Honey fungus

Armillaria (honey fungus) is a genus of fungi within the Physalacriaceae family, belonging to the kingdom Fungi. As a facultative parasite and saprotroph, this pathogen is notorious for causing white rot in wood and devastating root rot, affecting both forest trees and agricultural crops.

This pathogen impacts a wide range of hosts, including fruit trees (apples, pears, plums, cherries), grapevines, and various coniferous or deciduous forest species. The disease manifests through the decay of the cambium and bark at the root collar, leading to branch dieback, leaf yellowing, and eventual plant death.

The biology of Armillaria is characterized by the production of rhizomorphs—dense, black-brown mycelial cords that spread through the soil. The fungus infects plants primarily through root wounds or root contact, subsequently colonizing the tissue and progressively depleting the host's nutritional reserves.

Disease development is highly dependent on soil moisture levels and the presence of stumps or decaying organic matter, which serve as primary infection reservoirs. Ideal conditions for fungal growth include moderate temperatures and high humidity, allowing the mycelium to survive in the soil for over a decade.

Control measures are primarily preventive and cultural: removing stumps from infested areas, improving soil drainage, and maintaining proper plant vigor. In cases of severe infection, it is essential to remove the affected plants, including their root systems, to minimize further spread to healthy vegetation.