|BEERS, ELIZABETH - Washington State University
|BEAL, DYLAN - Washington State University
|SMYTHEMAN, PETER - Washington State University
|ABRAM, PAUL - Agriculture And Agri-Food Canada
|DAANE, KENT - University Of California
|LOONEY, CHRIS - Washington Department Of Agriculture
|LUE, CHIA-HUE - City University Of New York
Submitted to: Journal of Hymenoptera Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2022
Publication Date: 6/30/2022
Citation: Beers, E.H., Beal, D., Smytheman, P., Abram, P.K., Schmidt-Jeffris, R.A., Moretti, E.A., Daane, K.M., Looney, C., Lue, C., Buffington, M.L. 2022. First records of adventive populations of the parasitoids Ganaspis brasiliensis and Leptopilina japonica in the United States. Journal of Hymenoptera Research. 91:11-25. https://doi.org/10.3897/jhr.91.82812.
Interpretive Summary: Spotted wing drosophila is a serious, invasive pest of berry and fruit crops in the U.S. Predators native to the U.S. are not efficient at controlling this pest. Researchers at the USDA-ARS in Wapato, WA, with Washington State University, Agriculture and Agri-Food Canada, University of California, and the Washington State Department of Agriculture found two exotic parasitic wasps that attack spotted wing drosophila in Washington State for the first time. These wasps are from the native range of the pest. The researchers identified these wasps by appearance and DNA analysis. They also used DNA analysis to determine that one of the wasp species is a strain that is the most specific to attacking spotted wing drosophila. Now that these wasps are present in Washington State, they can be moved into orchards where spotted wing control is needed, and their biology can be studied to improve the control of the pest.
Technical Abstract: We report the first known incidence of two parasitoid species of the invasive pest, Drosophila suzukii, in the United States (US). The discovery of Ganaspis brasiliensis and Leptopilina japonica (Hymenoptera: Figitidae) in northwestern Washington State (United States) was made shortly after their discovery in nearby southwestern British Columbia (Canada), indicating that contiguous populations of these species are established in both countries. The first Washington specimen of L. japonica was collected in the fall of 2020, when it was found in a rice wine/orange juice trap deployed to survey the spread of Vespa mandarinia in Washington. Subsequent examination of trap contents from the 2020-2021 seasons indicated the presence of both L. japonica and G. brasiliensis. In September of 2021, live collections of both G. brasiliensis and L. japonica were made, reared from D. suzukii-infested wild blackberry in Whatcom Co., WA. Adult parasitoid identifications were based on morphology and COI DNA barcodes. All sequenced specimens to date from Washington and British Columbia are the G1 group of G. brasiliensis, the only one approved for release as a classical biological control agent in the US.