Don't Spread Oak Wilt Disease this Spring!

by Anna Mitterling, Wildlife Cooperative Coordinator, MUCC

The snow is gone, the sun is out, the birds are chirping - time to get outside and work on habitat! However, spring and summer are also times where certain trees are vulnerable to different diseases. For a detailed outline of which trees you need to keep an eye out for, please check out DNR's website on Forest Health.

oak_wilt.jpgOak Wilt is the disease I am going to cover today. This disease is deadly to healthy red oaks, and can effect some white oaks as well. Red oaks that drop their leaves suddenly in the summer are likely candidates for Oak Wilt.  The disease spreads through the tree roots, by beetles, and by moving infected fire wood.

To help avoid spreading Oak Wilt, DO NOT prune or cut oak trees between April 15 and July 15. Oak trees suspected of having Oak Wilt should be reported at 517-284-5895 or

For other considerations, please do not hinge cut oak trees, especially Red Oaks. This makes them vulnerable to this disease as well - and for a longer period of time than simply pruning an oak tree.

 Per the DNR:

Why we care: Oak wilt kills healthy red oaks. White oaks can also be affected but are more resistant and less vulnerable to mortality from the disease. Once a red oak becomes infected with the oak wilt fungus, the tree will die, and there is no treatment to save the infected tree. Once an oak wilt infection is confirmed, however, treatments are available to save surrounding oaks and stop the spread of this disease.

What is at risk? All red oaks are susceptible to oak wilt. Red oaks are common urban and suburban landscape trees. The loss of these trees can have a significant negative impact. In the forest, red oaks are also an important producer of acorns for wildlife habitat. Using 2011 Forest Inventory and Analysis data along with the current average stumpage price for red oak sawlogs, it is estimated that the value of red oak timber in Michigan is approximately 1.6 billion dollars.

The threat: Oak wilt moves slowly on its own through root systems and travels short distances overland when new spores are moved by beetles from an infected tree to a freshly pruned or injured tree. Oak wilt can be moved long distances when people move infected firewood from one location to another. Look for red oaks that suddenly drop their leaves in the summer. The disease spreads, killing nearby oaks from one year to the next. Currently, oak wilt is generally distributed throughout the Midwest and Texas.

What could happen in Michigan? Once established, if not treated, oak wilt will continue to spread, killing all red oaks in a neighborhood or a forest. What can you do? DO NOT prune oak trees during the growing season. If you need to prune oaks, DO NOT prune them between April 15 and July 15. DO NOT move firewood: oak wilt is spread by the movement of infected wood.

Showing 1 reaction

Please check your e-mail for a link to activate your account.
  • commented 2016-03-18 16:21:31 -0400
    Can planting bare root seedlings transfer oak wilt to new areas? Are nurseries who handle red oak seedlings screened for wilt?