Citrus psorosis

Psorosis, often referred to as citrus psorosis, is a chronic viral disease caused by the Citrus psorosis virus (CPsV). It is a systemic infection that colonizes the phloem and cambium layers of citrus trees, leading to long-term physiological stress and structural damage to the bark.

The disease affects a wide range of citrus species, including oranges, mandarins, grapefruits, and lemons. While younger trees might look asymptomatic, the virus persists, often manifesting as distinct wood and bark abnormalities as the tree matures and reaches its peak fruiting years.

The primary symptom is the scaling of the bark on the trunk and main scaffold branches. As the disease progresses, the bark cracks and peels off in irregular flakes, exposing the underlying wood which may show brownish deposits. This process, often called scaling, weakens the tree's structural integrity and disrupts nutrient transport.

Development and spread are primarily driven by the use of infected budwood or grafting scions. Because the virus can remain latent for years, it is frequently introduced into new orchards unknowingly. Transmission can also occur via root grafting in closely spaced plantations or through contaminated pruning equipment.

There is currently no cure for infected trees, making strict preventative measures essential for orchard health.

• Use certified, virus-free nursery stock.
• Implement rigorous sanitation for pruning tools.
• Remove and destroy symptomatic trees promptly.
• Establish barrier zones in areas with known history of infection.