- 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.