Xylariales fungi

The order Xylariales consists of a diverse group of Ascomycota fungi, many of which act as significant plant pathogens and saprotrophs in forest and orchard ecosystems. These fungi are primary agents of wood decay, often colonizing stressed or wounded trees to derive nutrients from structural tissues.

The pathogens belonging to this order, particularly genera such as Xylaria and Biscogniauxia, operate by colonizing the vascular system and heartwood. The disease type is characterized as white rot, where the fungus progressively breaks down lignin, leading to the loss of mechanical strength in the trunk and branches of the host plant.

Susceptible crops include a wide range of woody plants, from fruit-bearing species like walnuts and pome fruits to hardwoods like oaks and beeches. These pathogens typically target the most vulnerable individuals—those suffering from drought, poor nutrition, or secondary damage caused by pests and climate extremes.

Symptoms of infection are distinct and often visually prominent. These include the formation of carbonaceous, coal-like stromata on the surface of the bark. Internally, the wood may show signs of discoloration and softening. Advanced stages of the disease manifest as canopy dieback, wilting of branches, and, in severe cases, structural failure and the collapse of the tree.

Protection and preventive strategies focus on maintaining tree vigor and minimizing entry points for spores. Key measures include:

• Rigorous sanitary pruning of infected limbs.
• Sterilization of pruning tools to prevent cross-contamination.
• Application of protective wound dressings to fresh cuts.
• Avoidance of mechanical damage to tree trunks during orchard maintenance.
• Strengthening tree immune systems through balanced fertilization and correct irrigation.