This disease has been found in the area East of the tracks and North of the Railroad tracks. This is a serious disease that affects many species of oak trees. Oak Wilt is caused by a fungus that invades the water conducting system of a tree and interferes with the normal water flow. In most cases oak trees that contract Oak Wilt die within a short period of time. Red, pin and black oak are most affected, and will die with one year, with white, bur and swamp oak being less susceptible to the disease which may die within 2-3 years.
Spread of Oak Wilt
Oak Wilt moves from tree to tree in a variety of ways: It usually occurs by root graft, with infected tree roots intertwining with a healthy tree. The other ways are by insects carrying the fungus and boring into a healthy tree, animals and pruning tools.
Symptoms usually progress from the top of the tree downward. Generally the leaves at the top of the tree turn a dull green, then tan, then wilt and start falling. This can occur in late June to early July. As the disease progresses individual leaves quickly discolor, taking on a bronzed appearance. The discoloration progresses around the margins of the leaf from the tip to the base. Leaves fall rapidly as the disease progresses. Trees can defoliate within a few weeks of symptoms onset.
Diagnosis and Management
There are two ways to contain the disease: 1) provide a root graft barrier by trenching between the infected tree and healthy trees, and 2) remove the infected tree as soon as possible. To protect non-infected trees an arborist can inject a chemical that will help protect the healthy tree from the disease.
As a precautionary measure, no pruning of oak trees should occur between April and October. The beetle that carries the fungus is attracted to freshly cut wood. Any firewood from an infected tree that is kept must have the bark peeled off.
There is chemical and mechanical control for healthy trees. Please visit this website http://web.aces.uiuc.edu/vista/pdf_pubs/618.pdf for more information or contact Public Works Department.
Please watch for Oak Wilt symptoms in your neighborhood. If you think a private tree may have symptoms contact a professional arborist immediately. If your tree has been positively identified for OWD contact the Public Works Dept. If you think a public tree has symptoms contact the Public Works Department at 469-6756.