CONTROL OF POST HARVEST GREEN MOLD OF ORANGES AND TANGERINES BY HEAT TREATMENTS, AND CARBONATE AND BICARBONATE SALTS

Control of citrus green mold caused by Penicillium digitatum, was evaluated on artificially inoculated oranges and tangerins immersed in 3 and 4% sodium bicarbonate (SB)(wt/vol) and potassium bicarbonate (PB)(wt/vol), with or without 200 ppm sodium hypoclorite for 60 or 180s; in 3 and 4% sodium carbonate (SC)(wt/vol) and potassium carbonate (PC)(wt/vol) at 25, 37, 45 or 53°C for 60, 180 or 300s; and kept in hot air (37°C) for 24, 48 or 72h. Hot air and water experiments were done in two sets of before and after treatment inoculations. After 3 weeks of storage at 10°C and 80% RH, the incidence of decayed fruits was determined. Results revealed that SB 4 and 3% for 180s reduced decay in Tompson Navel by 67, 65.11% and Shahsavar oranges by 80.16 and 76.04% respectively. SB4% and SB3%+ NaClO 200ppm for 60s reduced decay in tagerines by 59.84 and 58.43% respectively. Control treatments caused 100%, 97-98%, and 89-90.5% decay respectively. In before treatment inoculations, PC and SC 4% at 53°C for 180s, PC3% at 45°C for 300s, PC and SC 3 and 4% at 53°C for 300s reduced decay in Tompson Navel by 100%. SC3% at 53°C for 60 and 180s, PC3% at 45°C for 180s, PC4% and SC 3 and 4% at 53°C for 300s reduced decay in Shahsavar oranges by 100%. PC and SC 4% at 53°c for 180s, PC 4 and 3% and SC4% at 53°c for 300s and PC3% at 37°C for 180s reduced decay in tangerines by 85, 82.5, 80, 77.5, 75, and 75% respectively. Control treatments caused 92%, 100%, and 80% decay respectively. In before treatment inoculations, Hot air for 72, 48 and 24h in Tompson Navel; for 72, 24 and 48h in Shahsavar oranges; and for 48, 72 and 24h in tangerines reduced decay by 95, 95 and 92%; 100, 85.14 and 66.22%; and 100, 95 and 33% respectively. Control treatments caused 100%, 74%, and 100% decay respectively. However, some damages observed on fruits treated with hot air for 72h.