Small, black pycnidia may appear in the centers. Leaves that are heavily infected will drop from the tree. Infected areas of branches and limbs are reddish brown and are sunken slightly below the level of surrounding healthy bark. These cankers may expand each year, a few eventually reaching several feet in length. Pycnidia are produced abundantly on limb cankers.
Fruit rot usually appears at the calyx end of the fruit.
It can originate at any wound that penetrates the epidermis, including insect injuries. There is usually one spot per fruit, a characteristic that distinguishes black rot from bitter rot. Initially, the infected area becomes brown and may not change in color as it increases in size, or it may turn black. As the rotted area increases, often a series of concentric rings form . The flesh of the decayed area remains firm and leathery.