Fenestella

Fenestella (Fenestella fenestrata) is a fungal plant disease characterized by necrosis and canker formation on the bark and woody parts of trees. It is caused by an ascomycete fungus that thrives on weakened or physically damaged woody tissues.

The disease affects a variety of fruit and deciduous forest trees, including species such as apple, pear, and various hardwood trees. It poses a significant threat in orchards where trees are prone to environmental stress, such as winter sunscald or mechanical injuries that provide entry points for the pathogen.

Typical symptoms include the development of necrotic lesions on the bark, which can progress into deep, sunken cankers. As the fungus colonizes the tissue, the bark often cracks and discolors. Small, black fungal fruiting bodies, known as ascostromata, frequently appear on the surface of the infected areas, releasing spores that can spread the infection.

Development and spread are driven by high humidity and moderate temperatures, which facilitate spore germination. Rain and wind act as the primary vectors for dispersal, carrying spores from infected surfaces into healthy wounds. Prolonged periods of moisture increase the risk of rapid colonization of healthy branches and trunks.

Management practices focus on sanitation and preventive care. Key measures include the removal and destruction of infected limbs, pruning wounds dressing with protective compounds, and maintaining overall tree vigor through proper fertilization and watering. Preventing bark damage is critical to restricting the entry of Fenestella fenestrata.