Emerging and threatening postharvest diseases in pome fruit in the Netherlands

Abstract: Pome fruit may remain for up to 12 months in storage, during which time fruit rot diseases may develop. Despite the use of fungicides and improved storage technologies, postharvest diseases still remain an important limiting factor for the long-term storage of apples and pears. Postharvest diseases of pome fruit are caused by a range of fungal pathogens. Typically, symptoms of disease occur after several months in cold storage with controlled atmosphere. In this study, packinghouse surveys of postharvest diseases on stored apple and pear fruit were conducted from 2012 to 2016. Decayed apple and pear fruits were sampled from commercial packinghouses, representing orchards of various apple and pear producing areas and cultivars in the Netherlands. Approximately 300 samples were analyzed during the storage seasons from 2012 to 2016. A sample consisted of 10-15 representative decaying fruits from each grower lot. The survey revealed that the most important postharvest pathogens were Cadophora luteo-olivacea causing side rot on pears, and Fibulorhizoctonia psychrophila as the causal agent of lenticel spot on apple and pear. Also, new problems were noticed caused by pathogens not earlier described in the Netherlands on apple or pear, such as F. avenaceum on pear and apple, Neonectria candida and Neofabraea kienholzii on pear, and Colletotrichum godetiae and Truncatella angustata on apple.