Are these galls on my pin oak?

Asked May 25, 2017, 6:54 PM EDT

I have these gross deformities on the ends of the branches on my 18 ye old, 30' tall pin oak. As best as I can identify them is galls. What should I do about them? Will they harm this tree and others? And why now? The mild winter?

Washington County Pennsylvania

1 Response

Thanks for your question. Another Master Gardener has identified the cause of these galls as the Gnarled Oak Leaf Midge Gall. Here's a link to an Ohio State article about them, and another one from the Missouri Botanical Garden with the (limited) list of suggestions on how to deal with it. I hope these are helpful. Good luck!