Pathogenicity and Germination of the Entomopathogenic Fungi Beauveria bassiana and Purpureocillium lilacinum under Different Temperature Changes against Spodoptera littoralis Larvae

Since thermal stress influences the whole infection pathway, temperature is a critical factor in determining the efficiency of entomopathogenic fungi in microbial pest management. This study aimed to determine how temperature changes affect the germination rate of two isolating entomopathogenic fungi. In addition, we looked at how different entomopathogenic fungi performed against Spodoptera littoralis second-instar larvae after being incubated at various temperatures. Two locally isolated entomopathogenic fungi were identified morphologically as Beauveria bassiana and Purpureocillium lilacinum. Both fungi were incubated at 15, 20, 25, 30, 35, and 40° C to evaluate their germination and pathogenicity. Results showed that both fungi could germinate effectively at 20-35° C. Results also showed that P. lilacinum can germinate at all tested temperatures. No germination was obtained at 40° C for both fungi. B. bassiana was more pathogenic against S. littoralis larvae than P. lilacinum. The results showed that the isolated fungi can be developed as potential biopesticides against S. littoralis under different temperatures, although proper formulation is still required.