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ARS Home » Northeast Area » Newark, Delaware » Beneficial Insects Introduction Research Unit » Research » Publications at this Location » Publication #390860
Research Project: Biology, Ecology, Genetics, and Genomics of Introduced Species for Biological Control of Invasive and Other Insect Pests

Location: Beneficial Insects Introduction Research Unit

Title: Monitoring the impact of introduced emerald ash borer biocontrol agents: Factors affecting Oobius agrili dispersal and parasitization of sentinel host eggs

Author
item QUINN, NICOLE - University Of Massachusetts
item Duan, Jian
item ELKINTONB, JOSEPH - University Of Massachusetts, Amherst

Submitted to: BioControl
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2022
Publication Date: 7/13/2022
Citation: Quinn, N.F., Duan, J.J., Elkintonb, J. 2022. Monitoring the impact of introduced emerald ash borer biocontrol agents: Factors affecting Oobius agrili dispersal and parasitization of sentinel host eggs. Biocontrol. https://doi.org/10.1007/s10526-022-10149-3.
DOI: https://doi.org/10.1007/s10526-022-10149-3

Interpretive Summary: The emerald ash borer (EAB) is a serious invasive forest pest in the United States and Canada. The parasitic wasp Oobius agrili attacks EAB eggs and was one of several natural enemies introduced from the pest’s native northeast Asian range to the U.S. for EAB biocontrol. We examined the dispersal distance and attack rate of EAB eggs after field releases of adult wasps, using sentinel EAB eggs deployed in green ash and white fringe trees at various distances. After the deployed EAB eggs were retrieved and examined for parasitism, we observed no difference in EAB attack rates by distance or tree species. However, more EAB eggs were parasitized following longer compared with shorter deployment periods. These findings suggest that sentinel EAB eggs may be deployed on ash or white fringe trees to effectively monitor the establishment and spread of this introduced natural enemy.

Technical Abstract: Emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive, wood-boring pest of North American ash trees (Fraxinus spp.). Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae), a solitary egg parasitoid, was one of several parasitoids introduced from the pest’s native northeast Asian range to the U.S. for EAB classical biocontrol. Since its introduction, this agent has been released in over 31 States against EAB, yet determination of the spread and impact of this parasitoid has proved difficult partly because of its small size and cryptic host eggs. This study examines the dispersal distance and parasitism of O. agrili shortly after release, as well as the impact of tree species, where the host eggs were deployed. Sentinel EAB eggs were deployed on pairs of green ash (Fraxinus pensylvanica) and white fringe (Chionanthus virginicus) trees in circles around the release point up to 45 m away. After 48 or 120 hours, the eggs were retrieved and examined for parasitism. There was no significant difference in observed parasitism by distance or tree species. However, significantly more EAB eggs were parasitized in the longer deployment compared to the shorter deployment. These findings suggest that sentinel EAB eggs may be deployed on ash or white fringe trees to effectively monitor the establishment and spread of O. agrili. Future studies using sentinel host eggs in natural ash stands may yield further insights into the spread rate of O. agrili post-release and its effectiveness in suppressing the targeted pest populations over time