Residues of Cypermethrin and Ethion in Cotton Seed and Lint

Six applications each of cypermethrin @ 50 and 100 g a.i. ha⁻¹ and ethion @ 400, 800 and 1600 g a.i. ha⁻¹ were applied on cotton at 10d interval and the residues were estimated in cottonseed and lint. The residues of cypermethrin (0.17–0.25 mg kg⁻¹) and ethion (0.18–0.62 mg kg⁻¹) were detected only in lint samples. However, the lint samples collected at the second pick did not show the presence of any insecticide. The residues of cypermethrin and ethion in cottonseed samples remained below their detectable level.