Dissipation of Chlorpyriphos on Cauliflower (Brassica oleraceea. Var. botrytis)

Dissipation of chlorpyriphos on cauliflower was studied following applications at recommended dose (500 g ai ha⁻¹) and double dose (1000 g ai ha⁻¹) for the two consecuttve years 2004 and 2005 to work out the safe preharvest waiting period. The average initial deposits varied from 0.56–0.86 and 1.29–1.43 mg kg⁻¹, respectively. The residue half-life of chlorpyriphos varied from 1.4–1.5 and 1.5–1.6 days for lower and higher dose, respectively. The residues reached below the MRL of 0.05 mg kg⁻¹ in 5.0–6.3 and 7.1–7.3 days at normal and double dose, respectively.