Brief Summary of Minutes of Annual Meeting

Summary of Meeting minutes.

In attendance: Christopher Adams, Philip Fanning, Ashfaq Sial, Rufus Isaacs, Julianna Wilson, Steve Van Timmeren, Frank Zalom, Adam Wong, Doug Fifer, Christelle Guedot, Vaughn Walton, Cesar Rodriguez-Saona, Jay (a student in Mary Roger’s lab).

The group meet in Portland at the annual Entomological Society of American annual meeting. The group shared current research findings and plans for the upcoming season. Funding at the national level has become challenging. The group has plans to approach commodity groups for research support in the coming years. Several labs are looking at alternative control tools including attractants, repellents, sterile insect release, and biological control.

3. PROGRESS OF WORK AND PRINCIPAL ACCOMPLISHMENTS:

Objective 1: Improve our understanding of SWD populations and develop tools to accurately predict SWD risk to various crops.

1. Degree to which objective has been accomplished:

Michigan: A fruit sampling method was developed to test blueberries for presence of SWD larvae. This was first reported by Van Timmeren et al. (2017), and we have been working to improve this method to make it faster, less expensive, and more reliable. Results from these trials were reported in Van Timmeren et al. (2021).

New York: 1. On farm test of a decision tree based on larval sampling where we compared spray decisions based on grower normal practice with decision based on larval sampling and a threshold of above 0.02 larvae per berry.  Use of decision tree resulted in one fewer insecticide application compared to conventional grower method.  Data will be combine with other researchers as part of test of the use of larval sampling based decision tree.

2. Summarized data from NY and other sites on relationship between male captures on red sticky cards and larval infestations as basis for potentially developing an economic threshold for SWD in high bush blueberries.

Oregon: We have established and maintained a trapping network of monitoring traps tracking SWD populations in both summer and winter. Weekly trapping data is shared with stakeholders to help improve management decisions and reduce grower costs. Winter SWD population movement and population size is used to guide management decisions in the following season.

1. Incomplete work or areas needing further investigation:

Michigan: Studies are underway to better understand how to adapt the fruit sampling methods into practical IPM programs for fruit growers. This research is further advanced in some regions than others. In Michigan, we still need to conduct weekly sampling in commercial farms to better understand optimal sample size for specific levels of precision and to increase adoption of this approach to identify the greatest opportunities for reducing the need for insecticide applications.

Oregon: We continue to analyze why populations build in the winter and what resources they are relying on. Understanding how populations build in the off season is critical to reducing overall populations.

Florida: An improvement in trap efficiency using microbial bait has increased our ability to detect SWD populations. Commercial red panel traps have been compared to conventional cup traps using Drosalure have found efficiencies in trap capture.

Objective 2: Optimize use of pesticides to reduce reliance upon them, monitor and address the development of resistance, and minimize disruption of beneficial insects.

1. Degree to which objective has been accomplished:

Michigan: Resistance monitoring methods have been tested by a team working across the United States (Isaacs et al. 2022). This RAPID method provides a relatively simple approach for standardized testing of whether SWD populations are resistant or susceptible. Use of this method across eight states revealed variable levels of resistance, with some California populations having resistance to spinosad and the rest of the country showing susceptible populations. Trials on new tools such as Zivalgo (Plinazolin) have shown to be effective against SWD.

Arkansas: Use of the Rotating Cross-Arm Trellis (RCA) System in blackberry to suppress SWD and Optimize Pesticide Applications. Work continues in Arkansas to diversify management of spotted-wing using novel trellis systems for blackberry. The RCA trellis system has been found in Arkansas to attract less SWD (Duncan et al. 2023) and result in less eggs and larvae on fruit. Data indicate the RCA trellis system creates a less ideal environment for SWD, while also resulting in better pesticide coverage on berries (Cato et al. 2023). Data is still being collected to determine whether lower spray volumes can be used with heightened effectiveness to decrease the economic burden of SWD on growers. Future work will include optimization of sustainable insecticides with trellis systems that optimize coverage and potentially enhance efficacy.

New Jersey: In 2024, Drosophila suzukii individuals from three populations in New Jersey were sent to Dr. Joanna Chiu at UC Davis to test for the expression of resistance genes.

California: Investigating the genetics of insecticide resistance. Looking into releasing susceptible populations in riparian areas to combat pesticide resistance. Keeping populations of flies susceptible to the tools we have will extend the life of these important tools.

1. Incomplete work or areas needing further investigation:

There is a plan to re-survey populations for their insecticide susceptibility in 2024, to determine whether susceptibility has remained stable across the country.

Further dose-response laboratory studies are being conducted on select populations to confirm their resistance to insecticides.

Objective 3:  Develop non-pesticide-based tactics, including biological control, for SWD management and evaluate sustainable management programs to provide best management practices recommendations to stakeholders.

1. Degree to which objective has been accomplished:

Michigan: Classical biological control is underway through 2022 and 2023 releases of Ganaspis brasiliensis in Michigan blueberry farms across the southern region of Michigan where most of the production regions are located. Monitoring of the wasp in wild and managed areas has detected parasitism in multiple farms and up to 2700 ft away from the release point in 2023. This monitoring also detected Leptopilina japonica in multiple farms in both years, and this adventive species now seems well established in Michigan. The sampling has also identified which wild host plants have the highest parasitism, showing that blackberry, raspberry, elderberry, and pokeweed have higher densities of parasitic wasps. This information will allow for focused sampling of specific host plants at specific times of the year to monitor establishment in future years. Sampling in the upper peninsula of Michigan in August detected no parasitic wasps in fruit sampled at four locations. Additional non-pesticide tactics included the use of reflective mulch which has shown to reduce SWD infestations in blueberry.

New York: 1. Tested use of the candidate repellent 2-pentylfuran (2pf) with and without attract and kill in fall raspberries for control of SWD infestations.  Generally, did not result in significant reductions in infestations in 2024 compared to control plots.  Did show that larval parasitism rates were higher in plots where we released 2pf.

2. Reared and released classical biocontrol agent Ganaspis kimorum at 5 blueberry farms in NY state and assessed parasitism by larval parasitoids from SWD infesting wild fruits and cultivated blueberries at each farm site multiple times during the season.

New Jersey: In 2024, we tested two novel repellents—ethyl butanoate and ethyl (E)-but-2-enoate—for Drosophila suzukii isolated from blueberry fruits infected by the disease anthracnose (causal agent Colletotrichum fioriniae) under field (cage) conditions. Results demonstrated that both compounds significantly reduced SWD oviposition and adult emergence from blueberry fruits, with ethyl (E)-but-2-enoate occasionally performing better than ethyl butanoate. Additionally, we are testing the efficacy of a bait formulation (Combi-protec) and methyl benzoate, a naturally occurring chemical found in many plants and FDA-approved food additive, and its analogs to manage D. suzukii.

We are currently conducting releases of the parasitoid Ganaspis kimorum, a biological control agent of D. suzukii that is widely distributed in East Asia. In 2024, G. kimorum was released at 10 commercial blueberry farms in New Jersey, and its establishment is being monitored. Fruit samples were collected monthly from May through October from non-crop habitats surrounding 15 blueberry farms in southern New Jersey to evaluate D. suzukii infestations and parasitoid emergence.

We are investigating the non-target effects of behavior-based control strategies for D. suzukii, focusing on the bait Combi-protec (Andermatt USA) and its impact on G. kimorum. Our study evaluates five insecticides—Delegate, Exirel, Imidan, Mustang Maxx, and Entrust—using two application methods: cover sprays and bait sprays. Additionally, we are assessing residual effects by aging the treatments for 0, 3, and 7 days post-application.

Oregon (Adams lab): Classical biological control has been underway in 2022, 2023, and 2024. Releases of Ganaspis brasiliensis in Oregon sweet cherry orchards across the Mid-Columbia region of Oregon where most of the cherry production is located. Monitoring of the wasp in and around managed areas has detected SWD parasitism in multiple locations. Monitoring has detected large numbers of a native wasp Pachycrepoideus vindemmiae which has learned to utilize this new invasive species. Efforts are underway to augment the population of this native parasitoid against SWD.

Oregon (Walton lab): a new attract and kill technology has been developed and is being commercially sold. Decoy is a food-based gun that works as an ovipositional attractant for females. It has been shown to reduce egg laying in fruit by 50%.

California: Drip-irrigation systems are being used to apply entomopathogenic nematodes against SWD pupae as a classical biological control tactic. Water filter mesh size of 120 allows nematodes to pass through.

1. Incomplete work or areas needing further investigation:

Michigan: Monitoring will continue in future years to track establishment of Ganaspis brasiliensis in Michigan and to determine how this species interacts with Leptopilina japonica in populations of SWD.

New York: 1.  Need to find more effective repellents and attract and kill methodology.  Further screening of repellents, trying combination of different repellents that work in different ways (e.g. spatial repellent in combination with contact oviposition deterrent).

2. Need more work on mechanistic basis of repellents.
3. Need to complete the identification of parasitoids reared from fruit from release sites.
4. In future, need to assess impact of introduced larval parasitoids on SWD populations (see objective 1).
5. Evaluate other strains of G. kimorum to see if can find better match to release environment.

New Jersey: In 2025, we will continue to evaluate repellents against SWD. We will continue to conduct releases of G. kimorum and assess its establishment in New Jersey. We will continue to evaluate the effects of insecticides combined with the phagostimulant Combi-protec on G. kimorum.

Objective 4:  Coordinate grant-funded research and extension efforts to minimize redundancy and ensure knowledge transfer across multiple states and regions.

1. Degree to which objective has been accomplished:

Michigan: Our team has collaborated with others within the SWD projects funded by the SCRI program and the OREI program, which has kept us connected to the ongoing research trials and plans underway across the country.

New York: 1. Participated in SWD multistate project meeting to share information

2. Participated in monthly meeting with other researchers who are participating in the SWD SCRI project and in process, sharing results and discussing future needs.
3. Gave multiple presentations to NY berry growers on progress of SWD research including efforts on monitoring, behavioral control, biological control and chemical control.
4. NYS IPM program has maintained a monitoring network for 5 years, providing dates of first adult activity in various areas of NY to stakeholders, extension agents and researchers.

New Jersey: In 2024, we shared findings from these studies at various scientific and grower-focused meetings, including the Entomological Society of America Eastern Branch Meeting (Morgantown, WV), the Atlantic Coast Agricultural Convention and Trade Show (Atlantic City, NJ), the Mid-Atlantic Fruit & Vegetable Convention (Hershey, PA), the Blueberry Open House (Hammonton, NJ), the International Society of Chemical Ecology Annual Meeting (Prague, Czech Republic), the Ecological Society of America Annual Meeting (Long Beach, CA), the International Congress of Entomology (Kyoto, Japan), and the Entomological Society of America Annual Meeting (Phoenix, AZ).

Oregon has participated in the multistate research project and has collaborated with others across the country to minimize redundancy. Research results have been shared with stakeholders at local, regional, and national meetings.

1. Incomplete work or areas needing further investigation:

Extension bulletins are being developed for Michigan growers regarding the status of resistance, biological control, and SWD management.

We will continue to facilitate the adoption and awareness of research findings from this project via presentations at scientific and grower meetings, newsletter articles, factsheets, meeting proceedings and abstracts, and through social media (blogs and websites).

I see these directions indicate only publications from the current year.  If that is the case then we have no publications to report for 2025. The form i was working on indicated the last three years. Sorry for the confusion. I can make edits if i have this wrong, but i am inlcuding the list for the last three years. 

Gale, C.C., Ferguson, B., Rodriguez-Saona, C., Shields, V.D.C., and Zhang, A. 2024. Evaluation of a push–pull strategy for spotted-wing drosophila management in highbush blueberry. Insects 15, 47. doi: 10.3390/insects15010047.

Quadrel, A., Urbaneja-Bernat, P., Holdcraft, R., and Rodriguez-Saona, C. 2024. Elicitors of plant defenses as a standalone tactic failed to provide sufficient protection to fruits against spotted-wing drosophila. Frontiers in Agronomy 6:1381342, section Pest Management. Research Topic on “Latest Research Advances in Biology, Ecology, and Integrated Pest Management of Invasive Insects”. doi: 10.3389/fagro.2024.1381342.

Sosa-Calvo, J., M. Forshage, M. L. Buffington. 2024. Circumscription of the Ganaspis brasiliensis (Ihering, 1905) species complex (Hymenoptera, Figitidae), and the description of two new species parasitizing the spotted wing drosophila, Drosophila suzukii Matsumura, 1931 (Diptera, Drosophilidae).Environmental Entomology, v. 53, 6,  https://doi.org/10.1093/ee/nvae086

Shrestha, B., Hesler, S.P., Meier, L., Cha, D.H., and Loeb, G.M. 2024.  Field testing of 2-pentylfuran as a behavioral control tool for spotted-wing drosophila in raspberries.  Journal of Applied Entomology, DOI.org/10.1111/.

Gariepy, T.D., Abram, P.K., Adams, C., Beal, D., Berrs, E., Beetle, J., Biddinger, D., Brind’Amour, G., Bruni, A., Buffington, M. Burrack, H., Kaane, K.M., Demchak, K., Fanning, P., Gillett, A., Hamby, K., Hoelmer, K., Hogg, B., Isaacs, R. Johnson, B. Lee, J.C., Levensen, H.K., Loeb, G., 2024. Widespread establishment of adventive populations of Leptopilina japonica (Hymenoptera, Figitidae) in north America and development of a multiplex pcr assay to identify key parasitoids of Drosopohila suzukii (Diptera, Drosophilidae). NeoBiota, 93: 63-90, doi: 10.3897/neobiota.93.121219.

Roh, G.H., Meier, L., Hesler, S., Zhu, J.J., Kendra, P., Roda, A., Loeb, G. Tay, J., Cha, D.H. 2023. A 2-component blend of coconut oil derived fatty acids as an oviposition deterrent against Drosophila suzukii.  Journal of Economic Entomology, 116: 1671-1678, DOI.org/10.1093/jee/toad092.

Hubhachen, Z., Fanning, P.F., Abeli, P., Perkins, J., Isaacs, R., and Beaudry, R. 2023. Postharvest control of spotted-wing drosophila and blueberry maggot by low temperature conditions and fumigation with sulfur dioxide. Postharvest Biology and Technology.

Hanna McIntosh, Christelle Guédot, Amaya Atucha. 2023. Plastic mulches improve yield and reduce spotted-wing drosophila in primocane raspberry. Scientia Horticulturae, v320, 112203.