Spotted wing drosophila (SWD) has been a major concern for all small fruit crops, including berries and soft fruits, in British Columbia since its detection in 2009. Climate change is increasing the occurrence of mild winters and unpredictable summer weather that create ideal conditions for SWD, while also making it more difficult for growers to manage the pest.
Currently, the most effective and widely used method of management for SWD is regular insecticide applications from the beginning of fruit ripening until the end of harvest. Concerns about the risk of spray resistance are increasing, and there are few treatment options for organic growers. Unpredictable summer weather is also making management with insecticides less effective. Thus, alternative management methods for SWD are much needed.
In a three year study mass traps were placed in hedgerows adjacent to blueberry fields of early to mid-season varieties in the Fraser Valley, BC. After comparing between two trap types using the same lure, the pairing of the Scentry IPM-MLT SWD trap and the SC-SWD L pouch lures (Scentry Biologicals Inc.) was found to be the most effective at catching higher levels of SWD, even during the early spring.
The mass trapping treatment methods used did not appear to reduce SWD pressure to the crop. However, mass trapping methods could be adjusted to increase effectiveness, for example by placing mass traps along all field edges in a perimeter set-up.
A research summary provides a description of the trials and result highlights. The results report provides further detail on research design, data collection and findings.