Byssomerulius corium

Byssomerulius corium is a widespread wood-decaying fungus belonging to the Meruliaceae family. While it primarily acts as a saprotroph in nature, it can behave as a facultative parasite, causing white rot disease that targets the woody tissues of various deciduous trees.

This pathogen commonly affects fruit trees like apples and pears, as well as several species of hardwoods. It exploits structural weaknesses in the tree, typically entering through deep bark fissures, frost cracks, or wounds left by improper pruning that have not been properly sealed or treated.

The primary symptom of infestation is the appearance of leathery, crust-like fruiting bodies on the surface of the bark, which often exhibit white, cream, or pale pink colors. Inside the tree, the fungus initiates white rot, degrading lignin and cellulose, which turns the wood into a bleached, fibrous, and fragile substance.

• Prolonged periods of high humidity and rainfall.
• Lack of air circulation within dense canopy structures.
• Inadequately treated pruning wounds.
• Presence of frost-damaged or sunburned bark.

The severity of the damage caused by Byssomerulius corium lies in its ability to compromise the structural integrity of the plant. Over time, the internal decay leads to a decline in physiological function, resulting in reduced fruit yields and a high risk of branch or trunk failure during strong winds or heavy fruit loads.

Effective management requires strict sanitation practices. Growers should immediately remove and destroy infected branches, ensuring that tools are disinfected to prevent spore spread. Maintaining tree vigor through proper fertilization and sealing all significant wounds with professional-grade wound dressings are critical steps to prevent the establishment of this pathogen.