Spots on red-skinned apples often become bleached. The tissue under the spots is soft and egg shaped, with the long axis parallel to that of the core. Several spots may merge to involve all or much of the fruit. As the rot progresses, the skin color becomes dark brown and superficially resembles black rot, except that with black rot the decayed tissue is firm, instead of soft and mushy. Beads of exudate appear on the surface of fruits completely rotted by white rot.
Mature fruits are most susceptible to the disease.
Apple fruits often become infected from mid-summer on without showing external symptoms. Thus, fruit may be infected without symptoms appearing in the orchard. Disease development is checked when these apples are placed in cold storage. However, when they are removed from cold storage an internal rot develops and the fruit may deteriorate very rapidly at room temperature. The spots enlarge, become somewhat sunken, and fill with a watery fluid.