Oak tree disease

Asked July 6, 2018, 8:25 AM EDT

I'm fairly certain this tree is an oak, but not sure what species. The leaves get orange-brown areas on them and seem to have lots of holes on the margins. The leaf buds that look like nodules all have numerous black holes in them that look like an insect has been boring into them. Any help in identifying the tree and the problem and any remedies would be appreciated.

Washington County Minnesota

5 Responses

Hello and thank you for contacting AaE for help.

This is damage caused by caterpillars feeding. Without further evidence the exact species cannot be identified from the shot holes in the leaves of your tree. Some possibilities based on those known to feed on oaks in the spring include cankerworms (paleacrita vernata), june beetle (phyllophaga spp) and, remotely, gypsy moth (Lymantria dispar). Here is a link to the U of MN Extension page describing these possible culprits and more. Each has a link to additional information about them including possible control methods but some of those links may not have been uploaded during the upgrade the U of MN is currently performing. I encourage you to continue to try over the next few weeks as they work to complete the upgrade.

I hope this information helps.

I see no indication of any caterpillars or larvae on the stems or leaves of the tree. Are the multiple holes on the nodules of the tree indicative of any thing? There is no indication of June beetle in the sod area under or around the tree and the lawn is sprinkled with no dead patches under or near the tree.


I'm not sure what you mean by nodules. Could you supply a photo of these holes on the nodules?

The only holes I see are in the leaf that is prominent in the one submitted photo. Disease will not cause a leaf to form holes, something has eaten them whether a bug like the June bug or a larva of some other insect.

You could engage the assistance of a professional arborist to diagnose the situation. There can be many factors involved in making a diagnosis and a physical examination is sometimes best. I have provided you with some common possible causes and cannot be thought of as a definitive diagnosis.

Feel free to send an additional photo and I'll see what I can tell you but, again, it may be best to consult with an arborist.


Here is a picture of the "nodules" with holes.


Your tree has two issues. The 'nodules' as you call them are galls. They are probably gall wasps which is the most common cause of galls on oaks. Adult gall wasp larvae feed inside the gall. Adult gall wasps do not feed. Here is a link to the U of MN Extension web page on galls where you can learn more about them and some ways to control them. Here is another link about gall wasps that may help you understand their complicated life cycle.

As for what is eating the leaves, it may be spending the day in the underbrush and comes out at night. But something is eating the leaves.

I hope this information helps.