Non-target effects of the phagostimulant Combi-protec on Ganaspis brasiliensis, a parasitoid of Drosophila suzukii

Spotted-wing drosophila (SWD), Drosophila suzukii, is a global invasive pest that affects soft and thin-skinned fruits. Since its introduction to the United States in 2008, SWD infestations have posed a significant threat to the nation's small fruit industry. Currently, SWD management relies heavily on chemical control. Therefore, diversifying control methods is crucial for sustainable management of this serious pest. This study investigates the non-target effects of Combi-protec, a phagostimulant bait used for SWD behavioral control, on Ganaspis brasiliensis (Gb), a parasitoid of SWD. In laboratory experiments, Gb males and females were exposed to various insecticides, both with and without Combi-protec. Additionally, two application methods of Combi-protec were tested: cover spray and bait spray. To assess residual activity, experiments were conducted at three insecticide rates and at intervals of 0, 3, and 7 days after treatment. Gb mortality was measured over a 72-hour period. The average mortality across 10 replicates was calculated, comparing the lethality of different insecticides, the effects of Combi-protec presence, application methods, and residual activity. The findings from these experiments will shed light on the compatibility between SWD behavioral and biological control methods, contributing to a more comprehensive IPM strategy for this significant pest.