Canker stain of plane: what the agencies record
What Forest Research, the UK Plant Health Information Portal pest alert and Penn State Extension say about canker stain of plane: the fungus, the plane and sycamore hosts, how wounds and tools carry it, the staining and canker signs, the 2014 London survey, and the notifiable status in the United Kingdom.
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. It lists what the sources record about canker stain of plane and does not diagnose any tree. It states a reporting rule and import measures for the United Kingdom, so the exact wording is on the pages linked below. The list of other diseases is on the tree diseases page, and the reporting lines are in the United Kingdom report-a-pest guide.
At a glance
| Item | What the sources say |
|---|---|
| Pathogen | Ceratocystis platani, a fungus (an ascomycete). Forest Research says it was formerly known as Ceratocystis platani f. platani and Ceratocystis fimbriata s. sp. platani, and that the disease has also been called plane tree wilt. |
| Hosts | Plane trees (Platanus). Forest Research says most species can be infected, including London plane and its parents, eastern and western plane. Penn State Extension says London plane and sycamore are susceptible. |
| Where | Forest Research lists Albania, Armenia, France, Greece, Italy, Switzerland and Turkey, and some western and eastern states of the United States. |
| Status in the United Kingdom | Not present, and notifiable. The pest alert says "if you see it, you must report it." |
| Report to | Great Britain: TreeAlert. Northern Ireland: TreeCheck. Trade premises: the plant health authority for the country. See the United Kingdom guide. |
How the sources say it spreads
Forest Research says infection commonly occurs when spores enter fresh wounds on healthy planes, such as wounds from wind, birds, insects and tree-care tools like saws and knives. It says contaminated gloves, ropes, clothes and boots might also spread the fungus, that root contact between neighbouring trees and water can carry it, and that the spores are long-lived and can persist in soil and on unsterilised tools. It names water as thought to be the main route for the infection of the plane avenue along the Canal du Midi in France. Penn State Extension says sap-feeding insects can carry the fungus naturally but the worst outbreaks are mostly traced back to pruning and similar tree work, that the fungus enters only through fresh wounds, and that infection is least likely in December and January. It says spores stick to pruning tools, ropes and ladders. The pest alert says staining extends along the sapwood at 50 to 100 cm a year, and Forest Research gives the same rate.
Symptoms as the sources state them
- Crown. The pest alert describes severe wilting of the canopy and a sparse, thin crown with discolored leaves, because the fungus affects the water-carrying vessels. Forest Research adds yellowing of the leaves. Penn State Extension describes sparse foliage and small leaves.
- Bark. Forest Research and the pest alert describe sunken, elongated or lens-shaped cankers, with orange and purple streaking around the edges in the alert, that can become roughened and black with age.
- Under the bark. The pest alert describes dark brown to violet streaking or spotting, more visible on the outside when the bark is wet. Penn State Extension says the wood under a canker shows a wedge of bluish-black or reddish-brown staining when cut across.
- Season. The sources give no season for symptoms. Penn State Extension notes that water sprouts form below cankers as the disease progresses.
- Time to death. Forest Research says trees die within two to ten years once infected. The pest alert says trees with trunks 30 to 40 cm across can die in as little as two years, and Penn State Extension says pole-sized trees may die within 2 years.
Other fungi and testing
Penn State Extension says secondary wood-rotting fungi often invade cankers and cause further damage. The sources read give no look-alike list and describe no laboratory test.
The 2014 London survey
Forest Research says the London Tree Officers' Association surveyed 2,979 London plane trees at 53 sites across 28 London boroughs in 2014, on behalf of the Forestry Commission, and found no positive cases.
What the agencies publish for control and regulation
Forest Research says the disease mostly spreads through human activity, so spread can be limited by sourcing plant material from disease-free regions and by hygiene such as disinfecting tools between trees and jet-washing large machinery. It lists removal and burning of infected material, says no effective chemical treatment is available, and says tolerant hybrid planes are being developed. Penn State Extension says no chemicals effectively control the disease. On regulation, Forest Research says national measures from April 21, 2020 require plane planting material other than seeds to have been grown throughout its life in an area free of the fungus, applying to imports from Albania, Armenia, Switzerland, Turkey, the United States and the EU-27. For moving wood in general, see moving wood and firewood. Who may apply pesticides is covered on the pesticide licences page.
Credit
The Forest Research and UK Plant Health Information Portal material was read under the Open Government Licence v3.0 and is restated here in our own words.