Ectolechiaceae lichens

Ectolechiaceae is a family of lichens that include foliicolous and corticolous species. While these organisms are not primary parasites in the sense of causing rapid tissue necrosis, their excessive colonization of tree trunks and branches is considered an agricultural issue that negatively impacts the physiological health and longevity of fruit and ornamental crops.

The organism acts as a symbiotic complex of fungi and algae. These lichens attach to the surface of the bark, leaves, or twigs, using the plant solely as a substrate. They do not consume nutrients from the plant host, but they create a damp, micro-environmental barrier that traps moisture, promoting a habitat for secondary pests and opportunistic pathogens.

Commonly affected crops include various fruit trees, such as apples, pears, and stone fruits. Ectolechiaceae thrive in neglected orchards or high-density plantations where poor ventilation and shade create a consistent humid environment, which is necessary for the successful settlement and growth of the lichen thallus.

Symptoms are identified by the presence of scaly, crusty, or leafy patches on the bark, ranging in color from pale grey to green. By covering the lenticels, the lichens impede the gas exchange process essential for the tree's bark respiration, which can lead to reduced plant vigor, stunted growth, and increased susceptibility to winter damage.

Management strategies focus on improving orchard hygiene and preventing excessive moisture buildup. Effective practices include regular pruning to ensure proper airflow and light penetration, as well as mechanical removal of thick lichen crusts from trunks. Chemical protection typically involves the use of copper-based fungicides applied during the tree's dormant season to eradicate lichen structures.