D3416: Good things are worth the wait: Establishment of introduced parasitoids of emerald ash borer in the southeastern U.S. (TN)

On July 27, 2010, emerald ash borer (EAB) was documented in Tennessee, representing the first confirmation of this invasive insect pest in the southern U.S. EAB is now present throughout eastern and middle Tennessee (in 65+ of 95 counties), where it has killed ca 20 million trees. A biological control program against EAB was initiated in Tennessee in 2012. From 2012 to 2016, more than 264,000 parasitoids (Spathius agrili and Tetrastichus planipennisi) were released at 9 locations in 7 counties. Yellow pan traps (YPT) were installed in 2015 and monitored at these sites for 3 years. The few parasitoid recoveries in 2015, 2016 or 2017 suggested that both species could overwinter in Tennessee, but establishment was uncertain. In 2020, monitoring of YPT at 6 of the release sites was restarted, and in 2021 a multi-year study utilizing EAB-infested ash bolts and YPTs was begun to assess establishment of these introduced EAB parasitoids, last released in 2016 in Tennessee. Both introduced parasitoid species are now established in Tennessee with recoveries of Spathius agrili confirmed by DNA analysis. A third exotic parasitoid species, S. galinaei, also was recovered (possibly originating from field cage studies). This poster will highlight the establishment of these three parasitoids, their distribution and spread in Tennessee, their seasonality, and their possible impact on EAB on ash. We encourage other researchers who have released these parasitoids to continue to assess establishment, even after multiple years. You may be surprised by what you find. Good things are worth the wait!