DECAY CONTROL OF CACTUS PEAR BY PRE- AND POST-COLD STORAGE DIP TREATMENTS WITH FLUDIOXONIL, SODIUM BICARBONATE AND WATER AT 50°C

Objective of this experiment was to assess the effectiveness of prestorage and poststorage treatments with fludioxonil (FDL) alone or in combination with sodium bicarbonate (SBC), either at room temperature (20°C) or at 50°C, to control postharvest decay of cactus pear fruit. Cactus pears cv Gialla of the first crop were dipped for 120 s in SBC (2%) or FDL at 20 or 50°C dissolved in water. FDL was used at 600 mg/L at 20°C or 300 mg/L at 50°C. After 4 weeks of storage at 5°C and 90-95% RH fruit were inspected for soft rot incidence, peel disorders, overall appearance and weight loss. Fruit free of soft rots were then dipped for 120 s in water at 50°C or in FDL emulsion either at 20°C (300 mg/L) or 50°C (150 mg/L) and transferred to 20°C and 60-65% RH for one more week to simulated marketing conditions (SMC). All of hot water (50°C) treatments reduced decay incidence at the end of cold storage, but the one with FDL was more effective. However, after 1 week at 20°C, soft rot incidence increased sharply in fruit not treated before storage with FDL, unless subjected to a poststorage treatment with FDL. In contrast, the protective activity of a prestorage treatment with FDL at 20 or 50°C lasted all over the week of SMC at 20°C. The final weight loss ranged between 7.4 and 9.6%, but generally no significant difference could be detected among treatments. Peel disorders in treated fruit were less severe than in un-treated ones and appeal of fruit treated with FDL at 20°C or dipped in water at 50°C either alone or in combination with SBC or FDL was still high at the end of SMC. A prestorage treatment with SBC at 50°C or water-dip at 50°C followed by a poststorage treatment with FDL at 300 mg/L and 20°C or 150 mg/L and 50°C or a single prestorage treatment with FDL at 600 mg/L and 20°C or 300 mg/L and 50°C, could be feasible strategies to effectively manage postharvest decay of cactus pear fruit.