Biscogniauxia

Biscogniauxia is a genus of ascomycete fungi responsible for severe necrotic diseases in woody plants, often referred to as "charcoal canker" due to the appearance of its fruiting bodies. These fungi act as opportunistic pathogens that thrive on host trees experiencing physiological stress.

The disease primarily targets a wide range of broad-leaved trees, including oaks, beeches, maples, and lindens. While healthy trees may occasionally be affected, the pathogen is significantly more destructive in trees that have been compromised by drought, extreme temperature fluctuations, or physical damage to the trunk.

The primary symptom is the formation of black, crust-like stromata that erupt through the bark, giving the affected areas a charred appearance. Beneath these structures, the fungus causes extensive decay of the phloem and cambium, effectively girdling the tree and preventing the transport of essential water and nutrients.

Outbreaks of Biscogniauxia are strongly correlated with prolonged dry weather conditions. Environmental stress weakens the host's natural defenses, allowing fungal spores to germinate and colonize the bark tissue through fissures or wounds. Once established, the fungus spreads rapidly throughout the internal structures of the tree.

Effective management focuses on preventive strategies, as chemical control options are generally unavailable once the infection has become systemic. Key actions include:

• regular inspection for early signs of bark lesions;
• prompt removal and destruction of infected wood to reduce spore load;
• proper silvicultural practices to maintain tree vigor and resistance;
• avoiding mechanical damage to trunks during forestry or landscaping activities.