Management of Popillia japonica (Coleoptera: Scarabaeidae) with Reduced Pesticide and Biological Control in Midwest Vineyards

Abstract

Popillia japonica Newman (Coleoptera: Scarabaeidae), is an economically important pest of many crop and ornamental plants. The adult beetle is the most substantial defoliator of grape in the upper Midwest region. With alternative management options resulting in insufficient population reduction, current management practices rely on broadcast insecticide applications targeting adults on foliage, that are hazardous to the environment, non-target organisms, and farm workers. Perimeter-focused management targets the borders of crop plots for pest control with use of a killing agent, preventing incoming economically damaging insects from entering an interior. Attract-and-Kill (A&K) strengthens the edge-effect leveraged in perimeter-focused management by integrating the use of pest-specific, semiochemical attractant lures with the killing agent on a substrate. The objectives of this study were to assess the impact of A&K and Perimeter Spray applied to grape block perimeters on 1) P. japonica adult abundance and 2) grape foliar injury, compared to grower standard broadcast pesticide programs. In the A&K treatment, commercial lures were deployed along the perimeter of the plot. In the combined A&K and Perimeter Spray plots, a border application of Sevin XLR PLUS (carbaryl) was applied every 15-18 days. Grower Standard plots followed the pesticide schedule selected by each grower, typically involving one to four full block insecticide applications across the growing season. Across two growing seasons (2024-2025), beetle abundance and defoliation did not differ significantly among treatments. A&K and Perimeter Spray performed comparably to each other and to the grower standard while reducing treated surface area by 88% and application time by 78%, demonstrating that the Perimeter Spray provided the most cost-effective option with an 88% reduction in cost relative to the Grower Standard. Evaluating the potential of A&K and Perimeter Spray as reduced input management tools will help Wisconsin grape growers consider practices that maintain pest suppression while lowering environmental impacts, direct costs and reliance on broadcast applications.