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Metarhizium anisopliae var. acridum (Deuteromycotina: Hyphomycetes) mycoinsecticide acts through direct contact and provides control equal to that of chemical insecticides in current use, although the speed-of-kill is slower. To test the dose-mortality response, doses ranging from 10(3)-10(8) conidia per insect were tested in the laboratory against fifth instar brown locust hoppers, Locustana pardalina (Walker). At the highest dose (10(8)), all insects died after 3-4 days, while 100 % mortality was achieved with the 10(7) and 10(6) dosage rates after five and six days, respectively. The 10(5) dose took 6-10 days to achieve 100 % mortality and a dose of 10(4) look 12-14 days to achieve mortalities of 75-87 %. The lowest dose rate (10(3)) produced no significant mortality before 9-10 days after inoculation, with final mortality reaching only 60 % after 21 days. This was a classic dose response. Locusts are pests because of: the crops and pastures that they consume and any reduction in food consumption is consequently of great value. All preliminary laboratory treatments caused a reduction in food consumption, even at a dose rate of 10(4) conidia per locust. These results may influence the future operational implementation of the mycoinsecticide in the field.