Dissipation rate and residual fate of thiamethoxam in tobacco leaves and soil exposed to field treatments.

Abstract

A two-year field experiment was conducted in two different locations to investigate the dissipation rate and residual fate of thiamethoxam in tobacco leaves and soil by high performance liquid chromatography with UV detection. The average recoveries for green, cured tobacco leaves and soil ranged from 89.7 %-94.8 %, 90.6 %-94.4 % and 89.0%-92.8 %, respectively, with relative standard deviations between 2.7 % and 9.2 %. The dissipation rates of thiamethoxam were described by first-order kinetics and its half-life values were in the range of 3.9-4.4 days in green tobacco leaves and 12.0-19.1 days in soil, respectively. The residue levels of thiamethoxam at harvest time ranged from 0.020-0.541 mg/kg in cured tobacco leaves, and 0.005-0.019 mg/kg in soil, respectively.