Laboratory assessment of plant volatile organic compounds as potential attractants for spotted wing drosophila

The spotted wing drosophila (SWD), Drosophila suzukii (Matsumura), has become an economic pest in the United States and throughout Western Europe in recent years. Research on chemical attractants as baits in monitoring traps have usually focused on fermentation products and host plant volatile organic compounds (VOCs).  Many combinations of such chemicals have reportedly been effective in attracting SWD, but unfortunately, such chemical baits are also highly attractive to many non-target species. High trap captures of non-target flies require much time and effort to remove while counting the usually smaller number of SWD.  The focus of our study was to evaluate reported host plant VOCs that are attractive to SWD, first singly and then later in combinations and at different doses, in hopes of determining a mixture that is a more species-specific attractant.  For the first phase of this study we examined the degree of attractiveness exhibited by SWD and D. melanogaster towards 15 compounds via electroantennography (EAG) and behavioral bioassays.  In the SWD behavioral assays, isoamyl acetate and β-cyclocitral attracted the greatest number of flies. In the EAG assays for SWD females, 2-heptanone and butyl acetate elicited the highest response and ethanol and acetic acid had the lowest responses.