Reduced spray programs for Drosophila suzukii management in berry crops

ABSTRACTSince the arrival of Drosophila suzukii M. (Diptera: Drosophilidae), field applications of broad-spectrum insecticides have increased in berry crop production to protect susceptible fruits from infestation. Field studies were conducted from 2011 to 2013 to determine whether alternate row middle or border spray programs could manage D. suzukii as well as complete sprays and have less of an impact on non-target arthropods. Four raspberry sites and one blueberry site were alternate row middle and border sprayed, respectively. Adult and larva counts of D. suzukii were compared to conventional complete spray programs. Non-target arthropods were evaluated 7 d post-harvest. In both reduced spray trials, no differences in mean adult numbers and larvae of D. suzukii were detected between treatments. Mean counts immediately after sprays (i.e. 3–12 d after treatment) were also similar in complete and alternate row sprays. Both reduced spray strategies had significantly more Stethorus spp.; additionally, alte...