Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2017
Publication Date: 5/22/2017
Citation: Cha, D.H., Adams, T., Landolt, P.J. 2017. Effect of chemical ratios of a microbial-based feeding attractant on trap catch of spotted wing drosophila (Diptera: Drosophilidae). Environmental Entomology. 46(4):907-915.
Interpretive Summary: Spotted wing drosophila (SWD) is a newly introduced pest of numerous fruit crops that is spreading rapidly through the U.S. and Europe, including areas of extensive commercial fruit production such as western U.S. Trapping with fermented food baits (chiefly vinegar or yeast baits) is presently the means of detecting and monitoring the fly, and warning growers of the need to apply insecticides. Recently, researchers at the USDA-ARS laboratory in Wapato, Washington developed a 4-component synthetic chemical attractants for SWD, for use in detection and management. By optimizing the amount of each blend component, they doubled the attractiveness of the lure to SWD. This new optimized formulation is a more powerful improvement over the prior reported lure formulation and should be of greater use in efforts to detect and monitor SWD.
Technical Abstract: Drosophila suzukii Matsumura (SWD) can be trapped with a feeding attractant based on wine and vinegar volatiles and consisting of acetic acid, ethanol, acetoin and methionol. Using that 4-component blend, we found that the catch of SWD increased with increases in the release rate of acetoin (from 0.5 mg/d to 34 mg/d) from polyethylene sachet dispensers, and with increases in the concentrations of acetic acid (from 0.25% to 4%) or ethanol (from 0.08% to 2%) when dispensed in the trap drowning solution. However, we saw no increase in SWD trapped with increase of the methionol release rate from 0.4 mg/d to 4.9 mg/d or from 0.19 mg/d to 0.8 mg/d, from sachets. A new formulation based on optimized amounts of these four chemicals yielded a doubling of SWD trapped compared to a previously reported formulation. Further field testing confirmed that the simultaneous increases in the release rate of acetoin from a dispenser and the amount of acetic acid in the trap drowning solution provided the increased SWD trap response to the new formulation. These findings provide a practical means to improve the power of this lure to detect and monitor D. suzukii.