Flammulina

Flammulina is a genus of fungi belonging to the Physalacriaceae family. In agronomy, certain species, most notably Flammulina velutipes, are identified as opportunistic pathogens that contribute to white wood rot, primarily targeting stressed, wounded, or decaying hardwood trees.

The fungus typically attacks deciduous trees, including fruit species such as apple and pear trees. It acts as a wound parasite, entering the tree's vascular system or structural tissues through pruning cuts, frost cracks, broken limbs, or other damages to the bark that leave the heartwood exposed to the environment.

The primary symptom of infection is the appearance of clusters of fruiting bodies on the trunk or branches. Internally, the fungus decomposes cellulose and lignin, leading to white rot. As the wood loses its structural integrity, the tree shows signs of decline, including premature leaf fall, reduced growth, and eventually branch dieback.

The development of the fungus is highly dependent on environmental conditions, specifically cool temperatures and high humidity, which are ideal for its growth and spore production. Once established, the mycelium continues to colonize the interior of the tree, even during colder months, making it a persistent threat in neglected orchards.

Effective management and protection strategies include:

• proper maintenance of tree health to ensure natural resistance
• sealing pruning wounds with protective agents
• immediate removal of dead or rotting wood from the site
• regular monitoring of tree trunks for fungal signs
• avoiding mechanical damage to the bark during maintenance work