UTTAR PRADESH JOURNAL OF ZOOLOGY

Insect pests cause substantial yield losses in agriculture, prompting widespread use of chemical pesticides that threaten environmental and human health. Biological control using Beauveria bassiana offers a sustainable alternative, but its efficacy is often limited by environmental stresses and formulation challenges. Encapsulating B. bassiana conidia with biopolymers helps protect the fungus from environmental stresses and improves shelf life by acting as a physical barrier. This study evaluated the compatibility of biopolymers, chitosan (0.1 %, 0.25 %, 0.5%, 1 % and 2.5 %) and lignosulphonate (1 %, 2.5 %, 5 %, 7.5 % and 10 %) with B. bassiana by assessing mycelial growth, spore production and virulence against Spodoptera litura larvae. Low chitosan concentrations (0.1–0.5 %) maintained high radial growth (up to 99.60 %), sporulation (2.00 × 10⁸ spores/mL) and larval mortality (88.33 %). However, at the highest concentration (2.5 %), chitosan significantly reduced B. bassiana performance, with radial mycelial growth declining to 90.21%, spore production dropping to 1.33 × 10⁸ spores/mL and larval mortality decreasing to 75.00 %. Lignosulphonate demonstrated superior compatibility, with mycelial growth above 98.8 % and larval mortality above 85 % at all concentrations. The control (without any added biopolymers) achieved 100 % mycelial growth, 2.00 × 10⁸ spores/mL and 91.67 % larval mortality. These results highlight lignosulphonate and low-dose chitosan as promising encapsulating agents for stable, effective B. bassiana formulations.