Biology and management of spotted wing drosophila,Drosophila suzukii (Matsumura) in small fruits in the Pacific Northwest

Abstract: The spotted wing drosophila, Drosophila suzukii (Matsumura) (SWD), was firstreported from day neutral strawberries in Washington State on 10 August 2009. It went on toinfest late variety blueberries, ‘Elliott’ and late-season caneberries. Red raspberries first becamesusceptible to SWD oviposition when < 25% of the surface showed color. The ovipositor ofSWD females differs from most drosophilids because it is highly sclerotized with prominentspines allowing the female to cut through the ripening fruit surface and insert the egg. Bioassayshave shown that at least 4 classes of insecticides are effective in controlling SWD. Successfulmanagement however remains challenging, requiring proper timing of sprays to protect the fruitthrough harvest, while coordinating with pollinators. Sustainable berry production is moredifficult with primarily two effective insecticides for SWD control, pyrethrins (Pyganic®) andspinosad (Entrust®). Preliminary testing of diatomaceous earth and a diatomaceous earthimpregnated with pyrethrins and piperonyl butoxide (Perma-Guard® D-21), applied as a wettablepowder to blueberries, was not effective on the adults and did not deter oviposition. Field barriersare being tested to determine efficacy in blueberry.