The leaves on my cherry tree have small holes in them and are turning yellow. What is the problem?
Cherry leaf spot is probably responsible for the symptoms on your cherry tree. Cherry leaf spot is caused by the fungus Blumeriella jaapii. The fungus produces small purple spots on the upper surface of the leaves. Eventually the spots turn reddish brown. After several weeks, the centers of the spots may drop out, producing a “shot-hole” appearance. Affected leaves often turn yellow and drop prematurely.
Cherry leaf spot occurs on both sour and sweet cherries in Iowa. Mild wet weather in spring creates a favorable environment for cherry leaf spot.
The cherry leaf spot fungus survives the winter on dead leaves on the ground. Spores that are released from these leaves during rainy periods in spring may infect newly emerging leaves. Raking and removing fallen leaves helps to break the disease cycle. The risk of infection can also be reduced by improving air circulation within the tree canopy with some light pruning. The application of fungicides, beginning at petal fall, is another way to control cherry leaf spot.