Does Habituation Affect the Efficacy of Semiochemical Oviposition Repellents Developed Against Drosophila suzukii?

The application of feeding and oviposition repellents is limited to arthropod systems in which habituation does not occur. Although several compounds appear to reduce Drosophila suzukii Matsumura (Dipetra: Drosophilidae) oviposition in berries, previous studies have yet to address whether habituation is a significant risk following preexposure. We tested the response of adult female D. suzukii to three previously identified semiochemical oviposition repellents, 1-octen-3-ol (octenol), ±-geosmin, and 2-n-pentylfuran, following adult and larval preexposure. Using a two-choice gated trap capture assay, we assessed captures in repellent-treated versus blank traps, female survival, and oviposition frequency in the selected trap. We did not find evidence of habituation to octenol or 2-pentylfuran in adult flies preexposed for 24, 48, or 72 hr. When exposed to each of the repellents as larvae, D. suzukii showed similar deterrence as those exposed as adults alone. However, mortality did decrease in F1 octenol treated flies. In contrast with previous investigations we did not observe repellent effects in response to geosmin. Our results suggest that neither exposure during the adult life stage nor during larval development inhibited the effectiveness of octenol and 2-pentylfuran. However, greater survivorship on octenol treated baits in F1 flies, combined with apparent neurotoxic effects of this compound, indicate that octenol may be less suited for field applications. For this reason, 2-pentylfuran appears to be a better candidate for ongoing research aimed at developing an effective push-pull system of behavioral management.