Diseases on oak leaves - Ask Extension
We have oak trees which have leaves showing signs of distress. They mostly have brown fuzzy balls on the leaves, but a few also have yellow smooth lum...
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Diseases on oak leaves #885598
Asked September 17, 2024, 2:51 PM EDT
We have oak trees which have leaves showing signs of distress. They mostly have brown fuzzy balls on the leaves, but a few also have yellow smooth lumps on them as well. Can you help us identify what is causing these?
Hartford County Connecticut
Expert Response
Hi,
These are great pictures of oak leaf galls. Could we use one for our October e-newsletter?
So a tiny wasp lays eggs in the spring on leaf buds and a chemical is injected into the leaf that causes an abnormal growth to occur and that is where the insect larvae is. So this causes a gall to form. The insect matures and eventually leaves (the wasps are very tiny). They really are just a cosmetic issue although they can make the leaves brown and fall a little earlier. We don't recommend any controls but if they are on a lower branch and you really don't like them you can cut them off.
These are great pictures of oak leaf galls. Could we use one for our October e-newsletter?
So a tiny wasp lays eggs in the spring on leaf buds and a chemical is injected into the leaf that causes an abnormal growth to occur and that is where the insect larvae is. So this causes a gall to form. The insect matures and eventually leaves (the wasps are very tiny). They really are just a cosmetic issue although they can make the leaves brown and fall a little earlier. We don't recommend any controls but if they are on a lower branch and you really don't like them you can cut them off.
Thank you for your quick and reassuring response. Of course you can use my photos.
Thank you so much. Do you get the UConn Home & Garden Education's Center monthly e-newsletter? If you would like to you can email them at <personal data hidden> and ask to be put on their mailing list.
Just wrote them to subscribe - - thank you!
On Sep 18, 2024, at 12:54 PM, Ask Extension <<personal data hidden>> wrote:
