Pathogenicity of Beauveria Bassiana (Hyphomycetes: Moniliales) to Larval and Adult Chalcodermus Bimaculatus (Coleoptera: Curculionidae)

Abstract

Five strains of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (four from Brazil and one from the USSR) were tested for virulence against final instars and adults of Chalcodermus bimaculatus Fiedler. The Brazilian isolates CP 7 and CP 1 were the most virulent to larval and adult weevils. Three of the five isolates caused 90% or greater mortality of larvae at a dose of 5.5 × 102 conidia per mm2, whereas none of the isolates caused high mortality of adults, even at a 100-fold higher dose. Results suggest that applications of B. bassiana targeting the larval stage would be more effective than applications against adult weevils