Pathogenicity of Metarhizium anisopliae and Beauveria bassiana against Phyllophaga crinita and Anomala flavipennis (Coleoptera: Scarabaeidae)

Abstract

Five isolates of Beauveria bassiana (Balsamo) Vuillemin and 3 isolates of Metarhizium anisopliae (Metschnikoff) Sorokin were tested against third-instar larvae of Phyllophaga crinita (Burmeister) and Anomala flavipennis Burmeister under laboratory conditions using the “maximum challenge test” protocol. The M. anisopliae strains were more virulent than the B. bassiana strains, with the isolates MAGL3N and MAGL4N of M. anisopliae causing the highest mortality in both white grub species. Regardless of scarab species, mortality caused by MAGL3N was >63% after 4 days and >96% after 10 days. The other strain of M. anisopliae, MAGC2N, also caused high mortality in A. flavipennis, but at a slower rate than MAGL3N. Median lethal time (LT50) for MAGL3N was 2.9 days for P. crinita and 3.0 d for A. flavipennis. The LT50 for MAGL4N was 5.3 d for P. crinita and 7.6 d for A. flavipennis while the LT50 for MAGC2N was 4.4 d for A. flavipennis. Metarhizium anisopliae is a potential biological control agent for P. crinita and A. flavipennis and should be further investigated for possible development.