Splanchnonema platani

M.E. Barr

An infected branch previously pruned low in the crown on a plane near Regents Park, London.
Looking more closely at the barkless upper section of an infected plane branch.
Similar barkless sections of branch high up in the crown of plane as seen from the ground.
Massaria-infected branch high up in a London plane as seen with a zoom lens.
A further example as again seen from the ground of a barkless branch.

An infected branch previously pruned low in the crown on a plane near Regents Park, London.
Looking more closely at the barkless upper section of an infected plane branch.
Similar barkless sections of branch high up in the crown of plane as seen from the ground.
Massaria-infected branch high up in a London plane as seen with a zoom lens.
A further example as again seen from the ground of a barkless branch.

Common name

Massaria disease.

Often found on

Plane.

Sometimes found on

None.

Location

Found within the crown structure of the tree. Often found on smaller branches within the inner crown though sometimes observed on larger lateral limbs over 150mm in diameter.

Description

The fruit body is inconspicuous and resembles a speckling of sooty carbon black along the branch. The more visible symptom is branch dieback and / or cinnamon-coloured exposed wood on the upper surface the branch (may extend some 2-3m). Can be hard to see from the round, in some cases.

Confused with

None.

Significance

Considered to generally be a weak pathogen that likely exists as a latent endophyte prior to visual establishment. Associated with a soft rot on the upper section of the branch (creating a v- or u-shaped area of discolouration along the branch cross-section), which greatly reduces branch strength and increases the risk of shearing – potentially in as little as 3 months from the onset of infection. Often functions as a ‘branch cleaning’ fungus, wherein small twigs are shed. During drought conditions, this fungus may become more virulent and therein more prevalent, which also has seen larger branches and limbs become subject to the soft rot. Anecdotal observations suggest this fungus greatly increase the risk of failure of limbs colonised by Inonotus hispidus. Where targets exist, infected branches should be identified (from the ground with binoculars, and potentially supplemented via climbing inspection) and, where necessary, removed within an appropriate timeframe.