Camelot Tree & Shrub Co. wants people to know something important: The battle against oak wilt in Michigan has begun, especially in the central and Midwest United States.

Oak wilt is a fungal disease that moves through the water-conducting tissue, or vascular system, of a tree. It essentially clogs the “veins” of an oak tree, which can kill stands of mature trees very quickly.

Even worse, the disease can spread underground through root grafts and negatively affect neighboring trees. It is a reason why oak wilt is acknowledged as such a perilous disease, because it spreads so effectively and the visual eye can’t even track such progress due to it occurring underground.

An article published in July 2014 by Michigan State University Extension says that of the two tree groups of white and red oaks, red oaks are more susceptible to oak wilt. Red oaks can wilt and die in a period of several weeks, while white oaks could theoretically survive for a year or more.

Symptoms tend to progress in late spring and early summer, when obvious signs include tree leaves littering the nearby ground. Another sign of wilting is when tree bark cracks due to a fungal mat that grows underneath. The mats attract sap beetles that pick up and release spores that contain the disease.

“The first symptom is browning leaves at the top of the tree,” the article states. “Leaves brown from their margins at the end of the leaf and continues to progress along the margins and down towards the mid-vein and stem of the leaf. Whole branches may be seen yellowing and then browning as the disease progresses down the branch.”

We at Camelot warn that leaving a diseased tree unaffected just leads to the possibility that nearby trees will also become diseased, creating a bigger problem than needs to exist.

We believe it’s vital to only prune trees during the winter(dormancy) season, when both beetles and spores are dormant. Doing things in this manner dramatically decreases the risks associated with the disease. Do not touch oaks during the growing season, either, as any wound literally opens up the tree to the possibility of being infected by the disease.


Image Courtesy of Great Lakes Now