Sudden oak death in Oregon

Where the disease is

The pathogen was first found in Oregon in 2001 in the wildlands around Brookings, and an interagency task force with affected landowners has worked on it since. ODF’s fact sheet is blunt about the trajectory: the early goal was eradication, by 2010 the program shifted to slowing the spread, and spread rates “have increased but the disease remains confined to Curry County.”

ODF’s 2023 program report measures the creep from the original 2001 site: about 30 miles north, 10 miles east and 8 miles south. Natural spread tops out at 3 to 4 miles a year, with a long-run northward average of 1.4 miles a year. Spores move in wind-blown rain during the wet season; the jumps come from people moving infected plants or soil.

The Port Orford find drew the most intensive survey in the program’s history: ODF logged 206 positive detections across more than 600 acres of ground transects in that priority area.

The federal picture matches. USDA APHIS (page modified February 7, 2026) lists the pathogen as confirmed on native hosts in 16 California counties and one Oregon county, Curry, and in no Washington county. APHIS dates the disease to 1995, when it was first reported on a tanoak in Marin County, California, and states there is no cure and no treatment for P. ramorum infection; prevention is the only defense.

The quarantine: what cannot move

Oregon’s state quarantine is OAR 603-052-1230 (some ODF documents mis-cite it as an ORS), layered over the federal rule at 7 CFR 301.92. ODF summarizes the practical effect for landowners:

Unlike emerald ash borer, whose federal quarantine APHIS dropped in 2021, sudden oak death is still federally regulated. APHIS’s rules run from 7 CFR 301.92 through 301.92-12, its published quarantined and regulated counties map is dated April 2022, and a separate federal order (April 18, 2012) restricts imports of host plants. On the ground in Curry County, the state map on ODA’s program page is the one to check, because the 2024 emergency expansion postdates the federal map.

If you are clearing, thinning or removing trees anywhere between Brookings and Port Orford, ask the crew whether the parcel is inside the current boundary and where the slash is going. A crew that chips tanoak and hauls the chips north to a Coos Bay yard-debris site is moving regulated material.

Hosts and what the disease does to them

ODF splits hosts into two groups. Tanoak and California black oak are the trees it kills: stem cankers girdle the trunk, the crown browns, and dead trees stand with red leaves. The second group gets leaf blight or shoot dieback but usually survives: rhododendron, evergreen huckleberry, Douglas-fir, grand fir and Oregon myrtle (California bay laurel). WSU adds that bay laurel tolerates infection and acts as a source of spores for plants around it, which is why a healthy-looking myrtle next to a dying tanoak is part of the problem.

Across its range the pathogen infects more than 100 plant species in over 37 families (WSU). In nurseries, ODA says the five genera most often found positive are Rhododendron, Camellia, Viburnum, Pieris and Kalmia, all common in Willamette Valley and Puget Sound yards.

Douglas-fir in the quarantine is a foliar host, not a dying one. If your fir is browning from the top, drought or root disease is far more likely; see Douglas fir and laminated root rot.

Oregon white oak, the native oak of the Willamette Valley and the Puget lowland, is not on ODF’s list of hosts this disease kills. Its newer threat is the Mediterranean oak borer, now in six northwest Oregon counties; that beetle, the oak’s size and root system, and the city rules that protect it are on Oregon white oak.

What to do with host material in Curry County

Treatment inside the quarantine is not a homeowner decision. ODF’s method is to cut, pile and burn infected plants plus the host plants around them within a set radius. Its reports say a 300-foot buffer done promptly after detection can eliminate the pathogen at a site; the current standard radius is 600 feet. The 2023 report prices the options per site at $1,650 for a minimal 20–50 foot radius, $35,750 for 300 feet and $143,000 for 600 feet, which is why the program’s funding, not the biology, sets the pace.

If you suspect sudden oak death on your land:

1. Report it to ODF Forest Health or ODA’s plant health program (503-986-4550) before cutting anything. Photos of cankers and the crown help.
2. Do not move wood, chips or soil off the parcel until the program tells you the material is clear.
3. Expect burning, not hauling. Infected material is burned on site. Burning on ODF-protected land needs a permit during fire season (ORS 477.505), so winter is the working season; rules are in Oregon yard debris burning rules.
4. Treat dead tanoak as hazard trees. A standing dead tanoak near a house or driveway is a removal job regardless of the disease program; a crew used to the quarantine will stage and burn on site. See dead tree removal.
5. Replant with non-hosts on the cleared ground, and keep rhododendron and bay laurel out of the buffer.

Larger clearing of tanoak and brush in the infested zone is a brush clearing job with a disposal plan written into it. Check the crew’s Oregon CCB or LCB license before they start; see Oregon tree service license lookup.

Why it matters north of Curry County

No wildland infestation exists in Oregon outside Curry County, and Washington has had none at all. What both states do have is the nursery trade. ODA runs a program for nurseries that have tested positive since March 2011 and ship regulated hosts out of state: twice-yearly inspections that sample suspect plants, water and soil. In Washington, WSU Puyallup reports the pathogen found “hundreds of times within 45 nurseries” since 2003, a few detections in local rivers, and outside nurseries only on salal; WSDA certifies nurseries that ship host plants out of state.

For a homeowner in Portland, Eugene or Seattle that means two things. Buy rhododendron, camellia, pieris and viburnum from nurseries that are inspected, and if a newly planted shrub develops blackened shoot dieback, do not compost it; bag it and get it tested.

APHIS adds three garden habits that cost nothing. Disinfest pruners and saws between plants. Because P. ramorum is a water mold that thrives in wet conditions, cut down on standing water and avoid overhead irrigation, which matters on the wet side of both states. And do not move plants that look sick. APHIS lists the symptoms as trunk and branch cankers, brown to black leaf lesions and twig dieback, and says an official diagnosis takes a trained professional and a laboratory test, so a photo alone will not settle it.

Oregon samples go through ODA; Washington samples go to the WSU Puyallup Plant and Insect Diagnostic Laboratory, which asks you to take its online screening quiz first. Compared with emerald ash borer, which is now spreading on its own through the Willamette Valley, sudden oak death is still a disease you keep out by not carrying it in.

Next steps

Inside the quarantine: report first, cut second, burn on site, and hire a crew that knows the boundary. Outside it: watch new plantings, keep bay laurel and rhododendron healthy and pruned, and treat a dying tanoak or oak as a hazard-tree question for a certified arborist (arborist services). Removal costs by tree height are on tree removal cost, and the rest of this site’s pest pages are under pests and diseases.