AERIAL RELEASES OF STERILE MEDITERRANEAN FRUIT-FLY (DIPTERA, TEPHRITIDAE) BY HELICOPTER - DISPERSAL, RECOVERY, AND POPULATION SUPPRESSION

Sterile Mediterranean fruit flies, Ceratitis capitata (Wiedemann), wer e released by helicopter over commercial coffee (Coffea arabica L.) fi elds and nearby habitats on the island of Kauai, Hawaii. Temporal and spatial dispersal patterns of released flies were expressed effectivel y by both asymptotic and exponential decay models. Approximately 90% o f the captured flies were located within 100 m of the release line. St erile flies remaining in coffee fields declined rapidly, with < 15% re maining within 5 d. Flies released by helicopter dispersed throughout a narrower band than those released at higher altitudes by the standar d airplane method. Our studies suggest that flight line intervals of 2 00 m every 3-4 d should provide adequate coverage and numbers of steri le flies in target areas. An 8-mo program of sterile fly releases (52 releases, total = 208 million flies) by helicopter was conducted throu ghout an interior 15-km(2) area to evaluate the effectiveness of the h elicopter. A small C. capitata population in coffee patches throughout the understory of a watershed forest was targeted. Fruit collections from the treatment area indicated a 90.6% reduction of the larval infe station rate. Higher levels of control or eradication of C. capitata i n riparian forest areas would probably require sterile fly releases th roughout surrounding areas to prevent reinfestation. Helicopters appea r to be well suited for sterile fly releases in mountainous areas wher e terrain and unpredictable weather conditions are unsuitable for airp lanes.