Identification Of Postharvest Diseases Of Citrus

Citrus is one of the most important fruits in the world.It is very popular for rich nutrition and delicious taste.The fruit rots caused by fungal diseases during the middle and late stages of citrus growth,transportation and storage are very serious,and lead to great economic losses to citrus industry.The accurately identification the pathogens is of great significance for the prevention and control of postharvest diseases.In this study,two new postharvest diseases were identified and the biological characteristics of these pathogens were also studied.The main results are as follows:1.One hundred diseased fruits were collected from Xingshan,Zigui and Yiling of Yichang,Hubei Province,and the pathogens were isolated.Two hundred and six fungal strains were obtained,among which 67 strains in 9 genera were proved to be pathogenic to citrus fruits.2.A new disease caused by Neuroficoccum parvum was identified in Yichang,Hubei Province.The diseased fruit was brown and hard,and became soft rot deeply into the flesh at high humidity.The conidia of strain LW45-1 were black,and the conidiophore was colorless and short with septum.The conidia were spindle-shaped or elliptical,thin-walled,separated,colorless,with oil balls inside.The optimum condition for the strains of N.parvum were 25?-30?,pH4.0 with 12 h/12 h light.3.A new disease caused by Trichoderma atroviride was identified in Yichang,Hubei Province.The diseased fruit was brown and soft rot with a large amoumt of white mold on the lesions.The conidiophores of the strains NHE and XSLW1-1 were approximately 90-degree unilateral branches,and the bottle stems were straight or curved.The solitary bottle stems were generally cylindrical and formed a neck-like shape,the bottle stems were flask-shaped.Conidia were smooth,green,and subglobose to ovoid.The optimum condition for the strains in T.atroviride was 25?,pH5.0,with 12 h/12 h light.The strains could also parasitize the hypha and scleortia of Sclerotinia scleotriorum.The rot index of strain NHE and XSLW1-1was 96.73 and 97.13 at 30 d post inoculation.In this study,two new postharvest diseases of citrus were identified for the first time.The results laid oundation for effective prevention and control of citrus postharvest diseases.