Dissipation of β-Cyfluthrin and Imidacloprid on Okra Fruits under Middle Gujarat Conditions

Dissipation of β-cyfluthrin and imidacloprid was studied on okra fruits following three applications of a combination product (β-cyfluthrin 9% + imidacloprid 21%) at 7 d interval @ 18 and 36 g a.i. ha⁻¹ with respect to β-cyfluthrin and 42 and 84 g a.i. ha⁻¹ with respect to imidacloprid, respectively. The initial deposits for β-cyfluthrin were observed to be 0.18 and 0.56 μg g⁻¹ at recommended and double the recommended dose, respectively. The corresponding levels for imidacloprid residues were 0.30 and 1.23 μg g⁻¹. At recommended dose both the insecticides reached below determination limit (BDL) of 0.01 μg g⁻¹ on the 3^rd d. However, at higher dose, β-cyfluthrin and imidacloprid reached BDL on the 5^th and 7^th d, respectively. The half-life (DT₅₀) of β-cyfluthrin and imidacloprid at recommended dosage was found to be 0.60 and 0.49 d, respectively.