Oak Leaf Blister

Gail Ruhl, Sr. Plant Disease Diagnostician, Department of Botany & Plant Pathology, Purdue University

Oak leaf blister, caused by the fungus Taphrina caerulescens, has recently been observed in Indiana on several different species of oaks . Infections occur as buds swell and open during wet, spring conditions. Leaf blister symptoms usually appear within several weeks following infection as 1/4-1/2 inch circular, light green bulges on the top surface of leaves. From the underside, the affected areas are sunken or depressed. These distortions may cause leaf bending or curling of narrow-leaved oak species. As the blisters age, they become dry, brown spots; severely diseased leaves may drop prematurely. This disease does not seriously harm healthy trees and control with fungicides is not usually recommended.

The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by the Purdue University Cooperative Extension Service is implied. Any person using products listed assumes full responsibility for their use in accordance with current direction of the manufacturer. Purdue University is an equal opportunity/equal access institution.

Information listed is valid only for the state of Indiana

Click image to enlarge