University of Illinois Extension
University of Illinois Extension - Selecting Trees for Your Home
Oak Leaf Blister
Taphrina caerulescens
Oak leaf blister symptoms.
Severity: 2 out of 5
Frequency: 2 out of 5
Symptoms: 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.
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.
Management: 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.
Associated trees: