Granulobasidium vellereum

Granulobasidium vellereum is a fungal pathogen belonging to the Basidiomycota phylum that primarily affects the bark and woody tissues of various deciduous trees. It functions as a saprotroph and weak parasite, often colonizing tissues that have been previously weakened or damaged by abiotic or biotic stresses.

The host range of this fungus includes species such as poplars (Populus) and willows (Salix), alongside other temperate deciduous species. It is commonly found in forest ecosystems, urban landscapes, and nursery settings where environmental conditions favor the proliferation of crust-forming fungi on host surfaces.

The primary symptom of infection is the development of a thin, felt-like or velvety fungal mat on the bark, typically appearing whitish to cream-colored. As the pathogen matures, it can cause the bark to become brittle, leading to cracking, localized necrosis, and the peeling of outer layers, which exposes the underlying cambium to secondary infections.

The development and spread of Granulobasidium vellereum are closely tied to moisture availability, particularly during humid seasons. Spores are disseminated by wind and splashing rain, allowing the fungus to rapidly colonize wounds, pruning cuts, or frost cracks on the trunks and branches of susceptible host trees.

• Implement strict sanitary pruning to remove symptomatic branches.
• Apply wound paint or pruning sealants to large cuts to prevent spore entry.
• Avoid damaging the bark of healthy trees during routine maintenance.
• Ensure adequate tree health through proper irrigation and fertilization.

The economic and ecological impact of this disease is observed in the gradual decline of tree vigor, leading to branch dieback and an overall decrease in the lifespan of the host. In managed forests or orchards, the presence of this fungus can lead to reduced timber quality and the necessity for costly removal of infected, unstable specimens.