The Oak Wilt Crisis in Michigan

Oak Wilt was first discovered in Texas where it currently infects over seventy-six counties and almost every city in the central part of the state. Individuals and municipalities have been battling oak wilt in the mid-west for years and now it occurs in twenty-one states. Oak Wilt is an up and coming problem in Michigan, so Arborjet’s Regional Technical Manager, Joe Aiken filled us in on the current situation.

First the Ash Trees, Now the Oaks

“In Michigan, we are ground zero for emerald ash borer and now red oaks (northern red, northern pin and black) are the primary species at risk, not only in the landscape but also in the forests. The oak wilt fungus, Ceratocystis fagacearum, is primarily spread by the picnic beetle. These beetles are attracted to the fresh wounds caused by pruning (especially in April – July) and storm damage, and their activity transmits the fungus to healthy, recently pruned oaks from nearby diseased trees. Trees which come into contact with the fungus in the spring are often dead by August or September. Once a tree has been infected the fungus can move through root graphs to neighboring trees.

Use Propizol for Oak Wilt

Unfortunately, there is no known way to save an oak tree already infected by the oak wilt fungus. The only way to maintain healthy trees is through prevention. Oak wilt infection can be prevented by trunk injecting the systemic fungicide propiconazole (Propizol). Recently, many people have been using Propizol, especially in the upper-northwest area of Lower Michigan where the problem is probably the worst right now. Once a tree has been infected it can go through the roots to touch the tree next to it and spread it that way as well. We are excited that the Department of Natural Resources is now experimenting with trunk injection as a viable option within the approach to oak wilt. Over the season we will be monitoring several test sites to confirm that the treatment can arrest oak wilt fungus to where it will actually die off in the soil.”

Get Involved

Homeowners and arborists should be on alert, aware and on the look-out for oak wilt so that when the time comes, they can make wise choices.  Do you have questions about oak wilt? Contact a service provider in your area or contact us directly.