This study aims to evaluate the efficacy of hot water and chitosan treatments to control green mould caused by Penicillium digitatum in 'Murcott' tangor. P. digitatum conidial germination and mycelial growth were evaluated in assays in vitro to verify whether chitosan (0.5, 1 and 2%) or hot water (45, 50, and 55°C, for 30 s, 1, 2, and 5 min) acts directly on fungus development. In vivo assays consisted of inoculating the fruit with P. digitatum (10⁵ conidia ml⁻¹) 4 hr before the chitosan and hot water treatments. Subsequently, green mould incidence and severity were evaluated in fruits stored at 25°C/80% RH for 4 days. Also, treatments combining chitosan and hot water were investigated for controlling green mould and the effect on postharvest quality of fruit stored at 5°C/90% RH. The results showed that P. digitatum conidia germination and mycelial growth were significantly reduced by the hot water treatments especially at 50°C/5 min and 55°C/2 or 5 min in the first case and 50 and 55°C/5 min in the second. These two treatments, when applied alone, 1 min dipping in 2% chitosan or hot water at 50°C/5 min, significantly reduced green mould development in fruit kept at 25°C/80% RH or refrigerated. However, the hot water dip combined with chitosan did not improve green mould control on ‘Murcott’ tangor at room temperature or under refrigeration. Besides, chitosan and hot water did not impair fruit quality. Thus, chitosan and hot water could be an alternative to synthetic fungicides to control green mould in citrus while also contributing to a decrease in the postharvest losses of ‘Murcott’ tangor.

中文翻译：

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壳聚糖和热水处理可减少'Murcott'丹戈尔收获后的绿色霉菌

本研究旨在评估热水和壳聚糖处理对“莫科特”丹戈尔中由指状青霉引起的绿色霉菌的防治效果。在体外测定中评估了数指参分生孢子的孢子萌发和菌丝体生长，以验证脱乙酰壳多糖（0.5％，1％和2％）或热水（45、50和55°C）持续30 s，1、2和5分钟）直接作用于真菌的发育。体内试验包括用数位假单胞菌（10 ⁵分生孢子ml ^-1）在脱乙酰壳多糖和热水处理前4小时。随后，评估在25°C / 80％RH下存放4天的水果的生霉菌发生率和严重程度。另外，研究了将壳聚糖和热水混合使用的处理方法，以控制绿色霉菌，以及对在5°C / 90％RH下储存的水果的采后品质的影响。结果表明，指状假单胞菌热水处理显着降低了分生孢子的萌发和菌丝体生长，尤其是在第一种情况下分别在50°C / 5分钟和55°C / 2或5分钟以及第二种情况分别在50°C和55°C / 5分钟。单独使用这两种处理方法时，浸入2％的脱乙酰壳多糖或50°C的热水中5分钟/ 5分钟，可显着减少在25°C / 80％RH或冷藏的水果中发霉的现象。但是，在室温或冷藏条件下，将热水浸入脱乙酰壳多糖中并不能改善“ Murcott”正切的生霉控制。此外，脱乙酰壳多糖和热水不会损害水果质量。因此，壳聚糖和热水可以替代合成杀真菌剂来控制柑桔中的绿色霉菌，同时也有助于减少'Murcott'tangor的收获后损失。