Yellow Sticky Cards Reduce the Numbers of Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae) Following Augmentative Releases against the Fruit Borers Carposina sasakii (Lepidoptera: Carposinidae) and Grapholita molesta (Lepidoptera: Tortricidae) in a Pear Orchard

Simple Summary: Laboratory and field observations were used to evaluate the compatibility of yellow sticky cards with augmentative releases of T. dendrolimi for control of orchard pests, particularly C. sasakii and G. molesta. Female T. dendrolimi showed stronger attraction to yellow and white than to red, green or blue. Yellow sticky cards trapped significant numbers of T. dendrolimi in the field, reducing biological control of C. sasakii as well as the number of lacewings naturally recruited to the orchard. Judicious use of yellow sticky cards in orchards is therefore recommended to avoid disruption of biological control, specifically removing them in May before peak flights of moth pests require releases of egg parasitoids. Integrated pest management relies upon mutual compatibility among pest control tactics. The fruit-boring moths Carposina sasakii and Grapholita molesta can be devastating pests of pome and stone fruit production. Trichogramma dendrolimi parasitizes the eggs of these pests, preventing their eclosion, but its efficacy can be reduced by other pest control tactics. We tested T. dendrolimi attraction to five colors, and moth attraction to six colors, in laboratory choice tests, and thereafter deployed yellow sticky cards in tandem with releases of T. dendrolimi in field trials in a pear orchard. Yellow sticky cards deployed at high density trapped T. dendrolimi and reduced their numbers post-release. They also trapped adult G. molesta, which appeared to compensate for reduced egg parasitism on this species, but not on C. sasakii, which had higher abundance in plots with yellow sticky cards. The cards also captured adult lacewings, likely reducing their numbers in the field, but did not capture large numbers of lady beetles. The results suggest that yellow sticky cards can be used at high density to control aphids, psyllids and leafhoppers in early spring (March and April) when natural enemies are in low numbers, then removed in May so as not to interfere with augmentative releases of T. dendrolimi that must be timed to coincide with peak flights of fruit-boring moths. This strategy should enhance the compatibility of yellow sticky cards with egg parasitoid releases. [ABSTRACT FROM AUTHOR]