Location: Beneficial Insects Introduction Research Unit
Project Number: 8010-30400-001-032-A
Project Type: Cooperative Agreement
Start Date: Jul 30, 2025
End Date: Jun 30, 2026
Objective:
Emerald Ash Borer (EAB) is one of the most destructive invasive pests of North American ash (Fraxinus spp.) in United States. The egg parasitoid, Oobius agrili, is one of the four EAB natural enemies introduced from Northeast Asia for biological control of this invasive pest. Our specific objectives are to:
(1) determine the host association of O. agrili with EAB and other Agrilus pests infesting their common host trees such as ash, birch, oak, and/or sugarberry in the EAB biocontrol release areas across a gradient of latitudes.
(2) quantify the impacts of O. agrili on EAB population densities in the long-term EAB biocontrol study sites established in Michigan (2008-2010) and the Northeastern states (2015-2017) including Connecticut, Massachusetts, and New York.
Approach:
The proposed work will be carried out in several states across four different EAB-invaded regions in U.S.A, where the introduced egg parasitoid (O. agrili) was also released at least two years prior to the study. In each study region, we will select a minimum of three to five study sites and deploy burlap traps at each study site on five to 10 ash trees (DBH > 5 cm; 2 traps per tree) with fresh woodpecker holes at various distances (within the radius of 15 – 30 km) to the original egg parasitoid release point at each study site in the spring (April to May) when adult EAB and nontarget Agrilus beetles begin to emerge. Observation of EAB eggs laid on the surface of ash trunks or branches covered by the spiraling wraps of each trap will be conducted every 2 – 3 weeks. At each observation time, all EAB and other nontarget Agrilus eggs will be collected and placed in ventilated plastic vials (5 ml), and the fate or hatching of each egg will be determined after approximately four weeks of incubation in a growth chamber under normal rearing conditions (25oC, long-day photoperiod L:D 16:8 h, and 65% RH).