Oak wilt, a deadly disease of oaks, has been found for the first time in Price County.
The Department of Natural Resources confirmed the find in wood samples from two red oak trees in the town of Elk, just north of Phillips.
"This find is particularly concerning considering the rarity of the disease in this part of the state," said Todd Lanigan, DNR forest health specialist.
Oak wilt is commonly found in the southern two-thirds of the state and is creeping north. Most of northern Wisconsin is still free of oak wilt, so it is still important to prevent the spread of this disease.
[Oak wilt is widespread in southern Wisconsin but in much of northern Wisconsin it is still a new and uncommon disease]
Prevent the spread of oak wilt to healthy trees
Oak wilt is easily brought to new areas on firewood and other raw oak materials from infected oaks. Beetles that feed on the sap from tree wounds spread the disease from tree to tree. To prevent this:
1. Avoid pruning or injuring oak trees from April 15 through July 15. In northern Wisconsin, this is when the disease and the beetles are most active and working together to spread the disease.
2. If oaks are removed, pruned, or damaged between April 15 and July 15, seal the wounds with a water-based (latex) paint or pruning sealer.
3. Keep firewood local. Leave oak firewood where it is cut for one year, or until the bark is naturally loose.
Preventing the introduction of oak wilt to a new area is much easier than treating infected trees. After a tree is infected, oak wilt spreads from one oak to another through connected roots between neighboring trees. Preventing this underground spread can be difficult.
Symptoms - what it looks like
"Symptoms of oak wilt are branches with wilted leaves and leaves on the ground in summer when you wouldn't expect to see that," said Lanigan. "These are not the brown, dry leaves you see in autumn. These are partially green to bronze-green and are not completely dry. Once symptoms are visible, a tree loses most of its leaves and dies within a few weeks," said Lanigan.
More information is available
The University of Wisconsin's Plant Disease Diagnostic Clinic at 608-262-2863 can help verify the presence of oak wilt. A sample must be sent to clinic, and a small fee is charged for the service.
Additional information about oak wilt and firewood is online: dnr.wi.gov, keywords "oak wilt" or "firewood."
Local DNR urban forestry coordinators have information about grants to help combat oak wilt at the community level. Individual property owners can contact their municipal forester or their DNR forest health specialist with questions or concerns.
Last Update: Dec 02, 2016 10:30 am CST
