It’s time to leave the oak trees be, at least until mid-summer, the Michigan Department of Natural Resources advises.

While spring might be the preferred pruning season for many tree species, it could prove fatal if done with oaks, the DNR warned in a news release.

Red oaks are vulnerable to oak wilt, which is spread by sap-feeding nitidulid beetles that carry viable oak wilt spores to fresh wounds on other oaks, the DNR explained.

In late winter, the risk of infection through sap-feeding beetles is still very low through April 15, even during warm days. But that changes from mid-April to mid-July, with recent research at Michigan State University indicating that oak infection risk peaks in May and June in the state.

There is no cure for oak wilt and an infected tree can die within weeks, the DNR states.

So to stop the spread, the DNR recommends not pruning or otherwise damaging any oak trees — not just red oak — from April 15 to July 15, to be on the safe side. That means those tending trails or rural roads should resist trimming branches as well.

First identified in the Midwest during the 1940s, oak wilt was confirmed in Michigan and management techniques were in trial phases by 1951. It now is common in the Lower Peninsula. It also has been identified in Dickinson, Iron and Menominee counties — in other words, in our backyard — plus most of Wisconsin, including Marinette and Florence counties.

Trees in the red oak family are most susceptible to the disease. These include black oak, northern red oak and northern pin oak — all have leaves with pointed tips. Trees in the white oak group have rounded leaf edges and include white oak, swamp white oak and bur oak. These trees are better able to block spread of the disease through the entire tree, preventing rapid death, according to the DNR.

Symptoms of oak wilt most often appear from late June until September. Affected trees will suddenly begin to wilt from the top down, rapidly dropping leaves, which can be green, brown or a combination of both colors. Left untreated, oak wilt will continue to move from tree to tree through grafted root systems, killing more red oak over an increasingly large area when oak trees grow close together.

If an oak tree is damaged during the high-risk period from April 15 to July 15, landowners can immediately cover all wounds with tree-wound paint or latex-based paint, the DNR advised. Painting tree wounds is not recommended for other trees species, as it can reduce the effectiveness of the healing process.

Oak wilt also can be spread by moving firewood cut from infected trees, which is why trees killed by oak wilt require special management. Any tree suspected of succumbing to oak wilt should be burned on site, chipped or debarking before April 15. Once the wood has been dried for longer than a year and/or all the bark loosens, the firewood can no longer spread oak wilt.

To minimize the risk of oak wilt infection caused by logging damage, the DNR restricts cutting of red oak trees on state-manage land between April 15 and July 15. The DNR recommends private forest landowners exercise caution during this period and, whenever possible, delay harvests in oak forests until after July 15.

Those who suspect oak wilt should —

— Report infections using the oak wilt interactive map.

— Contact a local DNR forest health specialist by email at DNR-FRD-Forest-Health@Michigan.gov for more information or to ask a question.

— Turn to the Michigan State University’s Diagnostic Clinic to verify oak wilt infection. Instructions are available online at https://www.canr.msu.edu/pestid/ or by calling 517-355-4536.

— Get help from an oak-wilt qualified specialist. Go online to MichiganOakWilt.org for a listing and more information.