Studies on the fate of ready-mix formulation of endosulfan and cypermethrin in tea.

Ready-mix formulation consists of two insecticides-endosulfan (35%) and cypermethrin (5%). To understand the dissipation pattern of the insecticides on made tea from the north-east region of India, it was applied twice in 10 day interval @ 1,000 mL/ha (350 g a.i. endosulfan + 50 g a.i. cypermethrin) and 2,000 mL/ha (700 g a.i. endosulfan + 100 g a.i. cypermethrin) along with untreated control. The made tea samples were collected at 0, 1, 3 and 7 days interval after last application. The dissipation rate of endosulfan and cypermethrin followed first order kinetics. The calculated half-life values were found in the range between 1.7 to 2.1 days for endosulfan and 1.0 to 1.1 days for cypermethrin.