|Throne, James - Jim|
Submitted to: Journal of Entomological Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/6/2004
Publication Date: 1/15/2005
Citation: Rodriguez-Del-Bosque, L.A., Silvestre, F., Hernandez, V.M., Quiroz, H., Throne, J.E. 2005. Pathogenicity of metarhizium anisopliae and beauveria bassiana against phyllophaga crinita and anomala flavipennis (coleoptera: scarabaeidae). Journal of Entomological Science 40: 67-73. Interpretive Summary: The white grubs Phyllophaga crinita and Anomala flavipennis are the most important soil insect pests of maize and grain sorghum in northeastern Mexico. Phyllophaga crinita also causes severe damage to agricultural crops, forage grasses and turfgrass in parts of the U.S., and Anomala flavipennis causes economic damage to several crops, including maize, wheat, potato, and grasses, in parts of the U.S. Historically, control measures for white grubs have depended mainly on conventional chemical insecticides. Although control of grub larvae is possible with microbes, such as bacteria, or with nematodes, use of these alternative control technologies is limited. Currently, at least two products formulated with fungal pathogens of insects are used commercially for controlling white grubs in Australia and Europe, so we investigated whether related fungi might be useful for control of the white grubs P. crinita and A. flavipennis. In laboratory studies, three strains of the fungus Metarhizium anisopliae caused rapid mortality of the white grubs. The five strains of the fungus Beauveria bassiana tested were not effective for control of these white grub species. This study showed that the fungus Metarhizium anisopliae should be investigated further as a potential biological control agent against white grubs.
Technical Abstract: Five isolates of Beauveria bassiana (Balsamo) Vuillemin and three of Metarhizium anisopliae (Metschnikoff) Sorokin were tested against third instars of the scarabs Phyllophaga crinita (Burmeister) and Anomala flavipennis Burmeister under laboratory conditions following the "maximum challenge test" methodology. The M. anisopliae strains were more virulent than the B. bassiana strains. The isolates MAGL3N and MAGL4N of M. anisopliae caused the highest mortality in both white grub species. Regardless of scarab species, mortality caused by MAGL3N was more than 63% after 4 days and 96% after 10 days. The other two strains of M. anisopliae, MAGL4N and MAGC2N, also caused high mortality in A. flavipennis, but at a slower rate than MAGL3N. Lethal mean time (LT50) for MAGL3N was 2.9 days for P. crinita and 3.0 days for A. flavipennis. LT50 for MAGL4N was 5.3 days for P. crinita and 7.6 days for A. flavipennis, and LT50 for MAGC2N was 4.4 days for A. flavipennis. This study showed that M. anisopliae should be investigated further as a potential biological control agent against white grubs.