Dendrostoma canker

Pathogen and Disease Type. Dendrostoma canker is a serious fungal disease caused by the ascomycete Dendrostoma castaneum. It is classified as a bark-inhabiting pathogen that attacks the vascular system of trees, causing localized necrosis and structural damage to the bark and underlying cambium layers.

Susceptible Hosts. The disease primarily affects the sweet chestnut (Castanea sativa). It is a significant concern for both forest stands and commercial chestnut orchards. The susceptibility of trees often increases if they are grown in unfavorable ecological conditions or if the host plant experiences physiological stress.

Symptoms and Signs. The primary symptoms include the formation of sunken cankers on the stems and branches. The affected bark becomes dark and necrotic, eventually cracking or sloughing off. Small, black, pimple-like fruiting bodies of the fungus emerge through the bark, which serve as the definitive sign for identifying the presence of Dendrostoma castaneum.

Conditions for Development and Severity. The disease spreads most rapidly in humid environments with frequent precipitation, which favors spore dispersal and fungal colonization. The pathogen is highly detrimental, as it interferes with nutrient and water transport within the tree, causing branch dieback, crown thinning, and, in severe cases, the death of the entire tree.

Protection and Prevention. Effective management relies on integrated cultural practices.

• Prompt removal and destruction of infected wood to reduce inoculum.
• Sterilization of pruning tools to prevent mechanical transmission.
• Application of copper-based fungicides during humid periods.
• Improving site conditions to enhance overall tree vigor.