Tree diseases: what the agencies record
A table of the tree diseases whose agency pages we have read: the pathogen, the main hosts, the countries that report it, the status the agency gives it, and where to send a report. One page each for the ones with enough sources.
Checked against the sources at the bottom of this page on October 8, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. The table below covers only the diseases whose agency pages were read on October 8, 2026. A blank in a cell means the page read did not say, not that nothing exists. The list is not complete.
The diseases read so far
| Disease and pathogen | Main hosts and where reported | Status and where to report |
|---|---|---|
| Oak wilt Bretziella fagacearum | All oaks, red oaks most susceptible. Reported from more than 25 eastern and mid-western US states and parts of Ontario. Not present in the UK. Read the full page. | Notifiable in the UK per Forest Research. See the state and province table and the US and Canada guides. |
| Dutch elm disease Ophiostoma fungi | Elms. Present in all parts of the UK; the Canadian Food Inspection Agency lists seven provinces, Ontario among them, as regulated areas. Read the full page. | No requirement to report in the UK per Forest Research. See the Canada and UK guides. |
| Ash dieback A fungus | Ash. Covered in our regulated-pest guide, not as a separate page. Read the full page. | Status and links in the ash dieback guide and the UK report guide. |
| Sudden oak death A water mould | More than 150 plant species; larch the main UK tree host. UK (wetter west), California and part of Oregon, nurseries in coastal British Columbia. Read the full page. | Notifiable in the UK per Forest Research; federal quarantine in the US. See the UK, US and Canada guides. |
| Acute oak decline Several bacteria | Mainly pedunculate and sessile oak. England and the Welsh Borders; not reported in Scotland or Northern Ireland as of 2020. Read the full page. | Reportable in the UK. TreeAlert (Great Britain) or TreeCheck (Northern Ireland). See the UK guide. |
| Beech leaf disease Associated with a nematode | American beech. First found in Ohio in 2012; reported across the north-eastern US and in southern Ontario. Read the full page. | New York DEC takes reports by form. See the US and Canada guides. |
| Kauri dieback A water mould | Kauri. Northland, Great Barrier Island and the Coromandel Peninsula, New Zealand. Read the full page. | Managed by Tiakina Kauri with rules and controlled areas. See the New Zealand guide. |
| Canker stain of plane A fungus | Plane trees, and sycamore per Penn State Extension. Albania, Armenia, France, Greece, Italy, Switzerland, Turkey and some US states; not present in the UK. Read the full page. | Notifiable in the UK per Forest Research. See the UK guide. |
| Xylella A bacterium | Oak, elm, plane, maple and many crops. Found in France, Spain, Italy, Portugal, the Americas and Taiwan; not known in the UK. Read the full page. | Notifiable in the UK per Forest Research. See the UK guide. |
| Sweet chestnut blight A fungus | Sweet chestnut (Castanea). North America, continental Europe and parts of England. Read the full page. | Notifiable and regulated in the UK per Forest Research. See the UK guide. |
| Bleeding canker of horse chestnut A bacterium | Horse chestnut. All parts of Great Britain. Read the full page. | Not notifiable per Forest Research. See the UK guide. |
| Thousand cankers disease A fungus | Walnut, black walnut most. Several US states and Lombardy, Italy; not found in Canada or the UK. Read the full page. | Notifiable in the UK per Forest Research. See the UK and Canada guides. |
| Dothistroma needle blight A fungus | Mostly pines. United Kingdom and western North America. Read the full page. | Reportable in trade in the UK per Forest Research. See the UK guide. |
| Myrtle rust A rust fungus | Myrtle family, including eucalyptus. Australia, New Zealand and other countries. Read the full page. | Unwanted organism in New Zealand per the Department of Conservation. See the New Zealand and Australia guides. |
| Elm yellows A phytoplasma | Elms; American elm most affected. Italy, France, Germany, eastern US states and southern Ontario; not present in the UK. Read the full page. | Notifiable in the UK per Forest Research. See the UK guide. |
| Sooty bark disease A fungus | Maples, sycamore most reported in the UK. North America, the UK since 1945, and continental Europe. Read the full page. | Not listed as notifiable by Forest Research, which asks for suspected cases through TreeAlert. See the UK guide. |
| Anthracnose of plane A fungus | Plane trees; American sycamore most susceptible. Common in the UK, continental Europe, the USA, Russia and New Zealand. Read the full page. | Not notifiable per Forest Research, which says reporting is not necessary. See the UK guide. |
| Phytophthora lateralis A water mould | Lawson cypress and Port-Orford-cedar, plus other cypresses. All four UK countries, the west coast of the USA, parts of Europe and Taiwan. Read the full page. | Notifiable in the plant trade in the UK per Forest Research. See the UK guide. |
| Pitch canker of pine A fungus | Pines; occasional records on Douglas fir. South-eastern US states, coastal California, Mexico, Chile, Japan, Korea, Spain and Portugal; not present in the UK. Read the full page. | Notifiable in the UK per Forest Research. See the UK guide. |
| Laurel wilt A fungus | Trees in the laurel family: redbay, sassafras, swampbay, pondspice, bay laurel, avocado. Coastal North Carolina to Mississippi, with inland detections in several south-eastern states; not found in California per NC State Extension. Read the full page. | No regulated or notifiable status on the pages read. NC State Extension asks for reports to NC State Extension or the NC Forest Service. See the US guide. |
Where the pages differ
Agencies use different words for the same idea. Forest Research uses notifiable for diseases it asks people to report, while a US state may only publish an advisory page. The same disease can be regulated in one country and carry no reporting duty in another, as Dutch elm disease shows. Read the child page for each source and its date. For moving wood that may carry a pathogen, see moving wood and firewood, and for the wider picture see pests and diseases.
Credit
Forest Research and Scottish Forestry material was read under the Open Government Licence v3.0 and is restated in our own words.