Residues of Synthetic Pyrethroids in Cotton Seed, Oil and Lint
A study was conducted to determine residues of fenvalerate, cypermethrin, deltamethrin and endosulfan on cotton ‘Hybrid-6’ during 1986 and 1987. Deltamethrin did not leave any residue in cotton seed, oil and lint. Penvalerate and cypermethrin residue levels were below the prescribed maximum residue limit of 0.2ppm in cotton seed. However, in cotton seed oil, fenvalerate residue exceeded the maximum residue limit of 0.1 ppm in the first picking at the recommended level. Application of fenvale-rate at lower and higher dose resulted in 0.141 and 0.261 ppm residues in oil, and 0.1 95 and 0.292 ppm in lint, respectively in the first picking. The corresponding values for cypermethrin were 0.147 and 0.309 ppm, and 0.097 and 0.151 ppm, respectively. Endosulfan residues at the first picking in cotton seed and oil were below the maximum residue limits of 0.5 and 0.2 ppm, respectively. Residues were considerably lower in the second picking for all the insecticides.