Meticulous methods for a boring beetle: A protocol to determine the efficacy of emerald ash borer biocontrol

The emerald ash borer (EAB; Agrilis planipennisi Fairmaire) has been killing ash trees in North America since the 1990s. Federal quarantine efforts, which began in 2002, have been deemed ineffective and were terminated in 2021. The current focus of the USDA APHIS for this invasive is biological control, and four species of parasitoid wasps have been approved since 2007. Data suggests three of these wasp species (Oobius agrilis Zhang and Huang, Tetrastichus planipennisi Yang, and Spathius galinae Belokobylskjj and Strazanac) have established populations at a majority of releases sites. However, determining the efficacy of these wasps, specifically along a north-south suitability gradient, has yet to be documented. We will provide updates on the success of parasitoid establishment across eight field sites from Duluth, MN, USA in the north to Poplar Bluff, MO, USA in the south. We have initiated a life table study at five of these sites to determine the effect of the parasitoids on EAB mortality. This project is ongoing, and the purpose of this talk is to share the methods (and pitfalls) of establishing a life table study. The methods for our study involve the successful hatching of live insect eggs placed on trees, which is a challenging and time-consuming task. We will also present some data on EAB and parasitoid populations at these sites, as well as data on the health of the ash trees.