Shaggy scalycap

Pholiota subsquarrosa, commonly known as the shaggy scalycap, is a fungal pathogen that acts as a parasite on deciduous trees. In agronomy and forestry, it is recognized for causing significant wood decay, specifically white rot, which leads to the structural degradation of the tree's trunk and root system.

The disease is initiated when fungal spores enter through bark wounds, pruning cuts, or damage caused by environmental factors like frost or animal activity. Once established, the mycelium penetrates deep into the heartwood, secreting enzymes that break down lignin and cellulose, effectively compromising the tree's internal support structure.

This pathogen primarily targets various hardwood species, including birch, maple, and sometimes apple or other orchard trees. It is particularly aggressive toward trees that are already stressed by drought, poor soil quality, or lack of proper maintenance, making them susceptible to secondary infections by this fungus.

The presence of P. subsquarrosa is easily identified by the appearance of dense clusters of yellow-brown mushrooms with characteristic dark scales on their caps, typically growing directly from the bark. Additional symptoms include localized swellings on the trunk, softening of the wood, and in advanced stages, the death of branches or the entire tree.

Control strategies focus primarily on prevention and physical removal. It is essential to keep trees healthy and vigorous through proper nutrition and hydration. Any wounds must be treated immediately with protective sealants, and infected parts should be surgically removed and destroyed to prevent the dispersal of spores throughout the garden or nursery environment.