This response is from our Iowa State University Extension and outreach horticulture specialist.

Oak wilt is a difficult disease to control once it is established in the tree. The first step will be to confirm that it is indeed oak wilt. This cannot be done conclusively from photos, but a sample can be sent to Plant and Insect Diagnostic Clinic at Iowa State University to confirm a diagnosis. More information about when and how to collect a sample can be found here: https://hortnews.extension.iastate.edu/oak-wilt.

The management of this disease is primarily through prevention. There are fungicide injections that can be done by certified arborists to treat infected trees if a small amount of the crown is showing symptoms. If symptoms are wide-spread, the tree will likely need to be removed. More information on oak wilt, including all of the management options, can be found here: https://store.extension.iastate.edu/Product/6624. Click on the “Download” button in the center of the page to download and open the free pdf file.