Phenotypic and genotypic characterization of fifty strains of Beauveria spp. (Ascomycota, Cordycipitaceae) fungal entomopathogens from diverse geographic origins against the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

BACKGROUND The diamondback moth (DBM) ( Plutella xylostella ) causes large losses to global crop production. Conventional insecticides are losing effectiveness due to resistance. Consequently, there is a growing interest in sustainable control methods like entomopathogenic fungi (EPF) in Integrated Pest Management. However, the field efficacy of fungi varies due to environmental influences. In this study, a group of 50 Beauveria strains sourced from different locations were characterized by genotype and phenotype with respect to their conidial production, temperature and UV‐B radiation tolerance, and virulence against DBM. RESULTS Phylogenetic analysis revealed two distinct species: Beauveria bassiana (84%) and B. pseudobassiana (16%). Most strains showed optimal growth between 25 °C and 28 °C, with germination severely affected at 10 °C and 33 °C. Notably, 44% displayed high resistance to UV‐B radiation (5.94 kJ m −2 ), with germination rates between 60.9% and 88.1%. Geographical origin showed no correlation with temperature or UV radiation tolerance. In virulence experiments, 52% of strains caused mortality rates exceeding 80% in DBM second instars at 7 days after exposure to a 4 mL conidial suspension (10 7 conidia/mL). CONCLUSION Survival under environmental conditions is crucial for EPF‐based commercial products against DBM. Results suggest strain tolerance to environmental stressors is more tied to specific micro‐climatic factors than geographical origin. Each strain exhibited unique characteristics; for example, the most virulent strain (#29) was highly UV‐sensitive. Therefore, characterizing diverse strains provides essential genotypic and phenotypic insights, which are fundamental for understanding their role as biocontrol agents while facilitating efficient biopesticide product development and uptake.