Evaluating Beauveria bassiana Strains for Insect Pest Control and Endophytic Colonization in Wheat

Certain entomopathogenic fungi, such as Beauveria bassiana, are highly pathogenic to arthropod pests and are able to colonize plant tissues, thereby enhancing both plant growth and disease resistance. This study assessed three B. bassiana strains (CBM1, CBM2, and CBM3) for their pathogenicity toward insect larvae and colonization potential in wheat. The insecticidal activity of the fungi against the larvae of the major lepidopteran pests Helicoverpa armigera, Spodoptera frugiperda, Mythimna separata, and Plutella xylostella was determined. The fungi were then applied to wheat plants using seed immersion and soil drench methods; their colonization rates were compared, and the impacts of fungal colonization on wheat growth and survival were evaluated. The results demonstrated that all three strains were effective in reducing insect damage, with B. bassiana CBM1 exhibiting the highest pathogenicity followed by CBM3 and CBM2. B. bassiana CBM1 was particularly effective, with a significantly higher colonization rate achieved through soil drenching compared to seed immersion. The soil inoculation of B. bassiana resulted in increased plant height at 30 days after sowing (DAS) and root length at 15 DAS compared to the control group. B. bassiana CBM1-colonized wheat increased the mortality of fall armyworm. This research has enriched the biological control microbial resource pool and highlights the potential of B. bassiana in integrated pest management strategies.