Efficacy of selected biopesticides and entomopathogens against Bihar hairy caterpillar, Spilarctia obliqua Walker infesting castor, Ricinus communis L. under field condition in India

Bihar hairy caterpillar (Spilarctia obliqua Walker) is a destructive polyphagous pest causing severe defoliation in castor (Ricinus communis L.), particularly during early crop growth stages leading to more yield losses. Although chemical pesticides provide quick control, their adverse effects on non-target organisms, environmental safety, and resistance development have increased the need for eco-friendly alternatives. Therefore, the present study evaluated eco-friendly biopesticides and entomopathogens for effective management of S. obliqua in castor. Field evaluation of biopesticides and entomopathogens was conducted during kharif 2024–25 at the Center for Oilseeds Research, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar, Gujarat, India. The results revealed that azadirachtin 10000 ppm @ 0.003% and NSKE @ 5% were most effective in reducing larval population (9.84 larvae/plant and 10.12 larvae/plant) and leaf damage (24.40% and 24.59%), respectively. These treatments also recorded higher seed yields of 3,057 and 2,910 kg/ha, respectively, followed by Agniastra at 10%, which yielded 2,506 kg/ha. The highest protection cost benefict ratio (PCBR) was recorded in NSKE (1:17.81), followed by azadirachtin (1: 17.16), indicating their suitability in integrated pest management (IPM) for effective management of Bihar hairy caterpillar in castor.