BACKGROUND: Dissipation patterns of insecticides(acequinocyl, chlothianidin, diflubenzuron, thiacloprid, thiametoxam) on strawberry in plastic-covered greenhouse grown were evaluated at 7 intervals including the pre-harvest interval after application. This study was performed to determine the residue concentrations, half-lives and dissipation rates in strawberry for the harvest periods.
METHODS AND RESULTS: Acequinocyl, chlothianidin, diflubenzuron, thiacloprid, thiametoxam were applied in accordance with critical good agricultural practices for strawberry. Strawberry samples were collected at 0, 1, 2, 3, 5, 7 and 10 days after application. Quantitaion was performed by HPLC/DAD and HPLC-MSMS system with C18 column. The limit of quantitation(LOQ) values varied between were 0.00025~0.05 mg/kg on strawberry. The recoveries of acequinocyl, clothianidin, diflubenzuron, thiacloprid and thiamethoxam at two concentrations ranged from 70.9~104.9% on strawberry. The half-lives of pesticide dissipation on strawberry for two fields ranged from 1.3~8.2 days. The dissipation rates were evaluated according to the statistics method with a 95% confidence.
CONCLUSION: The residue levels of insecticides(acequinocyl, chlothianidin, diflubenzuron, thiacloprid, thiametoxam) on strawberry at 0 days after application were below specified by Korean MRL. To estimate dissipation rate constant of pesticides on crop for harvest periods, it is important data to set the pre-harvest residue limit for human health and consumer protection in Korea.