Evaluating the Toxicity of Candidate Organic and Conventional Insecticides on Western Grape Leafhopper and Virginia Creeper Leafhopper (Hemiptera: Cicadellidae) under Vineyard and Laboratory Conditions

The western grape leafhopper (Erythroneura elegantula Osborn) and the Virginia creeper leafhopper (Erythroneura ziczac Walsh) are the two leafhopper pests frequently observed in Washington State vineyards. Organic viticulturists have difficulties controlling these leafhopper pests, and outbreaks can result in economic loss. We vineyard-tested the efficacy of several candidate bioinsecticides and conventional insecticides against the western grape leafhopper and the Virginia creeper leafhopper. This study included the initial testing of several alternative candidate insecticides for leafhopper control. Controlled laboratory bioassays also were completed, and the 50% and 90% lethal concentrations were calculated for the nonsystemic insecticides tested. Of the bioinsecticides tested, pyrethrum (PyganicTM, Valent Bioscience Corporation, Libertyville, IL) was the only product that provided effective control of leafhoppers in both the vineyard and laboratory components of this study. In vineyard effic...