Athelia epiphylla

Athelia epiphylla is a basidiomycetous fungus known for colonizing the bark of various woody plants. It belongs to the group of corticoid fungi, which form thin, crust-like or web-like growths on the surface of branches and trunks. While often considered a secondary colonizer, its ability to cover large surface areas can interfere with the physiological processes of the bark.

The host range of Athelia epiphylla is quite broad, encompassing numerous fruit trees, ornamental shrubs, and forest species. The fungus is most commonly found in moist, shaded environments where air circulation is restricted. Plants that have already been weakened by environmental stress or poor pruning practices are particularly susceptible to widespread colonization.

The primary symptom of infection is the development of a white to greyish, film-like fungal mat that adheres closely to the bark. Unlike beneficial lichens, this fungal growth can often be associated with localized bark decay or moisture retention that prevents the bark from drying properly. Over time, the area beneath the fungal mat may show signs of tissue softening or necrosis.

The development of this disease is highly dependent on humidity levels and microclimate. High-density planting and heavy canopy cover create an ideal environment for spore germination and mycelial expansion. Since the fungus spreads via spores in the wind or water splash, wet spring and autumn seasons are critical periods for new infections, especially in regions with frequent fog.

Effective management strategies for Athelia epiphylla focus on sanitation and environmental control:

• Pruning branches to improve airflow and increase sunlight exposure within the canopy.
• Maintaining tree vigor through proper fertilization and watering, which enhances natural defenses.
• Removing dead or heavily infested wood to reduce the local spore load.
• Applying copper-based fungicides when infection levels threaten the overall health of the tree.