Oak Galls and Wasps

Asked September 8, 2019, 10:09 AM EDT

The county planted two swamp white oaks in front of my house about 2 1/2 years ago. Both have experienced infestations of scale, which I have tried to scrape off in the spring before it sets. Now one of them has a heavy infestation of galls. Wasps are crawling over the galls, so it's a bit difficult to get close. Is this something to be concerned about, or will the problem take care of itself? I've tried to control the scale to ensure the young trees get a good start, but these galls and wasps are beyond me.

Montgomery County Maryland

3 Responses

The galls are not harming the tree. We would like to see photos of the scale insects so we can see what you are dealing with.


I haven't seen the scale since the spring. I got every one I could find. They were dark grey, oval shaped and about 1/4 inch long on the longer axis. MC county arborist pointed them out to me when he came to inspect the trees a couple of years ago. He showed me how to rub them off the branches before they set. I've tried to do this each spring since then, but the trees are getting too big for this now.

In order to recommend any control for the scale, it needs to be identified and without a photo that is difficult.
The following are the scale pages from our website, perhaps you recognize one of them. Look at the information on European lecanium scale this one is commonly found on oak trees, it is located on the soft scale page #4.