Peniophora root canker

Peniophora root canker, caused by the fungus Peniophora sacrata, is a destructive disease affecting the root systems and root collars of woody plants. It is particularly noted for its impact on Malus domestica (apple trees). The pathogen acts as a root and collar rot agent, causing a slow decline of the tree by compromising its vascular integrity.

The host range of this fungus primarily includes various orchard trees, with apple trees being highly susceptible under poor environmental conditions. The disease often initiates in the root collar area, slowly expanding downwards into the roots or upwards into the lower trunk, disrupting the vital sap flow of the tree.

Symptoms are often internal and may not be immediately visible on the canopy until significant damage has occurred. Externally, one may notice depressed lesions, bark splitting, and dark discoloration near the soil line. As the disease advances, thin, leathery fungal growth may appear on the bark surface, particularly during wet weather conditions.

The development of Peniophora sacrata is favored by poorly drained, waterlogged soils and high humidity. Mechanical injury to the roots, often caused by improper cultivation practices, provides entry points for the fungal spores. Once established in the soil, the fungus remains a persistent threat to adjacent healthy plants.

The harmfulness of this disease is significant, as it leads to tree chlorosis, stunted growth, and eventually, the death of the tree. Infected trees become unproductive and pose a high risk of spreading the pathogen to other healthy specimens in the orchard through soil movement or water runoff.

• Improve soil drainage to prevent waterlogging and reduce fungal activity.
• Practice careful cultivation to avoid damaging roots and the root collar of trees.
• Remove and destroy severely infected trees, including their entire root system.
• Monitor trees regularly for signs of bark discoloration or weeping at the base of the trunk.