龙眼采后炭疽病及对贮藏效果的影响

Development of postharvest anthracnose of longan and the effects of the disease on storage life of the fruit

研究了广东龙眼采后炭疽病(Colletotrichum gloeosporioides Penz.)发生情况和果皮上炭疽病菌潜伏侵染率以及对龙眼贮藏效果的影响。结果表明:广东龙眼采收后在常温(28℃)下贮藏,3～4d后开始表现炭疽病症状,6d后炭疽病发生率为89.7%,8d后炭疽病发生率为99.3%。龙眼从幼果期开始受到炭疽病菌的潜伏侵染,随着果实的生长果皮上炭疽病菌的潜伏侵染率不断上升,到采收时达到90%。炭疽病菌潜伏侵染率高的龙眼果实采后变褐腐烂快,贮藏效果差。采收时龙眼果皮上炭疽病菌潜伏侵染率越低,采收后贮藏效果越好。在龙眼果实生长期间喷雾3次杀菌剂可显著地降低果皮上炭疽病菌潜伏侵染率,减轻龙眼采收后炭疽病发生程度,提高龙眼贮藏效果。

The development of anthracnose of longan after harvest in Guangdong province and the effects of the latent infection rate of the pathogen （Colletotrichum gloeosporioides Penz.） in the pericarp on storage life were studied. The results showed that the symptom of anthracnose of longan fruit began to appear at 28℃ in 3 days or 4 days after harvest. The incidence of anthracnose was 89.7% and 99.3% respectively when the fruit was stored at 28℃ for 6 days and 8 days. The young fruit was latently infected by pathogen in 7 days after initial fruit setting; the latent infection rate in the pericarp was found to be increased gradually with growing of the fruit, reaching to about 90% at harvest. In general, the higher rates of the latent infection of the fungus of the fruit caused more serious postharvest browning and decay. The lower the latent infection rate was, the better the storage effect. The rate of latent infection of the pathogen, postharvest decay and browning of the fruits were found to be reduced and the effect of storage could be improved effectively by spraying fungicide twice or three times in the fruit growing season.