Detecting and controlling D. suzukii with traps

Understanding Drosophila suzukii preference for trap designs and baits allows for improved management of this invasive pest. Traps can be used for the detection of adult presence, treatment timing, establishing damage thresholds, and population control (e.g. mass trapping, attract and kill). Studies took place in mid-Willamette Valley, Oregon and Whatcom County, Washington over summers 2012-2014. Trap counts of male and female D. suzukii and other Drosophila spp. were recorded weekly.

Trap designs were tested in a wild Himalaya blackberry perimeter. Each trap contained a yeast/sugar solution. Headspace, the trap volume above the bait surface, was a significant factor affecting trap capture. Traps supplemented with a killing agent revealed significantly more D. suzukii than traps without. A mass trapping study is being performed in summer 2014 at two crop locations with paired treated and non-treated plots.

Bait preference trials were conducted on blueberry, wild Himalaya blackberry, cherry, and raspberry crops. Each bait was placed in a 32-oz side mesh clear trap. Chinkiang vinegar and H. uvarum had consistently high D. suzukii counts. Suzukii Trap® had variable results based on environmental factors (e.g. humidity and evaporation). Torula Yeast Pellets had poor efficacy until late-season, and BioLure® and Monterey Insect Bait® showed little to no efficacy. At post-harvest, apple cider vinegar showed increased D. suzukii capture. Other Drosophila spp. were dominant (85-95%) early season, whereas late season captures shifted to 85-95% D. suzukii. Early and mid-harvest yielded higher counts of female D. suzukii, and post-harvest yielded higher counts of males.