Common Diseases

Common Tree Diseases Seen in Oklahoma

Diseases infect weakened trees more readily than healthy trees. Good tree care can eliminate or reduce disease problems, as well as prevent them from occurring.

Common Leaf Diseases


Irregular dead areas on leaf margins,between and across and/or along veins, often moving ontothe shoots and small twigs; sometimes whole leaves areengulfed.

Leaf spot

Dead spot on the leaf that is well definedfrom healthy tissue.

Leaf blotch

Dead area on the leaf that often diffusesinto healthy tissues.


Loss of dead areas inside of spots that resultin a series of holes in the leaf.


Leaf spot or blotch that is swollen or raised, sothat the area appears blister-like on the upper surface of the leaf.

Powdery mildew

Superficial growth of white to gray‑white fungus material on leaves and shoots.