MORTALITY OF ANASTREPHA-SUSPENSA (DIPTERA, TEPHRITIDAE) IN CARAMBOLASTREATED WITH COLD-WATER PRECOOLING AND COLD-STORAGE

The Caribbean fruit fly, Anastrepha suspensa (Loew), is a pest of quar antine significance of carambolas. The fruits are subjected to cold st orage quarantine treatment when shipped to areas outside of the known range and where the fly could survive. In this study, rapid cooling in cold water increased mortality of Caribbean fruit fly larvae in caram bolas over passive air cooling. Air-cooled carambolas required more th an 24 h to cool to the treatment temperature of 1.1 degrees C, while w ater-cooled fruits required only about 45 min. After 1 day, Anastrepha suspensa larvae had greater than 65% mortality in water-cooled caramb olas, while mortality of larvae in air-cooled fruits was only 20%. Mor tality of larvae in water-cooled fruits was 98% at 4 days, and 100% (1 ,900 larvae treated) after 9 days. Twenty six larvae were recovered fr om air-cooled fruits after 4 days (1,900 larvae treated), and one larv a after 11 days of treatment. Larval mortality from cold-water-treated fruit reached probit 9 in 8 days, about 2/3 the time (13 days) requir ed for the same level of mortality of larvae in air-cooled fruits. Thi s difference in mortality is probably due to the rapidity of the cooli ng. It may be possible to use this modification to shorten the current cold treatment of 12 days at 1.1 degrees C for Florida carambolas.