Native Plants

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Wednesday - December 12, 2007

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders
Title: Determine oak wilt in red oaks
Answered by: Candace Fountoulakis

QUESTION:

I am concerned my red oaks have oak wilt. How can I tell what is wrong with them?

ANSWER:

Determining if oak wilt has been contracted by a red oak starts with looking at the tree while leaves are still present to see if any areas have turned brown or put on fall color before they should have, the presence of dead leaves on a single branch or if young green leaves have wilted or fallen off. Red oaks that are infected with the oak wilt fungus will die rather quickly. A professional evaluation of the tree on site where a sample from the trunk can be taken would be advisable. A lab analysis will determine if oak wilt is present. If the tree has been killed by the fungus, it should be cut down and the wood removed, not stored. The fungus can live on under the bark and created a new generation of spores in the spring from mats under the bark. This will cause the disease to spread to other trees when beetles are present as well.

Please visit the website www.texasoakwilt.org to see photos of diseased leaves, vendor lists and other helpful information about determining the health of your oaks. Other diseases of trees cause similar symptoms that may not be fatal to your red oaks, so a professional certified arborist is your most reliable resource to determine what is wrong with your trees. I have attached a link to our plant database on Shumard red oaks, as well as an image from our gallery.

Quercus shumardii (Shumard's oak)

From the Image Gallery

Shumard oak
Quercus shumardii