D3086: (2nd Place) Parasitoid response to emerald ash borer developing in non-ash hosts: Implications for natural enemy-free space

Emerald ash borer (EAB, Agrilus planipennis Fairmaire) is an invasive wood-boring beetle first detected in North America in 2002. Since then, it has killed millions of ash trees (Fraxinus spp.) across the continent, endangering native biodiversity and causing problems for homeowners, land managers, and the hardwood industry. In 2007, a biological control program was initiated, with four parasitoid wasps introduced to the U.S. from EAB’s native range. Though these parasitoids show evidence of successful establishment and spread, the EAB invasion continues to evolve. EAB was long thought to exclusively attack members of the Fraxinus genus, but has recently been observed completing larval development on white fringe tree (Chionanthus virginicus L.) and cultivated olive (Olea europaea L.). If parasitoids attack EAB developing on these novel hosts at a lower rate than on ash, they may serve as natural enemy-free spaces, providing a reservoir for the pest. In this study, we assess the ability for the larval parasitoid Spathius agrili Yang to detect and attack EAB on non-ash hosts. We present naive S. agrili females with a combination of lab-infested and healthy ash and white fringe tree bolts in a y-tube, recording the choice of at least 30 wasps per treatment combination. We then expose S. agrili to lab-infested ash and white fringe tree bolts, giving wasps choice and no-choice opportunities to attack larvae developing in each species. If parasitoids find and attack EAB on non-ash hosts at lower rates than traditional hosts, this will have major implications for the EAB invasion.