Lichenothelia

Lichenothelia is a genus of fungi belonging to the class Dothideomycetes that can colonize the bark of various plant species. While often appearing as epiphytic organisms on the surface of woody plants, these fungi can behave as pathogens under specific environmental conditions, potentially harming the vitality of the host plant by colonizing its protective outer layers.

The disease primarily targets the bark and outer structural layers of woody trees and shrubs. The pathogen utilizes the organic surface of the bark for development, but in severe cases or with compromised host defenses, it can infiltrate the surface tissues. This interaction disrupts the natural barrier of the plant, potentially leading to further physical degradation of the bark surface.

Symptoms are identified by the presence of small, dark, often black granular structures or spots scattered across the bark surface. These structures correspond to the fruiting bodies (ascomata) of the fungus. As the colony develops, the affected bark may show signs of premature flaking, minor cracking, or discoloration, which can be mistaken for natural aging but usually follows a more patchy or specific distribution.

The spread and development of this disease are closely linked to high humidity levels and poor airflow within the plant canopy. Frequent rainfall and moderate temperatures provide the ideal conditions for spore germination and colonization. Orchards or landscapes with dense, unpruned foliage are particularly susceptible, as they maintain a damp microclimate that supports the fungal growth cycle.

• Pruning to increase airflow and sunlight penetration.
• Sanitary pruning of dead or severely infected bark areas.
• Application of copper-based fungicides during the dormant season.
• General maintenance of tree health to improve natural resistance.
• Removal of excessive moss and debris from the main trunk.

The economic and agricultural impact of Lichenothelia involves the gradual weakening of the host plant. By compromising the structural integrity of the bark, the fungus creates openings for secondary infections and pests. Over time, persistent colonization can lead to reduced vigor, impaired growth, and a higher vulnerability to environmental stress, ultimately affecting the longevity and productivity of the affected plants.