PAW PAW, Mich. — Now is the last chance to prune oak trees before spring! Oak trees should always be pruned outside of the growing season (April-September) to avoid the spread of oak wilt, an invasive fungus that can kill red oak trees in just one year. Oak wilt is spread by a beetle, which smells the wound on the trees and then congregates to feed. When they reach the damaged tree, they can infect it with oak wilt spores. This fungus fills up the water moving tissues of the tree, eventually strangling it.
Oak wilt has been found in the SWxSW Corner CISMA, which covers Berrien, Cass, and Van Buren counties. It can spread quickly, especially on cut fire wood during the summer months. “A beetle or the spore of a fungi can’t go far by itself. But we can move a hundred miles away in a matter of hours, starting a new problem. If we want to keep our trees, the first step is to stop moving firewood.” Says Eleanor Serocki, Coordinator for the CISMA.
Though oak wilt can kill red oaks (typically with pointed leaf tips) in only one year, white oaks (with rounded leaf tips) are more resistant to the fungus. However, these trees are still susceptible to oak wilt, and should not be pruned in the growing season. White oaks, though, may be a better choice for new plantings.
To look for oak wilt in your trees, keep an eye out for die back this summer, before trees would usually shed leaves, and leaf die back from the tip and edges in (see photo). If you think your tree might have oak wilt, the SWxSW Corner CISMA, a grant funded program through your local Conservation District, can schedule a free home visit to diagnose the tree and discuss treatment options. Remember, trim trees now before bud-break and avoid damaging oaks, including accidental damage from weed whackers or mowers, during the summer!
To learn more about Oak Wilt, join the SWxSW Corner CISMA, the Berrien Conservation District, and ReLeaf Michigan for a 2 hour presentation on Saturday, March 31st from 10:30-12:30 at the Three Oaks Township Public Library. Dr. David Roberts of Michigan State University’s College of Agriculture and Natural Resources will discuss how the disease acts and spreads, its impacts, and how we can manage it in our forests and yards. Please RSVP to Nancy Carpenter at the Berrien Conservation District at (269) 471-9111 ext. 3 or nancy.carpenter@macd.org
The SWxSW Corner CISMA is a grant-funded organization working to help land owners, local governments, and concerned citizens understand and manage the invasive species threats in Berrien, Cass, and Van Buren counties. If you have invasive species on your property, or if you would like to have a CISMA representative speak for or work with your organization, please contact your county’s CISMA representative at any time! The CISMA is funded in part by the Michigan Invasive Species Grant Program, through the Departments of Natural Resources, Environmental Quality, and Agriculture and Rural Development.
— SWxSW Corner CISMA
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