Dissipation and Decontamination of Cypermethrin and Fluvalinate Residues in Okra

Dissipation and decontamination of cypermethrin (50 and 100 g ai ha⁻¹) and fluvalinate (40 and 80 g ai ha⁻¹) have been studied in okra fruits. Initial deposits of 0.274 and 0.382 mg kg⁻¹ of cypermethrin at 50 and 100 g a.i. ha⁻¹ treatments, dissipated to 0.013 and 0.020 mg kg⁻¹ in 15 days after third application with respective half-life values of 3.4 and 3.5 days and waiting periods of 2 and 3 days. Fluvalinate recorded initial deposits of 0.091 and 0.126 mg kg⁻¹, which dissipated below detectable level (<0.005 mg kg⁻¹) in 15 days. The half-life values were 2.5 and 2.3 days. As the initial deposits in both the doses were less than MRL, a safe waiting period of 1.0 day is suggested. Washing of okra fruits with tap water removed cypermethrin residues to the extent of 41.2–48.3% in 0 day samples and 37.1–46.0% in 5^th day samples. In case of fluvalinate, the extent of removal was 38.0–44.2% in 0 day and 32.4–41.8% and 5^th day samples.