Bitter pit and cork spot
Small, green to purplish to light brown, slightly sunken lesions appear on the surface of mature fruit (A). Individual lesions on the fruit surface are dry and do not extend deep into the fruit (B); however, cutting into the fruit can reveal numerous internal lesions. Bitter pit usually develops in storage and is most severe at the calyx end. A similar calcium-related disorder that occurs only on d'Anjou pears is named cork spot.
On apple, symptoms can be confused with other calcium-related physiological disorders such as Jonathan spot and the disease Brooks fruit spot.
This is a physiological disorder associated with calcium deficiency in apple fruit. It is common on the varieties Cortland, Gravenstein, Honeycrisp, Northern Spy, and York. Losses can be minimized by avoiding excessive tree vigor (because shoots compete with fruit for calcium) and applying calcium sprays during summer.
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