Fruit fly disinfestation in mangoes by hot water dipping.
Smith E. S. C.
Author Affiliation: Department of Primary Industries and Fisheries, Berrimah, Northern Territory 0828, Australia.
Proceedings of the 3rd International Conference on Plant Protection in the Tropics : 188-195
Abstract : Thermal mortality responses for eggs and final-instar larvae of the tephritid Dacus aquilonis [Bactrocera aquilonis] indicated that international quarantine standards might be achieved by disinfesting produce at 48°C for 20 min. Experiments on 5 varieties of mangoes showed that, depending on size, fruit may need immersion in water at 48°C for up to 90 min. Placement of infested fruit in water at this temperature for >30 min resulted in 100% mortality. Treated fruit was held at 25°C and scored for physiological characters, fungal rots and marketability. Criteria for acceptance included weight losses of 10% and >75% marketability of treated fruit. A strong relationship existed between weight loss and marketability. Fruit treated on the day of harvest often exhibited severe surface scalding within 5-6 days. Damage was reduced when fruit was treated 24-48 h after harvest. The Irwin variety had the least heat damage and Kensington Pride and Haden the most damage. Dipped fruits were unmarketable if stored at 13°C between harvest and treatment, but injury levels were acceptable when fruits were held at ambient temperatures. This paper was presented at a conference held in Genting Highlands, Malaysia, on 20-23 March 1990.