Reduced spray programs for <i>Drosophila suzukii</i> management in berry crops

<p>Since the arrival of <i>Drosophila suzukii</i> 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 <i>D. suzukii</i> 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 <i>D. suzukii</i> 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 <i>D. suzukii</i> 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 <i>Stethorus</i> spp.; additionally, alternate row sprays had significantly more <i>Psyllobora</i> spp. These reduced pesticide strategies are additional tools to consider in <i>D. suzukii</i> IPM programs that can reduce the area sprayed, application time, and input costs while conserving natural enemies.</p>