Xerula

The genus Xerula consists of wood-decaying fungi categorized as facultative parasites or saprotrophs. While they are often associated with dead organic matter, they can behave as pathogens, colonizing weakened or damaged living trees, leading to structural instability and the gradual decline of the host plant.

The disease is caused by fungal mycelium invading the woody tissue through wounds in the bark, frost cracks, or improper pruning cuts. Once established, the mycelium secretes enzymes that break down lignin and cellulose, which are essential structural components of the tree's vascular system.

A wide range of hardwood tree species, such as oak, beech, and various fruit trees, are susceptible to infection. The presence of these fungi is particularly concerning in managed gardens and orchards where valuable trees can be severely compromised by internal wood degradation caused by these organisms.

Key symptoms include the development of soft or white rot within the trunk, leading to structural weakness. Visible signs of infection are the presence of distinct, long-stemmed fruiting bodies emerging from the bark, alongside foliage chlorosis, premature wilting of branches, and a general loss of vigor throughout the canopy.

Preventative measures are essential, as fungal infections of the wood are difficult to cure. Best practices include maintaining vigorous tree health, ensuring proper wound closure after pruning, and avoiding mechanical damage to the trunk. Removing infected wood and improving drainage are also critical steps in managing the spread of the pathogen.