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.

Entomopathogenic fungi (EPF) are critical drivers of ecosystem processes such as pest regulation and material cycling. However, their distribution patterns and the drivers influencing them along the elevational gradients remain unclear. This study investigated the diversity and distribution of EPF along a 300–2550 m altitudinal gradient on Changbai Mountain, focusing on their responses to vegetation belts and soil properties. A total of 21 genera and 35 EPF species were identified, with species diversity significantly declining with altitude (Shannon index, p < 0.05). High‐altitude communities (1200–2550 m) showed similar structures across coniferous forests, Erman's birch forests, and alpine tundra, whereas low‐altitude communities (300–1050 m) in broad‐leaved and mixed forests were compositionally similar. Narrow‐range species dominated, with many EPF being restricted to specific vegetation belts. Broad‐leaved forests supported the highest EPF diversity, with families such as Cordycipitaceae showing strong preferences for these habitats. Soil properties (e.g., nitrogen, sulfur, phosphorus, moisture content, and pH) and shrub diversity were key drivers of EPF distribution. For instance, the abundance of Metarhizium , Cordyceps , Beauveria , and Polycephalomyces was positively correlated with nitrogen and phosphorus but negatively correlated with sulfur. Shrub diversity positively influenced EPF diversity in broad‐leaved forests but negatively in coniferous forests. These findings highlight the interplay between altitude, vegetation, and soil conditions in shaping EPF communities, emphasizing the importance of preserving fungal diversity in alpine ecosystems to maintain ecological balance and support biological control strategies.

Exploring host preference and resource partitioning among seed predator species is essential for understanding the coexistence mechanisms and guiding effective forest pest management. This study aimed to elucidate how seed traits influence infestation dynamics and species interactions, focusing on acorn weevils infesting Quercus mongolica. Species identification and clarification of their evolutionary relationships within the Curculio genus were performed through phylogenetic analyses of the mitochondrial cytochrome c oxidase subunit I gene sequences. The seed infestation patterns were assessed by comparing the infestation rates across various seed size classes. Furthermore, the correlations between the seed morphological traits (length, width, aspect ratio, and weight) and weevil abundance were analyzed. The phylogenetic results revealed well-supported monophyletic clades corresponding to Curculio arakawai and Curculio sikkimensis. This confirmed the clear genetic separation between these two distinct weevil species, thereby substantiating the divergence observed in weevil populations correlated with different seed hosts. The infestation patterns revealed the association of weevil species-specific preferences with seed size: C. arakawai predominantly infested larger acorn seeds, whereas C. sikkimensis predominantly infested smaller acorn seeds. C. sikkimensis favored smaller ones. Both species exhibited positive correlations between abundance and seed length and width in larger seeds; however, the seed weight displayed no significant effect. These results indicate niche differentiation mediated by seed size and morphology, which likely reduced interspecific competition and facilitated coexistence. This study elucidates species-specific host selection patterns in acorn weevils and highlights acorn traits as crucial factors shaping seed predator assemblages. The findings provide valuable insights for developing targeted pest management strategies and supporting sustainable oak forest regeneration.