Biology and biocontrol of the medfly parasitoid Diachasmimorpha tryoni Carmeron (Hymenoptera : Braconidae : Opiinae)

Fruit flies are important pests damaging fruit crops in Réunion Island. Among them the medfly, Ceratitis (Ceratitis) capitata (Wiedemann) is dominant in the hot and dry lowlands of the western area of the Island. The effects of indigenous larvo-pupal parasitoids on the medfly populations appears low in most cases. A new biocontrol program was initiated by CIRAD 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 introduced to various parts of the island. Acclimatization of the parasitoid has not yet been achieved. In addition, a study was conducted to improve our knowledge of the biology of this beneficial insect. The morphology of the pre-imaginal instars has been described and the influence of temperature on pre-imaginal development duration has been determined. These biological data are discussed with regard to the potential of the species as a biocontrol agent of the medfly in Réunion Island. (Résumé d'auteur