Bioefficacy and persistence of coragen 18.5 SC (Chlorantraniliprole) Against early shoot borer, Chilo infuscatellus Snellen in sugarcane and effects on beneficial arthropods

Field experiments were conducted over two consecutive seasons (2016-17 and 2017-18) at four locations in Punjab, India: Jalandhar, Sangrur, Kapurthala, and Gurdaspur. The study aimed to evaluate the efficacy of different doses of Coragen 18.5 SC (chlorantraniliprole) in managing the early shoot borer (Chilo infuscatellus Snellen) in sugarcane. The doses tested included 75, 100, 150, and 200 mL per acre, alongwith a standard treatment of Dursban 20 EC (chlorpyriphos) at 2000 mL per acre, and an untreated control. Prior to insecticide application, the percentage of dead hearts in the sugarcane plants ranged from 10.84% to 12.35%. After one and two months of treatment, the incidence of early shoot borer was significantly reduced across all Coragen 18.5 SC doses, with the percentage of affected plants ranging from 0.12% to 4.86% and 0.17% to 4.64%, respectively. In contrast, the untreated control showed significantly higher infestation rates of 14.98% and 15.81% at the same intervals. The incidence in plants treated with Dursban 20 EC was 4.36% after one month and 4.25% after two months, demonstrating its efficacy, though it was slightly less effective than Coragen at the higher doses. Among the various treatments, Coragen 18.5 SC at 150 mL per acre and 200 mL per acre performed equally well in terms of early shoot borer management, crop yield, natural enemy populations, and economic returns. However, the 150 mL per acre dose was the most effective, resulting in a significantly higher sugarcane yield of 313.87 quintals per acre and a net return of Rs. 68,760.00. Additionally, no residues of chlorantraniliprole were detected in sugarcane juice or soil samples, even at the highest application rates (30 and 60 g a.i. per acre), with detection limits of 0.05 mg/kg. These findings suggest that Coragen 18.5 SC at 150 mL per acre is an effective and environmentally safe alternative to conventional insecticides for managing early shoot borer in sugarcane, offering both economic and ecological benefits.