GROVE, CA 95758

JOHN JAEGER126.

916-683-1909john@jsjaeger.com

P.O. BOX 593LINDEN, CA 95236

ALLAN L JAMESMID VALLEY AG SERVICES

127.

209-614-5512ajames@midvalleyag.com

524 GALVESTON STW SACRAMENTO, CA 95691

SARAH JASPERTARGET SPECIALTY PRODUCTS

128.

800-533-0816sarah.jasper@target-specialty.com

1710 FLUETSCH COURTSTOCKTON, CA 95207

SCOTT A JOHNSONWILBUR-ELLIS CO.

129.

916-712-0499sjohnson@wilbur-ellis.com

PO BOX 1818WOODLAND, CA 95776

WALT JOHNSONTHE TREMONT GROUP, INC.

130.

530-662-5442wjohnson@tremontag.com

147146

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

DWR-36623 PEARL PLACEPALMDALE, CA 93550

RICHARD D JONESSTATE OF CALIFORNIA - DWR

131.

661-944-8530RICHJONS@WATER.CA.GOV

4173 S. CHESTNUTFRESNO, CA 93725

DARYL S JUEUAP

132.

559-487-1516DARYL.JUE@UAP.COM

PO BOX 3186MARTINEZ, CA 94553

JAY KASHETACLEAN LAKES, INC

133.

925-957-1905jkasheta@cleanlake.com

7 CENTER COURTLAGUNA NIGUEL, CA 92677

ALAN K KATOCALTRANS

134.

949-249-2217alan.kato@dot.ca.gov

136 COTTAGE GROVE AVECAMARILLO, CA 93012

STEVE O KAWAGUCHISOUTHLAND SOD FARMS

135.

805-484-4157steve@sod.com

1298 W. FREMONTFRESNO, CA 93711

GREG KAZARIANFOWLER PACKING CO.

136.

559-834-5911greg@fowlerpacking.com

9110 LAKE VICTORIA DR.BAKERSFIELD, CA 93312

RUSSELL KEEGANWESTERN FARM SERVICE

137.

661-858-2278

13834 WINESAP CTCHICO, CA 95973

DEBRA L KEENANRESEARCH 2000

138.

530-892-1829research2000@sunset.net

39962 VIA ESPANAMURRIETA, CA 92562-5732

BRUCE E KIDDDOW AGRO SCIENCES TURF &

139.

951-698-3081bekidd@dow.com

2907 S. MAPLE AVEFRESNO, CA 93725

LAURENCE KIMURAFRESNO IRRIGATION DISTRICT

140.

559-233-7161X303lkimura@fresnoirrigation.com

148147

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

P.O. BOX 91001PASADENA, CA 91109

COURTNEY KITESILENT FIRE INC.

141.

323-244-7144silentfire@charter.net

78 E. RIVER SPUR RDPRIEST RIVER, ID 83856

DAVID L KLUTTZDAVES WEED & PEST CONTROL

142.

208-448-2222dwpcontrol@wildblue.net

2121 2ND ST STE. B-107DAVIS, CA 95618

MARJA KOIVUNENMARRONE ORGANIC INNOVATIONS

143.

530-750-2800mkoivunen@marroneorganics.com

8024 FOLSOM-AUBURN RDFOLSOM, CA 95630

JERRY KREBSTESSENDERLO KERLEY

144.

916-719-0644jkrebs@tkinet.com

11905 CENEGAL RDATASCADERO, CA 93422

MIKE KREBSBACHMONSANTO

145.

805-461-6709michael.l.krebsbach@monsanto.com

10590 QUIET HAVENS CT.SACRAMENTO, CA 95830

MICHAEL KROPPBASF

146.

916-591-0580michael.kropp@basf.com

PO BOX 3356CENTRAL POINT, OR 97502

BENJAMIN LAMBRECHTSENINTELLI-SPRAY, INC.

147.

541-878-5074benjamin@intelli-spray.com

29875 TAVERNETTI RDGONZALES, CA 93926

LON LANINIWESTERN FARM SERVICE

148.

831-757-5391

1 SHIELDS AVE-DEPT PLANTDAVIS, CA 95616

TOM LANINIU.C. DAVIS

149.

530-752-4476wtlanini@ucdavis.edu

2 OLIVE AVE.PIEDMONT, CA 94611

JOHN T LAWVALLEYCREST COMPANIES

150.

510-364-1372jlawjr@msn.com

149148

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

4437 S LASPINA ST STE BTULARE, CA 93274

MICHELLE LE STRANGEU.C.C.E.-TULARE COUNTY

151.

559-685-3309X220mlestrange@ucdavis.edu

1126 OLD PEACHY CANYON RDPASO ROBLES, CA 93446

LELAND LEARNEDFMC CORP

152.

805-239-9228leland.learned@fmc.com

1918 HACKAMORE DRROSEVILLE, CA 95661

ROBERT C LEAVITTSTATE OF CALIFORNIA

153.

916-654-0768rleavitt@cdfa.ca.gov

6590 KAREN LANERIVERSIDE, CA 92509

CHARLES R LEEGERCAL TRANS

154.

310-503-5285charles_leeger@dot.ca.gov

5200 PARKFORD CIRCLEGRANITE BAY, CA 95746

MIKE LEESDOW AGRO SCIENCES

155.

916-791-8157mdlees@dow.com

2135 E. CALLE MADERASMESA, AZ 85213

MARTIN LEMONMONSANTO

156.

480-209-6192martin.d.lemon@monsanto.com

1225 DAY RD.GILROY, CA 95020

SIMON C LEMUSDOS NINAS VINEYARDS

157.

408-644-1225

18570 RANCHITO DEL RIO DRSALINAS, CA 93908

ROBERT LETTERMANTESSENDERLO KERLEY

158.

831-455-1366rletterman@tklnet.com

7106 N. BRAWLEY AVE.FRESNO, CA 93711

ROBERT H LINDEMANNVALENT USA

159.

559-244-3979blind@valent.com

27755 ENCINAL RDSALINAS, CA 93908

W.B. LINDLEYJ & L FARMS

160.

831-596-9902

150149

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

403 W. OMAHA AVE.CLOVIS, CA 93611

TINO LOPEZVALENT USA

161.

559-696-7334

328 MADERA AVEMADERA, CA 93637

TULIO MACEDOUCCE MADERA & MERCED COUNTIES

162.

559-675-7879X209tbmacedo@ucdavis.edu

P.O. BOX 1290CARMEL VALLEY, CA 93924

MARK M MAHADYMARK M. MAHADY & ASSOCIATES

163.

831-236-2929markmahady@aol.com

2889 N. LARKIN #106FRESNO, CA 93727

FLORENCE MALYCDFA

164.

559-294-6005fmaly@cdfa.ca.gov

P.O. BOX 2157LOS BANOS, CA 93635

LARRY MARQUESSAN LUIS DELTA-MENDOTA WATER

165.

209-826-4778

328 MADERA AVEMADERA, CA 93637

TOME MARTIN-DUVALLU.C.C.E.-MADERA CO.

166.

559-675-7879X213tmmartinduvall@ucdavis.edu

558 PRINTZ RDARROYO GRANDE, CA 93420

SUZANNE R MCCASLINSAN LUIS OBISPO FARM SUPPLY

167.

805-543-3751suzanne558@yahoo.com

5057 ABUELA DRSAN DIEGO, CA 92124

BRYAN W MCCLEERYAMVAC

168.

858-874-4430bryanm@amvac.net

U.C.R.-4101 BATCHELOR HALL EXT.RIVERSIDE, CA 92521-0124

MILT MCGIFFENUNIVERSITY OF CALIFORNIA

169.

909-560-0839milt@ucr.edu

P.O. BOX 3186MARTINEZ, CA 94553

THOMAS MCNABBCLEAN LAKES, INC

170.

925-957-1905tmcnabb@cleanlake.com

151150

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

374 N. LOOP DR.CAMARILLO, CA 93010

NEALE P MCNUTTTRI-TECH AG PRODUCTS, INC.

171.

805-432-1254

3120 GRAYBROOK LANEHYDESVILLE, CA 95547

ROBERT H MELENDEZCALTRANS

172.

707-445-6391bob.melendez@dot.ca.gov

1175 DELL AVENUECAMPBELL, CA 95008

DENNIS K MERRILLKILLROY PEST CONTROL, INC.

173.

408-364-2050dennis@kilroy.com

7800 RODRIGUEZ CIRCLESACRAMENTO, CA 95829

BEAU MILLERDOW AGRO SCIENCES

174.

916-296-2811bjmiller@dow.com

9854 OAKPLACE EASTFOLSOM, CA 95630

RICK MILLERDOW AGRO SCIENCES

175.

916-212-8598rmiller@dow.com

7816 CAROL SUE CTBAKERSFIELD, CA 93308

JOHN A MOOREGROWERS CROP CONSULTING

176.

661-399-8813GROWERS@BAK.RR.COM

31320 VIA COLINAS #114THOUSAND OAKS, CA 91362

TOM MOORHOUSECLEAN LAKES, INC

177.

818-889-8691tmoorhouse@cleanlake.com

P O BOX 850SALINAS, CA 93901

ED MORAD'ARRIGO BROTHERS

178.

831-753-5448

13851 RAVEN CTSARATOGA, CA 95070

MARIA MORALESHYDRO_MECHANICAL_OBLITERATIO

179.

408-205-5757

7521 W. CALIFORNIA AVE.FRESNO, CA 93706

MAURICIO MORELLDOW AGRO SCIENCES

180.

559-494-3322mmorell@dow.com

152151

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

PO BOX 1084YUCCA VALLEY, CA 92284

ERNIE MORITECHSCAPE

181.

760-365-1851EKMORI@EARTHLINK.NET

2376 WILLET WAYARROYO GRANDE, CA 93420-6510

DWAIN E MORTONDOW AGRO SCIENCES

182.

805-489-2743DEMORTON2@DOW.COM

175 MESQUITE CT.BRENTWOOD, CA 94513

JAMES P MUELLERDOW AGRO SCIENCES

183.

925-634-8768jpmueller@dow.com

27448 ROAD 140 KVISALIA, CA 93277

PHIL MUNGERBASF

184.

559-732-1785philip.munger@basf.com

P.O. BOX 697ORLAND, CA 95963

DOUG MUNIERU.C.C.E.-GLENN COUNTY

185.

530-865-1153djmunier@ucdavis.edu

1171 EDWARDS STST HELENA, CA 94574-1208

RICHARD T NAGAOKAGRAPE DOCTOR

186.

707-963-5955

P O BOX 1406ALAMO, CA 94507

DAVID NAJERAAQUATIC ENVIRONMENTS, INC.

187.

925-521-0400dnajera@aquamog.com

1415 S. STOVER CTVISALIA, CA 93292

KEVIN NAYLORSEPRO CORPORATION

188.

916-955-2464

12300 LOWER AZUSA RDARCADIA, 91006 91006

SHERLAN NEBLETTCOUNTY OF LOS ANGELES AG

189.

626-575-5462sneblett@acwm.lacounty.gov

1995 MARKET STRIVERSIDE, CA 92501

MIGUEL NEGRETERIVERSIDE COUNTY FLOOD

190.

951-955-1307

153152

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

P O BOX 1548GRASS VALLEY, CA 95945

STEWART F NELSONALL SEASONS WEED CONTROL

191.

530-273-2323allseasonswc@sbcglobal.net

8701 WOODLAND HEIGHTSSALINAS, CA 93907

BRIAN NIETONIETO AG CONSULTING

192.

831-809-6458

9735 HILLVIEW TERRACESALINAS, CA 93907

CHARLES NIETONIETO AG CONSULTING

193.

831-809-5587

PO BOX 1548GRASS VALLEY, CA 95945

GREGORY NOWELLALL SEASONS WEED CONTROL

194.

530-273-2323allseasonswc@sbcglobal.net

DEPT PLANT SCIENCE-MAIL STOPDAVIS, CA 95616

JON O'BRIENUNIVERSITY OF CALIFORNIA DAVIS

195.

530-752-8284jonobrien@ucdavis.edu

1253-27 LOS OLIVOS DRSALINAS, CA 93901

MARTIN J O'CONNORWESTERN FARM SERVICE

196.

831-214-7776

1428 ABBOTT ST.SALINAS, CA 93901

BRAD OLIVERCOUNTY OF MONTEREY

197.

831-759-7325

3045 LINNE RDPASO ROBLES, CA 93446

BERNARD OLSENARYSTA LIFE SCIENCE

198.

805-239-7913bernard.olsen@arystalifescience.com

PO BOX 2484FAYETTEVILLE, NC 28302

JEFF OLSONR.E. MASON ENTERPRISES, INC.

199.

910-483-5016INFO@UTECK.COM

2 SOUTH GREEN ST.SONORA, CA 95370

SCOTT R ONETOUCCE TUOLUMNE COUNTY

200.

209-533-5686sroneto@ucdavis.edu

154153

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

1655 S MAIN STYREKA, CA 96097

STEVE B ORLOFFU.C.C.E. - SISKIYOU COUNTY

201.

530-842-2711sborloff@ucdavis.edu

1060 MARTIN LUTHER KING BLVDRIVERSIDE, CA 92507

THOMAS R ORTEGAU.C. RIVERSIDE

202.

951-827-5906tom.ortega@ucr.edu

2478 N. SUNNYSIDE AVEFRESNO, CA 93727

DEAN W OSBORNTARGET SPECIALTY PRODUCTS

203.

800-827-4389dean.osborn@target-specialty.com

P O BOX 20006BAKERSFIELD, CA 93390

GARY W OSTEEN204.

661-665-2824gwosteen@aol.com

624 MERLOT AVE.MADERA, CA 93637

TERRI OSWALDDUPONT CROP PROTECTION

205.

559-674-3440terri.l.oswald@usa.dupont.com

2150 #A AIRSTRIP RDREDDING, CA 96003

DON PALMERREDDING SPRAY SERVICE

206.

530-221-3007

941 HUNTINGTON COMMONFREMONT, CA 94536-3205

SHARON O PARKERJENSEN LANDSCAPE SERVICES, INC.

207.

510-552-3001soparker@yahoo.com

524 GALVESTON STW SACRAMENTO, CA 95691

ANNE-MARIE PATTERSONTARGET SPECIALTY PRODUCTS

208.

800-533-0816anne-marie.patterson@target-specialty.com

16791 S. AVENUE 2 1/4 E.YUMA, AZ 85365

CRAIG PAULYBASF

209.

928-341-4793PAULYC@BASF.COM

12300 LOWER AZUSA RDARCADIA, 91006 91006

MICHAEL PEARSONCOUNTY OF LOS ANGELES AG

210.

626-575-5462

155154

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

2156 SIERRA WAY STE ASAN LUIS OBISPO, CA 93401

GAIL E PEREZCOUNTY OF SAN LUIS OBISPO

211.

805-781-5910gperez@co.slo.ca.us

1841 NORA DR.HOLLISTER, CA 95023

DON F PERRYCAL-AGRA, INC.

212.

831-801-6000DPERRY@CALAGRA.COM

935 E. DISCOVERY LN.ANAHEIM, CA 92801

LAURA PETROCDFA

213.

714-520-6866lpetro@cdfa.ca.gov

3499 BROOKSIDE RD. STE. F BOX 336STOCKTON, CA 95219

GEORGE F PICCARDOWILBUR-ELLIS CO.

214.

916-296-2041gpiccard@wilbur-ellis.com

2722 SEQUOIA STLODI, CA 95242-4690

MARK A PINHEIROMILLER CHEMICAL

215.

209-481-9063

35 HOMESTEAD AVESALINAS, CA 93901

CATHERINE PINTOSYSCO CORP

216.

831-759-3351pinto.cathy@corp.sysco.com

37490 TORONTO AVEBURNEY, CA 96013

CARRI PIROSKOCDFA

217.

530-545-9119CPIROSKO@CDFA.CA.GOV

PO BOX 297DIXON, NM 87527

BARBARA J POLLOCKCALTRANS

218.

505-579-9199bpollock@dot.ca.gov

1037 E. VARTIKIANFRESNO, CA 93710

FAITH POTTERBEST SULFUR PRODUCTS

219.

559-269-1241FPOTTER@MSN.COM

5660 RESEDA BLVDTARZANA, CA 91356

MARVIN PRUITTCALTRANS

220.

818-881-6074MARVIN_PRUITT@DOT.CA.GOV

156155

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

5655 SILVER CREEK VALLEY RDSAN JOSE, CA 95138

MARIO QUEZADAWEED OUT INC.

221.

408-531-0600info@weed-out.com

1636 E. ALISAL STSALINAS, CA 93905

JOHN RACHUYU.C. DAVIS

222.

831-594-8750jsrachuy@ucdavis.edu

PO BOX 96FARMINGTON, CA 95230

ROBERT RATKOVICHWEST COAST GRAPE FARMING

223.

209-495-2689

3521 W. 12TH LANEYUMA, AZ 85364

MARTIN J REIDDUPONT CROP PROTECTION

224.

928-343-1198martin.j.reid@usa.dupont.com

9330 10TH AVEHESPERIA, CA 92345

JESSE M RICHARDSONDOW AGRO SCIENCES

225.

760-949-2565jmrichardson@dow.com

801 S GRAND AVESAN JACINTO, CA 92583

ROBERT A RIEHLEWESTERN FARM SERVICE

226.

909-519-8873bobr@wfsriverside.com

PO BOX 1049HAMILTON, MT 59840

DAVID H RILEY227.

209-993-1124ogwani@aol.com

12377 LOMA RICA RDMARYSVILLE, CA 95901

WALTER RILLINGCAL TRANS

228.

530-740-4882walter_rilling@dot.ca.gov

555 NORTH GUILD AVELODI, CA 95240

JAMES ROBERTSONCLARK PEST CONTROL

229.

916-275-1891jrobertson@clarkpest.com

1701 SOSCOL AVE STE 4NAPA, CA 94559

JOHN A RONCORONIU.C.C.E. NAPA

230.

707-253-4221jaroncoroni@ucdavis.edu

157156

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

P.O. BOX 509WHEATLAND, CA 95692

VICKI E ROSEWILBUR-ELLIS CO.

231.

916-813-9836vrose@wilbur-ellis.com

54 PASEO DE VAQUEROSSALINAS, CA 93908

ARNOLD ROVERAMVAC

232.

831-594-9595

28951 FALCON RIDGE RDSALINAS, CA 93908

DALE RUSHRUSH, MARCROFT & ASSOC.

233.

831-484-4834AG4N6@COMCAST.NET

2175 AIRPORT BLVDSANTA ROSA, CA 95403

BLAINE R RUSSELLCOUNTY OF SONOMA PUBLIC WORKS

234.

707-565-7579

431 DAISY LNSAN MARCOS, CA 92078

GREG SACCOTARGET SPECIALTY PRODUCTS

235.

800-237-5233greg.sacco@target-specialty.com

1840 BIDDLE RANCH RD.SAN LUIS OBISPO, CA 93401

FRANK SANCESPACIFIC AG RESEARCH

236.

805-594-1800frank@pacificaggroup.com

7508 SONG SPARROW WAYELK GROVE, CA 95758

CURTIS L SANDBERGFMC CORP

237.

916-691-2119

P.O. BOX 248ARBUCKLE, CA 95912

JOHN W SCHEIMER238.

530-476-2663jwscheimer@frontiernet.net

726 E KIP PATRICK DRREEDLEY, CA 93654

JACK SCHLESSELMAN239.

559-638-7003rangeoflightphoto@comcast.net

PO BOX 519LINCOLN, CA 95648

DEB SHATLEYDOW AGRO SCIENCES

240.

916-434-2266dgshatley@dow.com

158157

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

9240 S. RIVERBEND AVE.PARLIER, CA 93648

ANIL SHRESTHAUNIVERSITY OF CALIFORNIA

241.

559-646-6534anil@uckac.edu

3301 STONEHURST DREL DORADO HILLS, CA 95762

DAVID P SILLSSILLS AG CONSULTING, INC.

242.

916-941-9005davesills@earthlink.net

4553 CO. RD. RRORLAND, CA 95963

MICHAEL SILVEIRAWILBUR ELLIS CO.

243.

916-952-2488

4951 ST ANDREWS DRSTOCKTON, CA 95219

CHRIS A SIMONIJ.R. SIMPLOT CO.

244.

209-951-9135

1248 CAPRA WAYFALLBROOK, CA 92028-9244

CONRAD SKIMINA245.

760-723-4227cskimina@aol.com

7201 SCHIRRA CT. STE. HBAKERSFIELD, CA 93314

CHRIS SLAUSONBAKER PETROLITE

246.

661-203-3303christopher.slauson@bakerpetrolite.com

12242 SPRUCE GROVE PLSAN DIEGO, CA 92131-2215

BEN SMITH247.

619-985-9325bentoncs@yahoo.com

2869 BRIDGEPORT AVE SESALEM, OR 97306

JOHN H SMITHBASF

248.

503-391-5644JOHN.SMITH@BASF.COM

800 BUCHANAN STALBANY, CA 94710

LINCOLN SMITHUSDA-ARS

249.

510-559-6185lsmith@pw.usda.gov

1432 ABBOTT STSALINAS, CA 93901

RICHARD F SMITHU.C.C.E. - MONTEREY COUNTY

250.

831-759-7357rifsmith@ucdavis.edu

159158

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

2831 ASHLAND DRROSEVILLE, CA 95661

JAMES STURGESDOW AGRO SCIENCES

251.

916-774-9858jesturges@dow.com

501 TAFT HWYBAKERSFIELD, CA 93307

TERRY R SUTTONKERN DELTA WATER DISTRICT

252.

661-834-4656terrys@kerndelta.org

2302 A ST. S.E.S.E. AUBURN, WA 98002

KB SWAINNORSTAR INDUSTRIES, INC.

253.

253-735-1881kbs@norstarind.com

2478 N. SUNNYSIDE AVEFRESNO, CA 93727

CHUCK D SYNOLDTARGET SPECIALTY PRODUCTS

254.

559-291-7740tspsynold@earthlink.net

P.O. BOX 4015SACRAMENTO, CA 95812

MAC TAKEDACDPR

255.

916-445-3838mtakeda@cdpr.ca.gov

220 GLACIER DRMARTINEZ, CA 94553

BOB TAMORICOUNTY OF CONTRA

256.

925-646-4150

PO BOX 1266CLAYTON, CA 94517

PETER TAORMINAPMT PEST CONTROL SERVICE

257.

925-330-3135

2413 SEQUOIA AVESANGER, CA 93657

MARK TESTERMANVALENT USA

258.

559-284-1913mtest@valent.com

135 N. MANCHESTER AVEANAHEIM, CA 92802

BRYAN X THOMPSONPEST OPTIONS INC.

259.

714-224-7378bthompson@pestoptions.com

1295 S. 33RD DR.YUMA, AZ 85364

BARRY TICKESUNIVERSITY OF ARIZONA

260.

928-580-9902btickes@ag.arizona.edu

160159

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

P O BOX 915LINDSAY, CA 93247-0915

JEFF A TIENKENT & T AG SERVICES

261.

559-562-6554

10306 RIO SAMBA CT.OAKDALE, CA 95361

EDWARD TOBIASMODESTO IRRIGATION DISTRICT

262.

209-526-7637edt@mid.org

PO BOX 1359SUITE 600ATASCADERO, IN 93423

KATIE TOUGERONSEPRO CORPORATION

263.

530-308-3298katie@sepro.com

1701 NIMBUS RD STE. FRANCHO CORDOVA, CA 95670

JOEL TRUMBOCA DEPT FISH & GAME

264.

916-358-2952jtrumbo@ospr.dfg.ca.gov

88 MCCALL DRCOLLIERVILLE, TN 38017

RONNIE TURNERDUPONT CROP PROTECTION

265.

901-746-6006ronnie.g.turner@usa.dupont.com

31130 HILLTOP DR.VALLEY CENTER, CA 92082

BRUCE UBERCROP INSPECTION SERVICE

266.

760-805-3255buzzuber@cs.com

9269 MANTLE CTELK GROVE, CA 95758

TIM UNDERWOODMONSANTO

267.

916-761-3098timothy.r.underwood@monsanto.com

P.O. BOX 850SALINAS, CA 93902

JOSE ALONSO VALDEZD'ARRIGO BROTHERS

268.

831-753-5496

1995 MARKET STRIVERSIDE, CA 92501

AVELINO VALENCIARIVERSIDE COUNTY FLOOD

269.

951-955-1495

3415 MORRO BAY AVEDAVIS, CA 95616-5640

JOE VANDEPEUTECAL/EPA-DPR

270.

916-324-3951jvandepeute@cdpr.ca.gov

161160

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

20251 AVE 17 1/2MADERA, CA 93637

RON VARGASRON VARGAS CONSULTING, LLC

271.

559-395-3375vargasconsulting@earthlink.net

P.O. BOX 850SALINAS, CA 93901

JESUS VASQUEZD'ARRIGO BROTHERS

272.

831-424-3955

2121 2ND ST. B-107DAVIS, CA 95618

JULIE VERSMANMARRONE ORGANIC INNOVATIONS

273.

530-750-2800X201JVERSMAN@MARRONEORGANICS.CO

1155 MABURY RDSAN JOSE, CA 95133

NANCY VOORHEESTARGET SPECIALTY PRODUCTS

274.

800-767-0719NANCY.VOORHES@TARGET-SPECIAL

731 VIA BANDOLEROARROYO GRANDE, CA 93420

GORDON VOSTIBAYER CROP SCIENCE

275.

805-481-8838gordon.vosti@bayercropscience.com

115 RALSTON RDSLIPPERY ROCK, PA 16053

GARY C WAKEFIELDMILLER CHEMICAL

276.

724-794-3530gcwakefield@zoominternet.net

4100 TRAFFIC WAYSACRAMENTO, CA 95827

BRIAN WALSHSACRAMENTO COUNTY DOT

277.

916-875-5171walshbr@saccounty.net

16310 ROBIE LANELOS GATOS, CA 95032

MARK E WANDERSANTA CLARA VALLEY WATER

278.

408-265-2607X3851MWANDER@VALLEYWATER.ORG

PO BOX 1515BRAWLEY, CA 92227

VINCE WAVRA279.

760-344-7590

217 MEADOWLARK RDPASO ROBLES, CA 93446

ROBERT E WELTYVALENT USA

280.

877-696-4204robert.welty@valent.com

162161

60TH ANNUAL CALIFORNIA WEED SCIENCE MTG.January 28, 2008 - January 30, 2008

15420 N 29TH AVEPHOENIX, AZ 85053

PAUL WESTCOTTAPPLIED BIOCHEMISTS

281.

602-896-8288PAULWESTCOTT@APPLIEDBIOCHEMI

5183 W FREMONTFRESNO, CA 93722

ROY S WHITSONUNITED PHOSPHORUS INC.

282.

559-277-5501roy.whitson@uniphos.com

1 LOS PIONEROSRANCHO SANTA MARGARITA, CA

DANIEL WICKHAMWILBUR-ELLIS CO.

283.

949-981-0945dwickham@wilbur-ellis.com

2723 SEPULVEDA BLVDLOS ANGELES, CA 90064

CYNTHIA A WILLIAMSCALTRANS

284.

310-575-3491cynthia_williams@dot.ca.gov

3009 E. CARDELLAFIREBAUGH, CA 93622

FRANK WILLIAMSWIND FALL FARMS 1

285.

559-659-3932

34534 116TH ST. EASTPEARBLOSSOM, CA 93553

RON K WOLFEDWR

286.

661-944-8508dbilly@water.ca.gov

4437-B SOUTH LASPINA STTULARE, CA 93274

STEVEN D WRIGHTU.C.C.E.-TULARE COUNTY

287.

559-685-3303sdwright@ucdavis.edu

P O BOX 775ELK GROVE, CA 95759-0775

KEN YELLEJOHN DEERE LANDSCAPES

288.

916-826-2113kyelle@johndeerlandscapes.com

288Participant Count:

163162