Oak Wilt is a fungal disease that infects Oak trees, caused by the fungi Ceratocystis fagacearum, which is new to our area. Oak Wilt is believed to have been introduced to North America from Europe or Asia, and has been found throughout the Mid-Western and South-Westerns U.S. for at least 50 years. Oak Wilt can affect Oaks from both the Red Oak and White Oak family, however, for Red Oaks infections is a death sentence, sometimes in as little as a few weeks after initial infection. Oak Wilt is an extremely serious threat to our area - the Red Oak family includes all of our native Oaks (Pin Oaks, Northern Red Oaks, Black Oaks); our native Oak trees cannot survive Oak Wilt without intervention.
Ceratocystis fagacearum fungi cause Oak Wilt by clogging the Xylem in Oak trees (the tree's vascular tissue, used to transport water and nutrients throughout the tree), creating symptoms that resemble drought stress. The fungi is spread most commonly through "root grafting", a common condition in which two Oak trees near one another have interwoven/interconnected root systems, allowing the fungi to travel through the root system of an infected tree into the root system of a healthy tree. The fungi can also spread via a variety of insect vectors, whose bodies pickup fungal spores from an infected tree and deposit them on a healthy tree.
The only way to treat Oak Wilt in the Red Oak family is to prevent infection from happening. Luckily, research-backed products and methods of preventing infection are now available. Trunk injections of the systemic fungicide Propizol (Propiconazole) have been shown to be up to 99.5% effective at preventing Oak Wilt symptoms in the Red Oak family. Propizol can protect healthy trees from Oak Wilt for 2 years (some research has shown up to 6 years), and applications are quick, safe, and affordable (broadly speaking, applications cost between 10-30% of the cost of tree removal).
If you or someone you know has an Oak tree (or many Oak trees) that you value, please give us a call! We've attended in-person training at Morris Arboretum on the best methods of trunk injection to give our Oak trees the best shot at survival. We're hoping that by spreading awareness of this threat to our Oak trees we can avoid the near extinction that has recently occurred to our Native Ash tree population.
Alec M. Wallace,
Certified Arborist #PD-2833A
President of Miles Tree and Stump