Cold tolerance of emerald ash borer parasitoids: Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae), Spathius agrili Yang (Hymenoptera: Braconidae), and Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae)

University of Minnesota M.S. thesis. May 2013. Major: Entomology. Advisor: Robert C. Venette. 1 computer file (PDF); vi, 96 pages, appendix 1.Three Chinese parasitoids are currently being released in North America to control emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae): Spathius agrili Yang (Hymenoptera: Braconidae), Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae), and Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae). The degree to which cold climates may limit their potential distributions in North America is unknown, especially in areas like Minnesota that experience a wide range of winter temperatures. To assess parasitoid cold tolerance, I developed a new thermocouple design to reliably measure the temperature of small insects, such as parasitoids. I then exposed the parasitoids to temperatures from 0 to -35°C in the lab to assess their cold tolerance. NAPPFAST software was used to forecast overwintering mortality of S. agrili and T. planipennisi in North America. These forecasts of overwintering mortality will aid researchers and policy makers in deciding where the parasitoids should be released