Characteristics of Cork Spot Like Disorder in Japanese Pear ‘Akizuki’ and ‘Oushuu’

Symptoms of cork spot like disorder, a physiological flesh disorder, in Japanese pear (Pyrus pyrifolia) ‘Akizuki’ and ‘Oushuu’ were investigated thoroughly by slicing fruit transversely at a 5-mm thickness. The symptoms were observed more markedly in the late maturing fruit in both cultivars, but especially in ‘Akizuki’. In addition, the severity of the disorder showed an association with the fruit fresh weights: more cork spots appeared on bigger fruit. More cork spots were observed in the middle of the fruit, with few at the stem end. However, they appeared on all parts of the fruit from the stem end to the calyx end, and then from the core to skin. Gibberellin paste treatment at 30–40 days after full flowering significantly increased cork numbers and made the disorder severe in both cultivars, although the rates of occurrence were not affected.