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.

Since methyl bromide(MB) has been designated as ozone deplete substance(ODS) by Montreal protocol (1989), many MBalternative fumigants like ethyl formate and phosphine gas were developed and commercialized. Ethyl formate(EF) is an effectiveMB alternative fumigant to control insect pests on imported fresh commodities. It is important to develop a proper evaporationmethod to apply EF on large scale fumigation because EF has a high boiling point(54℃). Recently, concurrent treatment ofethyl formate and nitrogen(EF+N2 treatment) has been newly developed. At preliminary test, EF+N2 treatment showed goodevaporation rate and showed high efficacy on quarantine pests without phytotoxicity on fresh commodities. In this trial, we’veapplied the EF+N2 treatment on imported orange and lemon at pilot scale (0.5m3, 10m3) containers and commercial scale containerto validate efficacy and phytotoxicity. 70g/m3 of EF liquid was applied on orange and lemon by EF+N2 treatment method,and showed 100% mortality on tested insect pest(Tetranychus urticae) without phytotoxicity at 0.5m3 and 10m3 scale fumigationtrials, respectively. At commercial scale trial, EF+N2 treatment also showed 100% efficacy on T. urticae and there was nophytotoxic symptoms on imported orange and lemon fruit. These results indicate that the newly developed EF+N2 treatmenthas a potential as a MB alternative, and can be applied on imported fresh commodities for quarantine and pre-shipment purpose.