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Oak wilt in Minnesota

Quick facts

  • Oak wilt covers a large area in Minnesota and affects all species of oak trees. Check the DNR website for an up-to-date oak wilt disease map.
  • To manage oak wilt 
    • Stop below-ground spread.
    • Prevent spread by insects.
    • Don't move firewood from oak wilt infected areas.
    • Use fungicides on high-value trees.
  • Don't prune, wound or cut down oaks from early April to mid-July.

Protect your oaks from oak wilt

Oak wilt is caused by the fungus Ceratocystis fagacearum, and is responsible for killing large numbers of oaks every year in Minnesota. 

Map of confirmed occurrence of oak wilt in Minnesota
The known range in Minnesota where oak wilt is threatening shown in red areas. Map updated May 2018.

Oak wilt is most severe in red oak group species such as northern red oak and northern pin oak. Fortunately, this valuable resource can be protected by utilizing effective management techniques.

Oak wilt occurs in 24 states in the eastern United States and is not known to occur elsewhere.

Where is oak wilt found in Minnesota?

In Minnesota, the disease is currently found in an area bounded on the north by Pine County, on the west by Stearns and Nicollet counties, and south to the Iowa border. 

The greatest concentrations of oak wilt are found in Sherburne, Anoka, Isanti and northwestern Dakota counties.

A white oak tree

Oak wilt risk status - LOW

Mid-July through late October

Exact dates for the beginning and end of this status period may vary from year to year.


Jennifer Juzwik, research plant pathologist, US Forest Service; Brian Schwingle, forest health specialist, Minnesota DNR; and Matthew Russell, Extension forester

Reviewed in 2018

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