Grammotheleaceae

The Grammotheleaceae family belongs to a group of wood-decaying fungi within the Polyporales order. From an agronomic perspective, these fungi act as pathogens causing various types of wood rot, affecting both forest species and fruit trees in orchards. The disease type is classified as xylotrophic degradation, where the pathogen feeds on the cellulose and lignin of the plant tissue.

The primary targets for infection are weakened or physically damaged trees, as well as deadwood. The fungus is frequently found on deciduous trees and less commonly on conifers. In intensive orcharding, it may infect older fruit trees by penetrating through bark wounds, pruning cuts, or frost cracks, making it a significant factor in reducing orchard productivity and longevity.

The key symptoms of the infection include the emergence of specific fungal fruiting bodies on the surface of the bark or wood. These can appear as corticioid, resupinate, or slightly effused-reflexed forms. Internal signs include wood discoloration, loss of mechanical strength, and the development of white or brown rot, which eventually leads to the complete loss of structural integrity of the trunk and branches.

The development and spread of the fungus are directly dependent on moisture levels and the availability of a nutritional substrate. Optimal conditions for vegetative growth include moderate temperatures and high humidity, which promote spore germination on sites where the epidermis is compromised. Spores spread primarily through airborne dispersal or via insect pests that damage tree bark.

The harmfulness of Grammotheleaceae lies in the gradual but irreversible destruction of the tree's vascular system, leading to branch dieback and, ultimately, the death of the plant. For control and prevention, timely orchard sanitation is recommended: removing infected parts, disinfecting wounds with grafting wax or fungicides, and maintaining the overall tree immunity through proper fertilization and irrigation.