Spotted wing drosophila, Drosophila suzukii, causes damage on several fruits include strawberry in Korea. D. suzukii lays egg inside fruit surface, and this behavior makes D. suzukii hard to detect, so many countries designated D. suzukii as a quarantine pest. Recently, Australian government demand methyl bromide fumigation on Korean export strawberry to prevent D. suzukii invasion. In this study, we tested methyl bromide to control D. suzukii, and also tested separate and concurrent treatments of methyl bromide to evaluate phytotoxicity on strawberry. When 40 g/m3 of methyl bromide was treated for 3 hours, all stages of D. suzukii were completely controlled. When treated separate and concurrent with cold temperature treatments of methyl bromide, there’s no specific phytotoxicity on strawberry. This result indicates that separate and concurrent treatments of methyl bromide do not cause phytotoxic effect on strawberry and methyl bromide is effective to control D. suzukii.

The susceptibility of three fumigants, methyl bromide, ethyl formate and phosphine, and concurrent treatment of ethyl formate and phosphine were tested on Lasioderma serricorne. Susceptibility assessment were performed by treating 5 to 6 initial dosage on every growth stages of L. serricorne. The LCT50 of methyl bromide was 13.896mg h/L for egg, 36.038mg h/L for late larvae, 25.172mg h/L for pupae and 21.758mg h/ L for adult, respectively. The LCT50 of phosphine was 0.317mg h/L for egg, 0.649mg h/L for late larvae, 3.748mg h/L for pupae and 0.703mg h/L for adult, respectively. In case of ethyl formate, the LCT50 was 43.657mg h/L for egg, 137.606mg h/L for late larvae, 72.676mg h/L for pupae and 52.951mg h/L for adult, respectively. Concurrent treatment of ethyl formate and phosphine was performed by treating 5 to 6 initial dosage of ethyl formate with 0.5 mg/L phosphine for 4 hours on every growth stages of L. serricorne. The LCT50 of ethyl formate concurrent treatment was 13.746mg h/L for egg, 8.156mg h/L for late larvae, 27.087mg h/L for pupae and 11.353mg h/L for adult, respectively, and these results indicate that concurrent treatment can control pest with lower dosage and shorter period. Sorption rates and ventilation periods of each fumigants were also calculated for efficacy and safety

Spotted wing drosophila, Drosophila suzukii, is an important pest of grape and strawberry because it lays egg inside fruit by damaging fruit surface. Recently, D. suzukii has been widely spreaded and causes several problems, so many countries include Australia designated D. suzukii as an important quarantine pest. Because of this, Korean farmers have trouble to export strawberry. In this study, we tested ethyl formate and phosphine to control D. suzukii, and also tested concurrent treatment of ethyl formate and phosphine to reduce phytotoxicity and enhance efficacy. When treated 35g/m3 of ethyl formate for 4 hours, mortality of egg, larvae, pupae and adult stages of D. suzukii was 22.2%, 21.1%, 19.2% and 28.3%, respectively. When treated 1g/m3 of phosphine for 24 hours, all stages of D. suzukii was completely controlled, but caused phytotoxic effect on strawberry. When treated with 35g/m3 of ethyl formate and 1g/m3 of phosphine concurrently for 4 hours, efficacy has been increased with less phytotoxicity than separate treatment. This result indicates that concurrent treatment enhanced efficacy with less phytotoxicity.