The Selection of an Isolate of the Hyphomycete Fungus,Metarhizium anisopliae,for Control of Termites in Australia

Ninety-three isolates ofMetarhizium anisopliae,mostly derived from a survey of termite material, were screened for activity againstNasutitermes exitiosusandCoptotermes frenchiorC. acinaciformisusing a grooming assay technique. Twenty-six of the most promising isolates were further evaluated by bioassay againstN. exitiosusandC. acinaciformis.All isolates were pathogenic withCoptotermesspp. being more susceptible thanN. exitiosus.A group of nine isolates, chosen for their level of pathogenicity for one or other genus of termites and to represent a genetically diverse group, was finally compared in a minicolony test using termite colonies in 1 liter jars. The isolate, code-named FI-610 (derived from nest-mound material ofC. lacteusin SE New South Wales), was one of the most effective isolates against termites from both of the two colonies tested. This isolate also grew relatively well on agar plates at 36°C. FI-610 was thus selected for field trials and was found to be effective in killing colonies ofC. acinaciformiswhen 10 g (=3 × 1011conidia) or more of conidial powder was blown into the center of the large mound colonies.