Ms. Schmidt-Jeffris discusses predatory mite biodiversity in Washington apple orchards. She offered a brief history of integrated mite management in apple in the Pacific Northwest.
Speaker: Rebecca Schmidt-Jeffris, Ph.D. student and Dr. Betsy Beers, Professor of Entomology. Affiliation: WSU Tree Fruit Research and Extension Center, Wenatchee, WA 98801-1230. Synopsis: Ms. Schmidt-Jeffris discusses predatory mite biodiversity in Washington apple orchards. She offered a brief history of integrated mite management in apple in the Pacific Northwest. She shared results from surveying for mites in commercial apples orchards across the state during 2011-2013. They found two predominate predatory mites species in most orchards, namely Ambyldromella caudiglans and/or Galendromus occidentalis. The former of these two is a relatively “new” predatory mite. They observed that G. occidentalis was much less prevalent in organic orchards than in conventional orchards. She noted that there was a difference in apple cultivar preference of the predatory mite species examined. This may be due to the presence/absence of trichomes on leaves. She noted that in orchards with more agricultural inputs (e.g., pesticides), you are likely to find more G. occidentalis while in orchards with fewer agricultural inputs A. caudiglans is more abundant. She shared the results of laboratory bioassays to test the impact of various classes of common orchard pesticides on these predatory mite species. They found that A. caudiglans experienced greater mortality than G. occidentalis after exposure to several pesticides. This work indicates that changes in pesticide regimes may also alter the community of available biological control agents in apple orchards.