Biocontrol potential of beauvericin produced in a submerged culture of Beauveria bassiana 331R against cotton aphid Aphis gossypii

Cotton aphid, Aphis gossypii, is a destructive pest with a rapid life cycle, high reproductive capacity, and increasing resistance to major chemical insecticides. These challenges have highlighted an urgent need for alternative, sustainable pest control solutions. This study aimed to achieve high-level production of beauvericin (BEA), an insecticidal secondary metabolite from Beauveria bassiana 331R, and to evaluate its efficacy against A. gossypii. Various media compositions, extraction methods, and thermal stability were assessed to enhance BEA production yield, after which the insecticidal activity of BEA was evaluated under both plate and pot conditions. Mealworm powder was identified as an important nutrient, and media composition enabled a maximum BEA yield of 516 mg l⁻¹—substantially higher than previous reports for B. bassiana strains. Drying and autoclaving of fungal mycelia prior to solvent extraction enhanced BEA yield by 19.9%. Notably, the insecticidal activity of BEA remained stable after autoclaving, with extracted BEA showing comparable insecticidal activity to autoclaved BEA in controlling A. gossypii nymphs at day 3. In pot experiments, BEA treatment alone significantly reduced aphid populations compared to negative controls. Mixture treatments with conidia further enhanced efficacy, with BEA playing a major contributory role. These findings establish a foundation for large-scale, sustainable BEA production and highlight its strong potential as an eco-friendly agent for integrated pest management in agriculture.