Factor analysis of synergistic effect between the entomopathogenic fungus Metarhizium anisopliae and synthetic insecticides

Abstract

Anomala cuprea larvae were inoculated with Metarhizium anisopliae after topical application of synthetic insecti-cides, and the blood cells in the larval bodies were counted. There were fewer granular cells in A. cuprea after a mixed application of M. anisopliae and fenitrothion or teflubenzuron than after a single application of M anisopliae. The phenoloxidase activity of larval hemolymph declined with time after the treatment of M. anisopliae and insecticides. One of the mechanisms of this synergistic effect is attributed to be weakening of the immune system of A. cuprea larvae by insecticidal stress, which facilitates infection of M. anisopliae to larvae.