Rhinelander, Wis. (WJFW) – There’s a lot of spring cleaning this time of year, but it’s important to protect your oak trees as they are at high risk for a certain disease.
“Oak wilt is a fungal disease that kills trees,” said Linda Williams, forest health specialist at Wisconsin DNR.
The DNR considers April through July to be a high-risk season for oak wilt, a fungus carried by insects.
“The beetles can bring the fungal spores to a new wound on an oak tree, and once those spores have grown into the oak tree, that oak tree will be dead by the end of the growing season,” Williams said.
The beetles that spread oak wilt are small and hard to see, but their damage can be bigger than a tree or two.
“All of a sudden, you can go from no oak wilt to a fair amount of oak wilt in an area pretty quickly, and we don’t like to see our oak trees die like that,” Williams said.
Once a tree has the disease, it spreads through the root system, eventually infecting other trees as well.
“Don’t prune or wound your oak trees in April, May, June, or July,” Williams said.
Regardless of the size of the branch, it is best not to prune. If you absolutely must prune your tree, apply a dressing immediately afterwards. The beetles can reach the tree within 15 minutes of pruning, so gardeners should paint the branch quickly.
“By painting that wound, it will keep the beetles that can introduce the fungus, it will keep them from coming into contact with that wound,” Williams said.
Oak wilt is not common in the Northwoods at the moment, so let’s keep it that way.
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