Can the floral volatile methyl benzoate protect blueberry from spotted-wing drosophila?

The spotted-wing drosophila (SWD), Drosophila suzukii, is an invasive pest of fruit crops such as grapes, strawberries, cherries, raspberries, and blueberries. SWD differ from other Drosophila in their preference to oviposition in fruits that are still ripening on the plant, rather than overripe or rotting fruits. To control SWD, pesticide applications must be performed close to the harvest date, which can present risks to consumers. If control measures are not taken, consumers might find SWD larvae in their fruits. The volatile organic compound methyl benzoate (MB) is a naturally occurring plant odor released heavily by snapdragon and petunia flowers. MB has a chemical structure similar to DEET, and preliminary laboratory assays have demonstrated that SWD oviposit less frequently in the presence of MB. To test whether MB reduces oviposition in the field, we conducted a study in a blueberry orchard in Maryland where SWD can be found in high numbers. We used a complete block “push-pull” experimental design, with MB as the repellent “push” agent, and a previously developed quinary blend of attractant compounds as the “pull” agent. Oviposition rates were compared across “push”-only (MB dispensers in bushes with non-baited traps hung nearby), “pull”-only (baited traps hung nearby with no MB dispensers in bushes) , “push-pull” (MB dispensers in bushes with baited traps nearby), and control plots (no MB dispensers in bushes with non-baited traps nearby) to determine whether the repellent or attractant can act independently or need to act in combination to reduce SWD damage to blueberries.