Oak Wilt can be avoided


If you have oak trees, don’t put away your pruning tools too soon. Oaks need pruning during the dormant season, which starts in November.

Pruning can be an important part of tree maintenance. Regular thinning improves the aesthetics and health of trees. Proper pruning allows air to flow freely through trees, helping the interior dry after rain. Thinning also allows sunlight to better penetrate through the canopy, reducing the severity of fungi that thrive in dark, damp places such as thick crowns of trees.

Pruning oak trees during their dormant season reduces the risk of a common and deadly disease called Oak wilt. Oak wilt is transmitted to oak trees through an insect called the Picnic Beetle. The Picnic Beetle is attracted to fresh wounds created by storm damage or pruning during the growing season.

If a Picnic Beetle lands on a fresh wound during the growing season, it may transfer the disease to the tree. Once infected, Oak wilt can kill a mature oak tree in a matter of months. If other oak trees grow nearby, they also may be infected and die. Oak trees can graft their roots together if they are close enough, and the Oak wilt disease can transfer from tree to tree through these root grafts. Pruning after mid-November and before the end of February reduces the risk of Oak wilt.

Symptoms in recently infected trees include browning around the margins of the leaves. The browning moves inward and from the leaf tips back to the leaf base. Leaves may appear to wilt. Some may fall off while others remain attached.

If you need more information, please call Garpiel Group’s arborist, Don Churchill, at (989) 797-4749.