https://doi.org/10.37229/fsa.fjb.2024.02.28

Cotton (Gossypium spp.) production faces significant economic threats from diverse pests, leading to an over-reliance on synthetic insecticides and subsequent environmental and resistance issues. This study focuses on the isolation, molecular characterization, and biocontrol potential of a native entomopathogenic fungal isolate, Beauveria bassiana, obtained from cotton agro-ecosystems. The isolate was identified through morphological observation and phylogenetic analysis of the Internal Transcribed Spacer (ITS) region, showing 99.63–100% identity with reference strains and was accessioned in GenBank (PQ550640). Laboratory bioassays were conducted to evaluate the concentration-dependent virulence of the isolate against second-instar larvae/nymphs of three key pests: the cotton leafworm (Spodoptera littoralis), the pink bollworm (Pectinophora gossypiella), and the cotton aphid (Aphis gossypii). Results demonstrated significant dose-dependent mortality across all species (P≤0.0052). At the highest concentration (1×10⁹ spores/mL), A. gossypii exhibited the highest susceptibility (90.3% mortality), followed by P. gossypiella (86.6%) and S. littoralis (85.3%). Even at lower concentrations (1×10⁷ spores/mL), substantial mortality was recorded, particularly for A. gossypii (61.3%). These findings underscore the potent virulence and broad-spectrum activity of this indigenous strain, suggesting it is a promising candidate for integration into sustainable Integrated Pest Management (IPM) programs to reduce chemical dependency in cotton cultivation.