Oviposition, survival, and seasonality of Oobius agrili (Hymenoptera: Encyrtidae), a parasitoid of emerald ash borer (Coleoptera: Buprestidae), in the southeastern U.S.

The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive species native to eastern Asia that has become a significant threat to Fraxinus species in North America. Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae), a solitary parasitoid of eggs of EAB from its native range, was approved for release by USDA APHIS PPQ and is included in the EAB Biological Control Program. All current knowledge about O. agrili was collected in northern climates. Thus, studies were initiated in Tennessee in 2013 to assess potential survivability of O. agrili in southern climates to further assess its role in EAB management. Adult O. agrili were released in 2013 and monitored using pan traps in 2014. Parasitoids were released in screened cages (n = 50 parasitized EAB eggs/cage) containing egg-laying adult EABs (n = 10 males and 10 females) and ash limbs (5 per cage; ca. 1 m long) to assess parasitism and survivability of O. agrili. Limbs were removed at regular intervals (weekly), and inspected for EAB eggs. All eggs were counted, and parasitism was determined by coloration differentiation. Limbs were then held and monitored regularly (every 2-3 d) throughout the summer to assess emergence of O. agrili. Further results of these studies will be presented and discussed.