United States Department of Agriculture

Technology Transfer Emerald Ash Borer

2016 Emerald Ash Borer National Research and

Technology Development Meeting

October 19 & 20, 2016 Wooster, Ohio

Animal and Plant Health Forest FHTET-2016-10 The Ohio State University Inspection Service Service November 2017

The abstracts were submitted in an electronic format and were edited to achieve only a uniform format and typeface. Each contributor is responsible for the accuracy and content of his or her own paper. Statements of the contributors from outside the U. S. Department of Agriculture may not necessarily refect the policy of the Department. Some participants did not submit abstracts, and so their presentations are not represented here.

Cover image and graphic by David Lance Animal and Plant Health Inspection Service (APHIS)

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2016 Emerald Ash Borer National Research and Technology Development Meeting

October 19 & 20, 2016

Ohio Agricultural Research and Development Center Wooster, Ohio

Sponsored by

The Ohio State University and the United States Department of Agriculture Animal and Plant Health Inspection Service

Compiled by

James Buck1,Gregory Parra2, David Lance3, Richard Reardon4, and Denise Binion4

1USDA-APHIS PPQ, Brighton, Michigan 2USDA-APHIS PPQ, Raleigh, North Carolina

3USDA-APHIS PPQ, Otis ANGB, Massachusetts 4USDA-FS FHTET, Morgantown, West Virginia

For additional copies of this or any of the previous fve proceedings (FHTET-2010-01, FHTET- 2008-07, FHTET-2007-04, FHTET-2004-02 and FHTET-2004-15), contact Gregory Parra in North Carolina, at (919) 855-7548 (email: gparra@fs.fed.us) or Richard Reardon in Morgantown, West Virginia at (304) 285-1566 (email: rreardon@fs.fed.us)

mailto:rreardon@fs.fed.usmailto:gparra@fs.fed.us

FOREWARD

The emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an invasive species that has shaped, and will continue to shape, the composition and richness of natural and urban forests in North America. All species of North American Fraxinus (ash) appear to be susceptible to attack by this beetle, and all succumb and die within a few years of colonization. Like chestnut blight (Cryphonectria parasitica) and Dutch elm disease (Ophiostoma ulmi), EAB has the potential to effectively eliminate en-tire tree species from our forests. In the case of EAB, it could potentially eliminate all of the species in an entire genus.

EAB was first discovered killing ash trees in 2002 near Detroit, MI, and results of subsequent den-drochronological studies suggest that the pest had been introduced at least 8 years earlier (Siegert et al., Diversity and Distributions 7,847 [2014]). The insect spread rapidly after its introduction and has been found in most states of the eastern U.S. with the exception of Maine, Rhode Island and Vermont; in all southern states with the exception of Mississippi and Florida; and west as far as Col-orado. It also occurs in Ontario and Quebec. The insect is an active flier, but longer-range spread has resulted from humans moving EAB-infested ash wood and nursery stock. Some progress has been made in limiting the human-assisted spread of EAB through an aggressive outreach program and regulations to control movement of ash trees and wood. However, movement of host material for personal use, especially as firewood, remains a threat as it is difficult to regulate. EAB now occurs in 31 states.

This volume contains abstracts from papers presented at the EAB Research and Technology Devel-opment meeting that took place October 19-20, 2016, in Wooster, OH. The studies described herein were aimed at the broad goal of improving our ability to manage EAB populations. The focus of this compendium is work conducted from 2014 through 2016, although some of the abstracts describe work across a broader time frame. These abstracts detail work to improve our basic under-standing of the insect and its ecology in North America, efforts to enhance our tools for containing, monitoring, and controlling populations of the pest, and development and evaluation of strategies to use these tools in management scenarios ranging from a single tree to national in scope. During the first day of the forum presentations focused host interactions and resistance mechanisms, trap-ping and chemical control, EAB biology, behavior and ecology; and regulatory, management and outreach initiatives. Day two was solely focused on EAB biological control, which has become the major focus of the USDA-APHIS Emerald Ash Borer Program.

USDA-APHIS continues to make investments in rearing EAB parasitoids at its Brighton, MI facili-ty. Currently, four species of parasitic wasps are being reared and distributed to cooperators. These species had previously been evaluated for such factors as host specificity and ability to attack EAB and reproduce in the field. Operational releases of these insects began in 2010 with recovery and/ or establishment of several of the species being documented in numerous states. Ongoing research and development efforts described here include studies on the biology of these insects in the field and assessments of their effectiveness as biological control agents.

The study of host resistance to EAB was initiated in the 2000’s and was subsequently the focus of an expanded 3-year research program starting in 2011. These efforts resulted in determining the relative resistance of various North American and Asian ash species, characterizing the chemical and genetic bases of resistance, and identifying any indigenous resistance in North American ash. In recent years, a few healthy “lingering” ash have been documented, but it is yet entirely known if these trees just escaped EAB, or if there are other biological mechanisms involved. Unfortunately, while everyone can agree that host resistance will be an integral part in preserving North American ash, funding for host studies has been minimal for the past few years.

Much progress has been made on understanding host dynamics and their interactions with EAB. Evidence is mounting that the replacement cohort of ash trees in an EAB aftermath forest is being afforded a degree of protection by parasitoids and woodpeckers. The host range of EAB has also expanded with the discovery of white fringetree (Chionanthus virginicus) as a host, as well as the possi-bility of commercial olive (Olea europea). However, it remains to be seen what the overall ecological significance of these hosts will be.

As the insect continues to fill out its projected range in North America, the program envisions tran-sitioning from regulatory to a broader management mode, with an overall goal of maintaining ash as a viable component in North American ecosystems. The program believes two key components are likely needed to achieve this goal in a sustainable manner: effective biological control and ash trees that exhibit greater resistance to EAB than do typical North American ash. Bringing this vision to life will require a greater level of resources, both programmatically and for developmental projects. The future of ash in North America’s natural and urban forests may depend on this effort.

CONTENTS

FOREWARD 5 PRESENTATIONS - BIOLOGICAL CONTROL 13

POPULATION DYNAMICS OF EMERALD ASH BORER AND ASH RECOVERY IN AFTER-MATH FORESTS IN MICHIGAN: HAS BIOCONTROL WORKED? Jian J. Duan, Leah S. Bauer and Roy G. Van Driesche 14

THE INFLUENCE OF HOST DENSITY ON DISPERSAL OF Tetrastichus planipennisi Juli Gould, Michael Jones, Melissa Fierke, and Gericke Cook 17

PHENOLOGY AND OVERWINTERING SURVIVAL OF THE INTRODUCED LARVAL PARASITOIDS OF EMERALD ASH BORER IN THE NORTHEAST Michael I. Jones, Juli R. Gould, and Melissa K. Fierke 19

COMPATIBLITY OF INSECTICIDES AND BIOCONTROL FOR CONTROLLING EAB IN URBAN ENVIRONMENTS Fredric Miller, Juli Gould, Mellissa Fierke, Michael Jones, and John Kaltenbach 22

WHO’S AFFECTING WHO? INTERACTIONS BETWEEN WOODPECKERS AND PARASITOIDS OF THE EMERALD ASH BORER Theresa Murphy, Joe Elkinton, Juli Gould, and Roy Van Driesche 25

AN UPDATE ON EAB BIOCONTROL IN VIRGINIA Max Ragozzino, Dr. Scott Salom, and Dr. Jian Duan 27

PARASITOIDS OF THE EMERALD ASH BORER: AN UPDATE ON THE REARING, RELEASE, AND RECOVERY Ben Slager 28

EMERALD ASH BORER AND ITS PARASITOIDS IN THE SOUTHEAST Greg Wiggins, Jerome Grant, Forest Palmer, and Juli Gould 31

PRESENTATIONS - BIOLOGY, BEHAVIOR AND ECOLOGY 33

FACTORS AFFECTING THE GROWTH RESPONSE OF NON-ASH TREES IN FORESTS IMPACTED BY EMERALD ASH BORER Kathleen S. Knight, Charles E. Flower, and Kyle c. Costilow 34

ECOLOGICAL IMPACTS OF EMERALD ASH BORER INVASION OF FORESTS OF SOUTHEASTERN MICHIGAN Daniel A. Herms, Kamal J.K. Gandhi, Annemarie Smith, Wendy Klooster, John Cardina, Kathleen S. Knight, Catherine P. Herms, Diane Hartzler, and Deborah G. McCullough 38

DIVERSITY OF INSECT FAUNA ASSOCIATED WITH LIVE AND DEAD GREEN ASH TREES (Fraxinus pennsylvanica) IN LOUISIANA Balwinder Kaur, Wood Johnson, and Rodrigo Diaz 39

FOREST RESPONSES FOLLOWING EMERALD ASH BORER - INDUCED ASH MORTALITY IN SOUTHEASTERN MICHIGAN Wendy S. Klooster, P. Charles Goebel, and Daniel A. Herms 40

RESPONSE OF GROUND-DWELLING INVERTEBRATE COMMUNITIES TO TEMPORAL PATTERNS OF ASH MORTALITY Kayla I. Perry and Daniel A. Herms 42

PRESENTATIONS - HOST INTERACTIONS 44

EMERALD ASH BORER AND CULTIVATED OLIVE: WHAT ARE THE CHANCES? Don Cipollini, Chad M. Rigsby, and Donnie L. Peterson 45

MECHANISMS OF ASH RESISTANCE TO EMERALD ASH BORER: A REVIEW OF 12 YEARS OF RESEARCH Daniel A. Herms, Don Cipollini, J.G.A. Whitehill, C.M. Rigsby, and P. Bonello 47

DISTRIBUTION, IMPACTS, AND ADULT LONGEVITY OF EMERALD ASH BORER (Agrilus planipennis) ON WHITE FRINGETREE (Chionanthus virginicus)Donnie Peterson and Don Cipollini 51

WHITE ASH – LIFE GOES ON – SOMETIMES Molly A. Robinett and Deborah G. McCullough 52

DEVELOPIING RNAi METHODS FOR EAB CONTROL – THE NEXT GENERATION OF PEST MANAGEMENT Thais B. Rodrigues, Lynne K. Rieske, Jian Duan, and Subba R. Palli 56

TRANSCRIPTIONAL, ENZYMATIC, AND PHENOLIC PROFILES OF RESISTANT AND SUS-CEPTIBLE ASH PHLOEM IN RESPONSE TO EMERALD ASH BORER LARVAL FEEDING David N. Showalter, Caterina Villari, Chad M. Rigsby, Donald F. Cipollini, Daniel A. Herms, Saranga Wijeratne, Asela Wijeratne, and Pierluigi Bonello 57

PRESENTATIONS - REGULATORY MANAGEMENT AND OUTREACH 59

A BATTLE PLAN TO MANAGE THE EMERALD ASH BORER IN KENTUCKY FORESTS: FROM RESEARCH TO OUTREACH Ignazio Graziosi and Lynne Rieske Kinney 60

FROM SCIENCE TO SOLUTION: THE CRUCIAL ROLE OF THE CITIZEN LOBBYIST Jeff Hafner 61

DEFINING THE OPPORTUNITY WINDOW FOR SAVING URBAN ASH TREES WITH A SIMPLE STAGING PROCEDURE Clifford S. Sadof and Matthew D. Ginzel 62

PRESENTATIONS - TRAPPING AND CHEMICAL CONTROL 65

PROTECTION OF LARGE DIAMETER ASH TREES AGAINST EAB IN THE URBAN ENVIRONMENT USING TREE-ÄGE®, A TREE-INJECTED INSECTICIDE Joseph J. Doccola, David Smitley, Terrance Davis, Mesude Duyar, and Steven Ashley 66

IMPROVING DETECTION TOOLS FOR EAB: UPDATE FROM 2015-2016 FIELD TRAPPINGS STUDIES Joseph A. Francese, Everett G. Booth, Vanessa M. Lopez, Benjamin Sorensen, David R. Lance and Emily Franzen 70

INSECTICIDES FOR CONSERVING ASH IN THE URBAN FOREST Daniel A. Herms 72

DECADE LONG EVALUATION OF 10 CHEMICALS AND FIVE APPLICATION TECHNIQUESFOR EMERALD ASH BORER CONTROL ON RESIDENTIAL STREET TREES Greg Mazur, John Siefer, Brian, Jeffers and Dr. Bal Rao 75

CAN INSECTICIDE TREATED ASH TREES PROVIDE ASSOCIATIONAL PROTECTION TO UNTREATED ASH AND MAINTAIN REPRODUCTION IN SOUTHWESTERN OHIO? Erin M. O’Brien and Daniel A. Herms 79

DIGITAL IMAGE CORRELATION OF STRESS/STRAIN RELATIONSHIPS, ACOUSTIC TRANSITION TIMES AND ROOT NECROSIS OBSERVED IN EMERALD ASH BORER IN-FESTED ASH TREES IN NORTH EAST OHIO Anand Persad, Gregory Dahle, David DaVallance, Oscar Rocha and Jason Grabosky 81

POSTERS - BIOLOGICAL CONTROL 80

CAN SPATHIUS GALINAE TARGET EAB FEEDING IN LARGE ASH TREES? Theresa Murphy, Roy Van Driesche, Juli Gould, and Joe Elkinton 81

COLD STORAGE OF SPATHIUS GALINAE: PROGRESS IN MASS PRODUCTION Ben slager, Jian Duan, Jonathan Schmude and Andrea Anulewicz 82

MONITORING FOR ESTABLISHMENT OF INTRODUCED PARASITOIDS OF EMERALD ASH BORER IN TENNESSEE James Palmer1, Jerome F. Grant1, Greg Wiggins1, and Juli Gould2 84

POSTERS - BIOLOGY, BEHAVIOR AND ECOLOGY 85 GOOD AND BAD NEWS ABOUT ASIAN CONSUMERS OF ASH IN EASTERN EUROPE Yuri N. Baranchikov, Denis A. Demidko, Viacheslav B. Zviagintsev, Sergei V. Panteleev, Lidia G. Seraya and Anna V. Yaruk 86

EMERALD ASH BORER INDUCED ASH DECLINE AND ITS EFFECTS ON BELOW-GROUND NUTRIENT AND MICROBIAL COMMUNITY DYNAMICS Charles E. Flower, Michael P. Ricketts, Kathleen S. Knight, Robert P. Long, and Miquel A. Gonza-lez-Meler 88

EFFECTIVENESS OF EMAMECTIN BENZOATE INJECTIONS ON ASH TREES IN VARIOUS STAGES OF DECLINE Charles E. Flower, Jennifer E. Dalton, Kathleen S. Knight, and Miquel A. Gonzalez-Meler 93

NATIVE BARK-FORAGING BIRDS PREFERENTIALLY FORAGE IN EMERALD ASH BORER INFESTED ASH TREES AND PROVE EFFECTIVE PREDATORS OF THE INVASIVE EAB Charles E. Flower, Christopher J. Whelan, Kathleen S. Knight, Lawrence C. Long, Joanne Rebbeck, Joel S. Brown and Miquel A. Gonzalez-Meler 97

THE RELATIVE IMPORTANCE OF EAB-CAUSED TREE MORTALITY AND ABUNDANCE OF AMUR HONEYSUCKLE ON TREE SEEDLING COMMUNITIES Brian M. Hoven, David L. Gorchov, Kathleen S. Knight, and Valerie E. Peters 100

EXPLORING THE POPULATION VIABILITY OF GREEN ASH (Fraxinus pennsylvanica)WITH A STAGE-BASED MODEL Rachel H. Kappler, Kathleen S. Knight and Karen V. Root 102

THE EAB INVASION WAVE: ASH AND EAB FROM 2007 TO 2012 IN A MICHIGAN FOREST Deborah G. McCullough, Nathan W. Siegert, Jacob N. Bournay, Therese M. Poland, James B. Wieferich and Andrew R. Tluczek 103

POSTERS - HOST INTERACTIONS 106

ENDOPHYTIC FUNGAL DIVERSITY OF GREEN ASH T.J. Dreaden, R.H. Kappler, K.S. Knight, J.L. Koch 107

IN VITRO PLANT REGENERATION FROM LEAF EXPLANTS OF BLACK ASH Junhung Lee and Paula M. Pijut 108

POSTERS - TRAPPING AND CHEMICAL CONTROL 109

EVALUATING IN-SITU GENETIC CONSERVATION OF WHITE ASH (Fraxinus americana)AT THE ALLEGHENY NATIONAL FOREST Eli Aubihl, Charles E. Flower , Stephen Forry, Andrea Hille, Kathleen S. Knight, William K. Oldland,Alejandro Royo, Richard Turcotte, and Jeremie Fant 110

DEVELOPING AND IMPROVING SURVEY METHODS FOR EMERALD ASH BORER AND OTHER BUPRESTIDS Joseph A. Francese, Benjamin Sorensen, Everett G. Booth Jacek Hilszczański, E. Schwartz-berg, Nadeer Youssef, Vanessa M. Lopez, Mandy Furtado, Sven-Erik Spichiger, Lawrence Barringer, Jason Hansen, Michael L. Rietz Jason Oliver, and David R. Lance 113

INTERACTIONS OF PACLOBUTRAZOL AND SYSTEMIC NEONICOTINOID INSECTI-CIDES APPLIED TO FOUR FRAXINUS SPECIES Sara R. Tanis, Andrew R. Tluczek, Deborah G. McCullough, James B. Wieferich and Phillip A. Lewis 115

HOW BAD IS BAD? CAN GREEN ASH TREES TREATED WITH EMAMECTIN BENZOATE RECOVER FROM EAB? Andrew R. Tluczek, Deborah G. McCullough and Therese M. Poland 117

CAN LIGHT ENHANCE EAB ATTRACTION TO TRAPS? James B. Wieferich and Deborah G. McCullough 119

EVALUATION OF SIX TRAP DESIGNS FOR EAB DETECTION IN LOW-DENSITY FORESTED SITES IN UPPER MICHIGAN James B. Wieferich, Deborah G. McCullough,Therese M. Poland and Andrew R. Tluczek 122

Presentations

Biological Control

POPULATION DYNAMICS OF EMERALD ASH BORER AND ASH RECOVERY IN AFTERMATH FORESTS IN MICHIGAN:

HAS BIOCONTROL WORKED?

Jian J. Duan1, Leah S. Bauer2 and Roy G.Van Driesche3

1USDA ARS Beneficial Insects Introduction Unit, Newark, DE

2USDA Forest Service, Northern Research Station, Lansing, MI

3University of Massachusetts,Amherst, MA

ABSTRACT

Classical biocontrol of the emerald ash borer (EAB), Agrilus planipennis Fairmaire, was initiated by the United States Department of Agriculture (USDA) five years after EAB was first detected in Michigan, USA in 2002 (see review in Bauer et al. 2015). This included the approval and release in Michigan of three hymenopteran parasitoids of EAB from China in 2007: the solitary egg parasit-oid Oobius agrili Zhang & Huang (Encyrtidae) and the two gregarious larval parasitoids Tetrastichus planipennisi Yang (Eulophidae) and Spathius agrili Yang (Braconidae). USDA approved and released a fourth EAB biocontrol agent from the Russian Far East starting in 2015: the gregarious larval para-sitoid Spathius galinae Belokobylskij & Strazanac (Braconidae).

A long-term field study was carried out from 2008 to 2015 at six study sites in southern Michigan to monitor establishment and impact of these introduced parasitoids (see Duan et al 2013). In 2015, the abundance and survival of ash saplings and trees of different sizes were also measured using 10 belt transects (50 x 2 m2) at each of the six study sites (five in release and five in non-release control plots at each site). The results of eight years of data on EAB showed that the larval and egg para-sitoids T. planipennisi and O. agrili successfully established self-sustaining populations at the six study sites (Duan et al. 2013; Abell et al. 2014). Life-table analysis of this data revealed that parasitism by T. planipennisi significantly reduced the net population growth rate of EAB in ash trees of the small to medium ash (7 to 21 cm DBH) within four years of its release (Duan et al. 2015a). The impact of this introduced larval parasitoid, coupled with additional mortality from woodpeckers, native para-sitoids (primarily Atanycolus spp.(Braconidae)), and O. agrili, reduced EAB larval densities in sample trees by ca. 90% at both release and control plots between 2009 and 2014 (Duan et al. 2015a). These findings suggest that successful biocontrol of EAB is possible, based on the combination of these sequential and/or contemporaneous mortality factors.

Surveys of EAB density and larval parasitism in ash saplings (2.5 – 5.8 cm DBH) from 2013 to 2015 found

Inventories of ash saplings and trees in our plots in summer 2015, showed abundant and healthy ash saplings and smaller trees (crown classes of 1 to 2, see Smith 2016) remaining in the six study sites. The density of healthy ash saplings (1 – 5.00 cm DBH) and pole size trees (5.1 – 20 cm DBH) across different study sites ranged from 300 to 647 saplings (200 – 500 per acre). However, the den-sity of larger healthy ash trees (DBH >20.1 cm) was relatively low (20.1 cm DBH) ash trees were less abundant than smaller trees, and a higher proportion of larger trees size were either declining or dead due to EAB infestation.

Findings of this 8-year field study in southern Michigan demonstrated that the introduced specialist biocontrol agent T. planipennisi effectively protected some ash saplings and pole–sized trees (

Duan JJ, Bauer LS, Abell KJ, Ulyshen MD, Van Driesche RG (2015a) Population dynamics of an invasive forest insect and associated natural enemies in the aftermath of invasion: implications for biological control. J Appl Ecol 52:1246–1254

Duan JJ, Gould GR, Fuester RW (2015b) Evaluation of the host specificity of Spathius galinae (Hy-menoptera: Braconidae), a larval parasitoid of the emerald ash borer (Coleoptera: Buprestidae) in Northeast Asia. Biol Contr 89:91–97

Smith A (2006) Effects of community structure on forest susceptibility and response to the emerald ash borer invasion of the Huron River watershed in southeast Michigan. MS Thesis, Ohio State University

Fig. 1. Location of the study sites where biocontrol agents were released against emerald ash borer be-tween 2007 and 2010 in southern Michigan (Duan et al. 2013). GSW = Gratiot-Saginaw State Game Area; MRE = Maple River State Game Area; RL = Rose Lake State Wildlife Area. BF = Burchfield Ingham County Park; CP = Central and Nancy Moore Meridian Township Parks; LP = Legg Park and Harris Nature Center in Meridian Township.

16 2016 Emerald Ash Borer National Research and Technology Development Meeting

THE INFLUENCE OF HOST DENSITY ON DISPERSAL OF Tetrastichus planipennisi

Juli Gould1, Michael Jones2, Melissa Fierke2, and Gericke Cook2

1USDA APHIS PPQ Center for Plant Health Science and Technology, Buzzards Bay, MA 02542 juli.r.gould@aphis.usda.gov

2SUNY-ESF, Syracuse, NY

3USDA APHIS PPQ Center for Plant Health Science and Technology, Fort Collins, CO

ABSTRACT

There is considerable anecdotal evidence about dispersal of EAB parasitoid populations over time. Researchers have recovered T. planipennisi and O. agrili at control sites > 1 km from the release sites after not very many years. Other researchers and the EAB Biocontrol Rearing Facility have also documented the recovery of T. planipennisi at random sites throughout Michigan. To quantify this movement, we defined the Minimum Dispersal Rate as the distance from the recovery site to the nearest release site divided by the time elapsed since T. planipennisi was first released. These rates are considered minimum values because T. planipennisi could have gone farther and/or faster but samples were not taken and recovery samples will not necessarily discover T. planipennisi the first year it invades a site. We calculated the Minimum Dispersal Rate for recoveries of T. planipennisi at 25 locations in Michigan and New York. Tetrastichus populations dispersed at least 0.25 km per year, but half of the values were greater than 2 km per year, and one recovery was made 8.9 km from the nearest release site one year after release. Tetrastichus is undoubtedly able to disperse well from the release sites.

When parasitoids are released in a forest, they can spread in all directions. As one moves away from the point of release in concentric circles, the number of traps necessary to sample a given area increased exponentially. We decided to look at the dispersal of T. planipennisi when it had to move in only two directions. Tetrastichus was released along a linear “Greenway” near Rochester, NY. The Greenway is along an abandoned canal with many ash trees and is currently used as a bike path. 1,800 T. planipennisi were released at each of 3 locations spread out equidistantly along 15.5 km of the Greenway in 2013 and the spring of 2014. One yellow pan trap (YPT) was placed at each re-lease point and every 250 m in all directions, for a total of 63 YPT’s. The YPT’s were sampled every week throughout the summer of 2013, 2014 and 2015. We recorded the number of EAB and EAB parasitoids in each trap. We established 63 10 m by 40 m ash plots to correspond with the location of each yellow pan trap. In each plot we measured ash density as well as the condition of each ash tree (crown class, epicormic shoots, woodpecker foraging). Values for these factors were summed to calculate an overall ash health rating.

17

mailto:juli.r.gould@aphis.usda.gov

In 2013, EAB recovery in yellow pan traps was greatest at the northern end of the Greenway, with no EAB caught in YPTs further south than Release Site 2. No parasitoids were recovered from any YPTs in 2013. In 2014, no EAB were captured in the 10 most northern traps and the distribution of EAB had shifted to the south. Our first ash health assessments showed that where EAB captures in YPTs were highest in 2013, the EAB infestation was severe and few adults were caught on those trees in 2014. We suspect that many of those trees had died. In 2014 in the north, where the EAB density was higher, the number of traps collecting T. planipennisi and the number of insects per trap was higher surrounding Release Site 1 than Release Site 2. Where the EAB density was lower sur-rounding Release Site 2, however, the parasitoids were found to have moved three times as far (1.6 km vs. 0.5 km) to find their hosts. Sampling in 2015 revealed that T. planipennisi populations contin-ued to follow the trajectory of the host populations. The number of parasitoid recoveries in general was greater in 2015, but the numbers of T. planipennisi recovered in YPTs surrounding Release Site 2, where densities of EAB were higher, was higher than those surrounding Release Site 1, where pop-ulations of EAB were declining as the trees died. Because of the dying trees in the north we shifted our sampling to the south in 2016. The distribution of Tetrastichus recoveries continued to fill in the gaps, with positive samples in 29 traps and a total of 469 parasitoids collected in the 63 traps in 2016. At the southern sampling point there were two small areas where trees showed signs of EAB infestation and EAB adults were caught in yellow pan traps. Even though these areas were over 4 km from the southernmost trap capture, T. planipennisi was recovered in the traps.

To further investigate the movement of T. planipennisi, in 2016 we placed traps parallel to the Green-way on average approximately 2 km to the east or west. We recovered 84 T. planipennisi in 17 of the 40 traps. Some of the positive traps were on trees that were in the middle of fields with no other ash trees nearby.

We conclude from this study that T. planipennisi is well suited to build in numbers when its host den-sity is high and to disperse long distances to find hosts when host population densities are lower.

18

PHENOLOGY AND OVERWINTERING SURVIVAL OF THE INTRODUCED LARVAL PARASITOIDS OF EMERALD ASH

BORER IN THE NORTHEAST

Michael I. Jones1, Juli R. Gould2, and Melissa K. Fierke1

1SUNY, College of Environmental Science and Forestry, Syracuse, New York 13210 mijone01@syr.edu

2USDA APHIS PPQ CPHST, 1398 West Truck Road Buzzards Bay, MA 02542

ABSTRACT

Three larval parasitoids (Hymenoptera) have been introduced to the United States for biological control of emerald ash borer (EAB), Agrilus planipennis. Two species, Tetrastichus planipennisi Yang (Eulophidae) and Spathius agrili Yang (Braconidae) were recovered from China (Liu et al. 2003) and have been released in most states with known EAB infestations. While T. planipennisi appears to be establishing well, S. agrili does not appear to be establishing in northern states (J. Gould, unpublished data). A third larval parasitoid, S. galinae Belokobylskij & Strazanac, was discovered in a more north-ern range in the Russian Far East, and climate matching suggest this species may be better suited for northern climates in North America (Duan et al. 2012). We conducted studies at three scales in Syracuse, NY (growth chambers, an open-air insectary, and caged trees in the field) to document phenology of all three larval parasitoids and EAB in the northeast in an attempt to determine if asynchrony between parasitoid development and host availability or climate could have an impact on establishment.

We documented EAB phenology from May to October for 2015 and 2016. In 2015, we found 3rd – 4th instar larvae throughout the sampling period, suggesting larvae undergoing one and two-year life cycles were present in trees. In 2016, we detected few living 3rd – 4th instar larvae during spring and early summer with a majority of dead larvae exhibiting symptoms of freeze damage (e.g., blackened necrotic tissue), suggesting high overwintering EAB mortality occurred during the winter of 2015 (Jones et al. in review). Numbers of 3rd – 4th instar larvae increased mid-summer as larvae hatched from eggs oviposited in May developed.

Open-air insectary trials for S. agrili were started mid-May 2015 from parental generations of adults obtained from the USDA rearing facility in Brighton, MI. Two complete generations emerged and a third generation started emerging late September until cold temperatures halted emergence. The number of adult S. agrili emerging from the first generation (n = 9) was substantially lower than the second generation (n = 130). Bolts containing the first generation were peeled and ~9% parasitism was detected compared to ~50% parasitism in bolts containing the second generation. Adult S. agrili from the last generation were used to establish overwintering populations. In 2016, the over-wintering generation of S. agrili did not start emerging until late July, ~5 weeks after EAB started emerging, and continued emerging until mid-September. A partial first generation emerged in early

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October. For all 2016 S. agrili generations, the sex ratio was skewed towards males (2:1).

Spathius galinae insectary trails were started early June 2015 from parental generations of adults ob-tained from USDA ARS BIIR (Newark, DE). One complete generation emerged and a second gen-eration partially emerged mid-September. Adults from the second generation were used to establish overwintering populations. In 2016, overwintering S. galinae started emerging ~1 week before EAB in early June. The next generation emerged from mid-July to early August, and another generation partially emerged in early September. Sex ratios were as expected at 2:1 female to males.

Growth chambers were programmed to mirror under bark temperatures collected from temperature probes placed in the field and set to record at 1 hr intervals. Bolts provided from the Brighton lab containing the parental generations of all three parasitoids were placed in growth chambers starting with temperatures from early May 2015. Adults from both Spathius spp. emerged from bolts mid-May to early June, while T. planipennisi emerged from early to mid-June. One complete generation emerged for all three species and a partial generation started emerging late August and continued into October. Several adults of both Spathius spp. emerged in early November. Overwintering pop-ulations were established and growth chambers are being maintained at minimum operating tem-perature for winter months (2 ºC no lights and 4 ºC with lights).

To establish an overwintering population of all three parasitoid species in the field, ~10 cages/ species were constructed around a 1 m section of the bole of infested ash (Fraxinus) in a woodlot during fall 2015. Adults of all three parasitoids were released into cages in mid-August. Yellow sticky cards placed into cages from early June to August 2016 detected adult S. galinae (n = 12) in 2/10 cages. No adults of S. agrili or T. planipennisi were detected. Subsequent peeling of the caged trees detected summer cocoons for both Spathius spp. as well as evidence of T. planipennisi parasitism (myconium and EAB head capsules), indicating all three parasitoid species completed one generation during the fall of 2015. Spathius galinae overwintering cocoons were the only ones detected, which was consistent with adult detections on sticky cards.

Results from our phenology studies indicate S. galinae is better adapted to the northeast than S. agrili and will be a more suitable biological control agent in northern climates of North America. Emer-gence of S. galinae before EAB suggests it can take advantage of EAB developing with one and two-year life cycles and can complete at least two generations a year. Field studies also suggest S. galinae is better adapted to fall temperatures in the northeast and can reach overwintering stages even when eggs are oviposited later in the fall and temperatures begin to decrease. Spathius agrili which emerged after EAB, partially completed one generation, and had difficulty overwintering, is from a more southern climate in China and appears to be asynchronous with both EAB development and climate in the northeast. Continued monitoring of parasitoid phenology should further elucidate factors inhibiting/facilitating establishment of biological control parasitoids in the northeast.

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REFERENCES

Duan, Jian J., Galina Yurchenko, and Roger Fuester. 2012. Occurrence of emerald ash borer (Coleoptera: Buprestidae) and biotic factors affecting its immature stages in the Russian Far East. Environmental Entomology 41 (2): 245–54. doi:10.1603/EN11318.

Liu, Houping, Leah S. Bauer, Ruitong Gao, Tonghai Zhao, Toby R. Petrice, and Robert A. Haack. 2003. Exploratory survey for the emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae), and its natu-ral enemies in China.” Great Lakes Entomol 36: 191–204.

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COMPATIBLITY OF INSECTICIDES AND BIOCONTROL FOR CONTROLLING EAB IN URBAN ENVIRONMENTS

Fredric Miller1, Juli Gould2, Mellissa Fierke3, Michael Jones3, and John Kaltenbach4

1The Morton Arboretum, Lisle, IL fmiller@jjc.edu

2USDA-APHIS-PPQ, Buzzards Bay, MA

3SUNY-ESF, Syracuse, NY

4Colorado Department of Agriculture, Broomfield, CO

ABSTRACT

The emerald ash borer (EAB) (Agrilus planipennis) has killed millions of North American ash trees throughout their range and continues to spread as far west as Colorado, south to Louisiana, north to Nebraska and Minnesota, and into New England. While chemical management for EAB has prov-en effective in protecting ash trees, it is not sustainable in the long term and treatment of large ash trees, in forest settings, is not feasible or economical. More recently, major efforts involving classical biological control (CBC) have been initiated to rear and release parasitoids in EAB infested urban and rural forested areas to provide a sustainable EAB management option. As a result, these para-sitoids are establishing in many states, parasitism rates are finally increasing, and the density of EAB is declining.

Here, we report preliminary results on the effectiveness of the combination of insecticide plus biocontrol treatments such that chemical treatments will protect the ash tree, in the short term (~4 years) long enough for the parasitoids to establish and build in population sufficiently to continue protecting the ash long term (particularly larger ash trees).

Beginning in 2014 and 2015, three (3) study sites were established across the U.S. one in Boulder, CO (2014), Naperville, IL and Syracuse, NY in 2015. The Colorado site is a recent EAB infestation, the New York site is building, and the Illinois site is peaking (EAB first found in 2006). At each of the three sites, a parasitoid release plot (PRP) and control plot (CP) were identified and established. The PRP and CP’s included a combination of residential parkway and landscape, and forest ash trees. The plots were one mile in diameter and the center points for the PRP and CP are a minimum of one mile apart.

Deployment and inspection of yellow pan traps (YPT’s) began in mid-May of each year. Thirty (30) green and/or white ash YPT trees were identified and established in a grid pattern every 250 m (750 ft) for both the PRP and CP sites (total=60 trees). GPS coordinates were taken for each YPT tree at both of the PRP and CP sites.

In addition, beginning in early June and again from mid to late-August of each field season, Tetras-

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tichus planipennisi, Spathius galinae, and Oobius agrili parasitoids were released in the PRP at approxi-mately seven (7) day intervals. The YPT’s were inspected weekly beginning in mid-June through mid-September. At time of trap collection, the trap contents were run through a paint filter, and then brought back to the lab for sorting of trap contents. All parasitoid-like insects were placed in vials with 70% isopropyl alcohol and labeled with the release site, YPT number, and date. Contents of yellow pan traps were sorted at The Morton Arboretum, Lisle, Illinois and specimens for positive identification were provided to Dr. Juli Gould for positive ID.

Concurrently with YPT tree establishment, an additional 150 trees were identified within each of the PRP and CP sites (300 trees total). Each group of 150 trees were divided into three groups of 50 trees. One group were designated trees with long term (>5 years) EAB chemical management, 50 trees with short term (

2016, 349 Spathius galinae parasitoids were released in the PRP. A total of 1,200 Oobius agrilus parasit-oids were released in groups of 200 over a period of six (6) weeks from mid-July through mid-Au-gust, 2016. A total of 3,961 T. planipennis, S. galinae, and O. agrilus parasitoids were released during the 2016 field season. GPS coordinates were recorded at the time of the release for both 2015 and 2016.

Similar numbers of parasitoids were released at the Syracuse site including 3,000 T. planipennisi, 1,200 S. galineae, and 2,400 O. agrili for 2015 and 2016 totaling 6,600 parasitoids.

YPT parasitoid recovery at the Naperville site, overtime, included a total of 17 T. planipennisi para-sitoids recovered from six (6) CP-YPT’s in 2015 and five (5) were recovered from three (3) YPT’s in 2016. In the PRP, six (6) T. planipennisi parasitoids were recovered in four (4) YPT’s in 2015 and six (6) T. planipennisi were collected in three (3) YPT’s in 2016. All total, 23 T. planipennisi were recov-ered in 2015 for both the CP and PRP sites and 11 T. planipennisi in 2016. No S. galinae nor O. agrili parasitoids have been recovered to date. Parasitoid recovery at the Syracuse parasitoid release site include a total of 22 T. planipennisi in 19 YPT’s and one (1) S. galinae in 2016. No parasitoids have been recovered at the Syracuse control site. In addition, no parasitoids have been recovered at the Boulder, Colorado site.

Parasitoid dispersal distances for both the Naperville and Syracuse sites are similar. The parasitoid, T. planipennisi, was recovered in the Naperville CP, a distance of approximately 1.5 miles (2.5 km) from release site and T. planipennisi was recovered at a similar distance in the Syracuse release plot. The one (1) S galinae was caught at the Syracuse trap site approximately 205 m (750 ft) from the release point. Disperal distances and locations for Naperville parasitoid recoveries were similar for 2015 and 2016.

Branch samples taken in late fall, 2015 at the Naperville PRP and CP sites revealed five, PRP trees with evidence of T. planipennisi parasitism, respectively. Thirty-two (32) T. planipennisi parasitoids were reared from one PRP branch sample. Branch samples taken in winter 2015 at the Syracuse site indicated trees were not currently infested, but several branches contained dead EAB larvae.

TCR’s appear to reflect typical EAB population spread and tree mortality with untreated trees having significantly higher (less healthy) TCR’s in both the CP and PRP’s. Early results are promising with Tetrastichus establishing and dispersing up to 1.5 miles (2.5 km) from the release site within two field seasons.

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WHO’S AFFECTING WHO? INTERACTIONS BETWEEN WOODPECKERS AND PARASITOIDS OF THE EMERALD

ASH BORER

Theresa Murphy1,2, Joe Elkinton1,2, Juli Gould3, and Roy Van Driesche2

1Organismic and Evolutionary Biology, University of Massachusetts Amherst, MA 10003

2Department of Environmental Conservation, University of Massachusetts Amherst, MA 10003

3USDA-APHIS-PPQ, Buzzards Bay, MA 02542

ABSTRACT

Since its discovery in Michigan in 2002, Agrilus plannipennis, the emerald ash borer (EAB), has spread to over half the states in the US and to two Canadian provinces, killing millions of native ash, Frax-inus spp., trees. Understanding the growth of invasive species and managing them requires detailed understanding of the population dynamics and mortality factors that control that species. EAB has been partially controlled by native biological controls, the most significant being woodpeckers. Woodpeckers can consume between 34% -88% of the EAB larvae in an infested tree. However, de-spite high predation rates, EAB populations continue to soar. Management is focused on controlling the population through classical biocontrol with the introduction of four parasitic wasps, including three larval parasitoids, of EAB from its native range. Since larval parasitoids and woodpeckers both attack the EAB larval stage it is possible and probable that woodpeckers will feed on these intro-duced biocontrols. Quantifying the relationship between these two key mortality factors is essential to understanding if we can regulate EAB populations and preserve ash trees in our forests.

Selective predation pressure on parasitized versus non-parasitized larvae by generalist predators has been important in other invasive species systems. In cases where predators avoid parasitized larvae, the mortality factors are said to be synergistic and control of the invasive population is enhanced. In cases where predators prefer parasitized larvae, the mortality factors are antagonistic and control of the invasive population is weakened. This study examined potential interactions between predation and parasitism of invasive EAB through experimental manipulation. Groups of parasitized EAB larvae were established in trees in Massachusetts and New York and then metal screening was used to exclude woodpeckers from some larvae, leaving other groups of larvae exposed to woodpecker predation.

Our results confirm that, when feeding on a given tree, woodpeckers did not discriminate between parasitized and non-parasitized larvae. However, at a stand-level, woodpeckers prefer to feed more extensively on trees where they do not encounter parasitized larvae. This suggests that while they do not or cannot discriminate against parasitized larvae on a tree-level, at the stand-level woodpeckers prefer to avoid parasitized larvae. We hypothesize that this avoidance may be because parasitized larvae are a lower food reward for woodpeckers. Further studies will be needed to conclude wheth-

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er the presence of parasitized larvae will reduce or enhance overall predation by woodpeckers on EAB within a stand. In our experimental plots, woodpeckers could choose between parasitized and non-parasitized trees, making a tendency toward aversion easier to detect. Amongst natural EAB populations once parasitoids become established parasitized larvae might occur in most or all trees. If established parasitoids do not aggregate and instead spread out, it could be that the presence of parasitoids reduces overall woodpecker attack rates on EAB in the stand. In that case, the two mortality agents would be antagonistic to one another. Alternatively, if parasitoids do aggregate, woodpeckers might be able to seek out trees with lower parasitism and attack those preferentially, as they did in our study. In that case, the two mortality agents might have a synergistic effect on overall EAB mortality in the stand. More work needs to be done as biological controls become established to mark any changes in woodpecker predation behavior. This study fills helps a gap in our current understanding of the population dynamics and mortality factors of EAB.

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AN UPDATE ON EAB BIOCONTROL INVIRGINIA

,Max Ragozzino1 Dr. Scott Salom1, Dr. Jian Duan2

Virginia Tech, Department of Entomology1

USDA ARS2

ABSTRACT

Since fall of 2015, a total of 6 field sites in VA and NC were found where the EAB infestation is recently discovered, the infested trees are suffering from less than 50% canopy dieback, and the trees are accessible and in high enough numbers to justify use as a field site. Sites include two private landowners in Blacksburg, VA & Natural Bridge Station, VA; two State Parks, Leesylvania State Park in Woodbridge, VA & Douthat State Park in Millboro, VA; one County Park, Mid-County Park in Christiansburg, VA; and Cherry Research Farm in Goldsboro, NC. EAB infestations varied from newly discovered to established for multiple years. In spring of 2016, 10,000 Tetrastichus planipennisi and 200 Spathius agrili were requested from Ben Slager at USDA APHIS, Dr. Jian Duan provided 500 S. galinae. Each site was to receive 2000 adult female T. planipennisi, with a minimum of 500 adults per release. Due to field site characteristics, New River Junction in Blacksburg, VA received 1000 adults and Douthat State Park in Millboro, VA received 3000 adults. All other sites received approximately 2000 T. planipennisi. Yellow pan trap & larval sentinel log monitoring was set up at each site. Yellow pan trap monitoring data are still being processed, so far no T. planipennisi have been recovered.

Larval sentinel logs were generally unsuccessful, and no parasitoids were recovered. Felling and de-barking has yet to take place, and is scheduled for early 2017. Interspecies competition experiments were set up between S. agrili & S. galinae to determine the impact of competition for oviposition sites and potential for multiparasitism. Due to high EAB larval mortality & a fungal outbreak within our growth chamber, the majority of trials were lost. Moving forward we have adjusted our sanitary procedures to prevent this from happening in the future, and are planning to add additional trials to account for high mortality.

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PARASITOIDS OF THE EMERALD ASH BORER:AN UPDATE ON THE REARING, RELEASE,AND RECOVERY

Ben Slager

EAB Biological Control Facility, USDA APHIS PPQ, 5936 Ford Court Suite 200, Brighton MI 48116 Benjamin.h.slager@aphis.usda.gov

ABSTRACT

The Emerald Ash Borer (EAB) Biological Control Facility (BCF) in Brighton, Michigan has con-cluded its eighth season of programmatic releases of non-native EAB parasitoids. Three of the parasitoids (Oobius agrili, Tetrastichus planipennisi, and Spathius agrili) have been reared at the BCF since its opening in 2009 and in 2015 Spathius galinae was added to the rearing program. Over one million parasitoids were reared and released this season while implementing greater quality control for Tetras-tichus production and modifying the composition of species production. Parasitoids produced at the BCF have been released in 24 states (AR, CO, CT, IA, IL, IN, KS, KY, LA, MA, MD, MI, MN, MO, NC, NH, NJ, NY, OH, PA, TN, VA, WI, WV), the District of Columbia, and two Canadian provinc-es (Ontario and Quebec). Data collected by release cooperators suggest that Oobius and Tetrastichus are successfully establishing in the environment.

Parasitoid production is dependent on the availability of EAB eggs from the laboratory colony at the BCF. These eggs are provided to the egg parasitoid, Oobius agrili, or are allowed to develop on small ash tree segments (bolts). The developing, late instar EAB larvae underneath the bark of the bolts are then presented to one of the larval parasitoids. EAB egg production at the BCF increased by nearly 300,000 eggs from the 2014 to 2015 production seasons. This increase was largely due to a shift from one common EAB colony to several individual colonies that are the responsibility of a single technician. This shift enhanced vigilance for disease and subpar oviposition rates, which helps to increase egg production. EAB egg production is also influenced by the quality of leaves that adults are fed. During the 2015 and 2016 seasons, several field leaf resources of tropical ash, Fraxinus uhdei, were identified in California, Puerto Rico, and Hawaii, as well as greenhouse grown leaves from Michigan and Pennsylvania. Having this variety of leaf sources has helped to stabilize leaf quality and enhance EAB egg production. Egg production during the 2016 season surpassed 1.2 million, which represents a 350,000 egg increase over the 2014 production season and nearly 89,000 eggs over the 2015 season.

During the 2016 production season, 438,860 Oobius agrili were produced for release, which rep-resents a 62% increase from the previous season and a 157% increase from the 2014 season. The increase in Oobius production is in part due to greater egg production, but is also the result of tightening the organizational structure of the lab. Eggs that are used for bolt production are allowed to age for several days in a controlled environment to minimize desiccation and other complications that can occur prior to hatch and subsequent development. The eggs that are not set aside for bolts

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are provided to Oobius, the egg parasitoid, on the day of their collection. In an effort to maximize egg use efficiency, the number of bolts needed to be produced on a daily basis was projected for an entire production season. This schedule helped to determine the daily number of eggs to be saved for future bolt production, which was previously being overestimated. Consequently, a greater num-ber of eggs are able to be allocated to Oobius and production levels have increased.

The larval endoparasitoid, Tetrastichus planipennisi, has been the top parasitoid produced at the BCF since the 2010 release season. The 2016 release season is no different, with 521,701 individuals produced. This number represents a step toward a more accurate estimation process of the number of Tetrastichus released as compared to previous seasons. The number of adults that have developed under the bark of a given bolt is an unknown that is estimated. A percentage of parasitized bolts at the BCF are removed from a cohort that were produced in a similar time range and placed in indi-vidual rearing containers at standard rearing conditions to allow Tetrastichus adults to emerge. These data are then averaged and applied to the bolts that are sent to cooperators. In previous seasons these data points came from bolts that did not experienced cold storage. The majority of Tetrastichus bolts are produced during the winter and early spring months when it is not appropriate to release parasitoids. For this reason, they are stockpiled in cold storage until active EAB larvae are present in the environment. This season our process to estimate adult emergence occurred post-cold storage in order to include the mortality that likely occurred during this treatment. It was found that cold stored material had approximately 30% fewer adults emerge than those that did not experience cold storage. These data have helped to increase the accuracy of Tetrastichus release estimates.

The 2016 release season is the first season that the BCF reared the ectoparasitoid, Spathius galinae. During its first rearing season, 23,440 adults were produced from the 500 individual starter colony provided by Jian Duan at the Agricultural Research Service (ARS). The BCF collaborated with ARS to develop cold storage methods to allow for stockpiling of diapaused S. galinae until the appropriate EAB larval stages are active in the field (See Slager et al. – this publication). This study is ongoing, but the preliminary data will help to inform cold storage methods for the 2017 production season. The initial methods to rear S. galinae are similar to those of S. agrili. Methods for rearing and storing S. agrili have remained constant for the last several years and have helped to rear 21,623 individuals during the 2016 production season.

Currently, there are 30 states infested with EAB, which are made up of approximately 850 counties that are known to be infested. One or more parasitoids were released in 24 states and the District of Columbia, as well as two Canadian provinces (Ontario and Quebec) during the 2016 release season. In total, nearly 200 counties have received at least one parasitoid species since the beginning of the BCF releases in 2009. The number of parasitoids produced has increased through the years and the number of sites that cooperators are releasing these parasitoids has tracked that increase. However, the number of cooperators releasing parasitoids has remained constant and many are longtime co-operators. This dynamic has led to a clumped pattern in parasitoid releases across the landscape and to the reconsideration of release cooperator participation in the EAB parasitoid release program. Traditional partners to federally run programs typically include other federal agencies, state agencies, and universities. The BCF has worked to broaden its cooperator base to include city governments, Native American tribes, and non-profit organizations with a focus on forest health and ecology. It is hoped that with the addition of these “non-traditional” partners, parasitoids can be more efficiently distributed throughout the landscape.

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When parasitoids are recovered at a site the season following the last release, it is termed a recov-ery, whereas parasitoids that are recovered from a site at least two seasons after the last release is considered to be establishment. Establishment is a more substantial indicator of success because the subsequent generations of progeny from the original release have found EAB to parasitize and have successfully overwintered. As of October 2016, S. agrili has been recovered in 4 states, Oobius has been recovered in 8 states, and Tetrastichus has been recovered in 11 states (Data from mapbio-control.org – 2016). This is the first year of releases of S. galinae from the BCF and therefore, too early to collect recovery data. Establishment data show that of the sites sampled 5% have confirmed establishments for S. agrili (20 sites sampled), 53% for Oobius (15 sites sampled), and 63% for Tet-rastichus (19 sites sampled) (Data provided by J. Gould – personal communication). No S. agrili were recovered beyond the second year of recoveries. This suggests that although it appears that the introduced populations of S. agrili can persist for two years, most decline to undetectable levels by the third season post release. Many of the sites for S. agrili were located in northern states and these data further justify limiting releases to the infested area below the 40th parallel where the climate is a closer match to this parasitoids native range. The data for Tetrastichus and Oobius indicate that both have been largely successful at establishing at sites where they have been released. These data will be important to continue to collect, in addition to EAB population responses to parasitoid establish-ment, in order to measure parasitoid effectiveness in the field.

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EMERALD ASH BORER AND ITS PARASITOIDS IN THE SOUTHEAST

Greg Wiggins1, Jerome Grant1, Forest Palmer1, and Juli Gould2

1Department of Entomology and Plant Pathology, University of Tennessee, Knoxville,TN 37996 wiggybug@utk.edu

2USDA APHIS PPQ Center for Plant Health Science and Technology, Buzzards Bay, MA 02542

ABSTRACT

The invasive emerald ash borer (EAB), Agrilus planipennis, is native to eastern Asia and has devastated ash (Fraxinus spp.) populations in much of the eastern U.S. Since its initial discovery in Tennessee in 2010, controlled studies and open releases of introduced larval parasitoids (Spathius agrili and Tet-rastichus planipennisi) of EAB have been conducted in eastern Tennessee. In studies investigating the overwintering ability of larval EAB parasitoids using large and small cages, S. agrili has demonstrated the ability to survive the winters in the south and emerge the following season. However, no T. pla-nipennisi have been observed to successfully overwinter in these studies. Pan trapping at several open release sites has been initiated, and may show survival of one or both species of parasitoids. Results from pan trapping conducted during 2015 yielded one adult female S. agrili collected from Hamblen County, TN; pan trapping continues through 2016.

Phenology studies of EAB and three larval parasitoid species (S. agrili, S. galinae, and T. planipenni-si) were conducted in 2016. Examination of degree day accumulations (base of 50 degrees F) in Knoxville, TN, from 2011 through 2016 demonstrate that 500 degree days (when EAB usually begin emergence) are accumulated around late April, and 1,000 degree days (when EAB are thought to reach peak activity) are accumulated around late May. Bark removal at two sites in Knox County, TN, conducted every seven to fourteen days beginning April 2016 showed that EAB primarily undergoes a one-year life cycle. Generally, first- and second-instar EAB larvae were seen beginning in June, and third- and fourth-instars were seen beginning in July. Numbers of fourth instars peaked in mid-Au-gust, and numbers tapered as the larvae began to bore into the wood in August.

Larval parasitoid phenology was assessed by conducting a growth-chamber study initiated May 2016. Individual green ash (F. pennsylvanica) bolts (ca. 10 cm long and 4 cm diameter) artificially infested with third- to fourth-instar EAB larvae (n = two larvae per bolt) were placed in clear plastic cups (ca. 473 ml) with two females of each parasitoid species (one species per cup). Cups were placed in two programmable growth chambers set at temperatures recorded in an ash stand located in Blount County, TN, during 2015 and monitored daily for emergence. F1 individuals of all parasitoid species emerged, and mean development time ranged from 44 days (T. planipennisi), to 45.5 days (S. galinae), to 47.7 days (S. agrili). Individuals from this emergence were divided among new EAB larval-infested bolts, placed in growth chambers, and monitored for emergence. Only S. galinae had F2 individuals

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emerge, with an average development time of 56 days. Monitoring of remaining bolts in growth chambers will continue through 2016.

These findings indicate that EAB may more-commonly exhibit an annual life cycle in warmer climates, but variation of the progression of the EAB infestation in individual sites may influence EAB phenology and affect synchrony with introduced parasitoids. S. agrili is more synchronous with EAB expressing an annual life cycle, due to its emergence later in the summer when third and fourth EAB larval instars are more available. These findings allow us to more accurately allocate resourc-es to better target and time parasitoid releases for management of EAB and support the need for climate matching for new parasitoid species for warmer climates.

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Presentations Biology, Behavior & Ecology

FACTORS AFFECTING THE GROWTH RESPONSE OF NON-ASH TREES IN FORESTS IMPACTED BY EMERALD

ASH BORER

Kathleen S. Knight1, Charles E. Flower1, Kyle C. Costilow2

1USDA Forest Service Northern Research Station, 359 Main Road, Delaware, OH 43015 ksknight@fs.fed.us

2USDA APHIS PPQ Ohio Asian Longhorned Beetle Eradication Project, 1761 State Route 125, Suite A, Amelia, OH 45102

ABSTRACT

The response of forests to disturbance events is important to understand because it will shape the fu-ture ecosystem function of the lands that provide clean air and water, forest products, wildlife habitat, and many other ecosystem services to millions of people. Resilience is the ability of a forest to rapidly “bounce back” from a disturbance and maintain these vital ecosystem services (Peterson et al., 1998). Introduced pests and pathogens, extreme weather events, climate change, land use change, or a combi-nation of these factors can cause novel disturbance patterns (Flower and Gonzalez-Meler 2015). In or-der to manage forests for enhanced resilience, we must first understand how forests and trees respond to these novel types of disturbance.

Tree mortality caused by pests and diseases creates gaps in the forest canopy, which allows more light to reach the plants below. The dead trees also cease to take up belowground resources such as water and nutrients, and may release a pulse of nutrients as they begin to decay. These resources – light, water, and nutrients – are then available to neighboring trees, shrubs, and herbaceous plants in the subcanopy and understory of the forest. The individuals that are able to monopolize these resources and rapidly grow to fill in the gaps will determine the future trajectory of the forest (Runkle, 1981). For example, in a forest with a subcanopy of native tree species that are able to quickly respond to the death of overstory trees, these native trees may fill in the gaps, maintaining forest structure and ecosystem function (Figure 1). On the other hand, if trees in the subcanopy are not able to respond, then invasive shrubs or herbaceous plants may benefit from the increase in resources (Davis, 2000). This utilization of new resources could allow invasive species to form impenetrable thickets that could drastically change ecosystem structure and function (Royo and Carson, 2006).

The emerald ash borer (Agrilus planipennis) (EAB) is an introduced pest that causes forest disturbance by killing ash trees (Fraxinus spp.) (Gandhi and Herms, 2010). Because there are multiple species of ash in-habiting very different types of ecosystems, the effects of this disturbance will likely vary tremendously across the landscape. We studied the effects of EAB in riparian green ash (F. pennsylvanica) forests and lowland forests with a mixture of green, pumpkin (F. profunda), and black ash (F. nigra). Our goal was to understand the factors that affect the response of non-ash tree species to ash mortality in these forests.

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In 2005, prior to ash mortality from EAB, we established 47 permanent monitoring plots in seven forest stands in Northwest Ohio. We recorded the trunk diameter at breast height (DBH) and species identity of each tree >10 cm DBH in each 400 m2 plot, as well as the crown class of each tree (N=500 non-ash trees and N=801 ash trees). The crown class is a categorical measurement (suppressed, inter-mediate, codominant, and dominant) based on how much of the tree canopy is receiving direct sun-light. For example, the maple trees in Figure 1 start out as suppressed, and then

become intermediate when the ash trees above them die. The canopy health condition of ash trees in the plots was recorded yearly, while the crown class and DBH were re-measured in 2010 and 2011. We collected increment cores from a subset of 72 maple (Acer rubrum and A. saccharinum) trees in 13 of the plots in 2011 and used dendroecological methods to determine yearly growth of these trees. Symptoms of EAB first appeared in the stands in 2005-2007, and the stands reached nearly 100% ash mortality by 2010.

Figure 1: Illustration of potential responses of trees and shrubs in forest stands impacted by ash mortality. On the left, shrub species in the understory benefit from the gaps left by the mortality of ash trees. On the right, native tree species rapidly grow to fill in the gaps.

The DBH measurements on the full suite of trees from 2005 and 2011 was used to calculate relative growth rate (RGR, mm/cmDBH/year) for all species of trees present in these plots, and ANOVA was used to determine which factors affect RGR. The results indicated that several factors were im-portant predictors of how quickly the non-ash trees grew during this period of ash mortality (Flow-er et al., 2013). Growth differed among different genera (p

esis that disturbance severity can drive differential responses in residual species. As expected, very large trees had lower RGR’s than smaller trees (p=0.013). In this analysis of the full suite of trees, the initial canopy class of the tree did not make a difference in its growth response (p=0.37).

The tree cores from the subset of 72 maple trees were used to further understand the growth re-sponse of this important species to ash mortality (Costilow et al., in press). In particular, the cores allowed us to examine the yearly growth of the trees both prior to and after EAB impact in the forest stands. We separated the trees into two groups based on their crown class ratings: a canopy advancement (CA) group whose canopies gained greater sunlight exposure due to the death of surrounding ash trees and a non-canopy advancement (NCA) group whose crown ratings did not in-crease. We used a RMANOVA to examine the mean pre-EAB and post-EAB growth rate (cm/year) of CA and NCA trees and a hierarchical mixed effects model to examine the effects of multiple predictors on growth response (defined as post-EAB mean yearly growth increment minus pre-EAB yearly growth increment). We found that both groups experienced an increase in growth (p

The rapid growth response of non-ash trees to ash mortality, especially in areas with greater dis-turbance severity, illustrates the potential for certain types of resilience of some ash ecosystems to disturbance. Our research suggests that maple species may have particular importance in these riparian and lowland ash-dominated ecosystems due to their abundance (Knight et al., 2012) and rapid growth response (Costilow et al., in press; Flower et al., 2013). While these studies showed rapid growth increases of non-ash trees, this response was unable to compensate for the loss of ash carbon uptake in these systems, at least in the short term (Flower et al., 2013). Further research is necessary to understand how different components of ecosystem structure and function respond to forest disturbance from invasive insect outbreaks, to understand threshold density and composition of non-host trees necessary to maintain these ecosystem functions, and to ultimately provide guid-ance for managers to bolster the resilience of the forests we all depend on.

REFERENCES

Costilow, K.C., Knight, K.S., Flower, C.E. In press. Disturbance severity and canopy position control the radial growth response of maple trees (Acer spp.) in forests of northwest Ohio impacted by emerald ash borer (Agrilus planipennis). Annals of Forest Science.

Davis, M.A., Grime, J.P., Thompson, K. 2000. Fluctuating resources in plant communities: a general theory of invasibility. Journal of Ecology. 88, 528-234.

Flower C.E., Gonzalez-Meler M.A. 2015. Responses of temperate forest productivity to insect and pathogen disturbances. Annual Review in Plant Biology 66: 547-569.

Flower, C.E., Knight, K.S., Gonzalez-Meler, M.A. 2013. Impacts of the emerald ash borer (Agrilus pla-nipennis) induced ash (Fraxinus spp.) mortality on forest carbon cycling and successional dynamics in the eastern United States. Biological Invasions. 15(4):, 931-944.

Gandhi, K.J.K., and Herms D.A. 2010. Direct and indirect effects of alien insect herbivores on ecologi-cal processes and interactions in forests of eastern North America. Biological Invasions. 12, 389-405.

Knight, K.S., Herms, D., Plumb, R., Sawyer, E., Spalink, D., Pisarczyk, E., Wiggin, B., Kappler, R., and Menard, K. 2012. Dynamics of surviving ash (Fraxinus spp.) populations in areas long infested by emerald ash borer (Agrilus planipennis). In: Sniezko RA, Yanchuk AD, Kliejunas JT, Palmieri KM, Alexander JM, and Frankel S. J. Tech. Coords. Proceedings of the 4th International Workshop on the Genetics of Host-Parasite Interactions in Forestry: Disease and Insect Resistance in Forest Trees. July 31 – August 5 2011, Eugene, OR. Gen. Tech. Rep. PSW-GTR-240. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 143-152.

Royo, A.A. and Carson, W.P. 2006. On the formation of dense understory layers in forests world-wide: consequences and implications for forest dynamics, biodiversity, and succession. Canadian Jour-nal of Forest Research. 36(6), 1345-1362.

Runkle, J.R. 1981. Gap regeneration in some old-growth forests of the eastern United States. Ecolo-gy. 62, 1041-1051.

Peterson, G., Allen, C.R., Holling, C.S. 1998. Ecological resilience, biodiversity, and scale. Ecosystems. 1, 6-18.

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ECOLOGICAL IMPACTS OF EMERALD ASH BORER INVASION OF FORESTS OF SOUTHEASTERN MICHIGAN

Daniel A. Herms1, Kamal J.K. Gandhi1,2, Annemarie Smith1, Wendy Klooster1,3, John Cardina3, Kathleen S. Knight4,

Catherine P. Herms3, Diane Hartzler1, and Deborah G. McCullough5

1Department of Entomology,The Ohio State University, Ohio Agricultural Research and Development Center,Wooster, Ohio 44691 herms.2@osu.edu

2Current address: Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602

3Department of Horticulture and Crop Science,The Ohio State University, Ohio Agricultural Research and Development Center,Wooster, Ohio 44691

4USDA Forest Service, Northern Research Station, Delaware, OH 43015

5Departments of Entomology and Forestry, Michigan State University, East Lansing, MI 48824

ABSTRACT

We monitored patterns and effects of ash (Fraxinus spp.) mortality due to emerald ash borer (EAB, Agrilus planipennis) in 38 forest stands in the Upper Huron River watershed in southeastern Michi-gan from 2004-2013. Black (F. nigra), green (F. pennsylvanica), and white (F. americana) ash were the most common ash species in hydric, mesic, and xeric stands, respectively. By 2010, ash mortality of trees greater than 2.5 cm stem diameter was 99.7%. Four years of soil sampling found small numbers of seeds in 2005-2006; however, no ash seeds were found in 2007-2008. Ash demography was consistent with seed bank sampling. Density of new ash seedlings was 0.5 and 0.1 plant / ha in 2008 and 2009, respectively. No new ash seedlings were observed after 2009. Established seedlings and saplings essentially were the only demographic classes of ash surviving these stands. However, purple panel traps indicated that EAB adults continued to persist at low levels, suggesting that an EAB population might be sustained as established seedlings and saplings become large enough to be colonized. Ultimately, in the absence of ash regeneration, EAB may be locally extirpated as this orphaned cohort of juvenile ash is gradually depleted via EAB mortality. Alternatively, a dynamic equilibrium may establish in which some trees reach reproductive maturity before succumbing to EAB, especially if native and introduced biological control agents prove capable of regulating EAB at very low densities. Nearly simultaneous mortality of ash has resulted in wide spread formation of canopy gaps and a dramatic increase in accumulation of coarse woody debris on the forest floor. We documented pervasive direct and indirect ecological impacts of ash mortality on successional trajectories, growth rate of invasive plants, and soil invertebrate communities.

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mailto:herms.2@osu.edu

DIVERSITY OF INSECT FAUNA ASSOCIATED WITH LIVE

AND DEAD GREEN ASH TREES (Fraxinus pennsylvanica) IN LOUISIANA

Balwinder Kaur1, Wood Johnson2, Rodrigo Diaz1

ABSTRACT

Emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera, Buprestidae), a metallic wood boring beetle, is an exotic pest of ash trees (Fraxinus spp.) EAB can attack all the ash species in North America disrupting local food webs and has caused more than 200,000 million ash tree deaths since 2002. In order to describe the insect community associated with green ash, field studies were conducted to measure the diversity of insect fauna found on green ash (Fraxinus pennsylvanica) in Louisiana (LA). Ash logs were harvested from sites with (north LA) and without EAB presence (central and south LA). Two treatments were established based on log diameter (small and large) and log conditions (dead and live).Treatments were placed in emergence traps and insect collection done at bimonthly interval. All the insects collected from emergence chambers were identified to the lowest taxonomic level. The insect communities were compared between experimental sites using several indices of diversity. Understanding the impact of an invasive species before and after its invasion could provide critical information about potential changes in local food webs, document the presence of natural enemies, and to help develop an effective management plan against EAB in Louisiana.

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FOREST RESPONSES FOLLOWING EMERALD ASH BORER -INDUCED ASH MORTALITY IN SOUTHEASTERN MICHIGAN

Wendy S. Klooster1, P. Charles Goebel2, and Daniel A. Herms3

1Department of Entomology,The Ohio State University, Columbus, OH 43210

2School of Environment and Natural Resources,The Ohio State University, Ohio Agricultural Research and Development Center,Wooster, OH 44691

3Department of Entomology,The Ohio State University, Ohio Agricultural Research and Devel-opment Center,Wooster, OH 44691

ABSTRACT

Now that emerald ash borer (EAB; Agrilus planipennis) has been established in North America for at least two decades (Siegert et al. 2014), its detrimental impacts on populations of North Amer-ican ash (Fraxinus spp.) trees have been well-documented (Poland & McCullough 2006; Herms & McCullough 2014;). The question remains how this widespread and relatively simultaneous loss of ash is affecting other flora in impacted forests. Our objective was to examine radial trunk growth of a variety of tree species where ash mortality exceeded 99% by 2009, and the ash seed bank was depleted by 2007 (Klooster et al. 2014) to determine how they have responded to gap formation and release from competition with ash.

We sampled in 42 transects that were previously established to study ash mortality in southeast Michigan; each transect contained three 0.1 ha plots (Klooster 2012; Smith et al. 2015). Transects were classified according to soil moisture as xeric (white ash the most common ash species prior to EAB invasion), mesic (green ash most common), or hydric (black ash most common). Since gap for-mation and release from competition would be affected by the amount of ash trees initially present, we calculated ash importance values (IVs) (relative basal area × relative density × relative domi-nance) using tree data collected prior to ash mortality.

In 2013, trunks were cored from more than 850 trees comprising a variety of non-ash species, shade tolerance, drought tolerance, and canopy positions using a standard increment borer. Analyses of the tree cores indicated species-specific responses to ash mortality. The majority of species that exhibited positive correlations between ash IV and increased ring widths (trunk growth) were either shade-tolerant or intermediate, whereas the ring widths of shade-intolerant species generally were not correlated with ash IV. Canopy position of the trees (dominant, codominant, intermediate, or suppressed) also may have an effect on their response to ash mortality, as ring widths of some co-dominant species increased in size. However, additional analyses are being performed to clarify these preliminary results.

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REFERENCES

Herms, D. A., and D. G. McCullough (2014). Emerald ash borer invasion of North America: History, biology, ecology, impacts, and management. Annual Review of Entomology 59(1): 13-30.

Klooster, W. S. (2012). Forest responses to emerald ash borer-induced ash mortality (Doctoral disserta-tion). Department of Horticulture and Crop Science. Ph.D. Dissertation, The Ohio State University. Columbus, OH.

Klooster W. S., D. A. Herms, K. S. Knight, C. P. Herms, D. G. McCullough, A. Smith, K. J. K. Gandhi, and J. Cardina (2014). Ash (Fraxinus spp.) mortality, regeneration, and seed bank dynamics in mixed hardwood forests following invasion by emerald ash borer (Agrilus planipennis). Biological Invasions 16: 859-873.

Poland, T. M., and D. G. McCullough (2006). Emerald ash borer: invasion of the urban forest and the threat to North America’s ash resource. Journal of Forestry 104(3): 118-124.

Siegert, N. W., D. G. McCullough, A. M. Liebhold, and F. W. Telewski (2014). Dendrochronological reconstruction of the epicenter and early spread of emerald ash borer in North America. Diversity and Distributions 20: 847–858.

Smith, A., D. A. Herms, R. P. Long, and K. J. K Gandhi. (2015). Community composition and structure had no effect on forest susceptibility to invasion by the emerald ash borer (Coleoptera: Buprestidae). The Canadian Entomologist 147(3): 318-328.

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RESPONSE OF GROUND-DWELLING INVERTEBRATE COMMUNITIES TO TEMPORAL PATTERNS

OF ASH MORTALITY

Kayla I. Perry1 and Daniel A. Herms1

1Department of Entomology,The Ohio State University, Ohio Agricultural Research and Development Center,Wooster, Ohio, 44691 perry.1864@osu.edu

ABSTRACT

Ash mortality caused by emerald ash borer (EAB; Agrilus planipennis) has resulted in widespread, nearly simultaneous formation of canopy gaps in forests. Gap formation increases light availability, which induces environmental changes on the forest floor, including increased soil temperature, soil moisture, and understory vegetation growth. After several years, ash snags fall, either by uprooting or snapping along the bole, and high volumes of coarse woody debris (CWD; large branches and logs) can accumulate on the forest floor, depending on the density of ash trees. These environmen-tal changes have the potential to impact forest communities such as populations of ground-dwelling invertebrates.

Based on these patterns, an inverse temporal relationship is predicted for the effect sizes of cano-py gaps and accumulation of ash CWD caused by EAB-induced ash mortality on ground-dwelling invertebrate communities (Perry and Herms 2016a). During the early stages of EAB-induced ash mortality, canopy gaps are predicted to have the greatest impact on the ground-dwelling invertebrate community. Canopy gaps are predicted to be at their maximum size immediately following tree mortality and close over time as suppressed understory trees and surrounding canopy trees grow to fill the available space. Conversely, the amount of woody debris on the forest floor is predicted to be low because the trees are still standing as snags and increase as dead trees fall. Therefore, the greatest effects of ash CWD on ground-dwelling invertebrate communities are predicted to occur during the late stages of EAB-induced ash mortality.

Results of studies conducted during early stages of ash mortality in Ohio, and late stages of ash mortality in southeast Michigan were consistent with these predictions. When canopy gaps were at their maximum size and levels of downed CWD were low, ground beetle (Coleoptera: Carabidae) assemblages were altered by the creation of canopy gaps, but not the accumulation of low levels of woody debris (Gandhi et al. 2014, Perry and Herms 2016b). Gandhi et al. (2014) documented decreased ground beetle activity-abundance and diversity, as well as distinct assemblages in hydric forest stands dominated by black ash (Fraxinus nigra Marsh.) compared to mesic and xeric stands dominated by green (Fraxinus pennsylvanica Marsh.) and white (Fraxinus americana L.) ash, respectively. Perry and Herms (2016b) also reported decreased activity-abundances of two common ground bee-tle species, Cyclotrachelus convivus (LeConte) and Pterostichus stygicus (Say) in canopy gaps, but no effects of low levels of CWD. Perry and Herms (2016a) found decreased ground-dwelling invertebrate

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richness and diversity, which was driven by decreased activity-abundances of harvestmen (Opil-iones), ground beetles, scarab beetles (Scarabaeidae), camel crickets (Rhaphidophoridae), and three families of springtails (Hypogastruridae, Isotomidae, and Sminthuridae).

During the late stages of EAB-induced ash mortality, Ulyshen et al. (2011) documented higher densities of ground-dwelling invertebrates near ash logs, but no effect of small canopy gaps. Several invertebrate taxa, including earthworms (Annelida), spiders (Araneae), harvestmen, isopods (Isopo-da), millipedes (Diplopoda), beetles (Coleoptera), and springtails (Collembola), were more abundant in leaf litter near ash logs than in leaf litter away from logs. Further investigation in these same forest plots revealed increased total activity-abundance, evenness, and diversity near recently fallen ash logs compared to more decayed logs, but no effect of small canopy gaps. Invertebrate commu-nity composition was more similar near logs of the same decay class, but highly variable away from downed woody debris.

Results from these studies support the predicted inverse temporal relationship of the effect sizes of canopy gaps and accumulation of ash CWD caused by EAB-induced ash mortality on ground-dwell-ing invertebrate communities (Perry and Herms 2016a). This suggests there may be lasting effects of EAB on forest communities.

REFERENCES

Gandhi, K. J. K., A. Smith, D. M. Hartzler, and D. A. Herms. 2014. Indirect effects of emerald ash borer-induced ash mortality and canopy gap formation on epigaeic beetles. Environmental Entomology 43:546-555.

Perry, K. I. and D. A. Herms. 2016a. Response of the forest floor invertebrate community to canopy gap formation caused by early stages of emerald ash borer-induced ash mortality. Forest Ecology and Manage-ment 375:259-267.

Perry, K. I. and D. A. Herms. 2016b. Short-term responses of ground beetles to forest changes caused by early stages of emerald ash borer (Coleoptera: Buprestidae)-induced ash mortality. Environmental Entomology 45(3):616-626.

Ulyshen, M. D., W. S. Klooster, W. T. Barrington, and D. A. Herms. 2011. Impacts of emerald ash bor-er-induced tree mortality on leaf litter arthropods and exotic earthworms. Pedobiologia 54:261-265.

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Presentations Host Interactions

EMERALD ASH BORER AND CULTIVATED OLIVE: WHAT ARE THE CHANCES?

Don Cipollini, Chad M. Rigsby, Donnie L. Peterson

Department of Biological Sciences and the Environmental Sciences Ph.D. Program, Wright State University, Dayton, OH 45435

ABSTRACT

In 2014, Don Cipollini reported that emerald ash borer, Agrilus planipennis, was capable of feeding and completing development on white fringetree, Chionanthus virginicus, a native North American tree that is also used as an ornamental. This was the first successful use of a non-ash (Fraxinus) host re-ported for this invasive insect in North America. Subsequent studies revealed that emerald ash borer had been using white fringetree in ornamental landscapes for several years prior to this discovery and that the phenomenon had been occurring across the Midwestern and northeastern U.S. without detection.

Cultivated olive, (Olea europaea subsp. europaea; Oleaceae) is closely related to white fringetree and is more closely related to ash species than most of the other species that have been tested for their potential to be hosts to emerald ash borer. This tree of Mediterranean origin is grown throughout the world in suitable climates for its fruits, oil, and associated products, and it is also grown as an ornamental. While olive trees cannot tolerate temperatures below -9ºC, they require a chilling pe-riod to stimulate floral budburst that would satisfy the temperature requirements for emerald ash borer prepupae to break diapause. The ranges of several native and introduced ash species known to be susceptible to emerald ash borer overlap with olive throughout its major cultivated range in the Mediterranean basin, and also in North and South America and Australia. Emerald ash borer is encroaching on some olive growing regions in the southeastern U.S. at present, and it is certain to reach other olive growing regions throughout the world in the coming decades through their use of ash trees. Given the susceptibility of the closely related white fringetree to emerald ash borer, the compatibility of their climactic requirements, and their proximity to susceptible ash species through-out their native and cultivated ranges, we examined whether emerald ash borer was capable of feed-ing and completing development on olive trees in a series of no-choice laboratory tests.

In two preliminary studies using small olive stems lasting three weeks or less, significant feeding by EAB larvae was observed on cut stems of several olive cultivars (e.g., ‘Mission’, ‘Lucca’) and several live larvae were recovered when inoculated stems were debarked. In an experiment using 17 stem sections cut from a larger field grown tree (cv. ‘Manzanilla’), larvae emerged from 61 of the 155 eggs placed on the stems in this experiment. On the 14 stems periodically debarked during the larval feeding and growth period, feeding gallery lengths of living larvae increased steadily through time, reaching an average length of 37 cm by 69 days. On the stems debarked during this period, 22 live larvae were recovered out of 42 points of confirmed neonate entry on these stems. Five larvae were

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recovered dead (i.e. tree-killed) and the rest were either unaccounted, indicating that the larvae failed to enter the stems or died quickly, or produced small feed