Ascotremella

Ascotremella (lat. Ascotremella) is a genus of fungi belonging to the Ascomycota phylum. While primarily saprotrophic, they act as opportunistic pathogens that target weakened woody plants. The most well-known species, Ascotremella faginea, is commonly associated with the decay of broad-leaved timber species.

The primary hosts affected by this fungus include beech, oak, birch, and other hardwood species. The fungus is frequently found in woodland environments on decaying logs, but it can also opportunistically colonize living trees that have suffered from winter injuries, fire damage, or pruning wounds, where exposed xylem provides an entry point.

The symptoms of an Ascotremella infection are quite distinct. It produces characteristic jelly-like, purple or violet-colored fruiting bodies that are wrinkled and folded in appearance. Beneath these bodies, the internal wood structure often exhibits signs of degradation, turning soft and spongy, which compromises the tree’s overall structural integrity over time.

Development and spread are heavily dependent on moist, shaded conditions. The fungus releases spores that are distributed by wind, water splashes, and insects. High humidity levels, combined with poor ventilation within a stand or garden, create an ideal environment for spore germination and the subsequent colonization of susceptible host tissues.

The economic and practical impact involves the decay of timber and the decline of ornamental trees. To manage the risk of infestation, it is crucial to practice good hygiene in the forest or orchard. This includes removing dead wood, sealing large pruning wounds with specialized tree wound dressings, and ensuring trees are kept vigorous to prevent secondary pathogen colonization.

• Maintain high plant vigor through proper fertilization.
• Promptly remove and destroy dead woody debris.
• Use protective paints on large pruning cuts.
• Improve air circulation to reduce local humidity.