Shaggy scalycap

The shaggy scalycap (Pholiota squarrosa) is a parasitic fungus that causes white heart rot in a wide range of woody plants. As a wood-decay pathogen, it significantly impacts the structural integrity of both orchard trees and deciduous forest species.

This fungus primarily targets fruit trees, including apple and pear varieties, as well as species such as rowan, maple, beech, and linden. It enters the tree through wounds, pruning cuts, or frost cracks, allowing the mycelium to colonize the interior wood tissue.

Signs of infestation include the appearance of dense, scaly clusters of fruiting bodies at the base of the trunk or on major branches. Internally, the wood becomes bleached, fibrous, and loses its structural density, ultimately leading to limb breakage or the complete death of the host tree.

The spread of this fungus is favored by high humidity, poor aeration, and the presence of decaying organic matter within the plantation. Spores are easily disseminated by wind and water, landing on susceptible tree bark and initiating new infections through any minor damage to the protective layer.

Effective management requires strict sanitation: removing and destroying infected tree parts, applying appropriate wound sealants to cuts, and eliminating stumps or deadwood that serve as spore reservoirs. Maintaining healthy trees through proper fertilization and spacing remains the best defense against colonization.