- Spotted wing Drosophila (SWD), Drosophila suzukii (Diptera: Drosophilidae), is a pest of small and stone fruits that is widely distributed across much of the United States, Canada, Europe and Asia. Unlike other members of the Drosophilidae that only lay eggs in overripe or rotting fruit, SWD infest ripening and ripe fruit. The female SWD has a serrated ovipositor that allows her to lay eggs under the skin of a wide range of fruits, where the eggs hatch into larvae and they consume the inside of the fruit. This feeding results in fruit collapse and deterioration, and the hole created by the oviposition puncture allows for secondary infection by microorganisms, yield losses, reduced fruit quality and degrades. The current control is to apply an insecticide treatment when the fruit begins to color and continue to keep the crop protected with chemical treatments until harvest is complete. The current monitoring tools are not sensitive enough to attract SWD at the critical time to establish economic thresholds, appropriately time treatments and allow growers to make good management decisions.
The objective of this research project was to determine if a more sensitive attractant than the currently standard 5% acidity apple cider vinegar traps could be defined. A number of food products and commercially available lures were tested in greenhouse and field experiments for their attractiveness to D. suzukii. There were no bait treatments that captured significantly more D. suzukii than the currently standard 5% acidity apple cider vinegar(ACV)-baited traps. Balsamic vinegar, soy sauce, balsamic honey vinegar, a D. melanogaster lure, Monterey Insect Bait, rice vinegar, seasoned rice vinegar, and NuLure® performed similarly to ACV, broadening the field of starting material that could be investigated for their use as an SWD attractant. A number of fermentation compounds were also tested in greenhouse and field trials for their attractiveness to SWD. Four classes of compounds were tested: short chain alcohols, short chain carboxylic acids, low molecular weight acetates, and esters of 2-phenylethanol. In the greenhouse trials, some of the compounds alone were determined to be attractive and subsequently used in field trials. However, none of the compounds or combinations of the compounds tested improved attractiveness of apple cider vinegar traps when compared to the standard 5% acidity apple cider vinegar-baited trap.