Evaluating a push-pull strategy for management of Drosophila suzukii Matsumura in red raspberry.

BACKGROUND: Drosophila suzukii Matsumura is a serious pest of small fruits that lays its eggs in growing fruit. Current management strategies rely on an unsustainable schedule of foliar applications of chemical insecticides. Alternative approaches to suppressing oviposition are under investigation, such as attract-and-kill and the use of oviposition deterrents. Here, we evaluated two behavioral control approaches in combination as a push-pull strategy using laboratory and field assays.
RESULTS: In laboratory caged assays, both an attractive mass trapping device (pull) and an oviposition deterrent (push: 1-octen-3-ol) reduced oviposition by D. suzukii, and the combination of the two (push-pull) resulted in significantly greater reduction than either treatment alone. In field experiments, oviposition reduction was observed in fruit from plots treated with oviposition deterrent (push) or a combination of mass trapping devices and deterrent (push-pull) compared with fruit from control plots. However, oviposition in plots with mass trapping devices (pull) was higher than observed in all other treatments. Additionally, the protection provided by the deterrent in push plots extended to the entire plot rather than just in fruit closest to deterrent dispensers.
CONCLUSION: Push-pull treatments negatively affected D. suzukii infestation in both laboratory and field experiments. The reduction in oviposition observed in laboratory experiments was based on the additive effect of push and pull components acting on a finite population, while the reduction observed in field experiments appeared to be mainly based on the effect of pull components. We discuss potential underlying reasons for the discrepancy results and suggest potential improvements.