Fusicoccum canker

Fusicoccum canker is a serious fungal disease caused by the pathogen Fusicoccum depressum. This fungus primarily targets the bark and cambium layers of woody plants, leading to localized necrosis and long-term structural damage to branches and main stems, which often results in the death of the affected tree parts.

The disease is particularly destructive to stone fruit trees, including peach, apricot, and almond varieties. While healthy trees may exhibit some resistance, those weakened by frost, sunburn, or mechanical injuries, such as pruning wounds, are highly susceptible to infection, which can spread rapidly through the orchard if not managed properly.

Symptoms initially appear as small, slightly sunken discolored areas on the bark. As the pathogen colonizes the tissue, these spots develop into elongated cankers that turn brown or greyish. In advanced stages, the bark often cracks or peels away, and black, pimple-like fruiting bodies of the fungus emerge through the surface of the dead tissue.

The development and spread of Fusicoccum depressum are heavily influenced by environmental conditions, particularly cool, wet weather. Rain splashes and wind currents facilitate the dispersal of spores from infected trees to healthy ones. Moisture is a critical factor, as it allows spores to germinate and enter the plant through microscopic wounds or leaf scars.

Effective management requires an integrated approach to sanitation and chemical protection. Growers should prioritize the following strategies:

• Removal and destruction of all infected wood during dormancy.
• Disinfection of pruning tools between trees to prevent cross-contamination.
• Application of copper-based fungicides to protect wounds.
• Maintaining tree vigor through balanced nutrition and proper irrigation to increase natural resilience.