Ramalinaceae

Ramalinaceae is a family of lichens that often settle on the bark of woody plants. In agronomy, they are classified as epiphytes rather than disease-causing pathogens. While they do not directly parasitize or extract nutrients from the tree's vascular system, their extensive growth is a biological indicator of slow tree growth, excessive moisture, and suboptimal orchard maintenance.

These lichens consist of fungal and algal components that form symbiotic structures on the surface of branches and trunks. Their presence does not cause structural damage to the wood, but in dense clusters, they can trap humidity, creating a micro-environment that may attract wood-boring insects, mites, and scale insects, which pose a genuine threat to the tree's health.

The visual symptoms involve the formation of shrub-like, strap-shaped, or leafy thalli. These colonies can be various colors, such as light green, gray, or pale yellow, depending on the species and environmental conditions. Over time, they cover the bark, potentially interfering with natural lenticel gas exchange, especially in older, slow-growing specimens.

Development and spread are favored by prolonged humidity, poor air circulation within the canopy, and shaded environments. They are most commonly found on older trees where the bark has deep crevices that provide stable anchorage. Poorly maintained orchards that lack regular pruning and bark cleaning are primary targets for colonization by these organisms.

Effective management requires a combination of cultural and chemical practices. The following steps are recommended for control:

• Mechanical removal of old bark using soft wire brushes.
• Pruning to increase sunlight penetration and air movement.
• Whitewashing trunks to protect the bark and discourage growth.
• Application of copper-based fungicides to inhibit further lichen expansion.