Comparison of laboratory infection of aphids by Metarrhizium anisopliae and Verticillium lecanii

The pathogenicity of the only documented ‘aphid’ strain of Metarrhizium anisopliae for the aphid, Macrosiphoniella sanborni, was established by experimental infection. Its aphicidal potential was assessed by conducting parallel experiments with Verticillium lecanii, a fungus of proven efficacy in controlling aphids. The spore germination, growth and sporulation rates of M. anisopliae were slower than V. lecanii and were most likely the principal factors determining the higher LC., values in bioassay and slower propagation of this fungus amongst aphid populations. It is concluded that M. anisopliae, except perhaps in the salt marsh habitat from which it was originally isolated, would not prove as useful an agent as V. lecanii in biological control of aphids.