Brief Summary of Minutes of Annual Meeting

Brief summary of minutes of annual meeting:

The online business meeting was hosted and moderated by John Losey.

1. Funding opportunities in biological control. Dr. Robert Nowierski, National Program Leader for Bio-Based Pest Management, USDA-National Institute of Food and Agriculture (NIFA), provided helpful information about diverse funding from the USDA for biological control of arthropod pests and weeds, with special emphasis on the amounts of funds available in different programs, application deadlines and the potential match of our research to the goals of available programs.

2. Elections. Mark Whitmore will be the chair from 2020-2021 (after the current chair John Losey). Ellen Lake was selected as the next chair, to serve from 2021-2022.

3. Venue for next meeting. We considered two situations for the 2021 meeting of NE1832: in conjunction with the USDA Interagency Meeting on Invasive Species in Annapolis or in conjunction with the meeting of the ESA Eastern Branch in Philadelphia, PA, February 21-23, 2021. We took a vote and decided to meet in conjunction with the ESA Eastern Branch.

4. Discussion of a joint research proposal. Members revisited a discussed initiated at the 2019 meeting regarding potentially putting together a research proposal including members of our group to submit to an unspecified agency. There remains strong support and enthusiasm for a proposal to investigate climate change and biological control using 3-4 model systems and incorporating a quantitative modelling approach.

Symposium Program

To take advantage of the opportunity afforded by the joint meeting of the Eastern and Southeastern branches of the Entomological Society of America we planned a two-part joint symposium with the Southeastern biological control multistate group, SE1073.  We had also arranged a poster session, a mixer, and a group discussion on synergies and collaborations between the two groups.  Even though circumstances did not allow this to happen this year both groups feel the concept of a joint symposium has great merit so we are including the planned list of speakers and topics below.

Biological Control in the North and Southeast: Current Progress, Future Prospects, and Potential for Collaboration - Parts 1 & 2

Organizers

Ellen Lake USDA-ARS; Jason Schmidt University of Georgia; Rodrigo Diaz Louisiana State University; John E. Losey Cornell University; Elizabeth Tewksbury University of Rhode Island;

Ellen Lake USDA-ARS

Description

Our symposium will represent a broad reaching, high impact group of biological control specialists joining forces from the SE/NE Biological Control of Pests Multi-State Projects. Our program will feature leaders in the area of biological control, and exciting topics that span regions and biological control for weeds and insect pests.

Part 1: Tuesday, March 31, 2020 08:00 AM - 12:00 PM

Papers

Biological Control of Weeds in the Southern Region: A Florida Perspective

James Cuda, University of Florida, Gainesville, FL

Updates on biological control of giant and common salvinia in southeastern United States

Rodrigo Diaz, Louisiana State University, Baton Rouge, LA

Biological control of Persicaria perfoliata: A weed and weevil moving a mile-a-minute in the U.S.

EllenLake USDA-ARS, FortLauderdale, FL and JudithA.Hough-Goldstein, University of Delaware, Newark, DE

Biological control agents recommended for release against Chinese tallowtree in the southeastern US

Greg Wheeler, USDA - ARS, Fort Lauderdale, FL

Biological Control of Invasive Phragmites in North America with Archanara stem borers
Bernd Blossey Cornell University, Ithaca, NY; Patrick Häfliger CABI, Delémont, Switzerland; Lisa Tewksbury University of Rhode Island, Kingston, RI; Andrea Davalos SUNY Cortland, Cortland, NY; and Richard Casagrande University of Rhode Island, Kingston, RI

Brazilian peppertree in Florida: Adding another tool into the IPM toolbox

Carey Minteer University of Florida, Fort Pierce, FL; Gregory Wheeler USDA-ARS, Fort Lauderdale, FL; Eutychus Kariuki , Dale Halbritter and Min Rayamajhi , Florida A&M University, Tallahassee, FL

Potential for biotic interference between parasitoids and a weed biocontrol agent
Ellen Lake USDA-ARS, Fort Lauderdale, FL;  Lisa Tewksbury University of Rhode Island, Kingston, RI; Melissa Smith USDA-ARS, Fort Lauderdale, FL; Allen Dray Jr USDA-ARS, Fort Lauderdale, FL;   Alana Russell University of Rhode Island, Kingston, RI;  Paul Madeira USDA-ARS, Fort Lauderdale, FL;  Min Rayamajhi USDA-ARS, Fort Lauderdale, FL;  and Richard Casagrande University of Rhode Island, Kingston, RI,

Shared Parasitoids and Apparent Competition: Looking for Indirect Effects in Florida’s Weed Biological Control Agents
Melissa Smith USDA-ARS, Fort Lauderdale, FL; Philip Tipping USDA-ARS, Fort Lauderdale, FL; Carey Minteer University of Florida, Fort Pierce, FL; Ellen C. Lake , Karen Rice Fort Lauderdale, FL; and Alissa Marie Berro , University of Florida, Gainesville, FL

Part 2: Wednesday, April 1, 2020 08:00 AM - 12:30 PM

Papers

Merging biocontrol forces: Introduction to multi-state cross talk

Jason Schmidt, University of Georgia, Tifton, GA

A global view of natural enemy importance

Ann E. Hajek, Cornell University, Ithaca, NY

Give predators a complement: Balancing positive and negative diversity effects

William Snyder, University of Georgia, Athens, GA

Creepers, sleepers, and keepers: managing more pests in a changing climate with better biological control

John Losey, Cornell University, Ithaca, NY

The status of university, government and private sector biological control in the United States
Norman Leppla University of Florida, Gainesville, FL;  Lynn M. LeBeck Association of Natural Biocontrol Producers Clovis, CA, and Marshall Johnson University of California, Riverside, Parlier, CA

Biological control in ornamentals: Progress and challenges

Juang-Horng Chong, Clemson University, Clemson, SC

Bio-based pest management in a new decade

Robert Nowierski, USDA-NIFA, Washington, DC

Conservation biocontrol: Challenges and opportunities in NY and comparing methods for establishing insect habitat

Amara Dunn, Cornell University, Geneva, NY

Commercial biocontrol in the US: Background and research needs

Carol Glenister, IPM Laboratories, Inc, Locke, NY

Augmentative biological control of Asian citrus psyllid using parasitoids introduced from Asia

Jawwad Qureshi, University of Florida, Immokalee, FL

Assessing the potential role of Laricobius (Coleoptera: Derodontidae) and Leucopis (Diptera: Chamaemyiidae) species on populations of hemlock woolly adelgid and hemlock tree health.

Scott Salom Virginia Polytechnic Institute and State University, Blacksburg, VA;  Carrie Jubb Virginia Polytechnic Institute and State University, Blacksburg, VA;   Joseph Elkinton University of Massachusetts, Amherst, MA;  Kimberly Wallin University of Vermont ,Burlington, VT;  Darrell Ross Oregon State University, Corvallis, OR;  Mark Whitmore Cornell University, Ithaca, NY; Nathan Havill USDA-Forest Service, Hamden, CT;  Albert Mayfield USDA-Forest Service, Asheville, NC;  Rusty Rhea USDA-Forest Service, Asheville, NC;  and Carrie Preston Virginia Tech, Blacksburg, VA

OBJECTIVE 1:  Conservation of existing natural enemies: To conserve existing natural enemies and examine the effects of exotic species on ecosystem function

Assessment and conservation of pathogens of insect pests (Ann Hajek, Cornell)

Lycorma delicatula (Spotted lanternfly):  We published a paper about epizootics caused by 2 native species of entomopathogenic fungi decimating spotted lanternfly populations in southeastern Pennsylvania in October 2018. We have been investigating these two native fungal pathogens: Beauveria bassiana and Batkoa major. We conducted extensive sampling of spotted lanternfly populations in southeastern Pennsylvania across many sites at different times to evaluate infection during 2019. Samples of B. bassiana were collected to evaluate genetic diversity across southeastern PA. We sampled native insect populations in southeastern PA and in the southern tier of New York State to determine what native insects are the natural hosts of B. major, a species that is very poorly known in North America.

Sirex noctilio (Sirex woodwasp).  Studies continued on the genus of nematodes (Deladenus) used extensively for control of the pine-killing invasive woodwasp (Sirex noctilio) in the Southern Hemisphere but interest has now turned to native nematode species instead of the strain sold in Australia (D. siricidicola), which does not seem to be very effective against the strains of S. noctilio in North America. In addition, this species is not very host specific and perhaps it would be more environmentally safe to use a native species of Deladenus as different species of Sirex and associated communities are native in North America.  Genetic diversity among geographically diverse samples of this nematode genus were evaluated to help guide potential future explorations for new strains and species to use for control. Species of this nematode genus considered for biological control are dimorphic, with forms that are parasitic and forms that are mycophagous. The fungi they use are the symbiotic mutualists of Sirex. Deladenus are quite easy to grow in the lab as the mycophagous forms. However, under extended lab culture, they can lose the ability to become parasitic, which defeats our purpose for biological control of S. noctilio. The solution is cryopreservation but no method for cryopreservation of Deladenus has ever been published so our laboratory has been developing a method of cryopreservation for species of Deladenus.

Dimorphic species within Deladenus can be very specific regarding the fungi they eat, just as Sirex species are also specific to the fungal mutualists used by larvae as external rumens. It has been hypothesized that for biological control of S. noctilio to be effective, the nematode and woodwasp must use the same fungal species and strains. Our laboratory has been investigating this specificity for a native nematode, Deladenus roximus, to evaluate the potential of this strain for use against S. noctilio, studying choice of fungal strain by juveniles and what fungal strains or normally found associated with this nematode under natural conditions in the US.

Brown marmorated stink bugs (Halyomorpha halys):  The invasive brown marmorated stink bug, Halyomorpha halys, is infected with the chronic microsporidian pathogen Nosema maddoxi, which is native the North America. Our laboratory has been investigating the landscape ecology and seasonality of these infections. The host specificity of this pathogen is being investigated, especially with regard to the potential infection of Podisus maculiventris, a predatory stink bug used for biological control. Our laboratory has also assisted with studies conducted in Georgia (in the Caucasus) investigating the global distribution of this microsporidian species.

In a complementary project collaborating with A. Agnello [Cornell] we identified entomopathogens of BMSB that contribute to crashes of wild populations and laboratory cultures Carrie Preston completed her M.S. degree, working on Nosema maddoxi in brown marmorated stink bugs, Halyomorpha halys, advised by Drs. Hajek and Agnello. One chapter of her thesis was published in the peer-reviewed journal Biological Control. Major findings of this chapter were that N. maddoxi has been found in BMSB in all states where collections were made. N. maddoxi infects males and females equally and infection prevalence in the field ranged from 0-60%. N. maddoxi infections were more abundant in spring and we hypothesize that infection levels increase as the BMSB overwinter in aggregations. The second chapter was published in the Journal of Invertebrate Pathology; this chapter reports results from laboratory bioassays with adult females (using two concentrations for inoculum) and nymphs. The majority of treated H. halys females in the high spore concentration bioassay had high-intensity infections and treated females died significantly faster than controls. Treated nymphs died significantly faster than control nymphs. Of the treated nymphs, >50% died before molting into the fourth instar and only 26% eclosed to adults. Nosema maddoxi infections negatively impacted female fecundity in both adult spore concentration bioassays, causing decreases in the numbers of eggs per egg mass, the total eggs laid and the total egg masses laid. Egg viability was significantly lower in treated females compared with the controls for both adult spore concentration bioassays. Therefore, N. maddoxi infections negatively impact the lifespan of adult females, female fecundity, egg viability, and nymphal survival with great potential to impact H. halys population densities.

Conservation biocontrol through habitat plantings (Amara Dunn, Cornell University)

For existing natural enemies to thrive and assist with pest management, they need food, shelter, and protection from pesticides. Mixed plantings of native wildflowers and grasses that provide diverse plant architecture, continuous blooms from early spring through late fall, and abundant pollen and nectar can provide the food and shelter these natural enemies need. But, there are many ways to establish these plantings, including direct seeding or transplanting small seedlings, and a variety of different weed control strategies. In June 2018, we began establishing plots of native wildflowers and grasses using six different establishment methods. Each method was replicated four times on the edges of a research planting of Christmas trees. Since then, we have kept track of the monetary cost and the time required to install and maintain the habitat using each method. We also collected data on the percent of each plot covered by weeds in Fall 2018, Spring 2019, and Fall 2019. Interestingly, in the second year of establishment, the added time required for weed management in the non-mulched plots meant that over two years all transplanting methods are close to being equally time-intensive.

From May through September 2019, we sampled arthropods from these plots using pan traps, sweep nets, pitfall traps, and Pollard walks, for a total of 23 sampling dates. Data analysis is ongoing, but we are seeing some trends of differences among plots. For example, fewer syrphids were collected from mowed grass control plots and habitat plots with better weed control than from weedy habitat plots. Fewer spiders and harvestmen were collected from mulched habitat plots. Further analysis and additional seasons of data will be needed before conclusions can be drawn.

Outcomes and Impacts: Approximately 187 growers who attended four meetings learned new information about installation and benefits of beneficial insect habitat. We learned more about why they felt they should install beneficial habitat (pollinator protection, environmental stewardship, and pest control) and what the barriers were to doing that (concerns over the amount of time required and the need for more information about how to do this on their farms). There was also an increase in their intent to spend more time installing beneficial habitat, based on pre- and post-meeting surveys.

Evaluation of predators of hemlock woolly adelgid (Adelges tsugae) in Pacific Northwest and southeastern United States [Ryan Crandall, Joe Elkinton, University of Massachusetts.  Collaborators: Carrie Jubb, Scott Salom ,Tom McAvoy,  Virginia Tech;  Albert Mayfield USFS; Mark Whitmore, Cornell University;  Biff Thompson, Maryland Dept of Agriculture]

The Elkinton lab collaborated on an overwintering predator exclusion study of hemlock woolly adelgid, Adelges tsugae (HWA)  (Jubb et al. 2019). The study involved enclosing hemlock branches heavily infested with HWA in mesh bags that kept out the predators and comparing HWA mortality inside the bags with that on paired unbagged branches. The study showed that Laricobius nigrinus, a predatory beetle introduced from the Pacific Northwest now exists in significant numbers in adelgid populations in the southeastern United States and causes significant mortality to HWA ovisacs in late winter. However, a follow-up by Crandall et al (2020) at the same sites showed that populations of HWA rebounded completely the following spring because of density-dependent survival of the spring generation as predicted by an earlier simulation model.  The results suggested that additional biological control agents would be needed to effectively suppress HWA in the eastern United States.

Additional studies by R. Crandall in Washington Park Arboretum in Seattle conducted parallel predator exclusion studies on both eastern and western hemlock trees growing in the Arboretum. The purpose of the study was to explain why HWA remains at very low density throughout the Pacific Northwest on western hemlock. The results were conclusive. HWA performed equally well on the eastern and western hemlock, thus discounting the idea that the latter tree is resistant to HWA infestation. Densities inside the bag on both tree species were 100 fold higher than densities outside the bag proving the significant impact of predators on HWA populations in this region. In particular, the results showed that it was summer-active predators such as silver fly larvae (Leucopis spp) that produced this result. These findings provide strong support for the viability of biological control against HWA in the eastern United States but suggest that more predatory species need to be introduced to achieve that result. As a consequence of this work, the biological control effort in the eastern US now focuses on Leucopis spp.

Cold hardiness of Spathius galinae and Tetrastichus planipennisi, recently introduced parasitoids of emerald ash borer,  Agrilus planipennis. [Jen Chandler, Joe Elkinton, University of Massachusetts and Jian Duan, USDA,ARS]

Duan et al (2019) reported that in late January 2019, northern regions of the United States experienced a severe cold wave caused by a weakened jet stream, destabilizing the Arctic polar vortex.  Approximately three months later at six study sites in southern Michigan and three in southern Connecticut, we sampled the overwintering larvae of the emerald ash borer (EAB, Agrilus planipennis) and two larval parasitoids, Spathius galinae  and Tetrastichus planipennisi,  that are being introduced as EAB biocontrol agents in North America.  At these nine study sites, EAB-infested ash trees and/or saplings were sampled by debarking, and each overwintering EAB and parasitoid larva was examined for cold-induced mortality, as indicated by a brown coloration and limp, watery consistency.  In early spring in Michigan, we found 4.5 – 26% of EAB larvae, 18 – 50% of S. galinae larvae, and 8 – 35% of T. planipennisi larvae were killed by cold.  In Connecticut where temperatures were more moderate than in Michigan during the 2019 cold wave, <2% of the larval hosts and parasitoids died from cold injury.  Our findings revealed that cold mortality of overwintering larvae of EAB and its larval parasitoids varied by location and species, with higher mortality of parasitoid larvae compared to host larvae.

In a follow-up study, Chandler et al. (2020) determined the cold tolerance of Spathius galinae  by measuring the supercooling point (SCP) of mature S. galinae larvae exposed to winter temperatures at four different field locations that span a gradient of plant hardiness zones. We observed a significant effect of overwintering location on SCPs of S. galinae larvae collected from field populations, with lower SCPs observed at locations with lower minimum ambient temperatures. We also tested SCP of three stages (early instar, late instar, and mature cocooned larvae) of lab-reared parasitoids and found that SCP did not significantly differ between stages of lab-reared S. galinae. Our findings provide strong evidence that S. galinae can reduce SCP in response to below-freezing temperatures. The increase in cold hardiness of S. galinae in response to below-freezing temperatures should be considered in delineation of the optimal geographic range for biocontrol releases against EAB in North America.

Determining which plant species most effectively attract and retain ladybugs [John Losey, Leslie Allee, Harsimran Gill, Scott Morris, Rebecca Smyth, Danielle Wolleman, and Antonio DiTommaso]

To determine which plant species might most effectively attract ladybugs and other predators we conducted a series of complementary surveys of ladybug presence and density across plant taxa. The number of ladybugs was measured by surveys carried out one every 4-9 days at two locations on the Cornell University campus (Ithaca, NY, USA) and through evaluations of coccinellid images submitted to the Lost Ladybug Project (www.lostladybug.org).   The sites on the Cornell University campus were the Soil and Crop Sciences Weed Science Teaching Garden and the Robison Herb Garden, which is part of the Cornell Botanic Gardens.  Both of these areas feature a collection of plant species across multiple families and are managed without the use of pesticides so they afford a unique opportunity to assess the preferences of beneficial insects in a “common garden” setting.  While ladybugs were observed on plants from over 100 families, significantly more ladybugs were observed on three plant families Asteraceae, Apiaceae, and Rosaceae.  This work was completed in conjunction with a Department of Energy project (InSight II) that seeks to develop strategies to increase the value of ecological services (e.g. predation and pollination) from the area around solar production facilities.

Biological control of tree of heaven: Large scale deployment and enhanced formulation of the regionally successful Verticillium biocontrol of the invasive Ailanthus altissima  (Scott Salom, Anton Baudoin,  and Rachel Brooks, VA Tech and Matt Kasson and Kristen Wickert, WVU)

Tree-of-heaven (TOH, Ailanthus altissima) is an entrenched invasive woody tree species that occurs in >40 U.S. states, primarily as an urban and roadside weed and is especially abundant in the Mid-Atlantic United States where it has persisted for ca. 200 years.  Starting in the early 2000’s, widespread dieback and mortality of TOH was observed throughout PA, VA, and OH. More recently, similar mortality was reported from TOH in Europe. The causal agent, Verticillium nonalfalfae (Vn), a naturally occurring vascular wilt pathogen being evaluated as a biological control agent for TOH.  Our objectives are to: Increase our understanding of variability of responses of TOH to V. nonalfalfae in PA and VA in efficacy trials.  Additionally, we were interested in assessing the interaction of V. nonalfalfae with the less virulent V. dahlia

To help answer these questions, a three-year field inoculation study including 3,245 A. altissima trees in 13 sites across four hardiness zones of Pennsylvania and Virginia, U.S. was implemented. Disease progressed and spread at similar rates in A. altissima trees co-inoculated with V. nonalfalfae and V. dahliae as those inoculated with V. nonalfalfae alone, with no indication of disease progression changing in co-inoculated trees. Verticillium dahliae alone resulted in lower levels of disease, and no disease spread. Similar results were seen in a supplemental greenhouse inoculation study. Despite slight regional variation of disease progression and spread correlated to climate or stand variables, V. nonalfalfae always caused severe disease and spread rapidly to other A. altissima trees through the forested plots. Our results support the use of V. nonalfalfae as a biological control agent throughout the mid-Atlantic region of the U.S. regardless of stand and climate variables, and including sites where trees are already infected with V. dahliae.

Biological studies associated with Laricobius beetles (Scott Salom and Jeremiah Foley IV, VA Tech)

Spread of  L. nigrinus beetles into urban environments where hemlocks represent a sizeable portion of landscape trees.   A survey was done in two towns in S.W Virginia: Radford and Blacksburg.  No beetles had been directly released in either town previously. Surveys were divided into 0.40 km² grids. A total of 27 and 19 grids were randomly selected from each town, respectively. Hemlocks were present in 44 and 42% of the grids surveyed in Blacksburg and Radford, respectively. In Blacksburg and Radford, 86 and 100% of the grids with hemlocks were infested with HWA, and of those infested hemlocks, Laricobius spp. was present in 100 and 75% of grids, respectively. A total 154 Laricobius spp. (98% L. nigrinus and 2% L. rubidus) adults were collected from Blacksburg and Radford. This is the first documentation of L. nigrinus in the urban environment in the eastern United States where beetles have not been intentionally released. During the initial scouting for biological control agents of HWA in the Pacific Northwest, a common, reliable, and convenient location to collect L. nigrinus is in the urban environment which includes neighborhoods, parks, and cemeteries. The relatively high rates of recovery suggest that L. nigrinus can successfully establish in the urban environment within its newly introduced range. This supports our hypothesis that once released, L. nigrinus can disperse, locate its prey, and establish in environments outside of the forest setting. Following emergence, L. nigrinus likely use a combination of olfactory cues, visual cues, and semiochemicals from infested trees to locate its prey.

Assessment of soil site characteristics on success of establishment of the biological control agents Laricobius spp. (Coleoptera: Derodontidae)  Laricobius beetles drop to the soil in the spring, pupate, eclose into the adult stage and then go dormant till October.  No one knows much about their life in the soil including survivorship.  An experiment was set up to drop larvae into soil in modified PVC tubes and monitor emergence by time and compare among different soil types.  After the first season ca. 20% of the larvae dropped in the soil emerged.   This compares with ca 30% survival in the lab.  A second year of data are being collected.

Identification and description of the fungal gut community of Laricobius nigrinus (Coleoptera: Derodontidae)  Laricobius beetles are adelgid specific predators. All derodontid species are fungus feeders. We are assessing if Laricobius beetles acquire fungi during different ties in their life cycle and perhaps use fungi as a supplemental source of food.  In the first year of the study, numerous fungal species were found in the L. nigrinus guts and the composition of these fungal species differed in subterranean vs arboreal portions of their life

OBJECTIVE 2:  Augmentation programs involving repeated rearing and release: to release and evaluate augmentative biological control agents

Development and augmentation products and strategies to control Asian longhorned beetle and spotted lanternfly (Ann Hajek, Cornell)

Anoplophora glabripennis (Asian longhorned beetle):  Investigations continued toward development of a biopesticide, based on Metarhizium brunneum F52 microsclerotia, for control of Asian longhorned beetles, Anoplophora glabripennis. Studies focused on the efficacy of changing the microsclerotia:clay ratios and on application methodologies.

Lycorma delicatula (Spotted lanternfly):  As Beauveria bassiana was found naturally infecting spotted lanternflies at a majority of locations sampled in southeastern Pennsylvania, in 2018 and 2019 a field trial was conducted applying a commercially available strain of B. bassiana (BoteGHA). High levels of infection of adults were found with little non-target impact.

OBJECTIVE 3:  Introduction of new natural enemies against invasive plants

Classical biological control of mile-a-minute weed (Persicaria perfoliata) (E. Lake, USDA-ARS Invasive Plant Research Laboratory and L. Tewksbury, Univ. of Rhode Island)

Present efforts on mile-a-minute weed biological control focus on continued release of the weevil Rhinoncomimus latipes (Coleoptera: Curculionidae) in mile-a-minute populations that have not yet been colonized, evaluation of impact on the target weed and associated plant communities under different environmental conditions, and development of integrated weed management strategies incorporating the weevil. The New Jersey Philip Alampi lab continues to rear R. latipes weevils and provide them to cooperators in the northeast. The Maryland Department of Agriculture is also rearing the weevil; it was previously reared at the Universities of Rhode Island and Delaware. We estimate that the 1 millionth weevil reared through these efforts will be released in 2020.

Key take home messages for land managers based on research conducted to date include:

• A portion of green mile-a-minute weed seed is viable. Thus, waiting until blue fruit is present to initiate management techniques will decrease efficacy and extend the seed bank, which can persist for up to six years.
• Mile-a-minute weed will produce more seed in the sun versus the shade and weevils will be more effective at controlling the weed in sunny habitats.
• Weevils are unlikely to colonize mile-a-minute patches in forest canopy gaps.
• A cool, wet spring can decrease weevil reproduction and efficacy throughout the growing season. The resulting increase in mile-a-minute growth and reproduction could supplement the seed bank.
• Integrating the weevil with herbicide applications and/or native plantings can reduce mile-a-minute weed growth and reproduction and increase the diversity and abundance of native plants. However, site specific adaptive management techniques may be necessary.

Classical biological control of swallow-worts (Vincetoxicum spp.) (L. Tewksbury, University of Rhode Island, L. Milbrath, USDA ARS, R. Bourchier, Agri-Food Canada, M. Szucs, Michigan State, D. Parry, Syracuse University, A. Villiard, Philip Alampi Lab in new Jersey.

The first releases of Hypena opulenta for biocontrol of Vincetoxicum spp. In North America were made in Canada in 2014 and in the United States in 2017.  Current research involves evaluating field releases and determining optimum release timing and conditions.  Establishment has been documented in Canada and overwintering has occurred in the US.  This has been a colloborative effort with several researchers involved.  In 2019 the Philip Alampi Lab in New Jersey began rearing H. opulenta with the intention of providing them for future releases, once release and monitoring protocols were established.

Classical biological control of Japanese knotweed (Fallonia japonica) using Aphalara itadori. (F. Grevstad, Oregon State University, L. Tewksbury, Univeristy of Rhode Island, J. Elkinton, University of Massachusetts, B. Blossey, Cynthia Detweiler, New Jersey State Department of Agriculture.)

The first US releases of Aphalara itadori for management of Japanese knotweed were made in 2020.  This is an experimental phase of the release, coordinated by Fritizi Grevstad of Oregon State University.  Releases were made in the northwest, as well as in North Carolina, West Virginia, New Jersey, New York, Rhode Island, and Massachusetts.  Releases began in June and monitoring continued through September.  Monitoring data is going to be evaluated over the winter.

OBJECTIVE 4:  Introduction of new natural enemies against invasive insects

Successful biological control of winter moth in the northeastern United States

[Joe Elkinton, George Boettner, Hannah Broadley. University of Massachusetts]

Winter moth, Operophtera brumata, (Lepidoptera: Geometridae) native to Europe, invaded the northeastern United States in the late 1990s, where it caused widespread defoliation of forests and shade trees ranging from 2,266 to 36,360 ha per year between 2003 and 2015 in Massachusetts. In 2005, we initiated a biological control effort based on the specialist tachinid parasitoid Cyzenis albicans, which had previously been introduced along with the generalist ichneumonid parasitoid Agrypon flaveolatum to control winter moth in Nova Scotia in the 1950s and British Columbia in the 1970s. Due to concerns of possible non-target impacts by A. flaveolatum, we focused entirely on the specialist C. albicans. Each year for 14 years, we collected several thousand individuals of C. albicans from British Columbia and released them across widely-spaced sites in the northeastern United States. As of 2020, we had established C. albicans at 41 of 44 sites from coastal Maine to southeastern Connecticut. By 2016 winter moth densities (pupae/m²) had declined at least 10-fold at six widely spaced release sites and was coincident with the onset of 10-40% parasitism. At one site, this decline occurred in 2012 and winter moth densities have remained low for seven subsequent years. Defoliation in Massachusetts has been reduced to undetectable levels since 2016. DNA sequencing of the barcoding region of the mitochondrial gene CO1 confirmed that all C. albicans reared from winter moth matched the C. albicans collected from Vancouver Island and were distinct from parasitic flies (presumably a native species) reared from a native congener of winter moth, Bruce spanworm (O. bruceata). Our work represents a rare, if not the only, example of the biological control of a major forest defoliator that attacks a wide range of tree species anywhere in the world by the establishment of a single specialist natural enemy, but it builds upon the earlier work in Canada.

Meanwhile, Hannah Broadley completed her dissertation (Broadley 2018) that focused on the impact native natural enemies on winter moth as a complement to the released biological control agent. She discovered a previously undescribed pupal parasitoid (Broadley et al 2019) and measured the impact of predation on the pupal stage. Winter moth persists as pupae in the soil surface from late May through early November and is subject to high rates of pupal predation. Previous work by Roland in Canada analyzing the earlier biological control success in Nova Scotia in the 1950s and Victoria BC in the 1980s showed that parasitism by C. albicans induced an increase in predation rates on winter moth pupae, both in Nova Scotia and British Columbia. He argued that pupal predation was more responsible for the decline of winter moth densities following onset of parasitism than was parasitism itself. Data collected by Broadley (2018), however, show that predation rates on deployed pupae have not increased at our sites since 2005 and, in fact, there were slightly lower predation rates on pupae in plots where C. albicans had established compared to those where it was not established (Broadley 2018). Pupal predation did become density dependent after C. albicans establishment, and thus may serve to stabilize winter moth populations at low density, as Roland found in his analysis of winter moth populations following establishment of C. albicans in Canada.

Establishment of the parasitoid  Spathius galinae  in New England and studies of its biology and spread [Jian Duan. USDA, ARS. Joe Elkinotn Jen Chandler, Ryan Crandall, Roy van Driesche, University of Massachusetts; Juli Gould, Theresa Murphy USDA APHIS; Claire Rutledge, Conn. Ag Station]

The emerald ash borer (EAB), Agrilus planipennis, a buprestid beetle native to Asia, has become a serious pest of ash trees (Fraxinus spp.) in North America since the early 2000s. In this study (Duan et al 2019), we reported the first evidence for the establishment and impact of Spathius galinae,  a braconid larval  parasitoid native to the Russian Far East.  It was first released in North America in 2016 and 2017 at six mixed-hardwood forest sites, in Connecticut, New York, and Massachusetts. We also report current levels of abundance and parasitism of another introduced larval EAB parasitoid, Tetrastichus planipennisi  (Hymenoptera: Eulophidae), released in 2015 and 2016 in these same sites. Spathius galinae was recovered at all release sites in 2018, and its density in sampled trees had increased 1.5- to 20-fold (relative to the first postrelease sample year), reaching a final density of 2.3–14.3 broods/m2 of phloem area and causing 13.1–49.2% marginal rate of parasitism at four of the six sites. In contrast, T. planipennisi was only recovered in 2018 at four of the six release sites, and both its density (0.1–2.3 broods/m2 of phloem area) and parasitism (0.1–5.6%) were lower than that of S. galinae throughout the study at the four sites where recoveries were made. Our data fill a critical gap in the development of a biocontrol-based EAB management plan to protect surviving ash trees capable of reaching maturity and producing replacement trees.

Impact assessment of Laricobius nigrinus (Coleoptera: Derodontidae), a predator of hemlock woolly adelgid (Scott Salom, Virginia Tech and Joe Elkinton, Univ. Massachusetts)

Laricobius nigrinus (Coleoptera: Derodontidae) is a predator of hemlock woolly adelgid (HWA), Adelges tsugae (Hemiptera: Adelgidae). We are currently trying to control HWA through several different methods including through the use of predators such as L. nigrinus. Releases of this predator began in 2003, now since over a decade has passed since these initial releases, it has allowed for sufficient time for Ln to establish at these field sites and to assess their efficacy as a predator.

We set up nine field sites in six different states, from far north as New Jersey and as far south as Georgia.  This spans plant hardiness zones 6a – 7a. The field sites were chosen based on high densities of HWA, recovery of Ln, and Ln releases at least four years prior to the start of the study.  Exclusion cages studies were set up to assess the impact Ln was having on sistens and their progrediens eggs.  Population models for HWA have suggested that even upwards of 90% predation on eggs laid by the overwintering sistens generation will have minimal effect in reducing the population densities of HWA, if HWA are at high density. In this study, we tested the ability of L. nigrinus to reduce HWA densities, and experimentally tested these model predictions to better understand what impact, if any, L. nigrinus has on HWA densities.

Previously Reported Results 2014-2018: Significantly more HWA sistens ovisacs were disturbed on no-cage and open-cage branches than on caged branches where predators were excluded. Mean disturbance levels on cage, no-cage and open-cage branches was 8, 38, and 27 percent, respectively. Seven of nine sites had a mean HWA ovisac disturbance greater than 50% for at least one year. Winter temperatures were also a significant factor in overall mortality of the sistens generation with a mean of 46% on study branches. Six of nine sites had a mean overall mortality (winter mortality and predation) greater than 80% for at least one year. Larvae of Laricobius spp. were recovered at all sites during this study. Sequencing of the COI gene from recoveries in Phase One (2015 and 2016) indicated that 88% were L. nigrinus and 12% were L. rubidus LeConte. Microsatellite analysis performed during Phase Two (2017 and 2018) indicated that approximately 97% of larval recoveries were L. nigrinus, 2% were hybrids of L. nigrinus and L. rubidus, and 1% were L. rubidus.

2018-19 Results

In both years, we found that despite high rates (greater than 80% ovisac predation) of predation by L. nigrinus on uncaged branches compared to caged branches, there were no significant differences in subsequent densities of the HWA spring generation between caged and uncaged treatments, as predicted by our model.

Determine distribution/range expansion of adventive Trissolcus japonicus in the US [P.

Jentsch, A. Agnello, Cornell University]  Sentinel brown marmorated stink bug (BMSB, Halyomorpha halys Stål) egg masses continued to be placed in host trees adjacent to pheromone trap sites in multiple locations in the Lake Ontario and Hudson Valley apple regions, to assess the presence of adventive populations of T. japonicus or any naturally occurring egg parasitoid species in locations near apple orchards where BMSB occurrence had been documented.  Alpha Scents sticky cards were placed along the orchard perimeter to determine the presence and establishment of T. japonicus from 2018 re-distribution sites in 14-day intervals. Recent finds of T. japonicus in Hudson Valley locations suggest expansion of its range and overwintering establishment in re-distribution locations. Continued redistribution into both urban and agricultural sites followed by monitoring with alpha Scents sticky cards is ongoing in 2020.

To determine and expand the distribution of adventive samurai wasp (Trissolcus japonicus) for biological control of brown marmorated stink bug in NY (George Hamilton, Rutgers University)

To determine the distribution of adventive Trissolcus japonicus in central and northern NJ, yellow sticky cards were deployed at the interface between woods and either tree fruit, vegetable or field crops at 12 locations. Each week, from the beginning of June to the middle of October, all traps were removed and replaced on a weekly basis, taken to laboratory, and evaluated for the presence of T. japonicus adults. Possible candidates were removed from the sticky cards and will be sent to Elijah Talamas for species confirmation. In addition, BMSB egg masses, deployed at the interface between woods and either tree fruit, vegetable or field crops at 3 locations in 2018 and 4 locations in 2019. In 2019 the egg masses were deployed once in July and will be deployed once in September. Once deployed the egg masses will be removed after 24 hours and taken to the laboratory to await parasitoid emergence. Once emerged, specimens will be identified and representative Trissolcus specimens will be sent to Elijah Talamas for species confirmation. When possible, remaining individuals have been used to create a several colonies. In July, one egg mass collected from a location in Hunterdon County, NJ was positive for Trissolcus japonicus. Additional positive egg masses were collected from a location in Mercer County. A colony has been created from each positive egg mass.

Development of classical biological control methods against spotted lanternfly (Lycorma delicatula White) (Juli Gould and Hannah Broadley, USDA APHIS; Kim Hoelmer USDA ARS; Charles Bartlett, University of Delaware; Lisa Tewksbury, Univerisity of Rhode Island).

Relevance: Eradication and containment of the spotted lanternfly (SLF) has been considerably challenging, and this devastating exotic pest has now spread. To support the SLF program and current management strategies, we are pursuing biological control.

Response:  USDA scientists, Drs. Juli Gould and Kim Hoelmer, have been collaborating with researchers at the Chinese Academy of Forestry since 2015 to search for natural enemies of SLF throughout China, the native range of SLF.  Hannah Broadley joined the team in 2018. 

Results: To date, we have recovered two potential biocontrol agents from China; these parasitoids are the egg parasitoid Anastatus orientalis and the nymphal parasitoid Dryinus sinicus. We have made substantial progress with A. orientalis in understanding its life cycle, general biology, rearing conditions, and host range, but further research is necessary in both the native range and in the lab to complete these studies.  In the first two years of testing, we have found that A. orientalis is able to parasitize nine of the 18 species we have started testing in no-choice tests; these included parasitism in a variety of non-target families including planthoppers, stink bugs, squash bugs, and silkmoths.  We are moving on to choice tests and behavioral assays for these non-target species.  In 2018 and 2019 we collected Dryinus individuals and brought them to quarantine in the U.S. and have started a colony but rearing has proved difficult. Developing a rearing technique is the critical next step and research on the biology, genetics, and host specificity testing of D. sinicus is proposed.  We will continue the development of biological control methods for the management of spotted lanternfly by furthering exploration in China for natural enemies, initiating exploration for natural enemies in Vietnam, developing a collaboration in South Korea to study the role of A. orientalis on the SLF populations there, initiating collections of resident and native parasitoids in Pennsylvania and the surrounding area that can attack SLF; developing a rearing protocol for D. sinicus, and conducting research to better understand the life cycle, genetics, and biology A. orientalis and D. sinicus;and testing the host range of A. orientalis and and D. sinicus.

Determining the distribution and natural enemy complex of the roseau cane scale in Asia: research toward developing a classical biological control methods against roseau cane scale (Nipponaclerda biwakoensis Kuwana) (Hannah Broadley and Juli Gould, USDA APHIS; Kim Hoelmer USDA ARS; Rodrigo Diaz, Louisiana State University, AgCenter).

Relevance: Roseau cane is considered a critial species in wetland areas of the lower Mississippi Delta, Louisiana, where it holds together the marsh infastructure and prevents erosion. Recently, there has been widespread dieback and thinning of the stands in the Delta, coinciding with heavy populations of an invasive scale insect, the roseau cane scale (RCS), Nipponaclerda biwakoensis, which feeds on the stems. This project’s overarching goal is to find safe management options for RCS in Louisiana using biological control. Prior research shows that natural enemies suppress populations of RCS in their native range. At least six different species of parasitic wasps have been documented attacking RCS in China and Japan. Three of these wasps, Astymachus japonicus, Neastymachus japonicus, and Boucekiella depressa, have been found parasitizing the scale in Louisiana, but populations there remain at outbreak levels with as many as 2,000 scales per stem; additional mortality factors are needed to reduce population growth rate. 

Response:  Our research team, a partnership of ten institutions across five states and five countries, has started surveying for and evaluating natural enemies of RCS in its native range across Asia, focusing on the role and identity of parasitoids. We are evaluating scale density, host plant health, and parasitism rates across the growing season at 28 sites in six countries using a standardized protocol. We are comparing these results to data collected from parallel surveys in Louisiana to determine which parasitoids not already present in Louisiana may be promising biological control agents.

Results: In FY2019 and FY2020 (to date) we made substantial progress.  We recruited cooperators in Japan, Korea, Taiwan, China, and Vietnam and are completing our second year of sampling on host plant health, scale density, and the associated parasitoid community across the season, countries, and sites.  We have recovered an Aprostocetus sp. and two additional unidentified species of encyrtid wasps that are of interest for further study and expanded the known distribution of RCS to include Taiwan, Vietnam, and additional locations in Korea and China.  We are analyzing the scale population genetics and the host plants genetics.  Further, we developed a Phragmites propagation technique, commenced environmental niche modeling of the scale, and are developing a protocol for rearing RCS in our insect quarantine lab. Next year, we plan to complete this work and start rearing the scale and also analyzing population dynamics of scale populations in their native versus introduced range.  

Exploration, introduction, and evaluation of establishment of hemlock woolly adelgid predators in New York State (Mark Whitmore, Nick Dietschler, Tonya Bittner, Cornell University) 

We have been exploring for predators of hemlock woolly adelgid (HWA), Adelges tsugae (Hemiptera: Adelgidae) in the Pacific Northwest (PNW) since 2012. A strain of HWA is native to the PNW, feeding on western hemlock, Tsuga heterophylla, and a number of specific predators have been identified. The most abundant are Laricobius nigrinus (Coleoptera: Derodontidae), Leucopis argenticollis (Diptera: Chamaemyiidae), and Leucopis piniperda. We have been collecting hemlock foliage infested with HWA from the PNW and transporting it to the Sarkaria Arthropod Research Laboratory (SARL) quarantine facility at Cornell University in Ithaca, NY, where we rear predators to adults for experimental use and release. Over a hundred potential collection sites were identified and surveyed, and foliage from 24 sites was collected, packaged, and mailed to the SARL quarantine facility. We have previously released La. nigrinus at 17 sites across the state and have confirmed establishment and spread at 6 of them. In 2019 we released 2948 adult La. nigrinus at 3 additional sites. We continue to evaluate establishment using beatsheet sampling in fall and foliar sampling in spring.

We made our first releases of 253 adult Leucopis spp. at three sites in 2015. We increased collections and made releases of 2406 adults at 11 additional sites in 2017 and 2018. In 2019 we released 6633 adult Leucopis spp. at 8 sites, 4 of which were augmentative releases. Many of the releases in 2017 and 2018 were in mesh bags so we could evaluate reproductive success, and indeed, in 85% of the bags F1 generations were produced.  Subsequent foliage sampling has yet to find established Leucopis spp. surviving through the winter. 

Investigate the potential for lab rearing hemlock woolly adelgid predators in the laboratory (Mark Whitmore, Nick Dietschler, Tonya Bittner, Isis Caetano, Cornell University)

Our lab has been wild collecting hemlock woolly adelgid (HWA), Adelges tsugae (Hemiptera: Adelgidae) in the Pacific Northwest (PNW) and we were interested in developing cost effective techniques to lab rear two species in the most common genus, Leucopis spp., for experimental  work and eventual release on the east coast. We conducted preliminary studies rearing field collected Le. piniperda to adults and exposing them eastern HWA with eggs. We found Le. piniperda to be fecund, laying over 100 eggs per female adult and followed their development through to adults. Peak egg laying was during the second and third weeks post after pupal eclosion and continued at a diminished rate for up to 7 weeks. Offspring took an average of 119 days (SD: 16.43) with a range of 77–147 days to complete development from egg to adult at temperatures of 17 C day and 15 C night. 124 pupae from this work was used in Objective 3.

Investigate the potential for lab reared Leucopis piniperda, a hemlock woolly adelgid predator, to overwinter in New York State (Mark Whitmore, Nick Dietschler, Tonya Bittner, Cornell University)

As a result of our lab experiments with Leucopis spp. we have determined they most successfully overwintering as pupae. Since we have been unsuccessful at capturing F1 progeny from our field releases we decided to use lab reared Le. piniperda pupae in a field experiment to evaluate overwintering success. We used two field sites for this experiment, one in a warm site in the southern Hudson Valley (Plant Hardiness Zone  6b) and another in a much colder location just north of Ithaca, NY (PHZ 5b). The PHZ at point of origin for the parental predators in the Pacific Northwest was 8a. We devised a shelter for the pupae that kept them away from direct exposure to weather and deployed the same shelter at both locations. We placed 36 pupae in each of the shelters beginning in October 2019 and evaluated eclosion in April 2020. Pupal emergence in spring was strong with 89% of the pupae surviving in the colder location and interestingly only 68% emergence in the warmer location. We plan further experiments in 2020 to better understand this pattern.

OBJECTIVE 5. Conduct research to understand and enhance the effectiveness of biocontrol systems.

Development of organically approved dry, seed coating formulations of EPF (Alan Taylor [PI] and Kyle Wickings [Co-PI])

Research was conducted at Cornell AgriTech in Taylor’s lab on the development of seed treatments for the application of biological seed treatments on field crops: soybean, wheat, corn, and turf grass seeds: Kentucky bluegrass and tall fescue.  Two beneficial Entomopathogenic fungi (EPF): Metarhizium robertsii and Beauveria bassiana will be studied, and both EPF have unique sensitivity to extremes in moisture, as hydration/dehydration is lethal to their survival.  Most commercial seed treatment and coating technologies require water to apply biological formulations followed by drying for safe seed storage.  Therefore, the development of a dry seed coating process is being pursued.  This dry seed coating technique is termed a planter box method and is used commercially for the application of Rhizobia inoculant to legume seeds for nitrogen fixation.  Another advantage of a planter box method is that the seeds can be treated ‘on farm’ just prior to planting so shelf life of the biological is not a problem.  Selected solid particulates used for commercial seed pelleting and other seed treatment applications were obtained, and these solid particulates are generally fine powdered mineral materials such as bentonite clay, and they may be organically approved.  Therefore, the larger goal is to develop organically approved dry, seed coating formulations of EPF.

The specific sub-objectives of the research conducted in year 1 were to perform preliminary studies on the Entomopathogenic fungi (EPF), Metarhizium robertsii provided by the industry collaborator Lidochem. Metarhizium was mixed with selected solid particulates used in seed pelleting, and applied as a dry powder, seed treatment.  Water activity instruments in Dr. Taylor’s Seed Science and Technology Lab at Cornell AgriTech were used to accurately measure the water activity of small amounts of solid particulate mixtures with EPF as low moisture content is critical to maintain the viability of EPF. The solid particulate dry powder mixture including EPF must adhere onto seeds.  To examine the adherence and uniformity of solid particulate application, fluorescent tracers were added to the solid particulate mixture and viewed under long UV light.  Empirical research is ongoing to test different solid particulate mixtures with low moisture content on seed adherence.  CFU’s will be tested from selected solid particulates mixtures with EPF.

The potential for interference between successful arthropod and weed biological control programs (E. Lake, USDA-ARS Invasive Plant Research Laboratory and L. Tewksbury, Univ. of Rhode Island)

This collaborative project between the USDA ARS and University of Rhode Island investigated the potential for biotic interference between biological control programs using Lilioceris spp. as a case study. Lilioceris lilii (Coleoptera: Chrysomelidae), lily leaf beetle, was introduced to Canada in 1943 and Massachusetts in 1992. This beetle is a pest of cultivated and native North American lilies and Fritillaria spp., including several threatened or endangered species. After host range testing, three parasitoids were approved for release of L. lilii, which at that time was the only representative of the genus Lilioceris present in North America. Releases began in 1999 and the parasitoids have subsequently established and are limiting the impact of lily leaf beetle in some areas. However, lily leaf beetle continues to expand its range to the south, the known current southern limit is West Virginia. It is also spreading west and jumping some states, and is currently reported in Minnesota, Iowa, Michigan, Wisconsin, and Washington state.

Dioscorea bulbifera, air potato, is a perennial vine that has invaded Florida and parts of the southeastern U.S. and Hawaii. Air potato vines can grow more than 20m long, smothering native vegetation and altering community structure and function. The USDA ARS biological control program targeting air potato began after releases of the L. lilii parasitoids had commenced. Following host-range testing, a permit for release of the leaf-feeding beetle L. cheni was issued. Releases began in Florida in 2011 and the beetle is currently also being released in the southeastern U.S. Lilioceris cheni effectively controls air potato in many regions.

As populations of L. lilii expand their range to the south and those of L. cheni move north, there is potential for conflict between these successful biological control programs. Specifically, if the parasitoids could attack L. cheni, its efficacy could be reduced, and if the parasitoids preferred L. cheni, control of L. lilii could be disrupted. We conducted a series of choice and no choice laboratory tests with the three parasitoid species and larvae of L. lilii and L. cheni. During choice tests, the parasitoids preferred their target host, L. lilii. We did not detect successful parasitism of L. cheni.

Similar research with the parasitoids and L. egena, which has been recommended for release against air potato, is ongoing. The likelihood of interference between weed and arthropod biological control programs is low; however, as new agents are developed, biological control practitioners should be aware of the potential for interference.

Andersen JC, Van Driesche RG, Crandall RS, Griffin BP, Elkinton JS, Soper AS. In Review. Successful biological control of the ambermarked birch leafminer, Profenusa thomsoni (Hymenoptera: Tenthredinidae), in Anchorage, Alaska: status 15 years after release of Lathrolestes thomsoni (Hymenoptera: Ichneumonidae). Biological Control.

Bittner, T.D., Havill, N., Caetano, I.A.L., Hajek, A.E. 2019. Efficacy of Kamona strain Deladenus siricidicola nematodes for biological control of Sirex noctilio in North America and hybridization with wild-type conspecifics. Neobiota 44: 39-55. DOI:  10.3897/neobiota.44.30402 

Bourchier R.S, N. Cappuccino, A. Rochette, J. des Rivieres, S.M. Smith, L. Tewksbury, R.

Casagrande. 2019. Establishment of Hypena opulenta (Lepidoptera:Erebidae) on      Vincetoxicum rossicum in Ontario, Canada. Biocontrol Science and Technology. 29(9):917-923.

Broadley, H. J. 2018. Impact of native natural enemies on populations of the invasive winter moth, (Operophtera brumata L) in the northeast United States. Ph.D. dissertation, University of Massachusetts Amherst, Amherst, MA.

Broadley H, Kula RR, Boettner GH, Andersen JC, Griffin BP, Elkinton JS. 2019. Recruitment of native parasitic wasps to populations of the invasive winter moth in the Northeastern United States. Biological Invasions. 9:2871–2890. https://doi.org/10.1007/s10530-019-02019-4

Brooks, R. K., A. L. Snyder, E. Bush, S. M. Salom, and A. Baudoin.  2020.  First report of Verticillium wilt caused by Verticillium dahliae impacting Ailanthus altissima (tree of heaven) in Virginia, US.  Plant Disease.  104 (5): 1558.  https://doi.org/10.1094/PDIS-10-19-2064-PDN

Brooks, Rachel, Kristen Wickert, Antonius Baudoin, Matthew Kasson, and Scott Salom.  2020. Field-inoculated Ailanthus altissima stands reveal the biological control potential of Verticillium nonalfalfae in the Mid-Atlantic region of the United States. Biological Control. 148: 104298  https://doi.org/10.1016/j.biocontrol.2020.104298

Chandler, JL, Elkinton, JS, Duan, JJ,  2020. Cold hardiness in Spathius galinae (Hymenoptera: Braconidae), a larval parasitoid introduced for biocontrol of emerald ash borer in North America. Biological Control. https://doi.org/10.1016/j.biocontrol.2020.104343.

Clifton, E.H., Castrillo, L.A., Gryganskyi, A., Hajek, A.E. 2019. A pair of native fungal pathogens drives decline of a new invasive herbivore. Proc. Natl. Acad. Sci. USA 116 (19): 9178-9180. https://doi.org/10.1073/pnas.1903579116. (+ cover). 

Clifton, E.H., Cortell, J., Ye, L., Rachman, T.W., Hajek, A.E. 2019. Impacts of Metarhizium brunneum F52 infection on the flight performance of Asian longhorned beetles, Anoplophora glabripennis. PLoS ONE 14(9): e0221997. https://doi.org/10.1371/journal.pone.0221997

Clifton, E.H., Gardescu, S., Behle, R.W., Hajek, A.E. 2019. Asian longhorned beetle bioassays to evaluate formulation and dose response effects of Metarhizium microsclerotia. J. Invertebr. Pathol. 163: 64-66.

Clifton, E., Hajek, A.E., Jenkins, N.E., Roush, R.T., Rost, J.P., Biddinger, D.J.  2020. Applications of Beauveria bassiana (Hypocreales: Cordycipitaceae) to control populations of spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), in semi-natural landscapes and on grapevines. Environ. Entomol. (in press).

Clifton, E.H., Jaronski, S.T., Hajek, A.E. 2020. Virulence of commercialized fungal entomopathogens against Asian longhorned beetle, Anoplophora glabripennis. J. Ins. Sci. 20(2): (online).

Crandall, Ryan S., Carrie S. Jubb, Albert E. Mayfield III, Biff Thompson, Thomas J. McAvoy, Scott M. Salom, and Joseph S. Elkinton. 2020. Rebound of Adelges tsugae spring generation following predation on overwintering generation ovisacs by the introduced predator Laricobius nigrinus in the eastern United States.  Biological Control.  145:   104264.  https://doi.org/10.1016/j.biocontrol.2020.104264

Duan, JJ, Bauer, LS, Van Driesche, R, Schmude, JM, Petrice, T, Chandler, JL, Elkinton, J, 2020. Effects of extreme low winter temperatures on the overwintering survival of the introduced larval parasitoids Spathius galinae and Tetrastichus planipennisi: implications for biological control of emerald ash borer in North America. Journal of Economic Entomology, 113: 1145–1151.

Duan, JJ., Van Driesche, RG., Crandall, RS., Schmude, JM., Rutledge, CE., Slager, BH., Gould, JR. Elkinton, JS., 2019. Establishment and Early Impact of Spathius galinae (Hymenoptera: Braconidae) on Emerald Ash Borer (Coleoptera: Buprestidae) in the Northeastern United States. Journal of Economic Entomology.  112: 2121-2130.

Elkinton, J.S., Bittner, T.D., Pasquarella, V.J., Boettner, G.H., Liebhold, A.M., Gould, J.R., Faubert, H., Tewksbury, L., Broadley, H.J., Havill, N.P., Hajek, A.E. 2019. Relating aerial deposition of Entomophaga maimaiga conidia to mortality of gypsy moth (Lepidoptera: Erebidae) larvae and nearby defoliation. Environ. Entomol. 48: 1214-1222.

Foley, J. R., McAvoy, T. J., Dorman, S., Bekelja, K., Kring, T. J., & Salom, S. M. 2019. Establishment and distribution of Laricobius spp.(Coleoptera: Derodontidae), a predator of hemlock woolly adelgid, within the urban environment in two localities in southwest Virginia. Journal of Integrated Pest Management, 10(1), 30.

Hajek, A.E. 2020. Beneficial Insects by David V. Alford (book review). Quarterly Review of Biology 95: 69-70.

Jubb, Carrie S.  Ariel Heminger, Albert E. Mayfield III, Joseph Elkinton, Gregory J. Wiggins, Jerome F. Grant, Jeff Lombardo, Thomas McAvoy, Ryan Crandall and Scott Salom.  2020.^.  Impact of the biological control agent, Laricobius nigrinus, on hemlock woolly adelgid sistens generation and their ovisacs in the eastern United States. Biological Control. 143: 104180.  https://doi.org/10.1016/j.biocontrol.2019.104180

Kereselidze, M., Pilarska, D., Linde, A., Sanscrainte, N.D., Hajek, A.E. 2020. Nosema maddoxi infecting the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), in the Republic of Georgia. Biocontr. Sci. Technol. (in press).

Lake, E.C., L. Tewksbury, M.C. Smith, F.A. Dray, Jr., A. Russell, P.T. Madeira, M.B. Rayamajhi, and R.A. Casagrande. 2020. Potential for negative interactions between successful arthropod and weed biological control programs: a case study with Lilioceris species. Biological Control. 144: https://doi.org/10.1016/j.biocontrol.2020.104218

Ludwick D., Morrison III, W.R., Acebes-Doria, A.L., Agnello A.M., Bergh, J.C., Buffington, M.L., Hamilton, G.C., Harper, J.K., Hoelmer, K.A., Krawczyk, G., Kuhar, T.P., Pfeiffer, D.G., Nielsen, A.L., Rice, K.B., Rodriguez-Saona, C., Shearer, P.W., Shrewsbury P.M., Talamas E.J., Walgenbach, J.F., Wiman, N.G., and Leskey T.C.  2020.  Invasion of the brown marmorated stink bug (Hemiptera: Pentatomidae) into the USA: Developing a national response to an invasive species crisis through collaborative research and outreach efforts.  2020.  J. Integ. Pest Manag. 11(1): 1–16. doi: 10.1093/jipm/pmaa001

Morris, E.E., O’Grady, P., Csóka, G., Hajek, A.E. 2020. Genetic variability among native and introduced strains of the parasitic nematode Deladenus siricidicola. J. Invertebr. Pathol. 173: 107385. https://doi.org/10.1016/j.jip.2020.107385

Pilarska, D., Georgiev, G., Dobreva, M., Takov, D., Mirchev, P., Doychev, D., Georgieva, M., Nachev, R., Dermendzhiev, P., Draganova, S., Linde, A., Hajek, A.E. 2018. Pathogens and parasitoids of forest pest insects in the region of Forest Protection Station Plovdiv (Bulgaria) during the period 1990 – 2017. Silva Balcanica 19(3): 49-59.

Preston, C.E., Agnello, A.M., Hajek, A.E.  2020.  Nosema maddoxi (Microsporidia: Nosematidae) in brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae), populations in the United States.  Biol. Control. 144: 104213

Preston, C.E., Agnello, A.M., Hajek, A.E. 2020. Nosema maddoxi (Microsporidia: Nosematidae) in brown marmorated stink bug (Hemiptera: Pentatomidae) populations in the US. Biol. Control 144: 104213.

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