Abstract: The tephritid gall fly Procecidochares utilis Stone, a promising biological control agent of crofton weed Eupaterium adenophorum Spreng, was introduced to Kunming from Nyalam County, Xizang Autonomous Region in August,1984. Results of the host specificity tests showed that the fly does not attack any cultivated or otherwise important plants in the region into which it is to be released. Sixty three plant apecies were tested From October 1984 to September 1985 .E. adenophorum waa the only plant attacked by the fly.