Thelephorales fungi

The order Thelephorales consists of basidiomycete fungi that are primarily recognized for their role as decomposers in forest ecosystems. However, in an agricultural and arboricultural context, they can act as pathogens when they infect weakened or stressed woody plants. These fungi typically produce leathery or membranous basidiocarps that adhere closely to the bark or decaying wood surfaces.

These fungi mainly affect a wide range of woody plants, including various forest species and ornamental trees. Susceptibility is highest in trees that have sustained physical injuries, are suffering from environmental stress, or are located in poorly managed plantations. While they are not always the primary killer of healthy trees, they frequently colonize plants that are already struggling, thereby accelerating their decline.

Symptoms of an infection often include the visible presence of fungal fruiting bodies on the surface of the trunk or branches. These bodies may appear as patches, crusts, or shell-like structures with a distinct color, ranging from brownish to grayish. Internally, the fungus causes wood decay, which manifests as structural instability, discoloration of the xylem, and a general reduction in the tree's vigor and vitality.

Environmental conditions play a decisive role in the development and spread of Thelephorales. They thrive in environments with consistently high humidity, poor air circulation, and temperatures that favor fungal metabolic activity. Spores are disseminated through wind and splash, settling on wounds or fissures in the bark. Once a spore successfully germinates, the mycelium begins to penetrate the host's tissue.

The economic impact of these fungi is related to the loss of timber quality and the death of ornamental or forest trees. Preventive measures focus on maintaining optimal tree health, including the avoidance of mechanical bark damage and the prompt removal of infected wood debris. In managed orchards, the application of protective wound sealants and the implementation of appropriate pruning techniques are essential to prevent spore colonization.