Hexagonia

Hexagonia is a genus of fungi belonging to the Polyporaceae family, recognized primarily as agents of white rot in various hardwood species. As a plant pathogen, it targets the lignin within the wood structure, leading to significant structural degradation and eventual collapse of the infected stems or branches.

This disease mainly affects mature trees in both managed orchards and natural ecosystems. The infection cycle typically initiates when fungal spores land on open wounds, pruning cuts, or frost cracks, where the protective bark layer has been breached, allowing the mycelium to colonize the internal wood tissues.

The primary clinical sign of Hexagonia infestation is the appearance of distinctively shaped fruiting bodies on the trunk. These brackets are often tough and woody, with a characteristic honeycomb-like or hexagonal pore surface on the underside. Internally, the wood loses its tensile strength and becomes brittle, often appearing bleached or fibrous.

Environmental conditions conducive to Hexagonia outbreaks include consistently high humidity levels, poor air circulation within the canopy, and the presence of unsealed pruning wounds. The spores are highly mobile and easily disseminated by wind currents or contact with wood-boring insects, which can expedite the spread of the fungus throughout an orchard.

To mitigate the risk of damage, growers must prioritize strict phytosanitary measures.

• Regular inspection of bark integrity to identify and seal wounds promptly.
• Application of antifungal dressings to all pruning sites to prevent spore entry.
• Immediate removal and destruction of infected wood to reduce the local spore load.
• Ensuring optimal tree health through balanced fertilization and proper irrigation to boost resistance.