Drosophila suzukii (Matsumura), spotted-wing drosophila is an extremely destructive, invasive global pest of small fruit production. Frequent insecticide applications are the most commonly used management tool against this pest, as females deposit eggs in ripening fruit leading to larval infestation at harvest. However, other strategies aimed at reducing D. suzukii infestation continue to be explored to reduce reliance on insecticides and increase ecological sustainability. One such strategy is deployment of attracticidal spheres; these are visually attractive red spheres that provide a continuous release of a fresh toxicant and feeding stimulant mixture on their surface. However, optimal deployment strategies for spheres within small fruit plantings have not been developed to maximize their impact against foraging D. suzukii adults. Here, we evaluated deployment height of spheres within the canopies of small fruit plants (blueberry, raspberry and blackberry) in conventional production systems in 3 states, and whole plot (grid) and perimeter sphere deployment layouts in both conventional and organic blueberry production systems in 6 states. In separate studies, we also evaluated the potential for nontarget impacts on biological control agents and pollinators. While we observed reduced infestation, based on sphere deployment in some trials, results were not consistent likely due to differences in production practices and D. suzukii relative densities. We also did not observe negative impacts on natural enemies or pollinators. Ultimately, for attracticidal spheres to be of value to small fruit growers, more information regarding management practices that enhance or limit their efficacy must be conducted.
Leskey et al. (Tue,) studied this question.