Elbow-patch crust of plane (Fomitiporia punctata): what the sources record

This page reports what the official source says. It is not legal advice: ask the office named here.

This page describes what three published sources say about one fungus of plane trees. It does not identify a fungus from a photo and says nothing about any single tree. Forest Research and the Forestry Commission are UK government bodies; text adapted from their pages is used under the Open Government Licence v3.0. Contains public sector information licensed under the Open Government Licence v3.0. The parent page, wood decay fungi on trees, compares the fungi that have pages here.

Status and reporting

Forest Research lists elbow-patch crust as present in the United Kingdom and notifiable. It asks for suspected sightings in Great Britain through TreeAlert and in Northern Ireland through TreeCheck, both of which ask for clear close-up photographs. For the offices and routes in each part of the UK see report a pest in the United Kingdom.

Names and hosts

Forest Research says the fungus was known before 2016 as Phellinus punctatus, and earlier still as Polyporus punctatus and Poria punctata. The 2008 Forestry Commission advisory note uses the name Phellinus punctatus, so a reader comparing the two documents meets two names for the same fungus. Forest Research says London plane is known to be susceptible, that little is known about other planes or other plants, and that the fungus has also been recorded on hazel, kiwifruit and grapevine.

What the cankers and fruit bodies look like

Forest Research: says the cankers, called elbow patches, are pale buff and flat, so they can be hard to see on the mottled bark of plane in early stages. It says the fruit bodies merge into the bark and that a narrow to broad black zone at the top of the fruit body is diagnostic.
Forestry Commission advisory note: gives the same description and adds that the canker can have perennating rays.
Observatree plane guide: shows a Fomitiporia canker and fruit bodies on plane among the look-alike signs for plane wilt, and tells the reader the lesions of Massaria disease tend to be on the upper side of branches, not on the trunk.

The rot and what the sources say it can indicate

Forest Research and the advisory note both say the fungus first causes a rapidly spreading canker and then an intense white rot of sapwood and heartwood. The page on white, brown and soft rot compared sets out how rot types are defined. Forest Research says affected trees frequently suffer branch and stem failure from the decay, which it calls a public safety hazard if not found in time. The advisory note says affected trees have frequently suffered stem failure.

Forest Research also repeats an account within the tree trade of a plane clone from about the 1970s that develops weak forks and is more prone to breaking if infected, and says the advice is to source nursery stock carefully. The advisory note puts the clone's introduction at about forty years before its 2008 date.

First record and where it occurs

Forest Research says the fungus was first identified in the UK in 2008 on a London plane in West Sussex, and that it is widespread in Scandinavia and Western Europe, with isolated records as far east as Russia and in Japan, New Zealand and the Americas. The advisory note, dated 2008, says the first report in Britain was identified in March 2008 and that a stem canker of this type found in Dulwich, London, in 2006 was the first clear UK evidence of a major stem canker from this fungus, which are two further dates the other sources do not give.

Management, as Forest Research puts it

Forest Research lists destroying infected trees on site where permitted, good plant hygiene such as cleaning tools, footwear and equipment between trees, and following the rules on importing and moving plane material. It asks readers to check with the local authority and the environmental regulator about permitted destruction methods. For the people who examine trees see tree risk assessment methods and consulting arborist credentials.