Phomopsis canker and fruit rot

Phomopsis canker and fruit rot, caused by the fungus Fusicoccum amygdali (also known as Phomopsis amygdali), is a destructive disease that primarily affects almond orchards. This fungal pathogen targets the woody tissues of the branches and the fruit, leading to significant physiological stress in the trees.

The disease is highly host-specific to almonds, causing severe economic losses in commercial cultivation. It impacts the vegetative structure by disrupting vascular pathways and reduces the yield directly through fruit decay before or during the harvest period.

Initial symptoms are characterized by small dark lesions appearing on the bark, usually around lenticels or pruning wounds. As the fungus colonizes the internal tissues, these spots develop into elongated cankers that can eventually girdle the branches, causing the foliage above the infection site to wilt and die. On the fruit, the disease manifests as brown, sunken lesions that rapidly spread throughout the hull.

The development of Phomopsis is heavily favored by cool, wet spring weather. Spores are disseminated via rain splashes and wind, entering the tree through natural openings or wounds. The pathogen overwinters within necrotic bark tissues and mummified fruits, serving as a primary source of inoculum for the following growing season.

Mitigating the impact of this disease requires a rigorous integrated pest management strategy. To protect the orchard effectively, growers should focus on the following practices:

• Regular pruning to remove symptomatic branches, ensuring cuts are made well into healthy wood.
• Strict sanitation by removing all mummified fruits and debris from the orchard floor.
• Application of appropriate fungicides during the early spring and bloom periods to protect against spore germination.
• Maintaining tree vigor through balanced fertilization and proper irrigation to help the plant resist infection.