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.|