We have an elm tree that has many green long bumps on the leaves and many of...

Asked July 17, 2015, 12:30 PM EDT

We have an elm tree that has many green long bumps on the leaves and many of the leaves are turning yellow and brown and have holes in them. The tree is not very large and I plan to drop it so that whatever the problem is, it doesn't spread to and other trees. Can you tell me what is happening to this tree? Also, is it safe for me to dispose of the branches by piling them up back in my woods? If not, what should I do? Thank you.

Cuyahoga County Ohio tree health elm trees

5 Responses

I’m hesitant to diagnose the tree with so little information. The long green bumps make me think you have one or more kinds of insects that produce galls. The yellow and brown leaves could be Dutch elm disease. If it’s DED you’ll want to either burn or bury the tree. However, it would be wise to take an infected branch to your local extension office and let them examine it. The Cuyahoga County office is at 5320 Stanard Avenue, Cleveland, OH 44103; phone 216-429-8200.

For more information and some pictures that might help you further determine what’s happening to your tree, you might want to look at the following websites.




I have included two photos. One of the tree, with the lower branches removed. and the other showing a closeup of the leaves. These leaves are far from the worst, but temporarily I have dumped the removed branches back in my woods. You may need to zoom in on the leaves photo to see the green bumps. What do you think?
Thank you.

John Jencson

It looks like the bumps are galls. Galls can be caused by insects, mites, bacteria, fungi, or viruses. Since there are areas that may have been nibbled, it’s probably an insect. The good news is that it may not look especially pretty but it won’t harm your tree since it seems large enough to host a few bugs and still photosynthesize. Chances are a natural predator will control the insects. Since it’s possible that the galls contain future insects, you might want to rake any fallen leaves and get rid of them.

I’m not sure what’s causing the yellow and brown leaves. It may be bacterial leaf scorch or Dutch elm disease or that all the rain we’ve had this year is suffocating the roots. I’d recommend reading http://www.na.fs.fed.us/spfo/pubs/howtos/ht_ded/ht_ded.htm for a more detailed description of the three most common possible causes and how to identify them. If you have a nursery in your area with knowledgeable people on staff you may wish to take a branch to them. Of course, a certified arborist or your local extension agent is your best choice.

Thank you for the info. I have attached 3 more photos that I would like to get your comments on. Thank you.

The first two pictures definitely look like finger galls. The third picture shows that some insect had an excellent dinner on your tree. The following websites show pictures of elm leaf beetles and their larvae as well as a little information about them. While they're not the only insect that could produce that damage, they are a possibility. You could look at the pictures and see if you’ve noticed any of them around your tree.