Abstract

The susceptibility of the bean beetle Callosobruchus maculatus to Metarhizium anisopliae var. anisopliae(URM3349) and Metarhizium anisopliae var. acridum (URM4412) strains was assessed at concentrations of 10⁸, 10⁷, 10⁶, 10⁵ and 10⁴ conidia.ml^-1 under laboratory conditions. The beetles were raised in glass recipients on a natural diet of cowpeas (Vigna unguiculata). Concentrations caused mortality in adult insects. At the concentration of 10⁸ conidia ml^-1, mortality of C. maculatus caused by M. anisopliae var.anisopliae and M. anisopliae var. acridum was 74.45 and 58.27%, respectively. The LC₅₀ of M. anisopliaevar. anisopliae was estimated at 9.2 × 10³ conidia ml-¹. The results demonstrated that the fungal strains evaluated have pathogenic action against the bean beetles under laboratory conditions.

Key words: Entomopathogenic fungus, Metarhizium anisopliae, pathogenicity, Callosobruchus maculatus, mortality