Merulius

Merulius is a genus of fungi belonging to the order Polyporales, notorious for causing extensive wood decay. In agricultural and forestry practices, Merulius is recognized as a destructive saprotroph that can damage both living trees and essential wooden infrastructure, such as greenhouse frames, trellising supports, and storage crates.

The disease is caused by specific fungal species, most notably Merulius lacrymans, often referred to as the dry rot fungus. These pathogens thrive by secreting enzymes that decompose cellulose and lignin, effectively stripping the wood of its structural integrity and turning it into a brittle, darkened mass.

The susceptibility of crops and materials depends largely on moisture conditions. Wood that remains in contact with soil or is subjected to poor aeration is highly vulnerable to colonization. Once the fungus establishes itself, it spreads rapidly through mycelial strands, which can transport water and nutrients even through non-conductive surfaces.

Symptoms are easily identifiable: the wood develops a characteristic brown, crumbly appearance, often accompanied by dense, white or yellowish mycelial mats. In advanced stages, the fungus produces wavy or folded fruiting bodies on the surface of the affected substrate, indicating that the organism is actively releasing spores into the environment.

Effective control relies primarily on moisture management and preventative chemistry. It is essential to keep wood off the ground, use pressure-treated timber with preservatives, and ensure proper ventilation in greenhouses and storehouses. Any detected infection should be removed immediately to prevent spores from spreading to healthy plant tissues or equipment.