Effect of temperature on spore germination in Metarhizium anisopliae and Beauveria bassiana

Conidial germination in three strains each of Metarhizium anisopliae and Beauveria bassiana at 20–35°C was investigated. The lag phase for M. anisopliae strains was generally less than for B. bassiana at a given temperature and was temperature-dependent. However, B. bassiana strain 206–85 had a very short lag phase that was independent of temperature. The germination rate was species-dependent, with M. anisopliae strains having faster rates than B. bassiana. The combination of germination rate and lag phase resulted in M. anisopliae strains having higher germination levels (95% germination in 10–14 h) compared with the best B. bassianastrain (206–85; 95% germination in 14–15 h). These results demonstrate intra-specific differences in the germination response which should be considered when selecting isolates for development as myco-insecticides.