July 15 marks the end of the three-month window when oak wilt can be transmitted from diseased to healthy red oak trees. Although this time frame is coming to a close, the Department of Natural Resources reminds residents not to move wood from trees with oak wilt. Wood from oak wilt-killed trees can produce spores, which can infect healthy oaks if (the infected trees are) wounded between April 15 and July 15 the following year.
According to Dr. Robert Heyd, forest health management program manager for the DNR’s Forest Resources Division, oak wilt is a serious disease of oak trees. It mainly affects red oaks, including northern red oak, black oak and pin oak. Red oaks often die within a few weeks after becoming infected. Because white oaks are more resistant, the disease progresses more slowly.
“The normal time-tested advice is to prevent oak wilt by not pruning or otherwise ‘injuring’ oaks from April 15 to July 15,” Heyd said.
He added that the spread of oak wilt occurs during this time of year as beetles move spores from trees killed last year by oak wilt to wounds on healthy oaks.
Oak wilt has been detected in Alcona, Allegan, Alpena, Antrim, Barry, Benzie, Berrien, Calhoun, Cass, Cheboygan, Clinton, Crawford, Dickinson, Genesee, Gladwin, Grand Traverse, Iron, Kalamazoo, Kalkaska, Kent, Lake, Lenawee, Livingston, Macomb, Manistee, Menominee, Midland, Missaukee, Monroe, Montcalm, Montmorency, Muskegon, Newaygo, Oakland, Ogemaw, Oscoda, Ottawa, Roscommon, Saginaw, Shiawassee, St. Joseph, Van Buren, Washtenaw, Wayne and Wexford counties.
Although oak wilt hasn’t been detected in every Michigan county, Heyd said the need for vigilance is present statewide. Read more