Understanding Oak Wilt


November 10th, 2017



If you have an Oak tree in your landscaping, you should definitely read this. This serious disease could affect any Oak tree in our area. Oak wilt is caused by a fungus that stops an Oak’s ability of moving water throughout the tree. As the water movement throughout the tree slows, the leaves will fall off. The tree can be killed in as little as 30 days leaving a void in your landscaping, although some might take up to one year to die. Oak wilt can be spread underground through roots of nearby oak trees that are touching or on the surface through a beetle that is attracted to the wounds on Oak trees. All Oak trees, whether naturalized or planted in landscapes, can be affected.

Prevention. Do not prune an Oak tree from April to October. If an Oak is damaged during that time or needs an emergency pruning (i.e. storm damage) then tree wound paint should be used immediately.

Signs and Symptoms.  Here are some symptoms to look for. Leaves turn brown during the growing months, starting from the leaf tip and edges working inward. There may be a very distinct line between the brown and green part of the leaf.  Green, dead, and half dead leaves are dropped from the tree prematurely.

If you suspect an Oak tree that is important to you is infected, contact an arborist.