Pathogenicity of indigenous strains of three entomopathogenic fungi to the sisal weevil, scyphophorus acupunctatus (Gyllenhal) (Coleoptera: Curculionidae)

Abstract

The pathogenicity of indigenous isolates of Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea was evaluated in the laboratory against larvae and adults of the sisal weevil, Scyphophorus acupunctatus. Inoculation was achieved via immersion of individuals into conidia suspensions of different concentrations. All three fungal species proved high pathogenicity against larvae of the weevil, causing 100% mortality in most of the treatments. Beauveria bassiana caused the highest mortality of the adults (86.67±12%), followed by M. anisopliae (46.67±17.8%) and I. fumosorosea (40±17.5%). Mean survival time also differed significantly among treatments and life stages of the weevil. In total, larvae survived significantly fewer days than adults post infection. Results of the present study indicate the potential of indigenous strains of entomopathogenic fungi as biological control agents against the invasive weevil.