Biological study and use in biocontrol of the medfly parasitoid Diachasmimorpha tryoni Cameron (Hymenoptera : Braconidae : Opiinae)

Fruit flies are important pests damaging fruit crops in Reunion Island. Among them the medfly, eratitis (Ceratitis) capitata (Wiedemann) is dominant in the hot and dry lowlands of the western area. The incidence of indigenous larvo-pupal parasitoids on the medfly populations appears low in most cases. A new biocontrol programme was initiated by C~ in 1995, with the importation of the asiatic species Diachasmimorpha tryoni (Cameron) (Braconidae : Opiinae) from Hawaii, in collaboration with USDA Hawaii and the University of Hawaii. The parasitoid has been reared in the laboratory and, though inoculative releases have been made in various parts of the island, its acclimatization has not yet been achieved. In the meantime, a study has been conducted in order to improve our knowledge on the biology of this beneficial. The morphology of the preimaginal instars has been described and the influence of temperature on preimaginal development duration has been determined. These biological data are discussed with regard to the potential of the species in biocontrol of the medfly in Reunion Island. (Resume d'auteur)