Field Evaluation of Vinegar-Based Attractants and Their Volatile Profiles for Monitoring Drosophila suzukii (Diptera: Drosophilidae) in Blackberry and Blueberry Orchards

The spotted-wing drosophila, Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae), is an invasive pest causing substantial economic losses in berry production worldwide. Reliable monitoring is essential for effective integrated pest management; however, information on the field performance of locally produced vinegar-based attractants remains limited. This study compared the attractiveness of four vinegar-based attractants (homemade grape vinegar, homemade hawthorn vinegar, homemade apple vinegar, and commercial apple vinegar) for monitoring D. suzukii in blackberry (Rubus spp.) and blueberry (Vaccinium spp.) orchards in southeastern Türkiye during the 2023 and 2024 growing seasons. In addition, the volatile organic compound (VOC) profiles of the attractants were characterized using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC–MS). A total of 80,571 adult flies were captured during the study. Significant differences among attractants were detected in all host plant–year combinations (one-way ANOVA, p < 0.001). Generalized linear mixed model analysis further demonstrated significant effects of the host plant, attractant type, sampling week, and year on weekly trap captures (p < 0.05). Homemade grape vinegar consistently produced the highest trap captures, whereas commercial apple vinegar showed the lowest trapping performance. Fourteen volatile compounds belonging mainly to carboxylic acids, alcohols, esters, aldehydes, and monoterpenes were identified, revealing differences in the volatile profiles of the evaluated attractants. Overall, homemade grape vinegar proved to be the most effective vinegar-based attractant under the conditions of this study and represents a practical, low-cost option for monitoring D. suzukii in berry orchards. Further studies incorporating replicated chemical analyses and behavioural bioassays are needed to clarify the contribution of individual volatile compounds to insect attraction.