Fenvalerate (α-cyano-m-phenoxy-benzyl α-isopropyl-p-chlorophenyl acetate) residues in and on okra fruits

Okra crop was sprayed with sumicidin 20E (Fenvalerate 20% EC) at the rate of 300 ml/ha (C1), 375 ml/ha (C2) and 500 ml/ha (C3). Residues in fruit samples were determined by gas chromatography (Hewlett Packard 5890 A) at different time intervals to establish the safe waiting period for Fenvalerate. The initial deposits of Fenvalerate on okra fruits for C1, C2 and C3 were 1.4 ppm, 2.8 ppm and 4.5 ppm, respectively. Seven days after spraying, the initial deposits of C1, C2 and C3 decreased to 0.03 ppm, 0.05 ppm and 0.67 ppm, respectively. The residue values of Fenvalerate on okra fruits 7 days after spraying were below the tolerance limit (0.2 ppm; Anonymous, 1978; FAO, 1980) for C1 and C2, but above it in the case of C3. Ten days after spraying, the residue values of C1, C2 and C3 were below the tolerance limit.