Oak Apple Gall in North Texas

Date March 02, 2023

Author TreeNewal Staff

If you’ve taken a close look at your oak trees, you might have noticed something that looks a lot like an apple hanging from the branches. The golf ball-shaped item you see might be an oak apple gall. While the oak apple gall is not a fruit, the growth might look like one at first.

Oak apple galls typically develop in the hot summer months, and they’re not always hanging from oak trees. In fact, you might find most oak apple galls on the ground. If you’ve spotted these galls, here are a few things you should know about them.

What Are Oak Apple Galls?

Oak apple galls are growths caused by parasites. In fact, there are hundreds of organisms that create galls, many of which are insects. Some galls are the result of mites, bacteria, viruses, and fungi.

In the case of oak apple galls, they are often the result of female wasps injecting eggs into oak leaves that are just beginning to form. When the egg hatches, the leaf grows around it, creating a small home for the new wasp. The larvae secrete chemicals that cause the leaf to puff up. The wasp continues to grow into a pupa, leaving the gall bright green and spongy. When the adult wasp finally leaves the gall, the growth turns brown and thin before falling off the tree.

Do Oak Apple Galls Hurt Oak Trees?

Image via Unsplash by azimbek

An occasional oak apple gall won’t cause permanent damage to a tree. Of course, a gall can still be unsightly. If you see oak apple galls on your tree, you can pick them off before the pupa inside matures. In these situations, chemicals will not be beneficial.

On the other hand, a heavy infestation of galls on a tree can cause it to lose leaves. Even if your oak tree is infested, the damage is minimal to the tree’s health overall. You might notice some blackened or curled leaves now, but future growth will remain strong. If your tree seems to be experiencing an infestation, you can prune out branches and twigs impacted by galls with shears or a saw. Rake up the galls and dispose of them to end the cycle of wasps infesting your tree.

Can You Prevent Oak Apple Galls?

While you may not be able to completely prevent oak apple galls from growing, you can make your tree less susceptible to damage caused by galls. Healthy oak trees are less likely to experience damage related to oak apple galls. If you want to prevent damage, take the time to irrigate and fertilize your oak trees. You can also leave galls in place to encourage beneficial insects to live in your tree. In fact, having spiders and ants living in your oak tree may prevent wasps from returning.

If you have questions about oak apple galls and protecting your trees, TreeNewal can help. Applying fertilizer and treating oak apple gall damage early can help you avoid long-term health concerns for your trees.