Acttra SWD Bait Formulation Against Drosophila Suzukii and its Compatibility with Berry Pollination by the Honey Bee, Apis Mellifera

Abstract

Crop protection substances are continuously developed to prevent the decimation of non-target insect populations through insecticide use. The bait formulation Acttra SWD was created to attract the adult spotted-wing drosophila, a generalist pest of berries, and when mixed with insecticide would cause a reduction in the volume of insecticide applied, thus avoiding a complete coverage of crops and resulting in economic and ecological benefits to society. However, Acttra SWD has some compounds, including sugars and fruit odors, that might attract non-target fauna, especially insect pollinators. Therefore this study aimed (1) to investigate if Acttra SWD mixed with the recommended pesticide, i.e. spinosad (Entrust), is attractive to the honey bee, which is extensively used for berry pollination and (2) to evaluate the insecticidal activity of Acttra/Entrust in oral and contact tests on the same species. In all replicates, most foragers rejected feeders that offered Acttra/Entrust, and some switched to Acttra/Entrust-free feeders. Accordingly, mortality caused by this mixture in oral tests was low and did not differ from control, since the majority of bees did not consume the Acttra/Entrust treatment. However, mortality caused by this mixture was higher than in control groups in topical tests. Our results indicate that honey bees will not be attracted to and poisoned by crops sprayed with Acttra/Entrust, but contact with the bait would result in lethal or sub-lethal effects.