Asked August 18, 2015, 1:05 PM EDT

Client has 2 trees. They are located at hunting camp. They range from 10 to 12 feet high and are about 5 to 6 years old. He noticed the problem with the trees about 2 years ago. He is not sure if other trees are infected. He is only concerned about the Hybrid White Oak since he purchased them and planted them. Please identify problem and advise on how to treat.

Alpena County Michigan

1 Response

These all appear to be galls. Galls are abnormal plant growth or swellings comprised of plant tissue and are usually found on foliage or twigs. There are a variety of gall-forming species of small wasps and mites that commonly infest oak, Quercus spp ., trees in Michigan. These irregular plant growths are stimulated by the reaction between plant hormones and powerful growth regulating chemicals produced by these insects or mites and interfere with normal plant cell growth. Galls may occur on leaves, bark, flowers, buds, acorns, or roots. Most leaf galls on oak cause little or no harm to the health of a tree and rarely justify control measures.

If you Google for galls on oak leaves and then click on "Images" at the top of the page you will see dozens and dozens of different kinds of leaf galls. They are very common in both landscapes and in the woods.

If you have questions or additional concerns, please let us know.