REDUCTION OF POST-HARVEST ANTHRACNOSE AND DRY ROT OF PAPAYA BY HYDRO-THERMAL TREATMENT

Anthracnose (Colletotrichum gloeosporioides) and dry rot (Phoma caricae-papayae) of papaya (Carica papaya) reduce fruit post-harvest storage life. Therefore, this study evaluated under laboratory conditions the effect of the hydrothermal treatment of fruits on these diseases. Two types of tests were conducted: (1) fruit immersion in hot water (48 degrees C) for 10, 15, 20, 25 and 30 min; and, (2) fruit immersion in hot water at 44, 46, 48 and 50 degrees C / 20 min. The experiments were conducted in a randomized complete block design with five replications. Two isolates of C. gloeosporioides and one of P. caricae-papayae were tested in papaya fruits of cv. ' Sunrise Solo' and hybrid ` Tainung 1'. Fruits were washed, wounded (3mm), inoculated (50 mu L, 106 conidia mL-1), placed in humid chamber (24 h), and then treated. After treatment, fruits were water cooled (13 degrees C/ 20 min) and stored (14 days) in cold chamber (13 degrees C; 85-100% R. H.). Daily the diameter of lesions was evaluated for two weeks. Variations on time and temperature did not alter fruit firmness (kg cm-2), pH, total soluble solids (o Brix) e tritable acidity (% of citric acid) in comparison to non-treated fruits. However, in one case on ` Tainung 1' fruits, tritable acidity was higher at 48 degrees C / 20 min. Fruits treated with hot water at 48 degrees C / 20-30 min or 48-50 degrees C / 20 min presented less fruit rots.