Dryad's saddle

Dryad's saddle (Polyporus squamosus) is a parasitic fungus belonging to the Polyporaceae family that causes white rot in a wide range of hardwood tree species. It acts as a primary decomposer that attacks the living tissues of the tree, eventually leading to structural decay and the eventual decline of the host plant.

Common hosts for this pathogen include ornamental and fruit-bearing trees such as apple, pear, maple, walnut, and elm. The fungus typically enters the tree through wounds, pruning cuts, or frost cracks, where the wood has been exposed and lacks the natural defense mechanisms provided by healthy bark.

The primary symptom of infection is the development of large, shelf-like fruiting bodies on the trunk or large limbs. These fruiting bodies are characterized by a light-colored cap covered with dark, concentric scales. Inside the tree, the mycelium breaks down lignin and cellulose, turning the heartwood into a spongy, white mass that smells distinctively of flour or cucumbers.

The development of the fungus is highly dependent on environmental conditions, particularly high humidity and moderate temperatures. Once established, the fungus can spread rapidly throughout the trunk, weakening the tree's internal structure and making it hazardous, especially during high-wind events or storm conditions.

Managing Dryad's saddle focuses on prevention, as established internal decay is extremely difficult to cure. Key strategies include:

• Practicing proper pruning techniques to minimize large wounds.
• Applying protective wound dressings to significant cuts or mechanical injuries.
• Removing and destroying infected fruiting bodies before they release spores.
• Maintaining tree vigor through appropriate fertilization and water management to enhance natural resistance.