Dissipation pattern of profenophos on cabbage (brassica oleracea var.capitata)

An experiment was conducted during kharif, 2012 to evaluate the efficacy of seven insecticides viz., emamectin benzoate 5 SG at 11 g a.i.ha-1, emamectin benzoate 5 SG at 22 g a.i.ha-1, profenophos 50 EC at 500 g a.i.ha-1, profenophos 50 EC at 1000 g a.i.ha-1, spinosad 45 SC at 100 g a.i.ha-1, bifenthrin 10 EC at 100 g a.i.ha-1 and Bacillus thuringiensis at 5 WP at 25 g a.i.ha-1 against DBM (Plutella xylostella) on cabbage of which profenophos 50 EC (1000 g a.i.ha-1), applied twice as foliar spray was found to be most effective in controlling the P. xylostella for which the dissipation studies were conducted. The dissipation pattern of profenophos 50 EC (1000 g a.i.ha-1) was studied collecting samples at regular intervals i.e. 0, 1, 3, 5, 7, 10, 15 and 20 days after last spray and analyzed. The initial deposits of 0.99 mg kg-1 profenophos recorded at 2 hours after last spray dissipated to 0.85, 0.82, 0.16 and 0.07 mg kg-1 by 1, 3, 5 and 7 days after last spray, respectively and below determination level (BDL) by 10th day.