Impacts of insecticide application timing on the oviposition potential of Ganaspis kimorum

The larval endoparasitoid Ganaspis kimorum née brasiliensis (G1) (Hymenoptera:Figitidae) has been released across North America since summer 2022 as a classical biological control agent for the management of Drosophila suzukii Matsumura (Diptera:Drosophilidae). D. suzukii is an invasive pest of economic concern to the soft fruit industry. Many growers resort to regular insecticidal chemical applications to control D. suzukii in their fields, which can have negative environmental impacts as well as lead to insecticide resistance. In this talk we describe the impact of six common insecticides (Spinosad, Grandevo, Peracetic Acid, Pyganic, Delegate, and Assail) on the oviposition potential of G. kimorum under lab and semi-field conditions. For lab conditions, treatments were applied to store-bought blueberries using a Potter Spray Tower, with application timings ranging from pre-D. suzukii infestation to post-parasitization by G. kimorum, simulating parasitism occurring in sprayed areas across time. Semi-field conditions involved treating fruit in the field before collecting and returning to rear insects out of the fruit in the lab. The impact of these chemicals on the viability of G. kimorum has implications for its usage as an augmentative biocontrol measure near fields treated with insecticides.