Ochraceous trametes

Ochraceous trametes (Trametes ochracea) is a common polypore fungus that plays a crucial role in forest ecosystems as a decomposer of dead wood. However, in orchards and managed forests, it acts as a wound parasite. It induces white rot in hardwood species, systematically breaking down the lignin and cellulose in the wood's structure.

The host range of Trametes ochracea is broad, including various deciduous trees like birch, beech, and alder, as well as several fruit-bearing species such as apple and plum trees. It is particularly damaging to trees that have suffered physical injury, frost cracks, or improper pruning, as these provide an entry point for the fungus to establish itself.

Identifying this pathogen is relatively straightforward due to its distinctive fruiting bodies. These are leathery, bracket-shaped, and grow in clusters on the bark. They exhibit concentric zones of color, ranging from creamy white to deep ochre or brown. Internally, the infected wood turns pale, soft, and develops a fibrous texture, which significantly compromises the structural integrity of the affected tree.

The spread and development of the fungus are favored by moist conditions and poor ventilation within the tree canopy. Basidiospores are dispersed by wind or insects, landing on exposed xylem or phloem. Once established, the mycelium spreads vertically and radially throughout the stem or branches, eventually leading to structural instability and crown dieback.

Effective management focuses on physical and biological control. Pruning should be performed only during dry weather to prevent spore infection of fresh cuts. All pruning tools must be disinfected regularly. If infection is detected, the affected wood should be pruned back to healthy tissue, and the wound must be sealed with professional tree wound paste to support healing and prevent reinfection.