Compatibility of powdered sulphur and natural enemies for the control of Drosophila suzukii (Diptera: Drosophilidae): Effects on Anthocoris nemoralis (Hemiptera: Anthocoridae) and Trichopria drosophilae (Hymenoptera: Diapriidae) activity

Abstract

Spotted-wing drosophila (SWD), Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae) cause yield losses and important economic impacts in fruits with thin epicarp. In the present study, the combination of powdered sulphur and predators/parasitoids for the control of SWD was analysed. First, the interaction of powered sulphur with Anthocoris nemoralis (Hemiptera: Anthocoridae) on infested strawberry fruits and Trichropia drosophilae (Hymenoptera: Diapriidae) on SWD pupae was evaluated. Second, exposure of predators/parasitoids to strawberry leaves with powdered sulphur was also assessed. Additionally, sublethal effects of powdered sulphur on T. drosophilae parasitism were examined. The results show powdered sulphur did not interfere with the activity of A. nemoralis and caused a significant reduction in fruit infestation. In contrast, sulphur affected the activity of T. drosophilae, reducing parasitism when the two agents were combined. Direct exposure to powdered sulphur did not cause significant mortality of A. nemoralis and T. drosophilae. Finally, previous exposure to sulphur did not affect T. drosophilae in terms of parasitism rates and sex ratio. Based on the results obtained herein, sulphur and T. drosophilae impacts on different stages of SWD when they are applied separately. However, the effects of sulphur on T. drosophilae should be taken into account in combination control strategies of SWD.