University of Illinois Extension

University of Illinois Extension

Hort Answers

Fungal Disease

Oak Leaf Blister
Taphrina caerulescens

Oak leaf blister symptoms.
Oak leaf blister symptoms.
2 (1 = rare 5 = annual)
2 (1 = very little damage 5 = plants killed)
The fungus attacks species in both the red and white oak groups.

Plants Affected
The infection site bulges upward on the upper surface and is sunken on the lower leaf surface. The infected area starts out tan and turns brown as the disease progresses.

Life Cycle
The fungus overwinters on twigs and bud scales and infects new leaves while they are emerging from the bud when there are mild and moist conditions.

At this time, no chemical control is really necessary in the Midwest since this disease does not cause enough damage to justify a preventive fungicide treatment.

Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic