Comparing the efficiency of fungal spores and their metabolites in some entomopathogenic fungi against cotton leaf worm, Spodoptera littoralis

Spodoptera littoralis is the most destructive insect in Egypt and many other countries, where it attacks several economic crops, such as cotton and vegetables. Entomopathogenic fungi are widely used in controlling many pests. Usually, spores of them were used in the controlling process. In this study, intracellular and extracellular metabolites were extracted from broth cultures of four entomopathogenic fungi: Beauveria bassiana, Metarhizium anisopliae, Cladosporium cladosporioides, and Verticillium lecanii. The extracted metabolites and spores of fungal strains were evaluated to compare their efficiency against the 2nd instar larvae of S. littoralis. The results indicated that highly significant differences were found between the efficiency of intracellular and extracellular metabolites and fungal spores against the treated larvae, where the mortality percentage of S. littoralis larvae increased with the extracellular metabolites extract of C. cladosporioides and V. lecanii more than intracellular metabolites and spore suspension, while the intracellular metabolites extract of M. anisopliae was more effective compared with extracellular metabolites and spore suspension, but the spore suspension of B. bassiana caused significant mortality compared with intracellular and extracellular metabolites extracts. As a result, this study reported that it can be useful to use the metabolites of some entomopathogenic fungi in the control of S. littoralis because they may have more activity than fungal spores in some entomopathogenic fungi.