Dermea canker

Dermea canker, caused by the fungus Dermea cerasi, is a significant bark disease affecting stone fruit trees. As an ascomycete fungus, it disrupts the tree's vascular system, leading to necrosis of the bark and underlying tissues. If left unmanaged, the infection can cause systemic decline and the eventual death of branches or entire trees.

The primary hosts for this pathogen are cherry (Prunus cerasus) and sweet cherry (Prunus avium). However, other members of the Prunus genus are also susceptible. The fungus typically exploits entry points such as frost cracks, pruning wounds, sunscald injuries, or mechanical damage, making healthy trees with compromised bark defenses highly vulnerable.

Symptoms typically manifest as sunken, necrotic lesions on branches and trunks. As the disease progresses, the infected bark darkens, cracks, and may exhibit gumming. During periods of high humidity, the fungus produces small, dark, fruiting bodies on the surface of the infected areas, which serve as the source of inoculum for further spread.

The development of Dermea cerasi is favored by cool, wet weather conditions, particularly during spring and autumn. Spores are disseminated by wind, rain splashes, and insects, allowing the pathogen to colonize new sites. Once established, the mycelium spreads beneath the bark, killing the cambium layer and effectively girdling the branch, which eventually leads to wilting and death.

Management of Dermea canker relies heavily on rigorous sanitation and good horticultural practices. Control strategies include the following:

• Pruning and destroying infected branches to remove the source of inoculum.
• Sterilizing pruning tools between cuts to prevent cross-contamination.
• Protecting pruning wounds with appropriate sealants or wound paints.
• Maintaining tree vigor through balanced fertilization and adequate irrigation.
• Applying preventive fungicidal sprays during the dormant season and early spring.