*Present Address: Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya.
A 3-year field experiment was conducted to investigate the effect of phosphamidon [0,0-Dimethyl o (2-chloro-2-N, N-diethyl carbamoyl 1-methyl vinyl phosphate)] on the leaf physiological behaviour and yield of Indian mustard (Brassica juncea L. Czernr & Coss.) in relation to the persistence of the insecticide. The results showed that the pesticide application significantly increased the leaf temperature and stomatal diffusion resistance, while the photosynfhetic photon flux density and the transpiration rate were significantly reduced in comparison to the water-sprayed control. Pesticide application could not increase the seed yield and other yield components. The pesticide persisted till the 12th day after first spraying. Simple washing and cooking did not reduce residues in foliage significantly. Dissipation pattern of phosphamidon residues from first as well as second spraying was almost identical. No detectable residue was observed in seed.