Oak Leaf Blister
Natural History
Close-up of oak leaf blisters | Photo credit: R. L. Anderson - USDA Forest Service
Oak leaf blister is a common leaf disease among oaks in Florida, and is caused by the fungus Taphrina caerulescens. Although infected trees may have unsightly leaves, serious damage is uncommon.
Spores of the pathogen infect young oak leaves. As the pathogen develops within the leaf, it causes a disruption of normal development of leaf cells. The infected tissues appear swollen or blister-like. Severe infections can cause the leaf to become curled or twisted. Over time the infected tissues die - leaving gray-brown areas scattered within the given leaf.