Exclusion: The Case of SWD

Spotted wing drosophila on a raspberry. Photo by Hannah Burrack, NC State University, Bugwood.org.

Exclusion can be decisive in the battle against spotted wing drosophila (SWD). Since its discovery in 2008, this tiny vinegar fly (Drosophila suzukii) has established outposts in nearly every fruit and berry-growing region of North America. Unlike most vinegar flies, this one attacks undamaged fruit.

Screening may protect individual plants or crops in protected culture such as high tunnels or greenhouses. In Japan, using extremely fine mesh with openings less than .039 inches (.98 millimeter) wide (18 mesh or finer) protected blueberries. If screening is used, venting can be problematic; fans may be needed to increase airflow. You will need to introduce pollinators if the crop is in bloom.¹