Effects of ultralow oxygen treatments at low temperature on survival of spotted wing drosophila, <i>Drosophila suzukii</i> (Diptera: Drosophilidae), in blueberries and sweet cherries

Controlled atmosphere with ultralow oxygen (ULO) treatments were conducted to determine effects against eggs and larvae of spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), in blueberries and cherries at 3 °C in 19 liter cylinder chambers. ULO treatments of 72 h with 500, 200, and 100 ppm O2 were conducted against eggs and larvae in blueberries and cherries. ULO treatments of 96 h with 500, 200, and 50 ppm O2 were conducted against eggs in blueberries and against eggs and larvae in cherries. ULO treatments were effective against eggs and larvae of spotted wing drosophila but did not result in complete mortality of all life stages. ULO treatments were more effective against larvae than against eggs. ULO treatments of 96 h resulted in significantly higher mortality of eggs and larvae in cherries than 72-h treatments. ULO treatments of 72 h with 200 and 100 ppm O2 resulted in 100% larval mortality in blueberries and over 95% larval mortality in cherries. The same treatments yielded over 80% mortality of eggs in blueberries and cherries. All three 96-h ULO treatments resulted in over 99% mortality of larvae in cherries. The same treatments resulted in 82.29% to 91.73% and 92.10% to 95.00% mortalities for eggs in blueberries and cherries, respectively. This study demonstrated that ULO treatments were effective against eggs and larvae of spotted wing drosophila in blueberries and cherries. However, efficacy did not meet phytosanitary requirement, and more research is needed to develop a more effective ULO treatment for phytosanitary applications.