Beauveria bassiana as a potential biocontrol agent against the clover root weevil, Sitona lepidus.

Abstract

Three clover root weevil (Sitona lepidus) adults infected with the entomopathogenic fungus, Beauveria bassiana, were collected from pastures in the Waikato in 1997. Genotyping using rDNA comparisons showed the strain from weevils to be a cosmopolitan type. Application of fungal conidia topically and by contaminating leaf, soil and root surfaces showed that both B. bassiana isolated from S. lepidus in New Zealand and commercial preparations of this species were pathogenic to adult and larval clover root weevil, with up to 100% mortality within two to four weeks of inoculation. Isolates varied in their effectiveness against larvae and adults, with two isolates effective against adults found to be less pathogenic to larvae than a third isolate. Keywords: