The use of the entomogenous fungus, Beauveria tenella, isolated from the yellowspotted longicorn beetle, Psacothea hilaris, was evaluated both in the laboratory and in the field for the control of the whitespotted longicorn beetle, A noplophora malasiaca, in citrus orchards. The adult beetle was susceptible to the infection with the spraying of a spore suspension of B. tenella and then killed within 10 days at a spore dose of 10 7/ml, under laboratory conditions. In the field cage test, the application of wheat bran containing B. tenella conidia (10 7-10 8/g of dried wheat bran, 20g/tree) on the soil surface around the trunk of a 5 year old satsuma mandarin tree resulted in 95-100% mortality within 10 days for the adult beetles. A high mortality rate was also obtained by the banding of a polyurethane form containing culture substrates on which B. tenella had been cultured for about 3 weeks, around the lower part of the trunk of the citrus tree. These results suggest that it may be possible to use B. tenella as a biological control agent for the whitespotted longicorn beetle.