Sooty bark disease

Sooty bark disease is a severe fungal infection caused by the pathogen Cryptostroma corticale. It primarily affects the bark and vascular system of deciduous trees, leading to significant structural damage and, eventually, the death of the host plant if the infection remains unchecked.

The primary hosts of this disease are maple species, particularly Acer pseudoplatanus (sycamore maple). While other tree species may occasionally become hosts, the impact on maple populations is often devastating, especially in urban environments where trees are already subjected to various stressors.

The disease is characterized by the formation of black, soot-like spore masses under the bark. As the disease progresses, the bark cracks and peels, exposing these dark masses. Affected trees often show signs of crown dieback, wilting foliage that resembles drought stress, and necrosis of branches, eventually leading to full tree collapse.

High temperatures and drought conditions are the primary catalysts for the spread and development of the fungus. The pathogen thrives in warm, dry weather, which weakens the host tree's natural defense mechanisms, allowing the spores to germinate more effectively and colonize the sapwood.

Management of sooty bark disease relies heavily on preventative measures and strict sanitation. Infected trees should be promptly identified, felled, and destroyed to minimize the airborne release of spores. It is also crucial to avoid tree wounding and to provide supplemental watering during extreme heat waves to ensure the trees remain healthy and resilient.