Persistence of Some New Insecticides in Brinjal and their Efficacy against Brinjal Leafhopper and Borer

Persistence and efficacy of bifenthrin (10 EC, 25 and 50 g ai ha⁻¹), fipronil (5 SS, 50 and 100 g ai ha⁻¹) and carbosulfan (25 EC, 187.5 and 375 g ai ha⁻¹) along wiih endosull an (35 EC, 700 g ai ha⁻¹) was studied in brinjal crop following two spray applications. Residues of bifenthrin, fipronil and endosulfan were analysed by GLC and carbosulfan by HPLC. The residues of bifenthrin, fipronil and endosullan in brinjal fruits persisted beyond 10 days. The residues of carbosulfan persisted only for 3–7 days. The dissipation of all lhe insecticides followed first order kinettcs with half-life of ∼2.5 days for bifenthrin, 2.5–3.5 days for fipronil, 1.8–2.3 days for carbosulfan and 2.9 days for endosulfan. All the insecticides were found to give effective control of leafhopper and shoot and fruit borer in brinjal. The order of efficacy against leafhopper was fipronil 100 g ai ha⁻¹ (T₄) > fipronil 50 g ai ha⁻¹ (T₃) > carbosulfan 187.5 g ai ha-¹ (T₅) = endosulfan 700 g ai ha⁻¹ (T₇) > bifenthrin 25 g ai ha⁻¹ (T₁) > bifenthrin 50 a ai ha⁻¹ (T₂) and against shoot and fruit borer was carbosulfan 375 g ai ha⁻¹ (T₆) > fipronil 100 g ai ha⁻¹ (T₄) > endosulfan 700 g ai ha⁻¹ (T₇) > bifenthrin 50 g ai ha⁻¹ (T₂) > carbosulfan 187.5 g ai ha⁻¹ (T₅). Based on ADI values, a waiting period of 1 day is suggested for bifenthrin, carbosulfan and endosulfan and 7 days for fipronil.