Red fluffy balls on oak leaves

Q: What are these red fluffy balls that are ALL OVER my oak trees and raining down on my house and patio? Are they doing to hurt my trees?

— Madonna from Canfield

A: They are insects, but they are no harm to you or your oak tree.

These are one of many galls that form on oak trees. They are a fascinating insect to check out while you are walking in the garden or at the park this time of year.

Some galls look like a small brown, hollow, spherical planet attached to the leaf. Others make tiny brown discs on the underside of the leaf. Some distort leaves and make homeowners think a disease is affecting trees. Yet others cause a distorted growth on branches that look like they have little horns coming out of them.

These pink and red fuzzy balls that are “raining down” on everyone this year is one of the cynipid wasps that are commonly called woolly leaf gall wasps. But there is no recognized common name for the one we are seeing this year.

These tiny wasps are nothing to worry about. In fact, they are so small that you will not notice the adults — as you probably did not notice them when they were laying eggs on the leaves of your oak trees. The adult lays the egg in the leaf tissue. Then, a signal is sent to the leaf and the leaf grows this gall on its own.

What an amazing thing — the wasp gets the tree to raise its egg! This structure protects the larvae during its development.

We do not know a lot about this specific insect. Some species do all development inside the gall while others drop the soil and pupate in the soil over winter. According to Jim Dill from the University of Maine, this wasp does, in fact, burrow into the soil to complete its development. He also ensures us that they are nectar feeders and do not sting.

To learn more about a these types of gall forming wasps, go to http://go.osu.edu/woollyoakgalls.

For a segment with me showing pictures of oak galls in our area, go to http://go.osu.edu/wool lyoakgalls.

Barrett is The Ohio State University Extension educator for agriculture and natural resources in Mahoning County. Submit your questions to the Extension office at 330-533-5538. Regular clinic hours are 10 a.m. to noon Thursdays, or visit go.osu.edu/virtual clinic.


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