Prune oak trees in winter to avoid oak wilt

Leaves are down, temperatures are cooler, and that means it’s prime time for pruning oak trees, which can be infected by the oak wilt fungus if they’re pruned during the high-risk period April 15-July 15.

Beetles that can carry the disease from tree to tree are not very active now, and the trees are not vulnerable to infection. The beetles are attracted to fresh bark damage or wounds where tree limbs have been removed.

Firewood can harbor the fungus, too. If you suspect your firewood is infected, burn it, chip it or debark it before April. Once the wood has been dried over a year and/or all bark loosens, it can no longer spread oak wilt.

Oak wilt, identified in the 1940s, is widespread across Michigan’s Lower Peninsula and along the state line with Wisconsin in the Upper Peninsula. Red oaks are most susceptible and can die within weeks of infection. These trees have leaves with pointed tips and include black oak, northern red oak and northern pin oak. Trees in the white oak group have rounded leaf edges and are less susceptible. Affected trees will suddenly wilt from the top down, rapidly dropping leaves, which can be green, brown or a combination of both colors.

If you suspect oak wilt:

• Report infections at

• Contact a DNR specialist at or 906-203-9466.

• Verify an oak wilt infection with Michigan State University’s Diagnostic Clinic. Go to or call 517-355-4536.

• Visit for a listing of oak wilt-qualified experts.

Learn more about invasive species and diseases at

Want your deer tested for CWD? Here’s how

Deer check station locations and hours and days of operation will be reduced in 2020 to prevent unnecessary risk to hunters and Department of Natural Resources staff during the COVID-19 pandemic.

Chronic wasting disease (CWD) testing will continue free of charge for all deer harvested in southern Jackson, southern Isabella and western Gratiot counties, and from the core CWD surveillance area in the Upper Peninsula (portions of Dickinson, Menominee and Delta counties) from now until Jan. 4.

The DNR has partnered with U.S. Department of Agriculture-approved labs to accept hunter-harvested deer from anywhere in Michigan for CWD testing. Please note this testing will come at a fee set by the receiving laboratory.

For the 2020 deer hunting seasons, the Wisconsin Veterinary Diagnostic Lab and the Michigan State University Veterinary Diagnostic Lab are both accepting CWD samples. If a hunter chooses to use one of the services, it is recommended to look at the instructions to save time after the hunt.Information about CWD testing and deer check station safety procedures can be found at

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