Insecticide Efficacy against Earias Species Infestation of Okra and Residue Analysis of Chlorantraniliprole under Field Conditions in India

Abstract

A field study was conducted to compare the efficacy of 10 recommended insecticides against Earias spp. on okra. Three okra plots (3 m × 5 m (15 m2)) were subjected to each of the 10 insecticidal sprays applied twice at an interval of 10 days. On the third, seventh, and tenth day after each spray, percent shoot and fruit infestation and yield were calculated. All insecticides significantly reduced shoot and fruit infestation compared to the control. However, chlorantraniliprole 18.5%SC was the most effective across all time points and resulted in the highest yield. A second field study, to determine the time till the maximum residue limit (MRL—0.3 mg/kg) and the limit of quantification (LOQ—0.01 mg/kg) for both fruit and soil exposed to either the recommended (125 mL/ha) or a double strength dose (250 mL/ha) of chlorantraniliprole 18.5% SC was undertaken. MRL was reached on the same day following both doses. The LOQ was reached on the seventh and tenth day at recommended and a double strength dose, respectively. Chlorantraniliprole 18.5% SC provides effective control. However, Earias spp. resistance has been observed in other crops. Thus, constant monitoring in the field is needed to ensure its effectiveness.