| Abstract |
- Knowledge of Drosophila suzukii's preference for an attractive trap design and bait can be used to improve detection and management of this new invasive fruit pest. Desired trap and bait attributes include: high D. suzukii capture and species specificity; early-season detection prior to significant crop damage; higher capture of females than males; limit escapage from trap; and a positive response to seasonal changes in population, landscape, and weather. Bait trials were replicated 3-4 times in 4 different host crops, including: 'Spartan' cultivar blueberries on a no-spray farm (Benton Co. Oregon); a wild 'Himalaya' blackberry perimeter adjacent to a diversified, organic-certified farm (Benton Co., Oregon); no-spray Early 'Burlette' cultivar cherries on a diversified, organic-certified farm (Benton Co., Oregon); and organic 'Nleeker' cultivar raspberries on an organic-certified farm (Whatcom Co., Washington). Baits included: apple cider vinegar, Chinkiang vinegar, Saccharomyces cerevisiae yeast, Hanseniaspora uvarum yeast, BioLure®, Torula Yeast Pellets®, Monterey Insect Bait®, Suzukii Trap®, and a 4-compound (acetic acid, methionil, acetoin, and ethanol) lure. Each bait was placed in a 950 mL side-mesh entry clear cup trap. Chinkiang vinegar and H. uvarum-baited traps had consistently high D. suzukii counts in all crop types tested. Suzukii Trap® baited traps had promising results; however, factors such as humidity and bait evaporation affected captures in blueberry and blackberry crops. Consistently, Torula Yeast Pellets® baited traps had low efficacy, and BioLure® and Monterey Insect Bait® baited traps showed little to no efficacy. Traps with the 4-compound lure yielded moderate trap catch relative to other baits, but showed the highest specificity to D. suzukii across the season. During the late-season period, traps baited with apple cider vinegar showed increased D. suzukii capture compared to observed early-season counts. Early-season Drosophila species captures were primarily other Drosophila species (66 - 100%), whereas late-season captures were 90 - 95.5% D. suzukii. The gender distribution of D. suzukii shifted from higher counts of females early-season to higher counts of males late-season. Trap designs varied in color, entry type (mesh vs. hole), trap volume, bait surface area, and headspace (area between bait surface and entry holes). Designs were replicated 4 times and tested in the wild 'Himalaya' blackberry perimeter described above. Each trap contained a Saccharomyces cerevisiae yeast/sugar solution. Traps with higher trap captures of D. suzukii had a low volume between the surface of the bait and the entry holes and a high volume between the entry holes and the trap top. Three traps that captured the highest numbers of D. suzukii overall were: 1) "Clear 20-Hole" (950 mL; 20-holes; clear cup), 2) "Squatty Botty Fly Trap" (1183 mL; side-mesh; red-yellow-black vertical stripe cup), and 3) "Lucky 13" (530 mL 13-hole; red cup). Increased entry area improved trap catch, and color did not appear to impact capture. However, traps supplemented with a killing agent placed inside the lid revealed significantly more D. suzukii than traps without.
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