Pathogenicity and field efficacy of a native Beauveria bassiana isolate (UBKV Bb1) against selected insect pests

Growing concerns over the effects of chemical insecticide use across the globe have intensified interest in biological control. Entomopathogenic fungi are attaining commercial importance due to their wide host range and effectiveness against insect pests. The present study assessed the biocontrol potential and virulence of a native isolate of Beauveria bassiana (UBKV Bb1) against three insect pests representing different orders: Lipaphis erysimi (Aphididae: Hemiptera), Corcyra cephalonica (Pyralidae: Lepidoptera), and Sitophilus oryzae (Curculionidae: Coleoptera) under laboratory conditions. The mortality rates were 89.87% in L. erysimi at 6 days after treatment (DAT), 86.67% in C. cephalonica at 15 DAT, and 85.33% in S. oryzae at 25 DAT at 1×10⁸ conidia mL ^− 1 . Lethal concentration (LC ₅₀ ) values were 0.74 × 10 ⁶ , 1.2 × 10 ⁶ , and 1.8 × 10 ⁶ conidia mL ^− 1 for L. erysimi, C. cephalonica , and S. oryzae , respectively. LT ₅₀ values increased from 3.80 days (aphid) to 13.51 days (weevil) at 1×10⁸ conidia mL ^− 1 . Additionally, field evaluation studies showed that UBKV Bb1 was effective in managing mustard aphids with a 77.87% reduction over control in 2023–2024 and 83.98% in 2024–2025 after two sprays. Similarly, it was effective against diamondback moth with a 65.70% and 64.53% reduction in two consecutive years. Since it has a high B:C ratio, accompanied by less environmental impact, it can be integrated into an IPM programs, particularly in the northern region of India.