Evaluation of deployment strategies for attracticidal spheres for management of the invasive Drosophila suzukii in conventional and organic small fruit production systems

Authors: Leskey, Tracy; BAL, HARIT - Bayer Crop Science; Carper Jr, Garland; Cullum, John; ELSENSOHN, JOHANNA - Former ARS Employee; GRIESHOP, MATTHEW - California Polytechnic State University; HERNANDEZ-CUMPLIDO, JOHNATTAN - Rutgers University; Hott, Christian; Lee, Jana; NIELSEN, ANNE - Rutgers University; NIXON, LAURA - University Of Maryland; RICE, KEVIN - Virginia Tech; RODRIGUEZ-SAONA, CESAR - Rutgers University; ROUBOS, CRAIG - University Of Georgia; Rugh, Anthony; SHORT, BRENT - Trece, Inc; SIAL, ASH - University Of Georgia; BASTOS SILVA, DIEGO - Rutgers University

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: Spotted-wing drosophila is an extremely destructive pest of small fruit such as blueberries, raspberries and blackberries. While growers manage this pest with repeated conventional or organic insecticide applications and horticultural practices such as frequent harvesting, we tried to develop an alternative strategy to reduce these inputs and increase sustainability while protecting pollinators and natural enemies. We deployed what is referred to as attracticidal spheres; red spheres that are visually attractive to spotted-wing drosophila and have a toxicant incorporated into them to kill them when they land on spheres and feed. We evaluated the utility of these attracticidal spheres hung in small fruit plots on both conventional and organic farms and found that while in some cases, our results were not consistent. It is likely that other factors affecting spotted-wing drosophila infestations in plantings are reducing sphere utility, and therefore they are not a viable strategy currently.

Technical Abstract: Drosophila suzukii (Matsumura), spotted-wing drosophila is an extremely destructive, invasive global pest to small fruit production throughout North America and other parts of the world. 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 three states, and whole plot (grid) and perimeter sphere deployment layouts in both conventional and organic blueberry production systems in six states. In separate studies, we also evaluated the potential for non-target 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.