All rights reserved. Oak wilt, caused by a fungus Ceratocystis fagacearum, is responsible for killing large numbers of oaks annually in Minnesota.
Oaks are undoubtedly the most valuable and plentiful of our shade trees.
In contrast to Dutch elm disease, which has been very difficult to control, oak wilt can be more readily controlled and this valuable resource saved. Oak wilt, present in many of the eastern states, is most common in the Upper Midwest, including Minnesota. It has spread very slowly north to approximately North Branch and St. Cloud and west to Mankato. Oak wilt is easily identified in red oaks by the rapid wilting of affected trees. After symptoms first appear, a red oak will generally wilt completely in two to six weeks.