A residual contact vial plus water (RCVpW) bioassay method was established to monitor insectiside resistance in field populations of the melon thrips, Thrips palmi. Resistance level against six major insecticides were evalutated in five regions to test applicability of RCVpW as an on-site resistance monitoring tool. Reduced mortality in response to six test insecticides were exhibited compared to the RDA susceptable strain showing 100 % mortality, indicating different degree of resistance. An apparently reduced mortality to emamectin benzoate and chlofenapyr was observed in some field populations, suggesting uneven distribution of resistance to these insecticides in field populations. In addition, spinosad resistance was high and widely distributed in the test regions. Synergistic bioassay revealed that cytochrome P450-mediated metabolic factor is involved in spinosad resistance in the Korean population.

• Min Ju Kim(Department of Agricultural Biotechnology, Seoul National University)
• Kyungmun Kim(Department of Agricultural Biotechnology, Seoul National University)
• Tian-Bo Ding(College of Plant Health and Medicine, Qingdao Agricultural University)
• Ju Hyeon Kim(Research Institute of Agriculture and Life Sciences, Seoul National University)
• In Hong Jeong(Division of Crop Protection, National Institutes of Agricultural Science, Republic Development Administration)
• Deok Ho Kwon(Research Institute of Agriculture and Life Sciences, Seoul National University)
• Si Hyeock Lee(Department of Agricultural Biotechnology, Seoul National University/Research Institute of Agriculture and Life Sciences, Seoul National University)