This Spring Watch For Oak Wilt Disease
The Michigan Department of Natural Resources would like residents in state to watch for any appearance of oak wilt in their trees from April 15 to July 15. Red oak trees are at risk then because oak wilt can be transmitted from diseased to healthy trees during this period of time. The disease is carried by sap-feeding beetles who become active in the warmer weather and move spores from fungal fruiting structures on deceased oaks to wounds on otherwise healthy oak trees.
Red oaks, including the northern red oak, the black oak, and the pin oak, are worst affected. White oaks are also susceptible, but they take longer to die than red oaks which typically die only a few weeks after being infected with oak wilt.
Locally, oak wilt has killed trees in Kent, Allegan, Ottawa, Barry, and Muskegon counties, so trees in West Michigan are at risk. One of the ways it spreads this time of year is through the movement of firewood. When dead trees are cut down, the wood will often be taken to a location some distance away, on vacation or given away free to strangers. Beetles then spread oak wilt to wounded trees. Once an oak is diseased, the infection can then spread through its roots to other oaks with grafted or connected root systems. A whole stand of red oaks will then be susceptible.
It’s important, then, to avoid moving firewood around. The DNR recommends that anyone who suspects they may have dead oaks with oak wilt disease should instead cover any firewood with a tarp. This will keep beetles away and generate heat which will help kill the fungus. When the bark has separated from the core of the wood, it’s safe to use or move. If you have wood on your property that you cannot identify, remember: it’s always safer not to move it. Oak wilt is not the only disease currently putting Michigan trees at risk.
Fortunately, in addition to taking precautions with firewood, there are methods of dealing with oak wilt. The DNR, after identifying stands of diseased oaks, uses cable-laying equipment to cut the root connections between oaks. They then cut down any diseased trees and burn them. Property owners can also help by monitoring their oaks in spring and painting any wounds they observe with wound dressing or commercial tree paint.
It’s also possible to inject diseased oaks with the fungicide propiconazole, but this should be done only after consulting with a certified arborist. While this treatment doesn’t cure oak wilt, it can prolong the life of the tree, especially if the oak wilt is detected early on.
No one wants to lose a healthy and valued tree, so if you have any questions or concerns about oak wilt or any other disease, do not hesitate to call us at Chop. We would love to come and take a look at your trees and help you care for them.