Assessment of emerald ash borer parasitoid recovery methods in white ash stands in New York State

Emerald ash borer (Agrilus planipennis, EAB) is an invasive forest pest established throughout much of the midwestern and northeastern US and some areas of southeastern Canada. Now that EAB cannot be eradicated, substantial efforts are underway to develop an effective biological control program to mitigate the effects of EAB using the introduced parasitoid wasps Oobius agrili, Spathius agrili, and Tetrastichus planipennisi. Parasitoid releases occurred in New York State in 2011 and 2012 and will resume in June 2013 at two new sites with EAB infested white ash stands sites in Albany Co. near Selkirk, NY. 600 of each species of parasitoid will be released each week over a period of four weeks for a total of 2400 Oobius agrili, 2400 Spathius agrili, and 2400 Tetrastichus planipennisi. Following parasitoid releases at each site, four methods of parasitoid recovery will be evaluated: yellow pan traps consisting of bowls filled with liquid to entrap parasitoids; egg sentinel logs baited with EAB eggs; larval sentinel logs baited with EAB larvae in which larvae are allowed to undergo natural development; and larval sentinel logs baited with EAB larvae in which EAB larvae are inserted into small chambers excavated beneath a flap of bark. Each trap type will have 80 replicates and traps will be monitored throughout the summer to assess recovery rates and evaluate which are most efficient and cost-effective. In addition, yellow pan traps will be investigated for the first time as a means of Oobius agrili recovery. Determining which parasitoid recovery methods are most effective will be important in documenting the presence of parasitoids in the future and in evaluating the success of the EAB biological control program. The ability to easily and accurately confirm the presence of parasitoids will not only allow researchers to avoid unnecessary destructive sampling in search of parasitoids, but may help in gathering valuable information that will increase our understanding of post-release parasitoid activities.