|QUINN, NICOLE - University Of Massachusetts|
|PETRICE, TOBY - Us Forest Service (FS)|
|THERESA, POLAND - Us Forest Service (FS)|
|BAUER, LEAH - Us Forest Service (FS)|
|RUTLEDGE, CLAIRE - Connecticut Agricultural Experiment Station|
|VAN DRIESCHE, ROY - University Of Massachusetts, Amherst|
|ELKINTON, JOE - University Of Massachusetts, Amherst|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2023
Publication Date: 6/20/2023
Citation: Quinn, N., Petrice, T., Duan, J.J., Schmude, J.M., Theresa, P., Bauer, L.S., Rutledge, C., Van Driesche, R., Elkinton, J. 2023. Post-release assessment of Oobius agrili establishment and impacts in Michigan and the Northeastern U.S. Journal of Economic Entomology. 1-6. https://doi.org/10.1093/jee/toad120.
Interpretive Summary: The emerald ash borer (EAB) is a serious invasive forest pest of ash trees in the United States and Canada. The parasitic wasp Oobius agrili attacks EAB eggs and was introduced from the pest’s native Asian range to the U.S. for EAB biocontrol in 2007. It has since been released in many infested areas including Michigan, Connecticut, New York, and Massachusetts. We assessed its establishment, persistence, spread, and parasitism rates at some of the earliest release sites in Michigan, as well as more recent release sites in Connecticut, New York, and Massachusetts. Oobius agrili has established and persists in both regions at all but one release site. Levels of EAB egg parasitism were comparable in both regions, indicating that the beneficial parasitic wasp has successfully established and is contributing to EAB control in North America.
Technical Abstract: The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive woodboring pest of ash trees (Fraxinus sp.) in North America. Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae) is the only egg parasitoid introduced to the United States for biocontrol of EAB. To date, more than 2.5 million O. agrili have been released in North America; however, few studies have examined its success as a biological control agent of EAB. We conducted studies to assess O. agrili establishment, persistence, spread, and EAB egg parasitism rates at some of the earliest release sites (2007-2010) in Michigan, as well as more recent release sites (2015-2016) in three Northeastern U.S. states (Connecticut, New York, Massachusetts). We documented successful O. agrili establishment in both regions at all but one release site. In Michigan, O. agrili has persisted at release sites for over a decade and spread to all control sites located 0.6–3.8 km away. Overall EAB egg parasitism during 2016-2020 in Michigan ranged from 1.5–51.2 % with a mean of 21.4 %, and 2018-2020 in Northeastern U.S. ranged from 2.6–29.2 % with a mean of 16.1 % in the Northeast. Future research efforts should focus on factors affecting the spatiotemporal variation in EAB egg parasitism rates by O. agrili, as well as its potential range in North America.