Schizopora paradoxa

Schizopora paradoxa is a wood-decaying fungus that belongs to the Schizoporaceae family. It is primarily known for causing white rot in woody plants. While it is a common saprotroph found on dead wood, it can act as a facultative parasite, attacking weakened or injured living trees, thereby posing a threat to orchard health.

The host range of this pathogen includes various broad-leaved tree species. It frequently targets fruit trees such as apple and pear, as well as deciduous forest species like oak and birch. The fungus typically colonizes trees that have been compromised by environmental stress, pest activity, or improper pruning practices.

Symptoms of an infection include the appearance of annual or perennial fruiting bodies on the bark. These are typically effused-reflexed, white to cream-colored structures with distinct pores. Internally, the wood undergoes degradation, resulting in a white, fibrous, and soft rot that severely compromises the structural integrity of the tree's trunk and branches.

Development and spread are favored by high humidity and moderate temperatures. The fungus releases spores that are dispersed by wind and splashing rain. Once the spores land on an open wound—such as a branch stub, a frost crack, or a sunscald injury—the mycelium begins to colonize the xylem, feeding on the structural components of the wood.

Control strategies emphasize prevention rather than eradication, as treating internal rot is challenging. Effective management involves maintaining tree vigor through proper fertilization and watering, performing sanitary pruning, and ensuring that all major pruning wounds are treated with appropriate sealants. Removing and destroying heavily infested plant debris is essential to reduce the local spore load in the orchard.