CONCOMITANT DECAY REDUCTIONS WHEN MANGOES ARE TREATED WITH HEAT TO CONTROL INFESTATIONS OF CARIBBEAN FRUIT-FLIES

Four heat treatments for quarantine control of Caribbean fruit flies (Anastrepha suspensa) in mango (Mangifera indica) did not affect fruit quality but variably controlled two postharvest diseases. Immersion of fruit in water at a constant temperature of 46 C for 90-115 min significantly reduced anthracnose (Collectrichum gloeosporioides) on three cultivars by 60-87%. Stem end rot (Diplodia natalensis) also was reduced 61-88% by this treatment. Treatment by forced air at 46 C for 195 min or at 48 C for 150 min reduced anthracnose on two cultivars, but an immersion for 150 min in which the water temperature gradually rose to 48 C, following a gradient identical to that created by forced air treatment, had no effect on disease severity. Although all heat treatments led to increased weight loss during 2 wk of storage, fruit treated by gradient hot water immersion were least affected. Hot air treatment and gradient hot water immersion slightly accelerated the softening of fruit, and all heat treatments hastened the development of yellow pigmentation. Immersion in water at a constant temperature of 46 C is recommended for the disinfestation of mangoes because it most effectively controls disease without reducing market quality. Forced air treatment at 48 C, however, is tolerated by the fruit and is more effective than forced air at 46 C for disease control.