Trypethelium eluteriae

Trypethelium eluteriae is a species of crustose lichen belonging to the Trypetheliaceae family. While lichens are generally not considered plant pathogens, in an agricultural context, their presence on trunks and branches is often managed because they can hide pests and fungal spores, potentially impacting the physiological health of the host tree.

The causative biological agent is a symbiotic association between a fungus and algae. It colonizes the bark of various trees, particularly in humid tropical and subtropical environments. The organism extracts moisture and nutrients from the atmosphere and debris, forming a tight symbiotic complex that attaches firmly to the host's surface.

Symptoms appear as small, distinct spots or patches known as apothecia, which are usually yellowish or reddish-brown. Over time, these patches can coalesce, creating a crust-like layer that covers large sections of the bark. This coverage can lead to micro-cracks in the outer bark, which may further facilitate the penetration of wood-decay fungi.

Environmental conditions conducive to its development include high humidity, moderate temperatures, and lack of direct sunlight, which prevents the bark from drying out quickly. Such conditions allow the lichen to thrive and expand its range across the tree's surface during the wet season, utilizing wind-dispersed spores to colonize nearby trees.

The potential harm lies in the interference with bark respiration and the creation of a microhabitat for insects like scale insects or mites.

• Mechanical cleaning of the bark using soft metal brushes.
• Applying a whitewash mixture with added fungicides to the trunk.
• Proper pruning to improve air circulation and sunlight penetration.
• Chemical control using copper-based agents if the infestation becomes excessive.