University of Illinois Extension

University of Illinois Extension

Hort Answers

Fungal Disease

Smooth Patch
Several fungal genera

Smooth patch on oak.
Smooth patch on oak.
4 (1 = rare 5 = annual)
1 (1 = very little damage 5 = plants killed)
Smooth patch is sometimes called bark patch or white patch. At least three saprophytic fungi cause this disease, but none are known to cause any major damage to the tree.

Plants Affected
The fungi break down the outer rough dead bark leaving a smoother light gray bark behind. Small patches often merge to form large patches. The smooth patch fungi will produce whitish looking fruiting structures under the right conditions.

Life Cycle
The fungi survive on outer dead bark. Spores are spread by wind and water.

No control is recommended.

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