SUPPRESSION OF A CARIBBEAN FRUIT-FLY (ANASTREPHA-SUSPENSA (LOEW) DIPTERA, TEPHRITIDAE) POPULATION THROUGH AUGMENTED RELEASES OF THE PARASITOID DIACHASMIMORPHA-LONGICAUDATA (ASHMEAD) (HYMENOPTERA, BRACONIDAE)

Augmented releases of adult Diachasmimorpha longicaudata (Ashmead) to control the Caribbean fruit fly Anastrepha suspensa (Loew) were carrie d out in two urban Florida locations: Key Biscayne and Clewiston. In t he former, 60,000 adult parasitoids/km(2)/week were released near host trees, Fruit fly populations during winter and much of spring appeare d to be suppressed to 5-10% of levels found during a previous survey o f the Key Biscayne site and a neighboring control area. Parasitism lev els were difficult to quantify, but were generally higher in release a reas. Sampling difficulties also create problems in demonstrating caus ation. The Clewiston releases were less consistent in number and size, but previous to their temporary suppression, Caribbean fruit flies we re apparently also substantially suppressed, A second species of braco nid, Doryctobracon areolatus (Szepligeti), common in the Clewiston are a control sites, was apparently nearly eliminated from the release sit e, Sex ratios of wasps recovered from sampled fruit were male-biased i n both release areas though the factor(s) responsible are unknown. Aug mented releases of D. longicaudata may be particularly useful in suppr essing Caribbean fruit fly populations in areas where more traditional methods such as insecticide-bait sprays and sterile male releases are impractical. (C) 1996 Academic Press, Inc.