If you searched "oak wilt New York" because an oak in your yard is suddenly dying, start here: oak wilt is real, it is fatal to red oaks fast, and as of July 2026 it has been confirmed inside Monroe County for the first time. That confirmation was one tree in the Town of Greece, not an outbreak, and DEC did not declare a quarantine for it. New York's established infection centers remain in the Finger Lakes, just south and east of Monroe County. Many dying-oak cases in Upstate New York still trace to look-alike problems that are more treatable, so accurate diagnosis is the priority.
What is oak wilt, and why is it so feared?
Oak wilt is caused by the fungus Bretziella fagacearum. It develops in the xylem, the water-conducting cells inside an oak, plugging them so the tree dies of thirst from the inside out. In the red oak group (red, black, pin, scarlet oak), it can kill a mature tree fast, often within a few weeks to six months of the first symptoms. White oaks (white, bur, swamp white) are more resistant, take years to decline, and usually do not pass the disease to neighbors.
The disease spreads two ways. Above ground, sap-feeding beetles carry fungal spores from infected wood to fresh wounds on healthy oaks, which is why pruning timing matters so much. Below ground, the fungus moves tree to tree through grafted roots, so one infected oak can take its neighbors with it.
Is oak wilt in Monroe County or near Rochester?
Yes, as of July 31, 2026. NYS DEC confirmed oak wilt in one tree in the Town of Greece, the first known case anywhere in Monroe County. DEC did not open a quarantine district for it. The infected tree is being removed and its stump treated to stop the fungus spreading through root grafts, and the Town is monitoring nearby oaks.
One confirmed tree is not an outbreak, and it does not mean oak wilt is loose across the Rochester metro. It does mean the disease is now inside the county line rather than a county away.
The established New York infection centers are still in the Finger Lakes. In 2025, NYS DEC confirmed oak wilt at multiple sites there, with active infection centers in the towns of Bristol, South Bristol, and Naples in Ontario County and Middlesex and Italy in Yates County. DEC's oak wilt quarantine district, expanded in February 2026, covers parts of those Ontario and Yates County towns, which border Monroe County to the south and east.
A sick oak in Greater Rochester still most often has a treatable problem, but a confirmed case inside the county means a confident diagnosis is worth getting. Knowing when to call an arborist instead of guessing at a tree problem matters here: a certified pro can sample and confirm, and report a true suspected case to DEC.
Field note · When to call a pro
Want a certified arborist to take a look?
Monster Tree Service of Rochester offers free estimates and a full plant health care program across the Rochester area.
Get a Free Estimate →Why is my oak dying from the top down?
Top-down dieback (called crown dieback) is the symptom that sends people searching for oak wilt, but in the Rochester area it usually points elsewhere. Oak wilt in red oaks typically shows leaves wilting and bronzing from the leaf edge and tip inward, often dropping green-and-brown leaves rapidly across the whole canopy, not a slow top-down thinning.
Slow top-down decline is more often caused by root stress: girdling roots, deep planting, soil compaction over the root zone, or chronic drought. A root collar excavation to check for girdling roots often finds the real culprit at the trunk flare. Heavy clay and glacial till soils common across Monroe County hold water poorly in drought and drain poorly in wet spells, and both extremes stress mature oaks.
How do I tell oak wilt from anthracnose and other look-alikes?
Several common Rochester-area oak problems brown the leaves in summer, and only a lab test confirms oak wilt. Here is how the usual suspects differ.
- Anthracnose: A fungal leaf disease that browns and curls leaves, especially after cool, wet springs that the Finger Lakes sees often. It is rarely fatal. Our guide to anthracnose on shade trees in Rochester covers the blotchy, vein-following browning that sets it apart from wilt.
- Leaf scorch: Browning along leaf margins from heat and drought, common in exposed lawns during a dry Upstate summer. See why tree leaves curl, yellow, and die for how stress-driven browning differs from disease.
- Two-lined chestnut borer and spongy moth defoliation: Insect pressure that finishes off already-weak oaks. The two-lined chestnut borer attacks oaks stressed by drought or defoliation, and repeated defoliation by spongy moth in Upstate New York can push a stressed oak into the same decline.
- Bacterial leaf scorch and Armillaria root rot: Slower, chronic declines that need professional diagnosis.
A short field rule: oak wilt is fast, whole-canopy, and (in red oaks) usually fatal in a season. Anthracnose, scorch, and defoliation are slower, patchier, and survivable. When in doubt, do not guess. Schedule an arborist evaluation with Monster Tree Service before assuming the worst.
When can I safely prune an oak in Rochester?
This is the single most important thing a homeowner can control, and it matters more now that oak wilt has been confirmed inside Monroe County. NYS DEC recommends avoiding pruning oaks from March through September, when sap-feeding beetles are active and fresh wounds are most attractive. Prune oaks in the dormant season (late fall through winter) instead.
If a storm wounds an oak during the risk window, immediately sealing the fresh cut is the one exception NYS DEC and ISA recommend specifically for oaks, the opposite of the usual no-wound-paint advice for pruning cuts. For routine work, schedule oak pruning for the dormant season instead. Reputable crews that follow ANSI A300 standards will time oak pruning accordingly rather than cutting whenever it is convenient, which is one reason it pays to know how to choose the best tree service in Rochester.
Field note · When to call a pro
Want a certified arborist to take a look?
Monster Tree Service of Rochester offers free estimates and a full plant health care program across the Rochester area.
Get a Free Estimate →FAQ
Is oak wilt in Rochester or Monroe County? Yes. On July 31, 2026, NYS DEC confirmed oak wilt in a single tree in the Town of Greece, the first known case in Monroe County. That tree is being removed and its stump treated, and no quarantine district was declared for the county. New York's established infection centers are still in the Finger Lakes, in Ontario and Yates counties. A sick oak in the city is still more likely to have a treatable problem than oak wilt.
My oak is dying from the top down. Is it oak wilt? Usually not. Slow top-down thinning more often signals root issues, drought, or compaction. Oak wilt in red oaks tends to brown and wilt the whole canopy fast, not gradually from the top.
How can I tell oak wilt from anthracnose? Anthracnose causes blotchy, vein-following browning after cool wet springs and is rarely fatal, while oak wilt causes rapid, whole-canopy wilting that often kills red oaks in a season. Lab testing confirms it.
When should I prune my oak? Prune oaks in the dormant season (late fall through winter) and avoid the March-through-September window when sap beetles that can spread oak wilt are active.
What should I do if I think my oak has oak wilt? Do not prune it, do not move the wood, and have a certified arborist inspect and sample it. A confirmed or suspected case should be reported to NYS DEC through its Forest Health Reporting Form or information line.
