Spillover of <i>Drosophila suzukii</i> between noncrop and crop areas: implications for pest management

Abstract

Abstract Semi‐natural areas may promote Drosophila suzukii population dynamics by providing alternative host resources, overwintering habitats and refuge areas during cold, warm or dry periods, or when crops are sprayed with insecticides. In the present study, we investigated the spillover of D. suzukii between noncrop and crop areas using sweet cherry as a model crop. We sampled the pest at different heights and at different distances from the forest, from the the winter dormancy stage to the post‐harvest period. Drosophila suzukii activity‐density in the orchards declined strongly with increasing distance from the forest margin and with increasing height above the ground. The observed patterns varied over the crop phenological development stages, indicating that the pest used multiple habitats throughout the year. When the host plant was not suitable for reproduction, D. suzukii preferred to fly closer to the forest margin and at lower heights. When the host plant was suitable (i.e. ripe cherries), D. suzukii further colonized the orchards both horizontally and vertically, exploring the canopy volume more in depth. The results of the present study will contribute to the development of more effective and practical approaches for protecting fruit crops from D. suzukii and improving chemical, physical or mechanical control measures.