Exidia cartilaginea

Exidia cartilaginea is a species of fungus in the family Auriculariaceae. In an agronomic context, it is recognized as a saprotrophic organism that typically colonizes dead or decaying wood. While it does not primarily act as a parasite on healthy living tissue, its presence on a tree often serves as an indicator of advanced decay or localized tissue death in specific branches.

The pathogen is a jelly fungus that feeds on dead organic matter. The type of infection is classified as saprotrophic wood decomposition. It breaks down complex organic compounds within the tree structure, which, if left unchecked, can compromise the structural integrity of the affected wood over an extended period of time.

The primary hosts for this fungus include various deciduous trees, particularly alder, oak, and beech. The visible symptoms are the fruiting bodies, which appear as cartilaginous or gelatinous masses on the bark. These growths are firm and compact when dry but swell significantly and become jelly-like during periods of high humidity or rainfall.

The development and distribution of Exidia cartilaginea are heavily dependent on environmental conditions, specifically moisture availability and temperature. It spreads through spore release, which is most active during cool, humid weather. Spores typically land on wounds or fissures in the bark of weakened trees, where they germinate and begin to colonize the dead or damaged tissue.

The economic impact of the fungus is related to the acceleration of wood decay, which may attract further opportunistic pests. To mitigate its presence and protect tree health, growers should adopt the following measures:

• Perform regular sanitary pruning to remove dead, diseased, or decaying branches.
• Treat bark wounds or pruning cuts immediately to prevent colonization by fungi.
• Improve overall tree vitality through proper fertilization and watering practices.
• Ensure adequate air circulation within the canopy to prevent prolonged moisture accumulation.