In laboratory and field trials in China, the Australian isolate (FI-985) of the fungus Metarhizium anisopliae var. acridum caused high mortality of nymphs of the oriental migratory locust, Locusta migratoria manilensis. In the laboratory, various dilutions of Green Guard^®, the commercial M. anisopliae var. acridum product, caused 70 to 80% mortality of 4^th instar nymphs. In field trials conducted at Tianjin and in Henan province, backpack sprayers were used to treat 40 ha (2002) and over 160 ha (2003) with an ULV formulation of Green Guard^®.The spray was applied at a rate of 50 to 125g spores in 1125 to 1500 mL of oil/ha and, 8 to 11 d later, field populations had declined by 65 to 97%.