Mycoporum lacteum lichen

Mycoporum lacteum is a species of crustose lichen that inhabits the bark of trees and shrubs. While it is biologically classified as an epiphyte rather than a parasitic pathogen, its presence in managed orchards often indicates poor air circulation, high humidity, and the neglect of structural maintenance of the tree bark.

This species primarily affects deciduous trees, including various fruit-bearing cultivars. The lichen appears as small, crusty, whitish or creamy patches on the bark. Over time, these patches can coalesce, forming a more continuous layer that covers significant portions of the trunk and primary branches.

Symptoms are largely structural and aesthetic, visible as a change in the bark's surface texture. Although Mycoporum lacteum does not directly extract nutrients from the tree, the thick crust can interfere with bark respiration and gas exchange, creating a micro-habitat that may trap moisture and harbor pests.

The development of this lichen is favored by specific environmental conditions such as dense canopy shading, high atmospheric humidity, and lack of direct sunlight. Spores are easily disseminated by wind and rain, colonizing bark fissures and areas where bark vitality has already begun to decline.

To mitigate the impact of this organism, growers should prioritize cultural practices that promote tree vigor. Effective protection measures include regular pruning to improve canopy aeration, manual cleaning of the bark surface during the dormant season, and the application of agricultural lime or protective washes to the trunk to inhibit the settlement of lichen spores.