Ascocoryne

Ascocoryne is a genus of fungi belonging to the class Leotiomycetes. In agricultural and forestry contexts, these fungi are primarily classified as saprotrophs or weak parasites that thrive on dead, decaying, or physiologically stressed wood of broad-leaved trees. While they are not always the primary cause of tree death, their presence signals ongoing degradation processes within the woody tissue.

The disease is caused by fungi such as Ascocoryne sarcoides, which are Ascomycetes. It is characterized as a fungal wood decay disease. The fungus spreads through microscopic spores that colonize vulnerable areas of the tree, utilizing its enzymatic activity to break down complex organic compounds like lignin and cellulose, which are essential for the structural integrity of the tree.

The primary hosts affected by Ascocoryne include broad-leaved species such as birch, beech, oak, alder, and hornbeam. It is most commonly found on logs, stumps, and dead branches. However, if the tree has structural damage or is under significant stress, the fungus can penetrate deeper into the sapwood, compromising the health and mechanical stability of the plant.

The clinical signs of an Ascocoryne infection are marked by the formation of gelatinous, purple-to-magenta colored fruit bodies. These fruit bodies may be small, cushion-shaped, or cup-shaped. Inside the wood, the infection leads to discoloration and localized softening, making the wood texture spongy and brittle over time, which eventually causes localized decay.

Conditions favorable for the development of this fungus include high humidity, moderate temperatures, and the availability of damaged or exposed woody surfaces. Effective protective measures include strictly following sanitation protocols in the garden or orchard, sealing wounds with protective sealants, disinfecting pruning tools to prevent cross-contamination, and removing any decaying timber that could serve as an infection source.