Massaria disease

Massaria disease is a fungal infection caused by the pathogen Massaria platani (also known as Splanchnonema platani). This fungus primarily acts as a necrotrophic parasite, targeting the bark and underlying wood of susceptible trees, which often leads to severe structural damage and tree decline.

The disease is most commonly associated with the London plane tree (Platanus × hispanica). While the pathogen is often considered a weak parasite that attacks weakened trees, it has become a significant concern in urban forestry due to the public safety risks posed by falling branches, which can occur unexpectedly after the wood decays internally.

Key symptoms of Massaria disease include the formation of reddish-brown or grayish sunken lesions on the upper surfaces of branches. As the disease progresses, the bark may peel or crack, and characteristic small black fruiting bodies of the fungus become visible. Internally, the affected wood exhibits significant discoloration and rot, leading to a sudden loss of structural integrity.

The spread of the disease is highly dependent on environmental conditions, particularly high humidity and frequent rainfall, which facilitate spore dispersal. Spores enter the tree through small wounds or natural cracks in the bark. Once the pathogen colonizes the branch, it spreads through the tissue, often remaining undetected until the branch becomes unstable.

Preventive management is crucial for maintaining tree health and safety. Key strategies include:

• Regular visual inspections of tree canopies by certified arborists.
• Pruning and removing infected branches back to healthy wood.
• Ensuring adequate irrigation to reduce stress in urban trees.
• Sterilizing pruning tools between trees to prevent cross-contamination.
• Avoiding unnecessary wounding of the trunk and primary branches during maintenance activities.