Release of native Trichogramma minutum to control grape berry moth

Abstract

AbstractWe studied the effects of inundative releases of the egg parasitoid Trichogramma minutum Riley (Hymenoptera: Trichogrammatidae) on economic injury by grape berry moth, Endopiza viteana (Clemens) (Lepidoptera: Tortricidae). Trichogramma minutum originally collected from natural host populations near North East, Pennsylvania, was mass produced in tobacco hornworm hosts and Mediterranean flour moth. We released T. minutum in border rows, where grape berry moth infestation is typically high, of experiment field station and commercial vineyards from 1996 to 1999. We recorded significant reductions in economic injury in plots where parasitoids were released. In vineyards with low to moderate grape berry moth abundance, four releases during the growing season were adequate in reducing damage at harvest to below 3%. In high-risk vineyards, T. minutum releases reduced damage to levels below 15%. The use of buckwheat as a cover crop to provide nectar in combination with parasitoid releases showed potential benefits in parasitoid activity. A biocarrier and Biosprayer™ were used in mechanized parasitoid-release operations, and no adverse effect on parasitoid emergence was recorded from parasitized eggs using this approach.