Comparison of Attractants, Insecticides, and Mass Trapping for Managing Drosophila suzukii (Diptera: Drosophilidae) in Blueberries

The spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), is a serious economic threat to the small fruit industry. Although there has been progress on identifying new insecticides for use against D. suzukii in berry crops, growers often reach the seasonal maximum use allowed for key insecticides, and there are issues with long pre-harvest intervals. The use of border sprays and mass trapping targets D. suzukii immigration into the field, reducing damage to fruits, and the amount of pesticides used. The purpose of this study was to investigate novel alternatives to conventional insecticide techniques for management of D. suzukii in blueberries. In laboratory bioassays, captures of adult D. suzukii were similar for yeast + sugar bait, wine + apple cider vinegar bait, and the commercially available RIGA® bait. In the field, more adult D. suzukii were collected in yeast bait traps placed in the control and alternative row spray treatments over the sampling period, compared with mass trapping and border spray treatments. In addition, more D. suzukii were reared from blueberries collected in the control treatment compared with berries collected in the border spray treatment. Our study provided evidence that border sprays and mass trapping could be an effective and sustainable alternative to conventional spraying techniques for controlling D. suzukii in blueberries. Also, we recommend spacing traps approximately 2 m apart to effectively manage D. suzukii immigration into blueberry fields.