Yeast associations of spotted wing drosophila (Drosophila suzukii) in raspberries

The spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), is a native of Southeast Asia and a pest of berry and stone fruit crops. In 2008, following its identification in North America, caneberries had total revenue losses of $89.8 million dollars, more than any other Californian host. A closely related species Drosophila melanogaster Meigen has been shown to prefer and cultivate a specific yeast species. We hypothesize that D. suzukii will similarly exhibit a specific yeast association. The faunal profile of D. suzukii infested and uninfested raspberries for three different raspberry varieties were compared to evaluate feeding associations between D. suzukii and specific yeasts. D. suzukii adults and larvae were collected in raspberry fields near Watsonville, CA, and yeasts isolated from the midgut and frass to strengthen evidence for associations. Unsurprisingly, yeasts were found in D. suzukii midguts, and specific yeast species appeared to be more common. Knowledge of the specific biology of a pest allows for more targeted management programs as well as better use of biological and cultural controls. Management implications of a yeast association include improved bait lures, potential use of fungicides for control, and more precise prediction of D. suzukii host range.