Red oak with scale, scorch, or other?

Asked October 16, 2017, 3:38 PM EDT

Can you help diagnose my 35 foot red oak? This problem seems to have crept up over the last month or two. As you can see from the photo, only about 1/3 of the tree is affected. There appears to be no sign of scale, so we think it is scorch. What ever the case, can you advise how to treat the tree, without using a pesticide containing neonicotinoids? Thank you!

Howard County Maryland

5 Responses

We viewed the photos but could not make an accurate diagnosis. Has there been any damage to the root system or construction in the area? Red oaks are prone to bacterial scorch. Take a look at our website for more information and photos. Does this look like your tree? You can send us close up photos of the foliage so we can see what you may be dealing with.

This disease can be slow it can take over 10 years to develop and if the tree is stressed can be as little as 5 years. There are no good treatment options. Water during dry periods. Our fall seasons especially can tend to be dry. Prune dead wood.


Hello, MH,
Thank you for your response, and sorry for the delay in mine. I am attaching 3 close-up photos of leaves from the red oak in question. The leaves are all from the northeast side of the tree, which is the side that faces and overarches the paved street in front of our house. The southwest-facing side of the tree is still quite green, and has 90% of its leaves.
To answer your question, the roots of the tree have not recently been disturbed. However, three years ago, we had our water supply replaced, and that ground is located 15 feet from the base of the affected side of the tree.
Thank you for any advice you may be able to give.
Virginia Sauro

We viewed your photos but we cannot make an accurate diagnosis. The trees look stressed and thin and we notice some fall color. We cannot say for sure if you are dealing with bacterial leaf scorch. The foliage starts showing symptoms in August - September. You can send us photos next season, as soon as you notice symptoms.

Tree companies such as Bartlett and Davey will test for bacterial leaf scorch but there is no good treatment. All you can do is prune dead wood, water the trees during dry periods and going into the winter, and prune dead wood.
For an onsite diagnosis you can contact several certified arborists regarding the health of the trees


Thank you very much, MH. All you've said makes sense. We will be back in touch in late summer '18.
Virginia Sauro