Aerial Applications of Esfenvalerate to Suppress Contarinia oregonensis (Diptera: Cecidomyiidae) and Megastigmus spermotrophus (Hymenoptera: Torymidae) in Douglas-Fir Seed Orchards

Abstract

Aerial applications of esfenvalerate significantly reduced populations of a Douglas-fir cone gall midge, Contarinia oregonensis Foote, and a Douglas-fir seed chalcid, Megastigmus spermotrophus Wachtl, in mature Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, seed orchards. Populations of the spruce spider mite, Oligonychus ununguis (Jacobi), increased significantly in treated areas. Our results demonstrated that aerial applications can be made under conditions in the Pacific Northwest and can reduce insect damage levels with between 10 to 20 times less metric insecticide than when high-volume orchard sprayers are used.