Neem-Based Insecticides Deter Oviposition Activity in Spotted Wing Drosophila (Diptera: Drosophilidae) in Sweet Cherries.

Spotted wing drosophila, Drosophila suzukii (Matsumura), is an important invasive insect pest in the United States. Spotted wing drosophila females have serrated ovipositor that enables them to deposit eggs inside healthy, ripening softskinned fruits. In many berry and fruit crops, spotted wing drosophila is primarily controlled using synthetic insecticides in the organophosphate, pyrethroid, and spinosyn groups. However, alternative, reduced-risk insecticides with short residuals are necessary to minimize the possibilities of insecticide resistance and address other negative effects of synthetic insecticides. Neem-based products as alternative plant-based insecticides have antifeedant, repellent, antiovipository, and molting interference effects on insects and have been shown to affect the oviposition activities of some tephritid flies. We conducted laboratory studies to evaluate the oviposition deterrent activities of selected neem-based insecticides that contain either azadirachtin, or CHENO, or a combination of both, on spotted wing drosophila using sweet cherry in California. The results of the study showed that some of the neem oil products could reduce the degree of spotted wing drosophila oviposition by half compared with the control.