Efficacy and Species Specificity of Baits and Lures for Spotted-Wing Drosophila, Drosophila suzukii (Diptera: Drosophilidae).

Monitoring is an important element in management programs for Drosophila suzukii (Matsumura), helping users to avoid prophylactic treatments. Factors such as attractiveness, sensitivity, selectivity, longevity, and ease of use must be considered when developing a trap and lure system for monitoring and thresholds. We examined various baits and lures over a 5-yr period in sweet cherry orchards in the semiarid climate of eastern Washington. Using a jar trap, the attractants were evaluated for attractiveness (maximum capture), selectivity for D. suzukii (vs. other Drosophila species), and sex ratio of captured D. suzukii. We examined the relative performance of the attractants during periods of low (≈1 D. suzukii per trap per week) and high (232 D. suzukii per trap per week) density over the course of the growing season, which usually corresponded to mid-summer and autumn temperatures, respectively. The Scentry lure was consistently the most attractive lure, capturing the highest numbers of adult D. suzukii over the series of tests, but also had the highest levels of by-catch. Recipe-based baits (yeast, wine-vinegar, and apple cider vinegar) captured fewer D. suzukii overall, although the commercial baits Dros'Attract and Suzukii Trap were comparable to the Scentry lure in late season tests. The Trécé lures were consistently the most selective of the attractants, but had generally lower D. suzukii captures. Sex ratio varied widely among and within the tests, but with no consistent pattern among the various attractants. All attractants were successful in capturing flies, and the choice of attractant depends on the constraints and goals of the user.