Metarhizium anisoplia var. acridum, a gyphomycetous fungus registered worldwide for grasshopper and locust control, is currently under consideration as a worldwide for grasshopper and locust control, is currently under consideration as a potential alternative to chemical insecticides for grasshopper control in Canada. Research in this thesis has contributed data required for the registration of biological control agents in Canada. A diagnostic PCR assay was developed for the specific detection of M. anisopliae var. acridum DNA. The assay was highly sensitive and effective for the detection of fungal DNA in infected grasshoppers. A survey of southern Alberta soils conducted in the spring of 2004 revealed the presence of Metarhizium spp. at low natural incidennce. Two indigenous isolates demonstrated pathogenicity when bioassayed against laboratory-reared and field collected grasshoppers. One of the isolates demonstrated virulence comparable to a commercial isolate. An analysis of historical weather data revealed that summer weather in the Prairie provinces should not preclude the efficacy of M. anisopliae var. acridum under local conditions. / xv, 127 leaves : ill. (some col.) ; 28 cm.