Arthrorhaphidaceae

Arthrorhaphidaceae is a family of lichenized fungi that often colonize the bark of woody plants. While they are not typical aggressive plant pathogens, their presence in agricultural settings, particularly in orchards, is often an indicator of poor bark health and environmental conditions that favor biological overgrowth.

These organisms primarily affect deciduous fruit trees and shrubs. They tend to settle on older, rough-barked specimens where the growth rate of the tree has slowed, providing a stable, long-term substrate for the lichen to develop its thallus over several seasons.

The visible signs of colonization include the development of crustose or foliose structures on trunks and skeletal branches. These growths can vary in color, ranging from grey to green or yellow. By covering the bark, they may obstruct gas exchange and create a protective micro-environment for various insect pests and fungal spores to hide.

The development of Arthrorhaphidaceae is closely linked to ambient humidity and shading. They thrive in environments with low light penetration and high moisture, which are typical for dense, unpruned tree canopies. Spores are disseminated via wind and rainwater, settling easily into the crevices of the tree bark.

In terms of agricultural management, the focus is on mitigating their impact on the tree's vitality. Effective control strategies include

• regular pruning to improve canopy aeration;
• manual scrubbing of the bark with soft brushes;
• application of copper-based fungicides;
• white-washing trunks to discourage establishment.