Lachnum corticale

Lachnum corticale is an ascomycete fungus belonging to the Hyaloscyphaceae family. Primarily a saprotroph, it is frequently found on dead or decaying plant tissues, but under certain ecological stressors, it can colonize weakened woody plants. It is commonly observed in temperate forest ecosystems and managed orchards, where it utilizes specific substrates for its life cycle.

This fungus predominantly affects deciduous trees, including various pome and stone fruit species. It tends to establish itself in areas of the bark that have sustained damage, such as sunscald, frost cracks, or wounds caused by insect feeding. The presence of moist, stagnant conditions makes these sites highly susceptible to colonization by Lachnum corticale.

The primary diagnostic sign of this fungus is the formation of small, cup-shaped apothecia on the bark surface. These fruiting bodies typically appear as tiny, pale to yellowish-white, hairy or velvety discs. While the fungus is not always a primary killer, its presence indicates that the tree or the specific branch is under stress, leading to localized tissue degradation and potential bark necrosis over time.

The development of Lachnum corticale is heavily dependent on moisture availability. High humidity, heavy precipitation, and poor air circulation within the tree canopy create an environment conducive to the rapid production and dispersal of spores. These spores are easily transmitted through wind and rain splash, infecting new wounds or vulnerable sites during the active growth seasons of spring and autumn.

Effective management and prevention of this fungal agent involve maintaining high standards of horticultural hygiene. Strategies include:

• Regular pruning of dead, diseased, or heavily infested branches.
• Applying wound sealants or protective paints to large pruning cuts.
• Promoting good orchard airflow through strategic crown thinning.
• Implementing regular tree health monitoring to detect bark stress early.
• Applying prophylactic fungicide treatments as part of an integrated pest management program.