Dichostereum

Dichostereum is a genus of basidiomycete fungi within the family Lachnocladiaceae that acts as a serious pathogen, primarily causing wood decay in various tree species. These fungi function as wood-decay agents that target the structural integrity of trees, leading to significant economic losses in both forestry and horticulture by compromising timber quality.

The disease caused by this fungus is typically categorized as a white rot. The pathogen decomposes lignin within the wood, which is essential for the tree's structural support. Once the decay progresses, the internal wood tissue loses its tensile strength, rendering the tree vulnerable to physical failure and mechanical breakage, especially during adverse weather conditions.

This pathogen mainly affects hardwood species, such as oak, beech, and various fruit trees. The infection spreads primarily via basidiospores that colonize open wounds on the trunk or branches. These entry points often include pruning scars, frost cracks, sunscald injuries, or wounds left by insect infestations, which provide the fungus with the necessary access to susceptible wood tissue.

Visible symptoms often include the development of leathery or crust-like fungal sporocarps on the bark surface. These structures indicate an established infection. Internally, the wood undergoes discoloration and softening, often developing distinct zones of decay. Because the fungus often works internally, by the time symptoms become evident on the surface, the structural damage is frequently extensive.

Management and prevention of Dichostereum focus on minimizing risks through proactive care and sanitation:

• Maintaining tree health through proper fertilization and irrigation to boost immunity.
• Promptly treating and sealing all mechanical wounds or pruning cuts.
• Removing and destroying heavily infected plant material to reduce spore load in the environment.
• Sanitizing pruning tools between trees to prevent the mechanical transmission of fungal spores.