Antrodia malicola

Antrodia malicola is a species of wood-decaying fungus that acts as a pathogen in woody plants, specifically known for causing brown rot. Within the context of plant pathology, this organism colonizes the heartwood of trees, breaking down cellulose and leaving behind a brittle, cracked structure that eventually compromises the mechanical integrity of the tree trunk.

This fungus predominantly affects pome fruits, with apple trees being the most common host. The pathogen is typically opportunistic, meaning it targets trees that are already stressed due to age, poor nutritional status, environmental damage, or previous infections by pests or other pathogens, rather than attacking healthy, vigorous trees.

Key symptoms of an infestation include the development of perennial, crust-like or shelf-like fruit bodies on the outer bark. Internally, the wood undergoes a transformation: it becomes brownish, crumbly, and develops characteristic cubical fracturing. As the rot progresses, the tree may exhibit symptoms of decline, such as canopy thinning, reduced fruit yield, and, in severe cases, the structural failure of major branches or the entire main stem.

The development and spread of Antrodia malicola are highly favored by humid environments and the presence of open wounds on the tree. Spores are primarily dispersed through wind currents or water splashing, seeking out vulnerable entry points such as pruning cuts, cracks in the bark, or insect-damaged areas. Once settled, the mycelium begins to degrade the lignified tissues of the host.

Orchard management is the primary line of defense. Preventive measures should focus on the following strategies:

• Maintaining tree vigor through balanced fertilization and proper irrigation.
• Ensuring proper pruning techniques and immediate protection of wounds with wound dressing sealants.
• Removing and destroying infected wood or fruit bodies to reduce the local spore load.
• Sanitizing tools between pruning sessions to prevent the mechanical transmission of fungal spores from tree to tree.