Cotylidia undulata

Cotylidia undulata is a species of fungus in the Stereaceae family, recognized in agricultural and forestry pathology as an agent capable of causing wood decay. While often functioning as a saprotroph, it acts as a pathogenic agent under conditions where host trees are compromised by environmental stress, climate factors, or previous mechanical injuries.

The causal agent is a basidiomycete fungus that primarily attacks the bark and cambium layers of woody plants. The disease typically presents as a form of wood rot, where the fungus releases enzymes that degrade cellulose and lignin. This biological process leads to the structural weakening of the plant and disrupts the translocation of essential nutrients from the roots to the crown.

Host plants commonly include various deciduous tree species like oak, beech, and hornbeam. The fungus is most frequently observed in shaded, damp woodland environments where moisture levels remain high for extended periods, providing an ideal substrate for the development of fungal mycelia and subsequent fruit bodies.

The characteristic symptoms of a Cotylidia undulata infection involve the emergence of thin, wavy, funnel-shaped, or fan-like fruit bodies on the bark surface. As the infection progresses, the area of colonization may show signs of necrosis, and the wood underneath the bark becomes brittle, discolored, and soft, showing clear signs of advanced decay.

Prevention and management require a proactive approach to maintain forest hygiene. Key strategies include the immediate removal and destruction of heavily infested timber to reduce spore load in the immediate environment. Improving air circulation within the stand and protecting trees from unnecessary physical damage are crucial steps to preventing the entry of the pathogen into healthy host tissues.