Oak Wilt
A vascular fungal disease that can kill a red oak in a single season and spread from tree to tree through connected root systems. Early detection and prompt treatment are critical.
What is oak wilt?
Oak wilt is caused by the fungus Bretziella fagacearum. It clogs the tree's water-conducting vessels, causing rapid wilting and death. Red oaks (red, black, pin, northern pin) are highly susceptible and often die within weeks to months. White oaks are more resistant but can still be lost over several years.
How to spot oak wilt
- Leaves browning from the tip and edges inward, with the base still green
- Sudden wilting and leaf drop in mid-to-late summer
- Rapid canopy loss — often half the tree in a few weeks
- Leaves dropping while still partially green
- Fungal mats forming under the bark on red oaks (cracks in bark)
- Multiple neighboring oaks dying in a spreading pattern
Don't prune oaks in spring or summer
Sap-feeding beetles are attracted to fresh oak wounds and carry the oak wilt fungus. Avoid pruning oaks between April and July. If a branch must be removed, seal the wound immediately.
How we treat oak wilt
We only use professional trunk injections — the most efficient method — delivering treatment directly into the tree's vascular system. Treatment is highly effective as a preventative for healthy oaks near an infection, and can also save lightly-infected white oaks. We also advise on root graft disruption and removal protocols for confirmed infections. Licensed by the State of Minnesota with a commercial pesticide applicator license, certified to perform trunk injections.
Request an oak evaluation