1 weeds is to ignore or tolerate them. Some “weeds” are even aesthetically pleasing and break up the monoto- ny of a “perfect” lawn. When lawn weeds reach levels where they can- not be tolerated, active controls By William Quarles A number of alternative herbi- cides have been developed and are now either commer- cially available, or waiting for EPA approval. Major markets for these herbicides include the turfgrass industry and organic agriculture. Demand for “green” herbicides in turfgrass is being driven both by environmental concerns and regula- tory action. For instance, a number of provinces in Canada have banned cosmetic application of chemical pesticides such as 2,4-D for broadleaf weed control on lawns. Cultural methods can relieve some weed pressures, but alternative herbicides can make weed manage- ment less labor intensive (Abu- Dieyeh and Watson 2009; Hashman 2011; Bailey et al. 2010; Boyetchko et al. 2009). In organic agriculture, weeds are the number one pest management problem and conventional synthetic herbicides cannot be used. Current organic options include hand weed- ing, cultivation, mulching and flam- ing (Quarles 2004; Sivesind et al. 2009). Alternative herbicides can reduce or eliminate costs of hand weeding (Evans and Bellinder 2009; Avila-Adame et al. 2008). Alternative Herbicides in Turfgrass Canadian provinces of Ontario, Quebec, and New Brunswick have banned cosmetic application of pes- ticides on lawns. More than 166 Canadian cities have joined in the Provincial Bans. As a result, urban streams in Ontario have seen an 80% reduction of the three most commonly used lawn herbicides— 2,4-D, dicamba, and MCPP. About 77% of the Canadian population is benefiting from reduced exposure to synthetic lawn and garden pesti- cides (Ottawa 2010). Regulations on cosmetic pesticides in Toronto led to a 57% reduction in use on lawns between 2003 and 2007, and the use of alternatives has increased. In 2004, 49% of all households with lawns reported some use of natural lawn care methods. In 2007, this proportion was 67% (Toronto 2009). The regulatory ban of synthetic herbicides does not mean that turf- grass weeds cannot be managed. The easiest treatment for lawn In This Issue Alternative Herbicides 1 ESA Report 9 Calendar 8 Volume XXXII, Number 5/6, May/June 2010 Alternative Herbicides in Turfgrass and Organic Agriculture Photo courtesy of Marrone Bio Innovations Alternative herbicides can be effective. Pictured here is an irrigation chan- nel that has been treated with GreenMatch®, a reduced risk herbicide con- taining d-limonene.
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weeds is to ignore or tolerate them.Some “weeds” are even aestheticallypleasing and break up the monoto-ny of a “perfect” lawn. When lawnweeds reach levels where they can-not be tolerated, active controls
By William Quarles
A number of alternative herbi-cides have been developedand are now either commer-
cially available, or waiting for EPAapproval. Major markets for theseherbicides include the turfgrassindustry and organic agriculture.Demand for “green” herbicides inturfgrass is being driven both byenvironmental concerns and regula-tory action. For instance, a numberof provinces in Canada havebanned cosmetic application ofchemical pesticides such as 2,4-Dfor broadleaf weed control on lawns.Cultural methods can relieve someweed pressures, but alternativeherbicides can make weed manage-ment less labor intensive (Abu-Dieyeh and Watson 2009; Hashman2011; Bailey et al. 2010; Boyetchkoet al. 2009).In organic agriculture, weeds are
the number one pest managementproblem and conventional syntheticherbicides cannot be used. Currentorganic options include hand weed-ing, cultivation, mulching and flam-ing (Quarles 2004; Sivesind et al.2009). Alternative herbicides canreduce or eliminate costs of handweeding (Evans and Bellinder 2009;Avila-Adame et al. 2008).
Alternative Herbicides inTurfgrass
Canadian provinces of Ontario,Quebec, and New Brunswick havebanned cosmetic application of pes-ticides on lawns. More than 166Canadian cities have joined in theProvincial Bans. As a result, urbanstreams in Ontario have seen an80% reduction of the three most
commonly used lawn herbicides—2,4-D, dicamba, and MCPP. About77% of the Canadian population isbenefiting from reduced exposure tosynthetic lawn and garden pesti-cides (Ottawa 2010). Regulations oncosmetic pesticides in Toronto ledto a 57% reduction in use on lawnsbetween 2003 and 2007, and theuse of alternatives has increased. In2004, 49% of all households withlawns reported some use of naturallawn care methods. In 2007, thisproportion was 67% (Toronto 2009).The regulatory ban of synthetic
herbicides does not mean that turf-grass weeds cannot be managed.The easiest treatment for lawn
In This Issue
Alternative Herbicides 1ESA Report 9Calendar 8
Volume XXXII, Number 5/6, May/June 2010
Alternative Herbicides in Turfgrassand Organic Agriculture
Photo
courtesy
ofMarro
neBioInnovatio
ns
Alternative herbicides can be effective. Pictured here is an irrigation chan-nel that has been treated with GreenMatch®, a reduced risk herbicide con-taining d-limonene.
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2 Box 7414, Berkeley, CA 94707IPM Practitioner, XXXII(5/6) May/June 2010
Updatesuch as hand pulling, mechanicalremoval, flaming, or hot water canbe used (see Resources). Flamingcan kill broadleaf weeds while spar-ing turfgrass (see Quarles 2003ab).Organic management and good cul-tural methods such as overseeding,fertilizing, and mulching can beeffective. Special tools such as theWeed Hound make mechanicalmethods easier (Quarles 2003ab;Quarles 2008; Quarles 2009ab).
War on the Dandelion?But aesthetic thresholds for lawn
weeds vary considerably from per-son to person. When very low weedpopulations are demanded, integra-tion of reduced risk herbicides intothe IPM management program maybe necessary. Many of the newalternative herbicides target thehumble dandelion, Taraxacum offic-inale. The dandelion is a perennialweed that overwinters in the soil asseeds or as perennial roots. Plantsmay live 10-13 years, and popula-tions may vary considerably in ageand genetic composition (Abu-Dieyeh and Watson 2007b).One reduced risk pre-emergent
product already on the market fordandelion and lawn weed control iscorn gluten meal. Vinegar, essentialoils, citric acid, and soaps are avail-able for spot treatments (seeResources). New products includeiron chelates, sold under the brand-names Iron-X, Fiesta, and EcoSense(see Resources). A number of micro-bial herbicides are also in thepipeline. These include formula-tions based on Phoma macrostoma,Sclerotinia minor (Sarritor™), andStreptomyces sp (MBI 005).
Corn Gluten MealCorn gluten meal (CGM) is a
waste product left over from theprocessing of corn to produce cornsyrup. Corn gluten meal is 60%protein and approximately 10%nitrogen (N) by weight. It has beenused as an ingredient in dog food,fish food, and other animal feeds(Christians 1991; Christians 1995).Its high nitrogen content and her-
bicidal properties make corn glutenmeal a near ideal “weed and feed”
The IPM Practitioner is published six timesper year by the Bio-Integral ResourceCenter (BIRC), a non-profit corporationundertaking research and education in inte-grated pest management.Managing Editor William QuarlesContributing Editors Sheila Daar
Tanya DrlikLaurie Swiadon
Editor-at-Large Joel GrossmanBusiness Manager Jennifer BatesArtist Diane Kuhn
For media kits or other advertising informa-tion, contact Bill Quarles at 510/524-2567,[email protected].
Advisory BoardGeorge Bird, Michigan State Univ.; SterlingBunnell, M.D., Berkeley, CA ; Momei Chen,Jepson Herbarium, Univ. Calif., Berkeley;Sharon Collman, Coop Extn., Wash. StateUniv.; Sheila Daar, Daar & Associates,Berkeley, CA; Walter Ebeling, UCLA, Emer.;Steve Frantz, Global Environmental Options,Longmeadow, MA; Linda Gilkeson, CanadianMinistry of Envir., Victoria, BC; JosephHancock, Univ. Calif, Berkeley; HelgaOlkowski, William Olkowski, Birc Founders;George Poinar, Oregon State University,Corvallis, OR; Ramesh Chandra Saxena,ICIPE, Nairobi, Kenya; Ruth Troetschler, PTFPress, Los Altos, CA; J.C. van Lenteren,Agricultural University Wageningen, TheNetherlands.ManuscriptsThe IPMP welcomes accounts of IPM for anypest situation. Write for details on format formanuscripts or email us, [email protected].
CitationsThe material here is protected by copyright,and may not be reproduced in any form,either written, electronic or otherwise withoutwritten permission from BIRC. ContactWilliam Quarles at 510/524-2567 for properpublication credits and acknowledgement.
Subscriptions/MembershipsA subscription to the IPMP is one of the bene-fits of membership in BIRC. We also answerpest management questions for our membersand help them search for information.Memberships are $60/yr (institutions/libraries/businesses); $35/yr (individuals).Canadian subscribers add $15 postage. Allother foreign subscribers add $25 airmailpostage. A Dual membership, which includesa combined subscription to both the IPMPand the Common Sense Pest ControlQuarterly, costs $85/yr (institutions); $55/yr(individuals). Government purchase ordersaccepted. Donations to BIRC are tax-deductible.FEI# 94-2554036.
Lawn weeds can be managedby hand weeding and othermethods.
DrawingbyDianeKuhn
Weeding tools make the jobeasier.
Photo
courtesy
Steve
Ash
Handheld flamers are anotheroption for lawn weeds.
Photo
courtesy
FlameEngineerin
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product. The product can beapplied to mature turfgrass as a topdressing and fertilizer. Over time, itacts as a pre-emergence herbicidethat suppresses growth of annualweeds such as crabgrass, Digitariaspp., clover, Trifolium spp., anddandelion, Taraxacum officinale.Reductions of about 90% were seenover a 4-year period (Bingaman andChristians 1995; Christians 1991;Christians 1995; Quarles 1999).Corn gluten meal can be purchasedat feed stores and from a number ofgarden suppliers (see Resources).
Microbial HerbicidesSeveral microbials have shown
promise as herbicides. Divine® andCollego® were commercialized in1982. Devine was for control ofstranglervine, Morrenia odorata,and Collego was for postemergencecontrol of northern jointvetch,Aeschynomene virginica (Bailey andMupondwa 2006). Since then, veryfew microbials have been commer-cially developed.A review written in 2001 found
only 8 microbial herbicides hadbeen commercialized since 1980.These included 1. Phytophthorapalmivora (DeVine) used on stran-glervine, Morrenia odorata; 2.Colletotrichum gloeosporioides f.sp.aeschynomene (Collego) used onnorthern jointvetch, Aeschynomenevirginica; 3. C. gloeosporioides
(Hakatak®) used on Hakea sericea;4. C. gloeosporioides (BioMal® orMallet®) used on various mallowweeds, Malva spp.; 5. The rustpathogen, Puccinia canaliculata (Dr.BioSedge®) used on sedges such asCyperus esculentus; 6. The bacteri-um Xanthomonas campestris pvpoae (Camperico®) used on annualbluegrass, Poa annua;7.Cylindrobasidium laeve(Stumpout®) used on Acacia; (8)Chondrostereum purpureum(BioChon®) used on broadleafedtrees (Charudattan 2001; Baileyand Mupondwa 2006; Boyetchkoand Rosskopf 2006). Also,Alternaria cassiae (Casst®) is some-times sold for the control of sickle-pod, Senna spp. (BIRC 2010).Microbial herbicides have been
slow to catch on in the IPM market-place. Problems have been high costand generally narrow host range.When the host range is too narrow,so that only one weed is targeted,then the market is limited. If thehost range is too broad, there arepossible risks to economic crops.Because microbials developed havenot been broadspectrum materials,they have been sporadically avail-able only in niche markets(Charudattan 2001; Hallett 2005;Bailey and Mupondwa 2006).
New Microbial HerbicidesThe new microbial herbicides now
being commercialized have a widerspectrum of efficacy, and thus moremarket potential. Possible problemswith broader host range materialscan be minimized if they have eithershort persistence or limited disper-sal (Hallett 2005; Goettel et al.2001). One new microbial, Phomamacrostoma, has limited dispersaland relatively short persistence.When released, it lives about fourmonths. Another microbial, the fun-gus Sclerotinia minor, does notspread from the release point andonly lasts about 11 days in a turf-grass environment. Yet anotherproduct, MBI 005, uses the Bacillusthuringiensis strategy. The microbeitself is killed before release into theenvironment, limiting dispersalfrom the application site (Zhou et
al. 2004; Abu-Dieyeh and Watson2007ab; Hashman 2011).
MBI 005 (Streptomyces)MBI 005, which was developed by
Marrone Bio Innovations, is expect-ed to receive EPA registration inSeptember of 2011. The microbialStreptomyces acidiscabies is grownin a production facility where it pro-duces herbicidal secretions. The liv-ing organism is then killed and har-vested along with the herbicide ithas produced. This method of pro-duction allows the use of a broad-spectrum microbial that poses nonon-target problems in the field.Since it is not alive, it cannot growand spread beyond the releasepoint. According to Tom Hashmanof Marrone Bio Innovations, “Ourtesting and review of activity showsboth preemergent and postemergentactivity across a variety ofbroadleaf, grass and sedge weeds.There is excellent crop tolerance ingrassy crops such as cereals, riceand corn; we also see excellent util-ity in various turf species”(Hashman 2011).
Phoma macrostoma Strain94-44B
Phoma macrostoma was isolatedfrom Canada thistle, Cirsiumarvense, which was growing inSaskatchewan (Graupner et al.2003). It is a weak plant pathogen
3IPM Practitioner, XXXII(5/6) May/June 2010 Box 7414, Berkeley, CA 94707
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Dandelion, Taraxacum officinale
Large crabgrass,Digitaria sanguinalis
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4 Box 7414, Berkeley, CA 94707IPM Practitioner, XXXII(5/6) May/June 2010
Updatewidely distributed in nature that issaprophytic and lacks a sexualstage. When applied to soil, it killsseveral important weeds, includingCanada thistle, dandelion,Taraxacum officinale; chickweed,Stellaria media, scentlesschamomile, Matricaria perforata,and others. It colonizes plant leavesand roots, secreting compoundscalled macrocidins that bleachweeds and cause chlorosis(Graupner et al. 2006).Field tests have shown it effective
for dandelion (68%), annual sowthistle (97%) and wild mustard(82%). Soil moisture and uniformapplication rates are needed forproduct effectiveness, and it worksbest on emerging seedlings. Thefungus attacks broadleaf plantssuch as canola and lentil, butgrasses, and monocots such aswheat, barley, and oats are unaf-fected. Field tests in Guelph,Ontario found 92% dandelion con-trol at 84 days after application(Bailey 2009ab).A series of tests found application
to soil gave 36-100% control of dan-delion depending on doses usedand isolates employed. It persists insoil for about four months, and isnot detectable after a year. It is apoor competitor, and soils with highmicrobial activity restrict its growth.Commercial application rates areexpected to be 16-32 g/m2 (5-10oz/100 ft2), and it has limitedmobility in soil. Field tests found it1-8 cm (0.4-3.1 in) deep in the soil,but the fungus was not detected 30and 60 cm (12-24 in) away horizon-tally from where it was applied(Zhou et al. 2004).Generally, the fungus and its
metabolites stay where they areapplied. However, the macrocidinsare water soluble. This solubilityincreases efficacy because plantcolonization may not be necessaryfor herbicidal effectiveness. Weedsmay also absorb macrocidinsthrough their roots. Macrocidinsare released from the fungus withrainfall, and when soil is not satu-rated with water, bioactivityremains on site. When soil is satu-rated, macrocidins might be carriedoffsite with runoff; “hence, it is rec-
ommended that this bioherbicideshould not be applied when the soilis saturated” (Bailey et al. 2010).Scotts Co. of Marysville, OH
applied for EPA registration March10, 2010 and for California regis-tration January 6, 2010. Accordingto Karen Bailey, the researcher whoisolated the fungus, it shouldreceive EPA approval by September2011 (Bailey 2011).
Sclerotinia minorIMI344141 (Sarritor)
Sclerotinia minor was isolatedfrom diseased lettuce plants inQuebec. It has a broad host range
and 37 broadleaf turfgrass weedsare vulnerable. Damage to weeds isvariable and depends on degree ofcontact with the microbial and envi-ronmental conditions. The fungusespecially attacks and kills dande-lion seeds and seedlings. It isapplied in granular form as the for-mulation Sarritor. When appliedpre-emergent, the fungus reduceddandelion emergence by 78%; post-emergent application 10 days aftersowing dandelions led to a 97%reduction. Grasses show nolongterm damage from the fungus.Grass germination experimentsshowed a slight reduction of vigorat one week, but four weeks laterthe treated grasses were morerobust than controls (Abu-Dieyehand Watson 2007a).
S. minor has a broad host range.This fact means that it can success-fully attack many genetic variantsof dandelion. Young plants are morevulnerable than old ones. Grasscompetition increases efficacy ofdandelion control. The microbialplus overseeding reduced dandelionpopulations 70-80% in the firstyear, increasing to 95% in the sec-ond year (Abu-Dieyeh and Watson2007b; Abu-Dieyeh and Watson2009).Sclerotinia minor was registered
in Canada on September 22, 2010,and according to Jerry Walker ofSylvan BioProducts, U.S. registra-tion should be completed soon. It issold as a granular formulationunder the brandname Sarritor (seeResources).
Effectiveness of MicrobialsMicrobials act in a different way
than chemical pesticides. Sincethey are living organisms, theymust have a food supply and afavorable environment for growth.Efficacy can sometimes be compro-mised by environmental conditions.Lack of optimal growing conditionsof temperature and moisture canlead to product failure. Even if thematerial is broadspectrum, effec-tiveness can be a factor of timingand the age of the weed. So to makeproper use of microbials, moreknowledge is needed than with theapplication of chemical controls(Templeton and TeBeest 1979;Watson 1991; Hallett 2005).For instance, although Sarritor
can kill 37 different species of turf-grass weeds, it is most effectiveagainst dandelion. Herbicidal effectsmay be due to secretion of oxalicacid. Successful use depends ontemperature, moisture, and espe-cially relative humidity. Seedlingsand young dandelion plants aredestroyed, but older plants mayresprout from the root crown. Thebest time for application is in thefall and spring, and especially thespring. Sarritor works best withhelp from vigorous turfgrassgrowth. Thus, overseeding and goodcultural methods, such as highmowing height increases the effec-tiveness. After application, turf
Canada thistle,Cirsium arvense
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must be watered for at least threedays if rainfall is not present.During hot summer months,Sarritor is generally ineffectiveunless turf is covered for at leastthree days after application withjute or other material to increasethe relative humidity (Abu-Dieyehand Watson 2007ab; Abu-Dieyehand Watson 2009).
Microbial SafetyThe microbials being developed
occur naturally in the environment,and the product registration infor-mation available suggests few prob-lems. For instance, the S. minorfungus present in Sarritor is nottoxic to birds, bees, wild mammals,insects, or earthworms. But caremust be taken not to destroy non-target plants, especially aquaticplants. The formulation should notbe applied to water or to areaswhere the broadspectrum herbicidewill produce negative results. So,lawn clippings should not beapplied to gardens or allowed tocontaminate water (Canada 2010).Possible problems with microbials
include allergies (Goettel et al.2001). The granular formulationSarritor has potential to irritateskin and lungs, and the dustshould not be inhaled. The granulesshould be applied within 12 hours
of rainfall or irrigation. Oncewatered in, they present lessinhalation risk (Canada 2010).When registration of these micro-
bials is complete, we will report onany new information in futureissues of the IPM Practitioner.
Alternative Herbicides inOrganic Agriculture
Synthetic pesticides cannot beused in organic agriculture, butnatural or non-synthetic materialsare allowed. Commercially availablematerials include vinegar andessential oils such as clove andlemongrass oil (see Resources).Eventually, some of the new micro-bials may be registered for organicagriculture (Hallett 2005; Bailey2009b). Vinegar is obtained by theaerobic bacterial oxidation ofethanol, producing acetic acid. Thecharacteristic odor of vinegar is dueto acetic acid, and effectiveness ofvinegar as a weed killer increaseswith its concentration. For instance,200 grain vinegar contains 20%acetic acid. This product is muchstronger than table vinegar, whichcontains about 5% acetic acid(Evans et al. 2009).Vinegar is a broadspectrum her-
bicide, but some weed species arekilled easier than others. It is moreeffective for small weeds, and effica-
cy increases with the percent ofacetic acid. Researchers at theUSDA tested vinegar as an herbi-cide in 2002. They found vinegar at10, 15, or 20% acetic acid concen-tration provided 80-100% kill ofselected annual weeds, includinggiant foxtail, Setaria faberi; up to 3inches (7.6 cm) in height, commonlambsquarters, Chenopodiumalbum; up to 5 inches (12.7 cm),smooth pigweed, Amaranthushybridus; up to 6 inches (15.2 cm),and velvetleaf, Abutilon theophrasti;up to 9 inches (22.9 cm). Control ofannual weeds with table vinegar atthe 5% acetic acid concentrationwas variable. Shoots of Canadathistle, Cirsium arvense; were high-ly susceptible to 5% vinegar.However, there was regrowth fromthe roots (Quarles 2002; Miller2007).
EPA Registration of StrongVinegar
Commercial development of vine-gar herbicides has been hampereduntil recently due to lack of EPAregistration. In February 2011 acommercial formulation of vinegarcalled Weed Pharm® was given EPAapproval for use in organic crops(Lewis 2011). Earlier, Weed PharmEPA registration had been obtainedfor non-crop uses. The active ingre-dient of Weed Pharm is 20% aceticacid. A disadvantage of WeedPharm is that concentrated vinegaris corrosive, so care must be usedduring application. Respiratory pro-tection, gloves, safety glasses, andlong sleeved shirts are needed.Sprayers must be cleaned carefullyafter use, or corrosion will result.The advantage is that once it isapplied, it is degraded to carbondioxide and water, leaving no toxicresidues in the environment.Several studies have shown the
effectiveness of strong vinegar as aweed control product. As mentionedabove, mortality may vary with thespecies. For instance, 20% aceticacid led to 100% mortality of two-leaf redroot pigweed, Amaranthusretroflexus, 9 days after treatment.But velvetleaf, Abutilon theophrasti,showed only 18% mortality whentreated this way. Younger and
Strong vinegar is corrosive, so personal protection is needed when spray-ing. It degrades to carbon dioxide and water, leaving no toxic residues.
Photo
courtesy
SusanLew
is,Pharm
Solutio
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smaller weeds are more susceptiblethan older ones. Treatment is moreeffective when the sun is shiningand temperatures are warm.Increasing application volume cancompensate for reduced concentra-tions. So 15% vinegar applied at636 liter/ha (68 gal/acre) gives sim-ilar results as 30% vinegar at 318liter/ha (34 gal/acre). Since con-centrated solutions of acetic acidare corrosive, reducing concentra-tion makes the material easier tohandle (Evans et al. 2009).
Vinegar Herbicide inOrganic Corn
Weed management with vinegar inorganic agriculture is a balancing
act. Vinegar must be concentratedenough to kill the weeds, but not soconcentrated that it kills the crop.Best results are obtained whenapplications are made early in theseason. Smaller weeds are morevulnerable, and early applicationgives the crop time to recover beforeharvest. In one study, there was91% control of small weeds one DayAfter Treatment (DAT) with 20%vinegar at 636 liter/ha (68gal/acre). Average control over allweed sizes tested was 83%. Earlytreatment of Trinity or Avalon sweetcorn with 20% acetic acid at 318
liter/ha (34 gal/acre) led to similaryields as hand weeding (Evans andBellinder 2009).
Organic Onions andPotatoes
Vinegar is also useful in organiconions and potatoes. Application of15% vinegar at 636 liter/ha (68gal/acre) early in the season gaveabout 6% damage to onions oneDAT, but the crop recovered beforeharvest, and yields were similar tototally handweeded onions.However, the early vinegar treat-ment led to a 60% reduction in theamount of handweeding necessaryto produce high yields (Evans andBellinder 2009).
Other treatments for onionsinclude cultivation, flaming, and theapplication of corn gluten meal.Corn gluten meal applied to springtransplanted onions at 4,000 kg/hagave about 72% total weed controland 83% broadleaf weed control for46 days after planting. This is avery large application rate, and costmight be too great for commercialproduction (Webber et al. 2007;Quarles 2004; Sivesind et al. 2009).Potato foliage is extensively
injured by both early and late sea-son vinegar sprays. However, thecrop mostly recovers from injury. In
fields with heavy weed pressure,yields from vinegar treatments aresimilar to those seen withhandweeding (Evans and Bellinder2009).
Clove Oil in OrganicAgriculture
Effectiveness of clove oil dependson the concentration. For redrootpigweed 1.7% clove oil was margin-ally effective, but 3.4% applied atthe rate of 318 liter/ha (34gal/acre) gave 94% control after sixdays to the four leaf stage of theweed. Velvetleaf is harder to controlwith clove oil. The same 3.4% treat-ment resulted in 60% control of thefour leaf stage after six days (Evanset al. 2009).Clove oil is more effective on
small weeds than large ones, and ismore effective for broadleaf weedsthan grasses. In field tests conduct-ed in sweet corn, onion, and potato,clove oil did not control grassyweeds. Applications of 3.4% cloveoil at 318 liter/ha (34 gal/acre) ratealso did not give effective control oftypical crop weeds such as lamb-squarters, Chenopodium album;purslane, Portulaca oleracea, chick-weed, Stellaria media and others.Weed control averaged about 43%.In these tests vinegar was moreeconomical and “showed a greaterpotential for broadspectrum weedcontrol” (Evans and Bellinder 2009).Other researchers have found thatclove oil must be used at higherconcentrations to give effective con-trol of broadleafed weeds(Abouziena et al. 2009; Boyd andBrennan 2006).
GreenMatch® andGreenMatch EX®
Another alternative herbicide fororganic agriculture is GreenMatch.GreenMatch is approved by theOrganic Materials Review Institute(OMRI) for use in organic agricul-ture, and it has California EPA reg-istration for a large number ofcrops. The active ingredient ofGreenMatch is 55% d-limonene,which is a major component oforange oil. Orange oil has beencommercialized as a reduced risk
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IPM Practitioner, XXXII(5/6) May/June 2010 Box 7414, Berkeley, CA 947076
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This organic farmer is spraying GreenMatch® to suppress weedsbefore transplanting celery.
Photo
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ofMarro
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treatment for ants and drywood ter-mites (Mashek and Quarles 2009).The d-limonene dissolves the waxycuticle of plants, causing them todesiccate and die. GreenMatch ismore effective for broadleaf weedsthan grassy weeds. Good coverageis necessary for good weed control,and application rates of 60 gal/acre(560 liter/ha) or more are required.For broadcast operation, it is dilut-ed to about 14% of originalstrength. Spot applications use adilution to 20% (Marrone 2010).Treatment of younger weeds is
more effective than older ones. Forinstance, GreenMatch gives 96%control of 19-day old broadleafweeds such as pigweed,Amaranthus spp. and black night-shade, Solanum nigrum; but only17% control of 26-day old plants(Lanini 2010). Weed populations ofwild mustard, buckhorn plantain,hairy fleabane, lambsquarters andshepherd’s purse are reduced 90%at 28 days after treatment (Marrone2010).GreenMatch EX contains 50%
lemongrass oil, which is an EPA25b exempt material (Quarles1996a). According to company data,Greenmatch EX at 10-15% dilutionand applied at 100 gal/acre (935liter/ha) gave excellent controlagainst “spurge and thistle, goodcontrol against bindweed, clover,and crabgrass; and satisfactorycontrol against bermudagrass.”Smooth crabgrass was highly sensi-tive to the product. Poor efficacywas seen with henbit and dandelion(Avila-Adame et al. 2008).
ConclusionA number of alternative herbi-
cides have been developed and arenow either commercially available,or waiting for EPA approval. Majormarkets for these herbicidesinclude the turfgrass industry andorganic agriculture. Cultural meth-ods such as overseeding, fertilizing,and mulching reduce weed popula-tions in turfgrass, but alternativeherbicides may make weed manage-ment less labor intensive.Integration of alternative herbicidesinto IPM programs may produceeffective results without the envi-
ronmental problems seen with con-ventional chemical herbicides.In organic agriculture, weeds are
the number one pest managementproblem, and conventional synthet-ic herbicides cannot be used.Current organic options includehand weeding, cultivation,mulching and flaming. Alternativeherbicides may be able to relieveweed pressures, reducing or elimi-nating costs of hand weeding.
William Quarles, Ph.D. is an IPMSpecialist, Managing Editor of theIPM Practitioner, and ExecutiveDirector of the Bio-IntegralResource Center (BIRC). He can bereached by email at [email protected].
and M. Singh. 2009. Efficacy comparison ofsome new natural product herbicides forweed control at two growth stages. WeedTechnol. 23(3):431-437.
Abu-Dieyeh, M.H. and A.K. Watson. 2007a.
Grass overseeding and a fungus combine tocontrol Taraxacum officinale. J. Appl. Ecol.44:115-124.
Abu-Dieyeh, M.H. and A.K. Watson. 2007b.Efficacy of Sclerotinia minor for dandelioncontrol: effect of dandelion accession, age,and grass competition. Weed Res. 47:63-72.
Abu-Dieyeh, M.H. and A.K. Watson. 2009.Increasing the efficacy and extending theeffective application period of a granular turfbioherbicide by covering with jute fabric.Weed Technol. 23(4):524-530.
Avila-Adame, C., L. Fernandez, B. Campbell, E.Tan, M. Koivunen and P. Marrone. 2008.Field evaluation of GreenMatch EX: a newbroadspectrum organic herbicide. Proc.Calif. Weed Sci. Soc. p. 127.
Bailey, K.L. and E.K. Mupondwa. 2006.Developing weed control products: commer-cial, biological and technological considera-tions. In: Singh et al., pp. 431-473 of 892pp.
Bailey, K.L. 2009a. Phoma macrostoma: a bio-herbicide in the making. Sports TurfManager Summer: 11-12.
Bailey, K.L., W.M. Pitt, J. Derby, S. Walter, W.Taylor and S. Falk. 2010. Efficacy of Phomamacrostoma, a bioherbicide, for control ofdandelion (Taraxacum officinale) followingsimulated rainfall conditions. The AmericasJ. Plant Sci. Biotechnol. 4 (Special Issue
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Corn gluten meal—Gardens Alive, seebelow. Peaceful Valley FarmSupply, PO Box 2209, 125Clydesdale Court, Grass Valley, CA95945; 530/272-4769, Fax530/272-4794;www.groworganic.com. GrainProcessing Corporation, 1600Oregon St., Muscatine, IA 52761;563/264-4265, Fax 563/264-428;www.grainprocessing.com
Iron Chelate—(Iron X®) Gardens Alive,5100 Schenley Place,Lawrenceburg, IN 47025; 812/537-8650, Fax 812/537-8660;www.gardensalive.com
Iron Chelate—(EcoSense®, Fiesta®,Ortho Elementals®) Scotts Co.,Marysville, OH. www.scotts.com
Resources
Lanini, T. 2010. Organic herbicides—do theywork? W.T. Lanini, Dept. Plant Sciences, UCDavis, CA. UC Davis Field Day, September8, 2010. [email protected].
Lewis, S. 2011. Vinegar herbicide approved forcrop use. Press Release, Pharm Solutions,Cambria, CA. February 15, 2011. 1 pp.
Miller, T.W. 2007. Natural herbicides andamendments for organic weed control. In:Felsot and Racke, pp. 174-185.
Marrone (Marrone Bio Innovations). 2010.GreenMatch burndown herbicide. Factsheet,Marrone Bio Innovations, Davis, CA. 2pp.
Mashek, B. and W. Quarles. 2008. Orange oil fordrywood termites: magic or marketing mad-ness? IPM Practitioner 30(1/2):1-9.
Ottawa. 2010. Coalition for a Healthy Ottawa.http://www.flora.org/healthyottawa/news-flash.htm
Quarles, W. 1996. EPA exempts least-toxic pesti-cides. IPM Practitioner 18(9):16-17.
Quarles, W. 1999. Corn gluten meal: a least-toxic herbicide. IPM Practitioner 21(5/6):1-7.
Quarles, W. 2002. USDA tests vinegar herbicide.IPM Practitioner 24(8/9):9.
Quarles, W. 2003a. Herbicide free lawns.Common Sense Pest Control Quarterly19(1):3-7.
Quarles, W. 2003b. Integrated weed control forthe home and garden. Common Sense PestControl Quarterly 19(1):8-18.
Quarles, W. 2004. Thermal weed management:hot alternatives for urban areas and organicfarms. IPM Practitioner 26(5/6):1-9.
Quarles, W. 2008. Mulch optimization in inte-grated pest management. IPM Practitioner30(7/8):1-10.
Quarles, W. 2009a. Organic and IPM manage-ment of turfgrass. IPM Practitioner31(7/8):1-8.
Quarles, W. 2009b. Rethinking the Americanlawn. Common Sense Pest Control Quarterly25(1):3-10.
Rimando, A.M. and S.O. Duke. 2006. NaturalProducts for Pest Management. ACSSymposium Series No. 927, AmericanChemical Society, Washington, DC. 319 pp.
Singh, H.P., D.R. Batish and R.K. Kohli, eds.2006. Handbook of Sustainable WeedManagement, Haworth Press, New York. 892pp.
Sivesind, E.C., M.L. Leblac, D.C. Cloutier, P.Seguin and K.A. Stewart. 2009. Weedresponse to flame weeding at different devel-opmental stages. Weed Technol. 23:438-443.
TeBeest, D.O. ed. 1991. Microbial Control ofWeeds. Chapman and Hall, New York. 284pp.
Templeton, G.E. and D.O. TeBeest. 1979.Biological weed control with mycoherbicides.Ann. Rev. Phytopathol. 17:301-310.
Toronto. 2009. Final Evaluation of Toronto’sPesticide Bylaw and Summary of NewProvincial Pesticide Regulation.http://www.toronto.ca/health/pesticides/pdf/bylaw.pdf 12 pp.
Watson, A.K. 1991. The classical approach withplant pathogens. In: Tebeest, pp. 3-23 of284 pp.
Webber, C.L., J.W. Shrefler and M.J. Taylor.2007. Corn gluten meal as an alternativeweed control option for spring transplantedonions. Intl. J. Veg. Sci. 13(3):17-33. [CABAbstracts]
Zhou, L.C., K.L. Bailey and J. Derby. 2004. Plantcolonization and environmental fate of thebiocontrol fungus Phoma macrostoma. Biol.Control 30(3):634-644.
Agriculture and Agri-Food Canada,Saskatoon, SK, Canada.
Bingaman, B.R. and N.E. Christians. 1995.Greenhouse screening of corn gluten mealas a natural control product for broadleafand grass weeds. HortScience 30(6):1256-1259.
BIRC (Bio-Integral Resource Center). 2010. 2010Directory of Least-Toxic Pest ControlProducts. BIRC, PO Box 7414, Berkeley, CA94707. 52 pp. www.birc.org
Boyd, N.S. and E.B. Brennan. 2006. Burningnettle, common purslane, and rye responseto a clove oil herbicide. Weed Technol.20:646-650.
Boyetchko, S.M. and E.N. Rosskopf. 2006.Strategies for developing bioherbicides forsustainable weed management. In:Singh etal., pp. 393-430 of 892 pp.
Boyetchko, S.M., K.L. Bailey and R.A. DeClerk-Floate. 2009. Current biological weed controlagents-their adoption and future prospects.Prairie Soils and Crops 2:48-57.www.prairiesoilsandcrops.ca
Butt, T.M., C. Jackson and N. Magan, eds. 2001.Fungi as Biocontrol Agents. CABIPublishing, Wallingford, Oxon, UK. 390 pp.
Canada 2010. Registration Decision: Sclerotiniaminor strain IMI 344141. Health CanadaPub. No. ERC2007-02, September 22,2010.www.hc-sc.gc.ca
Charudattan, R. 2001. Biological control ofweeds by means of plant pathogens: signifi-cance for integrated weed management inmodern agroecology. BioControl 46:229-260.
Christians, N.E. 1991. Preemergence weed con-trol using corn gluten meal. U.S. Patent No.5,030,268.
Christians, N. 1995. A natural herbicide fromcorn meal for weed-free lawns. IPMPractitioner 17(10):5-6.
Evans, G.J. and R.R. Bellinder. 2009. The poten-tial use of vinegar and a clove oil herbicidefor weed control in sweet corn, potato, andonion. Weed Technol. 23(1):120-128.
Evans, G.J., R.R. Bellinder and M.C. Goffinet.2009. Herbicidal effects of vinegar and aclove oil product on redroot pigweed(Amaranthus retroflexus) and velvetleaf(Abutilon theophrasti). Weed Technol.23:292-299.
Felsot, A.S. and K.D. Racke, eds. 2007. CropProtection Products for Organic Agriculture.ACS Symposium Series No. 947, AmericanChemical Society, Washingon, DC.
Goettel, M.S., A.E. Hajek, J.P. Siegel and H.C.Evans. 2001. Safety of fungal biocontrolagents. In: Butt et al., pp. 347-375 of 390pp.
Graupner, P.R. A. Carr, E. Clancy et al. 2003.The macrocidins: novel cyclic tetramic acidswith herbicidal activity produced by Phomamacrostoma. J. Nat. Prod. 66:1558-1561.
Graupner, P.R., B.C. Gerwick, T.L.Siddall et al.2006. Chlorosis inducing phytotoxic metabo-lites: new herbicides from Phoma macros-toma. In: Rimando and Duke, pp. 37-47 of319 pp.
Hallett, S.G. 2005. Where are the bioherbicides?Weed Sci. 53:404-415.
Hashman, T. 2011. Pers. Comm., TomHashman, Marrone Bio Innovations, Davis,CA.
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IPM Practitioner, XXXII(5/6) May/June 2010 Box 7414, Berkeley, CA 947078
Update CalendarJanuary 3-6, 2011. 23rd Advanced Landscape IPMShort Course. College Park, MD. Contact: U.Maryland, 301/405-3913; Ex 3911.
January 22, 2011. Annual Bay Area EnvironmentalEducation Fair (BAEER). Civic Center, SanRafael, Marin County, CA. Contact: 510/657-4847;[email protected]
January 26-29, 2011. 31th Annual EcofarmConference. Asilomar, CA. Contact: EcologicalFarming Association, 406 Main St., Suite 313,Watsonville, CA 95076; 831/763-2111; www.eco-farm.org
January 30-February 1, 2011. Annual MeetingAssociation Applied IPM Ecologists. EmbassySuites, Monterey, CA. Contact: www.aaie.net
February 1-2, 2011. National Bed Bug Summit.Washington, DC. Contact: www.epa.gov
February 7-10, 2011. Annual Meeting WeedScience Society of America. Portland, OR.Contact: www.wssa.net
February 24-26, 2011. 22st Annual Moses OrganicFarm Conference. La Crosse, WI. Contact: Moses,PO Box 339, Spring Valley, WI 54767; 715/778-5775; www.mosesorganic.org
March 6-8, 2011. California Small FarmConference. Doubletree, San Jose, CA. Contact:www.californiafarmconference.com
May 12, 2011. EPA Conference, IndoorEnvironmental Quality in Schools. San Antonio,TX. Contact: Stacy Murphy,[email protected]
May 22-25, 2011. International Urban WildlifeManagement. Austin, TX. Contact: D. Foss, TexasParks and Wildlife, Houston, TX. 281/456-7029;Ext. 21; www.urbanwildlife2011.org
June 5, 2011. Organic Market Gardening.Farmington, MN. Contact: MOSES, PO Box 339,Spring Valley, WI 54767; 715/778-5775
June 19-23, 2011. 13th Annual IOBC WorkingGroup, Insect Pathogens and EntomoparasiticNematodes. Innsbruck, Austria. Contact: [email protected]
June 23-25, 2011. 68th Annual Convention, PestControl Operators of CA. Disneyland, Anaheim,CA. Contact: www.pcoc.org
August 6-10, 2011. Annual Meeting AmericanPhytopathological Society. Honolulu, HI. Contact:APS, 3340 Pilot Knob Rd., St. Paul, MN 55121;651/454-7270; www.aps.net
August 7-12, 2011. 96th Annual EcologicalSociety of America Conference. Austin, TX.Contact: ESA, 1900 M St. NW, Suite 700,Washington, DC; 202/833-8773; [email protected]
November 13-16, 2011. ESA Annual Meeting,Reno, NV. For more information contact the ESA(10001 Derekwood Lane, Suite 100, Lanham, MD20706; 301/731-4535; http://www.entsoc.org
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Texas, broadcast baits similar tothose used against red imported fireant, Solenopsis invicta, provide lessthan 50% L. humile control, soimprovement is needed.Field experiments against large
populations of L. humile inSomerville Lake, Texas, in April toAugust 2010 compared bait matricesof corn, soybean oil, fish oil, fish,and sugar. These bait matrices wereformulated with toxicants: metho-prene, fipronil, abamectin, boricacid, hydramethylnon, and pyriprox-yfen. Each bait product was placedon a plastic lid on the ground in acircle; numbers of ant workersattracted and amount of bait takenwas monitored every 30 minutes fortwo hours.Argentine ants were significantly
more attracted to and removed moreparticles of fish powder, fish oil,Advance Carpenter Ant Bait (ACAB;contains fish products), ACAB 375A,and pyriproxfen (Esteem™) plus fishpowder. Fish powder and confection-ers sugar increase attraction to less-preferred baits. Bait attraction ishighest in the warmest months, par-ticularly July and August. Bait test-ing is continuing in larger infestedareas. Similar bait selection test regi-mens are recommended in otherareas.
Argentine Ant Bait StationA heavy infestation of Argentine
ants, Linepithema humile, threatensendangered chicks of least tern,Sterna antillarum browni, atOceanside, California’s White Beach,where pesticide sprays are prohibit-ed. Thus, a PVC pipe bait station(with access holes and caps on thetop and bottom) containing sucrosebut lacking a toxicant was developedand tested in 2008 and 2009. “Thenovel bait station was referred to asa ‘virtual bait station’ because thesucrose solution bait itself did notcontain any toxicant,” said Dong-Hwan Choe (Univ of California,ESPM, Mulford Hall, Berkeley, CA94720; [email protected]).
products and are pests of poultryhouses, silkworm culture, museums,and a variety of stored foods,” saidJeff Lord, (USDA-ARS, 1515 CollegeAve, Manhattan, KS 66502;[email protected]). The bio-control fungi Beauveria bassiana,Metarhizium anisopliae and Isariafumosorosea all have “mycoinsecti-cide registration, broad host ranges,and variation in potency for targetinsects.” Moisture usually makes thefungi more effective against insects.However, stored product insects aremost susceptible under dry condi-tions when there is desiccationstress.“Of the three fungi tested, B.
bassiana is the most efficacious forD. maculatus larvae,” said Lord.“Like several previously tested storedproduct beetles, hide beetles aremore susceptible to B. bassianaunder desiccation stress than atunder higher moisture conditions,exclusive of saturation. Substrateseffect the persistence of fungalinoculum, and conidia that come torest on woody surfaces quickly loseviability.”
Argentine Ant Baits“The Argentine ant, Linepithema
humile, is an invasive ant considereda serious threat to urban, agricultur-al and natural environments thatexhibits strong associations withsap-feeding insects (i.e. aphids,scales),” said Cesar Valencia (TexasA&M Univ, College Station, TX77843; [email protected]). L.humile is best managed using toxicliquid baits with sugar attractants orsolid protein bait formulations.Workers collect and distribute thesebaits within the colony via trophal-laxis.“Management of L. humile in small
areas (less than 8 ha or 20 acres) isbest achieved by using liquid baitstations containing boric acid,” saidValencia. “For larger areas the man-agement using this strategy becomesnotoriously difficult, so broadcastbaits are recommended.” In central
By Joel Grossman
T hese Conference Highlightsare from the Dec. 12-15,2010, Entomological Society
of America (ESA) annual meeting inSan Diego, California. ESA’s nextannual meeting is November 13-16,2011, in Reno, Nevada. For moreinformation contact the ESA (10001Derekwood Lane, Suite 100,Lanham, MD 20706; 301/731-4535;http://www.entsoc.org
The squash bug, Anasa tristis, cantransmit cucurbit yellow vine disease(CYVD) bacteria, Serratia marce-scens. “Non-chemical control of A.tristis in cucurbit crops is almostimpossible without knowing theirpopulation dispersal from overwin-tering sites and within-field popula-tion dynamics,” said Vimal Varghees(West Virginia Univ, Morgantown, WV26506; [email protected]).“A. tristis overwinters in plant debrisand woods, but much informationregarding overwintering ecology of A.tristis is still not known.”In organic pumpkin plots, squash
bug eggs, adults, and nymphs werefound aggregated along the borders.Among the possible explanations:More sunshine makes field edgeplants more vigorous and attractiveto squash bugs; or adjacent wood-lands and grasslands may be over-wintering sites, with the field edgesoffering easy egg-laying access.Whatever the cause, the field edgeaggregation effect “indicates thatonly areas with squash bug aggrega-tion can be controlled to reduce pes-ticide input and management cost,justifying a site-specific pest control,”said Varghees. In other words,pumpkin borders can be treated likea squash bug trap crop.
Biocontrol Fungi BeatMuseum Beetles
“Hide beetles, Dermestes macula-tus, feed on carrion and dried animal
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Conference Notes
ESA 2010 Annual MeetingHighlights – Part 1
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“The LE nootkatone provided 100%control of I. scapularis in 2009, whilethe garlic-based product suppressedtick activity for 4 weeks,” saidBharadwaj. “The LE and ME nootka-tone provided 80% and 62% tickcontrol 8 days post-application,respectively, in 2010. Garlic provided89% and then 67% suppression ofticks for 1 week and 4 weeks post-application, respectively.” Residualtime was less than a week on filterpaper disks placed in the treatmentarea; persistence was longer in thesoil.
German Roaches ReturnAfter 50 years, German cockroach-
es, Blattella germanica, are onceagain back as a major problem inNorth Carolina homes, said RichardSantangelo (North Carolina StateUniv, Raleigh, NC 27695; [email protected]). Traditionally,PCOs have targeted the kitchen andbathroom for German cockroachtreatments, as this is where themajor food and water sources arepresumed to be. However, trappingstudies reveal that 50% of Germancockroach populations are elsewhere,in living rooms and bedrooms. Thus,whole-home gel-baiting by universityresearchers was compared with tra-ditional kitchen and bathroom gel-baiting by PCOs.A major end goal was reducing
German cockroach allergens (e.g. Blag1). In Raleigh, NC, it was remark-ably easy to find homes with over 30German cockroaches per two rooms.A helpful IPM approach includedpersuading occupants to change twocommon practices: eating and stor-ing food in bedrooms. Water in bed-rooms was associated with perma-nent cockroach aggregations.The PCOs, who were gel-baiting
kitchens and bathrooms unaware ofthe comparison aspect of the study,reduced German cockroach popula-tions 53%-76%. Universityresearchers treating whole homesreduced German cockroach popula-tions 97%-99%. Whole-home treat-ments eliminated cockroach reinfes-tations from populations outsidekitchens and bathrooms; therebyreducing return visits. However,whole-home gel-baiting requires
takes advantage of the fact that S.invicta tends to “quickly recruit anddominate resources” (such as hotdog lures). An area can be pre-baitedwith hot dog lures; if large numbersof S. invicta show up in 45-60 min-utes, then the active bait can besubstituted for the lure.Environmental impacts and non-
target effects are minimal, becauseso little bait active ingredient isused. But the main advantage is thatfire ants, not native ants, are therefirst to take the bait. When LSB issynchronized with boiling waterinjections into fire ant mounds,native ant populations increase.
Botanical Tick Control“Plant phytotoxicity and short
residual activity are two problemsthat may limit the potential to usenootkatone, a component of essentialoil derived from citrus, as a naturalacaricide to control the black-leggedtick, Ixodes scapularis,” said RobertBehle (USDA-ARS, 1815 N UniversitySt, Peoria, IL 61604; [email protected]). “Maillard and ligninencapsulated formulations reducedvolatility of nootkatone by 2.5x and5.0x, respectively when comparedwith emulsifiable formulation.” Inother words, encapsulated nootka-tone formulations lasted 250% to500% longer. Encapsulated formula-tions were just as toxic to ticknymphs, and had less plant toxicity.“Field trials to evaluate the ability
of the plant-derived compoundsnootkatone and garlic to controlnymphs of the black-legged tick,Ixodes scapularis, were conducted insummer 2008-2010 at residentialproperties in Connecticut,” saidAnuja Bharadwaj (Connecticut AgricExper Stn, 123 Huntington St, NewHaven, CT 06504; [email protected]). “An emulsifiable concentrateof nootkatone in 2008 provided100% control within a few days afterapplication, but control declined to21% by 3 weeks. A lignin-encapsu-lated (LE) nootkatone formulationwas applied in 2009, and both theLE nootkatone and a Maillard-reac-tion encapsulated (ME) were appliedin 2010. A minimal risk (25B) garlic-based product was also evaluated in2009 and 2010.”
“Foragers were permitted to crosssurfaces treated with diluted fipronilenroute to the sucrose solution baitdispensed in the bottom,” said Choe.“The workers picked up a dose thatshowed delayed toxicity over 3-5days. The fipronil was later trans-ferred to nestmates by physical con-tact.” Ant activity was significantlyreduced, and ants were still visitingthe bait station 10 weeks later.The “virtual bait station” was
buried in the sand to protect theinterior fipronil deposits. Bait car-tridges were refilled with sucrose orreplaced (exchanged) each monitor-ing period. Instead of fipronil, theinner liner of the bait station couldcontain other compounds such asinsect growth regulators or micro-bials. The inner lining containing thefipronil or other compound couldalso be made replaceable or refresh-able to improve bait station econom-ics.“Installation around residential
areas would be more practical withsmaller size,” said Choe. “It could behidden in garden vegetation orhedges. This will also help protectbait stations from direct sunlight,heat, or pets without burying themin the ground.”
Hot Dog Baits & BoilingWater
Central Texas landscapes havecaves, endangered camel crickets,native ant species needing protec-tion, and red imported fire ants,Solenopsis invicta, said NatalieCervantes (Texas Agrilife Ext Serv,3355 Cherry Ridge St, San Antonio,TX 78230; [email protected]). IPM alternatives such as toxicbaits used to fight fire ants need tobe used sparingly to protect nativeants and endangered crickets inthese areas.Though expensive and labor-inten-
sive, pickaxes are used to break intofire ant mounds. Then trucks injectboiling water into the mounds.Treatment of fire ant mounds is trig-gered when 300 S. invicta are cap-tured per 10 bait hot dogs. Esteem®Ant Bait (pyriproxyfen) needs to beused in a way minimizing impacts onnative ants and camel crickets.The lure-switch-bait (LSB) method
IPM Practitioner, XXXII(5/6) May/June 2010 Box 7414, Berkeley, CA 9470710
Conference Notes
traps stapled to a tobacco stick at(corn) ear height,” said Sedlacek.“Seven species of lady beetles, thebig-eyed bug, green lacewing, andbrown lacewing were captured in theconventional sweet corn. Five speciesof lady beetles, the big-eyed bug, andgreen lacewing were caught in theorganic sweet corn. Pink lady beetle,Coleomegilla maculata, and big-eyedbug, Geocoris sp. were the mostabundant predators caught, repre-senting over 75% and 17% of thetotal number of individuals caught,respectively, during 2009 and 2010.”
Beneficial Bugs InduceTomato Resistance
“The presence of generalist preda-tors can work as an early cue of thecloseness of herbivores, and mayimpact the induction of defensegenes in tomato,” said HeleneQuaghebeur (Pennsylvania StateUniv, 501 ASI Bldg, University Park,PA 16802; [email protected]). NorthAmerican tomato fields commonlyhave generalist predators preying onsoft-bodied herbivorous insect pests.Among the common predators areminute pirate bugs, Orius insidiosus,and spined soldier bugs, Podisusmaculiventris. Induction of jasmonicacid (JA) pathway defense genes bythese two generalist predators wasmeasured in 4-week old tomatoplants.“The presence of Orius insidiosus
adults significantly induces severalgenes of defense regulated by the JApathway,” said Quaghebeur. “Thelevel of defense gene expressiondepends on the gender and repro-ductive status of the predator. Matedfemales generally cause the highest,most significant level of gene induc-tion. Podisus maculiventris adultsand nymphs significantly induce JA-regulated genes, but generally not asstrongly as Orius insidiosus.”
Onion Thrips AvoidYellow-Green Foliage
“Onion thrips, Thrips tabaci, is themost important insect pest world-wide of onions, Allium cepa,” andcan cause over 50% yield losses, saidJohn Diaz-Montano (Cornell Univ,NYSAES, Geneva, NY 14456;[email protected]). Onion thrips are
hard to control, because they hide inthe narrow spaces between innerleaves and are resistant to insecti-cides. Onion cultivar resistance tothrips is linked to factors such asleaf and bulb color and leaf struc-ture.“We screened 49 onion varieties
and found that resistant varietieshad yellow-green colored foliage com-pared to the susceptible ones thathad blue-green color foliage,” saidMontano. “Most of the cultivarsresistant to onion thrips had lowerreflectance in the UV range com-pared to the susceptible checks. It ispossible that onion thrips preferonion cultivars with higher UVreflectance (270-400 nm) that pro-vides them with shelter from heatand this characteristic may makethese onion cultivars more attractedand susceptible to onion thrips.”
tural greenhouse industry needs toprevent cuttings from introducingwestern flower thrips, Frankliniellaoccidentalis, into chrysanthemumsand silverleaf whitefly, Bemisiatabaci Biotype B, into poinsettia.“Reduced risk control methods wouldpermit growers to establish insectpest-free and insecticide residue-freecuttings from the outset, thus ensur-ing that ongoing greenhouse biologi-cal control programs are not affectednegatively,” said Wendy Romero(Univ of Guelph, Guelph, ON N1G2W1, Canada; [email protected]).Greenhouse chrysanthemum cut-
tings can be disinfested with non-phytotoxic hot water. Hot water at39°C (102°F) for 30 minutes or 41°C(106°F) for 15 minutes produced over80% thrips mortality. Cuttings canalso be dipped into solutions ofinsecticidal soap, horticultural oil,spinosad, Beauveria bassiana (fungi),and Steinernema feltiae (nematodes).Spinosad and insecticidal soap pro-vided 60-75% thrips mortality.Horticultural oil killed 100% ofadults, and 64-82% of immaturethrips. Beauveria bassiana killedover 90% of immature and adultthrips. Steinernema feltiae provided50-60% thrips control.
more time; the first visit was thelongest, and thereafter visits lasted40 minutes per home.
Flowers Boost LettuceAphid Biocontrol
“Flowers are tried in many crops,but the ecological mechanisms areleft untested,” said Erik Nelson (Univof California, 137 Mulford Hall,Berkeley, CA 94720; [email protected]). “Therefore, biocontrolworkers can’t evaluate flower plant-ing as a general strategy. If we testthe mechanisms, we can improve theflower planting strategy.”Observations of 370 syrphid flies
(aphid predators) revealed that malesfed mainly on nectar, but females atepollen plus nectar. Field cage studiescontained 30 lettuce plants withaphids and 3 female syrphid flies,Eupeodes spp. Cages with flowershad very few aphids. Cages withoutflowers had several hundred aphids.Syrphid flies produced more off-spring in cages with flowers, result-ing in higher aphid consumption(more biocontrol).
Methyl Salicylate Lures“Exploiting chemical ecology in
conservation biological control incor-porates practices that attract insectpredators and parasitoids into cropsystems,” said John Sedlacek(Kentucky State Univ, 400 East MainSt, Atwood Bldg, Rm 126, Frankfort,KY 40601; [email protected]).In hops and grapes, synthetic methylsalicylate attracts green lacewings,Chrysopa nigricornis, aphid eatingsyrphid flies, predatory big-eyedbugs, Geocoris pallens, seven-spot-ted lady beetles, Coccinella septem-punctata, and spider mite eatinglady beetles, Stethorus punctum.Methyl salicylate has also beenshown to attract a spider,Erigonidium graminicolum, to cot-ton; and minute pirate bugs, Oriusspp., to cotton and strawberries.In these experiments, lures of
methyl salicylate (PredaLure®; AgBioInc) were stapled to tobacco sticks atcrop canopy height in the center oforganic and conventional sweet cornplots. “Beneficial insects were sam-pled weekly during silking using 15 x15 cm (5.9 x 5.9 in) yellow sticky
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Conference Notes
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12 Box 7414, Berkeley, CA 94707IPM Practitioner, XXXII(5/6) May/June 2010
has established in natural stands inthe eastern U.S. causing widespreadmortality of the two hemlock speciesnative to eastern North America.”Pest management efforts are
focused on classical biological con-trol with predatory beetles such asLaricobius nigrinus, said Grubin.The native western North Americanpredatory flies Leucopis atrifacies, L.argenticollus and L. piniperda alsoshow potential as classical biocontrolagents for introduction to the east-ern U.S.“In Great Smoky Mountains
National Park (GRSM), hemlockwoolly adelgid (HWA) was first report-ed in 2002,” said Abdul Hakeem(Univ of Tennessee, 205 EllingtonPlant Sci Bldg, Knoxville, TN 37996;[email protected]). “Since thenthousands of hemlock trees havedied due to excessive feeding of thisinvasive pest. In the southern U.S.death of hemlock trees usuallyoccurs within 5-7 years after infesta-tion.”In the absence of effective native
natural enemies in the eastern U.S.,half a million Asian lady beetles,Sasajiscymnus tsugae, were releasedat 166 sites in GRSM from 2002 to2008. Beat-sheet sampling andupper canopy sweep-net sampling at56 sites revealed that S. tsugae wasestablished at 18% of release sites,particularly older release sites; indi-cating 5-7 years for establishmentafter release.
Fly IPM With NaturalOdors
Catnip, Nepeta cataria; tropicalsandalwood, Santalum album; andbalsam torchwood, Amyris balsam-ifera contain good repellents againststable flies, Stomoxys calcitrans, andother fly species, said Junwei Zhu(USDA-ARS, Univ of Nebraska, 305BEntomol Hall, Lincoln, NE 68583;[email protected]).Catnip is one of the best repellents
against stable flies, house flies, hornflies, face flies, and other insects.Beta-caryophyllene, alpha-pinene,and ZE- and EZ-nepetalactone areamong the catnip compoundsrepelling stable flies. Catnip also hasgood fumigant toxicity towards stableflies and other flies, with less than10-20 minutes for knockdown at
most doses. Sprayable formulationsare necessary to knockdown stablefly populations.In cattle tests, 15% catnip formu-
lations repelled flies from cattle legs.Oil based formulations can supplyup to 14 hours repellency, versus 5hours for water formulations requir-ing higher dosages. A wax pallet withoatmeal is good for stable fly eggdevelopment; but when catnip isadded, larval growth is inhibited andpupal weight is lower. In Petri dishtests, catnip inhibits or suppressesseveral different bacteria. Dairies arebeginning to use catnip for its com-bined anti-bacterial activity, high rel-ative safety, and fly repellency. Goodrepellents for the horn fly,Haematobia irritans, besides catnipinclude geranic acid, geraniol,octanoic acid, nonanoic acid, anddecanoic acid.
Silverleaf whitefly eggs andnymphs on poinsettia cuttings werestopped (>83% control) by horticul-tural oil plus washing. Insecticidalsoap killed over 90% of whiteflynymphs, but under 15% of eggs. Hotwater at temperatures safe to poin-settia cuttings killed less than 20%of whitefly eggs and nymphs.
Microbial Beats BeetArmyworm
“A novel bacterium Burkholderiaspp. was isolated from a soil sampleand is being developed into a micro-bial bioinsecticide,” said HuazhangHuang (Marrone Bio Innovations,2121 Second St, Suite B-107, Davis,CA 95618; [email protected]). “Other species in this genusare beneficial for plants, and areknown to promote plant growth andsymbiosis.” Also, “B. xenovorans isknown for its ability to degradechlororganic pesticides and polychlo-rinated biphenyls (PCBs).”“The insecticidal activities of this
bacterium are due to multiple sec-ondary metabolites. One of the activecompounds with a molecular weightof 540 has been purified and identi-fied. The lethal median dose (LD50)of this compound against 3rd instarlarvae of beet armyworm, Spodopteraexigua, is 0.1 µg per individual bytopical application.” This Burk-holderia sp. also shows “good toexcellent activity” against cabbagelooper, Trichoplusia ni; diamondbackmoth, Plutella xylostella; tufted applebud moth, Platynota idaeusalis;codling moth, Cydia pomonella; andobliquebanded leafroller,Choristoneura rosaceana.
Hemlock Woolly AdelgidBiocontrol
“The hemlock woolly adelgid(HWA), Adelges tsugae, is an exoticpest of forest and ornamental hem-lock trees in the eastern UnitedStates,” said Sarah Grubin (OregonState Univ, 321 Richardson Hall,Corvallis, OR 97331; [email protected]). “Native to China,Japan and western North America,HWA was first found in the easternU.S. in 1951. As of 2009, 18 statesranging from Maine to Georgia havereported infestations of HWA. HWA
Conference Notes
13IPM Practitioner, XXXII(5/6) May/June 2010 Box 7414, Berkeley, CA 94707
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Box 7414, Berkeley, CA 94707
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Box 7414, Berkeley, CA 94707IPM Practitioner, XXXII(5/6) May/June 2010 Box 7414, Berkeley, CA 9470714
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Box 7414, Berkeley, CA 94707Box 7414, Berkeley, CA 94707IPM Practitioner, XXXII(5/6) May/June 2010 15
