Stop Oak Wilt

Cass & Crow Wing Counties

Stop Oak Wilt

Do you have property in Cass and Crow Wing counties? Oak wilt, Bretziella fagacearum, is an invasive tree disease that's close to entering these counties for the first time. It's easy to prevent, and deadly if left unchecked. Oak wilt can quickly kill oak trees, especially those in the red oak group (oaks with pointed leaf lobes).

Homeowners and Landowners

Simple measures can prevent oak wilt (see video below) and there are control options if it's caught early. But control can be expensive. Look for and report oak wilt in red oak trees on your property or in your neighborhood.

Oak wilt is harder to identify on trees in the white oak group (rounded lobes) and often requires laboratory testing.

Resort and Tourism Operators

Look for and report suspected oak wilt in red oaks on your property to allow quick management to reduce negative impacts.

oak leaf with oak wilt

Oak wilt ID

Check out this Minnesota DNR website to learn how to identify oak wilt. Pay close attention to rapid leaf drop in mid-summer and leaf wilting starting at the top and edges of the tree canopy.

Minnesota map with Cass and Crow Wing counties highlighted

When to report

If you live in Cass or Crow Wing counties, report suspected oak wilt in red oak trees between July 4 and mid-August. Clear photos of the tree, branch and leaves are most helpful.

How to report

  1. Great Lakes Early Detection Network (GLEDN) smartphone app

  2. EDDMapS online

Oak wilt management

This video provides a good overview of oak wilt prevention and control from the Wisconsin DNR.

Anxious to learn more about oak wilt? Check out this classic: USFS How to Identify, Prevent, and Control Oak Wilt and the MN DNR's oak wilt management website including the new Oak Wilt Guide for Minnesota link at the bottom.


All photos are from MN DNR staff.