Oak Wilt in our Woods!

July 3, 2018

The threat of Oak wilt is very real for us here in Crow Wing county as there have been confirmed cases close to home. It is hard to put a value on a mature tree that has a purpose in your yard. Here are some things to consider and look for to help prevent the spread of this disease in our woods.

Disease Facts:  Oak wilt is a fatal disease of oak trees found throughout the United States. It is caused by a fungus that leads to plugging up the water conducting vessels of a tree. Oaks in the Red oak family will defoliate and die within 4-6 weeks. While oaks in the White oak family, may take several months if left untreated. Oak wilt spreads mainly through the root systems of adjacent oak trees and can spread up to 75’ a year.

Symptoms: There are several key symptoms to look for in identifying the disease. First, the leaves at the edge of the canopy will wilt, making its way to the inner canopy. In mid-summer you will notice a blanket or a large amount of the dead leaves falling from the tree. This will occur a few branches at a time. About half of the diseased trees will produce fungal mats and pressure pads in the wood and some of the bark. They will have a fruity odor to them. At times, this may cause the bark to crack on the surface. These spot’s produce Oak Wilt spores. In some instances, the branches will have brown spots or dark rings in the wood. While these are only visual cues, the only way to confirm the identity of this disease is to send it in to a laboratory to be tested. This should be done by a professional as there are certain steps and measures that need to take place.

Management: Oak wilt treatments are directly injected into the base of the trees, just beneath the bark. Most oak treatments will occur June through September in Minnesota, because leaves must be on the trees for treatments to work properly. It is important to know if you have trees in the Red oak (pointed leaves) or White oak ( rounder leaves) family. Red oaks infected with the disease are untreatable and will parish. It is important to set up a plan to protect any of the other oak trees in that area. White oaks are more resistant to the disease and treatments are 80-90% effective and can usually be saved. It is best to have a professional do a property evaluation and put a management plan into effect.

Mikes Tree Company has four certified Arborists on staff to help manage your property. Contact us today to let us know how the Tree Doctors can help!


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