Rhodonia

Rhodonia (specifically the species Rhodonia placenta, formerly classified as Postia placenta) is a wood-decay fungus that causes severe brown rot in timber. It belongs to the Basidiomycota phylum and is known for its ability to decompose cellulose within wood structures efficiently.

The fungus primarily targets coniferous trees, such as pine, spruce, and fir. It is commonly found in forest ecosystems on stumps and fallen logs, but it also causes significant damage in industrial settings, affecting structural timber, lumber in storage, and railway sleepers.

The primary symptom of an infection is the wood changing color to a dark brown or reddish-brown hue. As the fungus consumes the cellulose, the wood loses its structural integrity, becomes brittle, and cracks into characteristic cubic fragments that can easily be crushed into a fine powder.

Development and spread of the fungus are favored by moisture content in wood exceeding 20% and warm temperatures ranging from 20°C to 30°C. In poorly ventilated environments, the spores spread rapidly, colonizing new wooden surfaces and continuing the destructive process of decay.

The economic impact of Rhodonia is significant due to the rapid degradation of wooden materials. Protective measures include:

• Chemical treatment of timber with effective wood preservatives.
• Maintaining low humidity levels in storage and construction areas.
• Ensuring proper ventilation to prevent moisture accumulation.
• Avoiding direct contact between wood and moist soil surfaces.

Regular inspection of timber structures is essential to detect early signs of decay. Once the wood has been significantly colonized by the mycelium, mechanical strengthening or replacement of the affected parts is usually required to ensure safety.