Porostereum

Porostereum is a genus of wood-decay fungi primarily responsible for white rot in woody plant species. As basidiomycetes, these fungi play a critical role in decomposing lignin and cellulose within the host plant, effectively breaking down the woody structure of the tree from the inside out.

The fungus typically affects deciduous trees, including ornamental, fruit, and forest species. It gains entry into the host primarily through wounds in the bark, improperly healed pruning cuts, or frost cracks, which provide the necessary access point for the fungal spores to establish a colony within the inner tissues.

Symptoms of an infection often include the emergence of crust-like or leathery fruit bodies on the surface of the trunk or branches. Internally, the wood becomes bleached, fibrous, and loses its structural integrity. This decay process compromises the plant's ability to transport water and minerals, leading to branch dieback and overall tree decline.

Development and spread are favored by high humidity and poor tree health conditions. Spores are dispersed through the air or by water droplets during rain, colonizing new hosts upon contact with vulnerable tissue. Once established, the mycelium spreads throughout the vascular tissue, making the infection difficult to treat if it reaches an advanced stage.

• Apply antiseptic wound dressings immediately after pruning.
• Maintain tree vigor through proper fertilization and irrigation.
• Remove and destroy infected wood from the growing site.
• Disinfect pruning tools between each tree to prevent cross-contamination.

The economic and ecological impact of Porostereum is significant, as it can kill valuable trees or create structural hazards in landscapes. Because the decay occurs internally, trees may appear healthy for some time while the wood is being actively degraded, emphasizing the need for regular inspections and proactive site management.