Cherry leaf spot is generally distributed throughout the U.S., Canada, and various parts of the world where humid conditions occur. In the eastern and Midwestern portions of the U.S., the disease most seriously affects the foliage of tart, sweet, and English Morello cherries.
Tart cherries are generally more susceptible.
In addition, various wild and cultivated hosts of the genus, Prunus, can also be affected by this disease, although a different species of the fungus affects plum. This fungus primarily attacks the leaves, although it may also infect leaf stems, fruit, and fruit stems. In the spring, one to three weeks after petal fall, the disease first appears as small, purplish spots on the upper surface of the leaves. These spots eventually turn brown. Frequently, there are areas around the spots which remain green, giving the leaf a mottled appearance.