David Roberts, a plant pathologist at Michigan State University, gave a free educational presentation in Kalamazoo to help homewoners and arborists ensure the long-term health of neighborhood trees.
Oak wilt is an aggressive disease that affects oak tree species, and is one of leading disease for tree mortality in the Eastern United States. The fungal pathogen that causes oak wilt is Certocystis fagacearum. Unfortunately, it was very difficult to isolate and identify the fungus until the 1980’s, allowing it to spread to many forest habitats before arborists could figure out how to control it. Oak trees are dominant in many of Michigan’s forests. While the fungus causing oak wilt disease can affect all oaks, red oaks are the most susceptible and often die within a month of infection. The fungus moves to neighboring trees up to 100 feet apart, via root grafts that create an underground connected system for the fungus to travel through. The fungus will spread progressively throughout an entire forest until there are no more oak tree hosts available to colonize.
Historically, trees killed by the oak wilt disease were marked and numbered for removal, because the fungus spreads rapidly through the roots and kills trees within weeks. The presentation showed members of the neighborhood how to identify oak trees affected by disease, and who to contact in order to get those trees removed as soon as possible. Other topics covered included how to manage oak wilt once identified, important dates and restrictions, what to do with disease wood, and guidelines for hiring tree service from an arborist.
For detailed information on how to identify, prevent and control oak wilt disease, please see the USDA brochure linked below.
The presentation was sponsored by ReLeaf Michigan, the City Kalamazoo, the Arboriculture Society of Michigan, and the DNR/Michigan Invasive Species Grant Program.
USA Information on How to Identify, Prevent, and Control Oak Wilt: