D3110: Can Drosophila suzukii Matsumura (Diptera: Drosophilidae) be controlled by micro-sprinklers in highbush blueberry?

Drosophila suzuki (Matsumura), spotted wing drosophila, is a detrimental pest in highbush blueberry production. Controlling D. suzukii is a challenging task and insecticides are mainly in use to keep the population under control. Delivering the insecticides onto the blueberry bush is mainly occurs via sprayers; however, micro-sprinkler can be an alternative method to apply insecticides. The aim of the current study was to evaluate the effects of insecticides on D. suzukii egg-laying, with a new application technique in commercial cropping systems and integrating the fecundity model simulations to estimate population levels. Field trials were conducted over periods of eleven days on commercial-standard highbush blueberry. Cyantraniliprole and spinetoram were applied both with micro-sprinkler and backpack sprayer, while Chromobacterium subtsugae and zeta-cypermethrin were only applied with backpack sprayer as a reference application. In addition, modeling simulations were used to estimate the egg infestation of both application methods. Both insecticides (cyantraniliprole and spinetoram) had a moderate suppression on D. suzukii and no statistical significance was found between micro-sprinkler and backpack sprayer application. Zeta-cypermethrin resulted in the most significant suppression of D. suzukii egg-laying over the whole experiment period, while C. subtsuage was not effective against D. suzukii egg-laying. Simulations indicated that backpack sprayer relatively reduced the population levels more than micro-sprinkler applications. In conclusion, micro-sprinkler systems provide an alternative and rapid spray application tool to combat D. suzukii in highbush blueberry systems.