2nd Place: Identifying repellents for spotted-wing drosophila from anthracnose-infected fruits

Spotted-wing Drosophila (SWD), Drosophila suzukii, is a severe pest of many small, soft-skinned fruits such as raspberries, blueberries, and strawberries. Due to the risk of SWD developing resistance to insecticides, research for alternative control methods is of particular interest. Like many insects, SWD rely on olfaction of semiochemicals in their environment to detect suitable hosts for feeding, mating, and oviposition. It may be possible to alter SWD behavior by manipulating these signals, either via masking attractive cues or by supplementing with odors which cause a repellent effect. One novel source of potential repellents could be found in volatiles emitted from fruits infected with the fungal pathogen Colletotrichum fioriniae, a main causal agent of anthracnose fruit rot, an important disease of blueberries. Following previous studies that demonstrated negative effects of anthracnose-infected fruits on SWD choice, oviposition, and development, we identified 14 specific volatiles that were emitted at higher levels in anthracnose-infected blueberry fruits relative to uninfected fruits. In this study, we tested these volatiles in a multi-choice assay. From the initial multi-choice assay, nine compounds were identified as repellent, and two of these compounds showed greater than 90% repellency. Finding effective repellents for SWD will help in the development of push-pull systems to manage this pest.