Impact of canopy and groundcover management on Drosophila suzukii (Diptera: Drosophilidae) in Eastern Washington cherry orchards

Spotted-wing drosophila (SWD), Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), has been an important pest of sweet cherry (Prunus avium) orchards in Eastern Washington since its detection in 2010.The establishment of SWD in berry and cherry growing regions has led to widespread adoption of prophylactic insecticide applications. However, recently there has been considerable research and grower interest in the development of a more sustainable integrated pest management approach. Application of two horticultural treatments, kaolin clay canopy sprays and reflective geotextile fabrics after harvest are gaining interest for their impacts on pests and may improve orchard sanitation. Similar horticultural practices, such as a weed mats and plastic mulches are currently employed for SWD in strawberries, raspberries, and blueberries. Here, we assess the impact of alternative control strategies on SWD management. In 2021-2022 field studies, reflective geotextile fabrics significantly reduced postharvest SWD trap capture in Eastern Washington cherry orchards. In lab and semi-field studies, we also explored potential mechanisms for the reduction of SWD trap capture by reflective geotextile fabric, including the potential to disrupt adult host orientation and serve as a physical barrier to pupation sites. Our preliminary results indicate biorational/cultural control strategies for SWD merit further investigation in Eastern Washington cherry orchards.