The present study was done in 2010–11 to compare the persistence of endosulfan and cypermethrin in ready-mix formulation of Endohyper 40 EC (endosulfan 35% + cypermethrin 5%) with individual insecticide endosulfan (Endocel 35 EC) and cypermethrin (Challenger 25 EC). Endosulfan and cypermethrin were applied at recommended rate 350 g and 50 g ai/ha and at double the recommended rate 700 g and 100 g ai/ha on cauliflower crop. The curds and soil samples were collected at different intervals and analyzed after second spray. Residues of both insecticides were determined by using gas chromatograph, Agilent 6890N having electron capture detector. In curds the endosulfan and cypermethrin residues reached below detectable limit in 15 and 7 days when applied at recommended rate and in 20 and 10 days when applied at double recommended rate. Endosulfan deposits were reduced to half in 1.81–2.32 days and cypermethrin deposits required 1.19–1.44 days to reduce to half as combi product but when applied individually endosulfan initial deposits were reduced to their half in 1.21–1.51 days and cypermethrin deposits became half in 1.38–1.69 days. In soil residues of endosulfan persisted for 0–20 days whereas residues of cypermethrin persisted for 0 day only.
Endosulfan, cypermethrin, cauliflower, residues, persistence
