Watercore is promoted by large fruit, high leaf to fruit ratio, high fruit nitrogen and boron, low fruit calcium, excessive thinning, high light exposure, Ethrel sprays, and girdling of trunks and limbs. Another type of watercore which is unrelated to maturity may occur during unusually hot weather. This watercore is found more on the exposed side of the apple and may be associated with sunscald. If moderate to severe, results in reduced storage life of the apple as internal breakdown develops in affected areas. Affected fruit must be marketed rapidly.
Incidence varies season to season but incidence can be very high.
A preharvest disorder resulting in water soaked regions in the flesh, hard and glassy in appearance, only visible externally when very severe. Water soaked areas are found near the core and around the primary vascular bundles but may occur in any part of the apple or involve the entire apple. Symptoms often increase rapidly as fruit become overmature but does not increase postharvest. If symptoms are mild to moderate, they may disappear completely in storage. However, when watercore is severe, internal breakdown can develop.