Massaria canker

Massaria canker is a fungal disease caused by the pathogen Splanchnonema platani (previously identified as Massaria inquinans). This condition primarily affects plane trees, leading to severe bark necrosis and the decay of branches, which poses significant safety risks in urban environments.

The fungus typically attacks the upper canopy of the plane tree. Because the initial infection often occurs on smaller, shaded branches high up in the tree, the disease is frequently overlooked until the branch is structurally compromised and breaks off.

Key symptoms include longitudinal necrotic patches on the bark, which turn grey to black as the lesion expands. Underneath the affected bark, the fungus creates a characteristic black, soot-like layer of spores. The wood beneath the lesion decays rapidly, causing the affected branches to become brittle.

The spread of the pathogen is facilitated by wind and rain, which transport spores to susceptible bark surfaces. The disease is most prevalent in trees that are stressed by environmental factors such as drought, restricted root zones in cities, or mechanical wounds caused by improper pruning or construction work.

Management and prevention focus on regular crown inspections by arborists to identify and remove infected branches. It is essential to sanitize all pruning tools to prevent transferring spores to healthy wood. Maintaining tree vigor through proper irrigation and soil care is the most effective long-term strategy for preventing Massaria infections.