Grifola

Grifola refers to a genus of polypore fungi that act as significant pathogens in forestry and agriculture. While some species are well-known edible fungi, as a plant pathogen, it causes severe white rot within the root system and the base of the trunk of broad-leaved trees.

The causal agent is a wood-decay fungus that breaks down the structural components of the tree. The type of infection is classified as a basal and root rot. By degrading lignin and cellulose, the fungus gradually compromises the wood's integrity, eventually hindering the tree's ability to transport water and nutrients.

This fungus typically attacks deciduous trees such as oak, beech, and various fruit trees. It is particularly dangerous in orchards where older or weakened trees provide a gateway for fungal spores to colonize the interior wood through injuries or pruned limbs.

Visible symptoms often include the emergence of large, clustered fruiting bodies at the base of the infected tree. Foliar symptoms include wilting, chlorosis, and premature leaf drop. The internal decay leads to a soft, spongy texture in the wood, making the tree structurally unstable and prone to toppling during storms.

The spread of the fungus is favored by high humidity, poor soil drainage, and existing mechanical damage. Spores travel via wind and water, settling into cracks or wounds, where they germinate and initiate colonization. In dense stands, the fungus can also spread through root grafts between adjacent trees.

Preventive measures are critical, as internal rot is often irreversible. These include maintaining tree vigor through proper fertilization, immediate sanitation of wounds, and pruning during dry weather to prevent infection. If a tree is severely colonized, removal of the entire specimen, including the root stump, is necessary to protect surrounding vegetation from further spread.