Efficacy of Biorational and Insecticides against Helicoverpa armigera (Hübner) in Pigeonpea

The field experiment conducted at Norman E. Borlaug Crop Research Centre (N.E.B.C.R.C.), Govind Ballabh Pant University of Agriculture and Technology, Pantnagar during Kharif 2024–25 evaluated the efficacy of six biorational insecticides against the gram pod borer, Helicoverpa armigera, infesting pigeonpea. All treatments significantly reduced the larval population compared to the untreated control. Chlorantraniliprole 18.5% SC was most effective in reducing larval population, recording as low as 0.33 larvae/5 plants at 10 days after second spray, with pod damage reduction of 77.44% and a substantial grain yield of 797 kg/ha, representing a 97.11% increase over the untreated control. Spinetoram and azadirachtin also provided significant larval suppression and pod damage control, achieving pod damage reductions of 71.43% and 40.60%, and grain yields of 745.67 kg/ha and 652.50 kg/ha, respectively. Bacillus thuringiensis var. kurstaki demonstrated effective pest suppression with 45.86% pod damage reduction, a 72.51% yield increase to 697.50 kg/ha, and the highest incremental cost-benefit ratio (ICBR) of 8.20, underscoring superior economic efficiency. Metarhizium anisopliae displayed moderate efficacy with 29.32% pod damage reduction and a 42.70% yield increase. These findings highlight the potential of Bt as a highly effective and economically viable component of integrated pest management strategies, capable of reducing chemical pesticide reliance while sustaining pigeonpea productivity and profitability.