Oak Leaf Blister

This fungal disease infects new leaves in early spring. The puckered, blisterlike spots are small and light green at first, and then enlarge and turn brown after the spores are produced. The fungus overwinters on the tree buds, and as the buds open in the spring, the fungus enters the young leaves.

Control: This disease is seldom serious on oaks. Although fungicides are available, it may be impractical to spray large trees.