Phleogena

Phleogena is a genus of fungi belonging to the order Atractiellales, known for causing bark-related infections in deciduous trees. Often identified as Phleogena faginea, this fungus behaves as a pathogen or saprotroph that targets stressed, dying, or already necrotic bark tissues on various broadleaved species.

The primary causal agent is the fungus Phleogena faginea. It primarily colonizes the bark of trees like beech, hornbeam, and oak. While it is often considered a secondary pathogen, its presence indicates significant bark compromise, and it contributes to the further degradation of the tree's outer protective layer.

The key symptoms of Phleogena infection include the appearance of small, pin-head-sized, globular or cushion-like sporocarps. These fruiting bodies are usually greyish or whitish and possess a cartilaginous or tough texture. They typically emerge from deep bark crevices where environmental moisture is retained, making them highly visible during humid seasons.

Environmental conditions that favor the spread of this fungus include persistent high humidity, poor air circulation, and the presence of bark wounds. Spores are disseminated by wind and splashing rainwater. Once the fungus establishes itself in the bark, it derives nutrients from the dying tissue, accelerating the break-down process of the tree's protective barrier.

Management strategies focus on reducing the fungal inoculum and maintaining tree vitality. Effective measures include the removal of dead or heavily infested bark, performing sanitary pruning to eliminate infected branches, and applying protective wound dressings. Preventive care involves ensuring adequate tree spacing for ventilation and minimizing mechanical injuries to the trunk to prevent opportunistic colonization.