Lemon scalycap

Lemon scalycap (Pholiota limonella) is a wood-decay fungus belonging to the Strophariaceae family. While it often acts as a saprotroph, it is frequently observed colonizing weakened or stressed trees, where it operates as a parasite, accelerating the decay of heartwood and sapwood.

The host range of this fungus primarily includes various deciduous trees, with a strong preference for birch, alder, maple, and sometimes orchard species. It typically targets trees that have already suffered from mechanical damage, frost cracks, or insect infestations, using these entry points to invade the vascular system of the wood.

Symptoms of an infestation are marked by the presence of dense clusters of bright yellow, scaly mushrooms growing directly from the bark or stumps of the host. Internally, the fungus triggers white rot, causing the wood to lose its structural integrity and eventually become soft and fibrous as the lignocellulose is decomposed.

The spread of Pholiota limonella is favored by damp, cool conditions and poor ventilation within the tree canopy or surrounding environment. Its spores are airborne and easily travel to new hosts, specifically targeting areas where the natural protective barrier of the bark has been compromised.

To prevent the spread and impact of this fungus, it is crucial to prioritize orchard hygiene. This includes proper pruning techniques with sterilized tools, the application of protective wound dressings on larger cuts, and the removal of severely decayed debris from the site to reduce the local spore load and prevent further infection.