Natural Resources
2:24 pm
Wed November 20, 2013

Oak Wilt Arrives in Minocqua-Woodruff

A lethal tree disease has been found for the first time in near Woodruff.  Oak wilt is prevalent in southern and central Wisconsin.  But tests have confirmed its presence in the Northern Highland American Legion State Forest. 

Oak wilt may be spreading north in Wisconsin.
Oak wilt may be spreading north in Wisconsin.
Credit Ronald Billings / Texas Forest Service

DNR Forest insect and disease Specialist Brian Schwingle says the finding is significant.               

“It’s concerning that we found it on our largest state property, the Northern American Legion state forest, where oak is an extremely valuable tree.”

Oak wilt was found near Three Lakes in 2010, but this is the first finding in the Minocqua Woodruff area.  Officials cut down the diseased tree and several others and removed stumps in hopes of eradicating the pathogen.

Schwingle says one sign of oak wilt is a tree rapidly dropping most of its green leaves. 

“Oak wilt is a pretty drastic disease.  It causes an oak to go from one hundred percent healthy to dead in about two months.

It’s largely spread to new areas through infected firewood.  Schwingle says this is a big concern with the gun-deer season set to open.

“Right now with gun deer season coming up here, without question there are probably hunter groups that are bringing up firewood up to their camps.  By people moving firewood all over the state, that’s how oak wilt gets transported to uninfected zones.”

Oak wilt infects trees through open wounds on the bark in the spring and summer. 

The DNR says one way to protect your oak trees is to prune them over the winter…before they become vulnerable to the disease spores.