Fate of thiodicarb and its metabolite methomyl in sandy loam soil under laboratory conditions.

Fate of thiodicarb and its major metabolite in sandy loam soil were studied by applying thiodicarb (Larvin 75 WP) at 500 and 1000 g a. i. ha(-1) under laboratory conditions. Samples drawn periodically were analysed on GC-FTD equipped with capillary column. The average initial deposits of total thiodicarb (thiodicarb and methomyl) were 0.025 and 0.035 mg kg(-1) at single and double dosages, respectively. Residues of thiodicarb reached below the determination level (BDL) of 0.005 mg kg(-1) after 15 days. Half-life periods for total thiodicarb were calculated to be 5.90 and 8.29 days at two doses, respectively, following first-order kinetics.