Violet-toothed polypore

Systematic position and nature of the pathogen: The violet-toothed polypore (Trichaptum abietinum) is a basidiomycete fungus belonging to the family Polyporaceae. It acts primarily as a saprotrophic organism that breaks down wood; however, it can also function as a necrotrophic parasite on weakened coniferous trees, causing a specific type of white rot known as white stringy rot.

Diseases and host plants: This fungus is a significant pathogen for many coniferous species, including spruce, fir, pine, and larch. It infects both deadwood, such as logs and stumps, and living trees that have sustained wounds or are stressed. The decay process destroys cellulose and lignin, leading to structural instability in the wood.

Biology and life cycle: The life cycle is characterized by the production of annual fruiting bodies that are often fan-shaped or bracket-like, typically showing a distinct violet color on the pore surface when young. These bodies release vast quantities of basidiospores that are dispersed by wind. Once they land on exposed wood tissues, they germinate and form a mycelium that colonizes the wood substrate.

Developmental conditions and harm: Trichaptum abietinum thrives in humid environments with moderate temperatures. It spreads efficiently in dense forest stands where airflow is limited and moisture persists on bark surfaces. Its negative impact is significant, as it degrades the technical quality of the timber, reduces the longevity of trees, and increases the susceptibility of stands to windthrow and secondary infestations.

Protection and control measures: Effective management focuses on silvicultural practices rather than chemical treatments. Key strategies include:

• Regular forest sanitation, including the removal of dead and decaying woody debris.
• Minimizing physical damage to healthy standing trees during logging and maintenance operations.
• Ensuring proper stand density to maintain tree vigor.
• Rapid extraction of harvested timber from the forest site to interrupt the fungal life cycle.