The Wisconsin Department of Natural Resources (DNR) announced that oak wilt, a fungal disease that can kill oak trees, has been identified for the first time in Manitowoc County. The infected tree was located in the Village of Mishicot after the property owner noticed abnormal leaf discoloration and contacted DNR staff.

How the disease was discovered

Forest Health Specialist Bill McNee explained that the tree’s symptoms prompted a site visit, confirming the presence of the fungus. While the exact pathway of the disease into the county is uncertain, McNee offered two possibilities. “When people take wood from infected trees and move that wood long distances, the fungus may still be able to spread through the beetles,” he said. He added that the disease may have been present at very low levels for years, going unnoticed because oak trees comprise only about 2% of the county’s rural forest and roughly 1% of urban trees.

Local monitoring and response

Brown County Parks Department Program and Natural Resource Manager Jason Petrella noted that his staff regularly surveys oak trees for signs of disease. “We’re always watching for any kind of potential issues, especially with oaks,” Petrella said. He praised the DNR’s quick identification and urged homeowners to stay vigilant.

Preventive steps for residents

McNee emphasized that panic is unnecessary. “The disease is so uncommon that we only have one known tree in the entire county,” he said, acknowledging that additional low‑level infections may exist. He recommended two key actions for property owners:

• Avoid moving firewood long distances unless it is fully seasoned and the bark has fallen off, as the fungus cannot survive in dry wood.
• Refrain from pruning oak trees between April and July, the period when beetles that spread the fungus are most active.

Petrella echoed these guidelines, advising anyone planning work on oak trees to consult DNR’s seasonal recommendations and to follow the agency’s research‑based protocols.

Broader context

Oak wilt has now been confirmed in 67 of Wisconsin’s 72 counties, making Manitowoc the latest addition to the list. The nearest known cases lie about 20 miles north in Brown County. The DNR encourages residents who suspect oak wilt on their property to contact the department’s forest health staff for assessment and guidance.

By staying informed and following preventive measures, Manitowoc County residents can help protect the limited oak population and limit the spread of this potentially destructive disease.

Original reporting: FOX 11 WLUK Green Bay (local) — read the source article.