none The oriental fruit fly, Bactrocera (= Dacus) dorsalis Hendel, is an economic important pest in Taiwan. Government and agricultural organizations have used the annihilation technique with attractants of poisoned methyl eugenol as a control method. The Braconid wasp, Diachasmimorpha (= Opius, = Biosteres) longicaudatus Ashmead, an efficient larval parasitoid of the oriental fruit fly, was introduced from Hawaii and has been successfully raised in the laboratory. This wasp will be used as an agent of biological control, and together with the annihilation technique will form an integrated control method. The important factors influencing parasitoid yield such as the culturing apparatus, host larva age, parasitoid maternal age and the exposure period to parasitoid oviposition as well as the biology of the parasitoid were studied. The parasitoids have been released into orchards.