Control of spotted wing drosophila, Drosophila suzukii, in cherry using a new low volume, reduced-risk technique

Abstract: Spotted wing drosophila, Drosophila suzukii (Matsumura), was first discovered in the USA in 2008 infesting strawberries and raspberries in Santa Cruz County, California. In 2009 D. suzukii was found infesting cherries in San Benito County and in the Northern San Joaquin Valley of California. It rapidly spread throughout the western USA and Canada in 2009 and eventually to all of the USA. D. suzukii has had a devasting effect on California’s cherry and berry pest management. D. suzukii was also found in Spain and Italy in 2008 and is spreading throughout all of Europe where it also is having a profound economic impact. Control has relied on repeated applications of full cover broad-spectrum insecticides. In an effort to develop a more integrated pest management (IPM) program, studies were conducted in California during 2013 and 2014 into the use of a low-volume technique using food bait combined with an insecticide. In 2013, studies demonstrated that low-volume (18.7 l/ha) applications of the combination of malathion or fenpropathrin with apple cider vinegar, Merlot wine and Monterey Insect Bait resulted in the significant reduction of D. suzukii infestation compared to bait alone and an untreated check. In 2014, studies demonstrated that low-volume (46.8 l/ha) applications of the combination of spinosad with Suzukii Trap bait resulted in the significant reduction of D. suzukii infestation compared to an untreated check. These studies are proof of concept that applications of low-volume reduced-risk insecticides combined with food bait can be a viable control option for D. suzukii as part of an IPM program. Growers can rapidly apply the bait and toxicant combination with potentially less disruption to beneficial insects and mites.