Trapping spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), with combinations of vinegar and wine, and acetic acid and ethanol

Recommendations for monitoring spotted wing drosophila (SWD) Drosophila suzukii (Matsumura) are to use either vinegar or wine as a bait for traps. Traps baited with vinegar and traps baited with wine, in field tests in northwest Oregon, captured large numbers of male and female SWD flies. Numbers of SWD trapped were significantly greater with a mixture of vinegar and wine compared with vinegar alone or wine alone. Attraction of SWD to vinegar and wine may be due in part to responses to acetic acid and ethanol evaporated from the two baits, respectively. Numbers of SWD captured in traps baited with 2% acetic acid in water were significantly greater than in unbaited traps, indicating a fly response to acetic acid. Very few flies were captured in traps baited with 10% ethanol in water. Traps baited with a combination of acetic acid and ethanol in water captured more SWD flies than traps baited with acetic acid or ethanol solutions alone. These results indicate a synergy of the two materials, and of the two chemicals, as lures for SWD. A comparison of a mixture of acetic acid with ethanol in water versus a mixture of vinegar with wine showed stronger fly attraction to the vinegar/wine mixture, indicating potential attractiveness of vinegar and wine volatiles in addition to acetic acid and ethanol.