Citrus bark rot

Citrus bark rot is a destructive plant disease primarily caused by soil-borne fungal pathogens, such as Phytophthora species. This condition attacks the bark and cambium of citrus trees, often leading to restricted nutrient transport and significant structural damage to the tree trunk.

The disease affects a wide range of citrus species, including lemons, oranges, and grapefruits. It is particularly problematic in commercial citrus groves and home gardens where environmental conditions favor the proliferation of fungal spores, especially in regions with high precipitation and poor soil drainage.

Symptoms typically manifest as dark, water-soaked patches on the bark, which may later crack and leak gum (exudation). As the infection advances, the inner tissue underneath the bark becomes necrotic and reddish-brown. Eventually, the canopy begins to thin, leaves turn yellow, and dieback of branches becomes evident as the tree loses its vitality.

The development of bark rot is closely linked to moisture levels. Overwatering, deep planting of trees, or injuries from horticultural tools provide entry points for the pathogen. Once established, the fungus spreads rapidly if the environmental conditions remain warm and humid, creating an ideal climate for infection.

Effective management requires a combination of surgical intervention and chemical control. Infected bark should be surgically removed to expose healthy tissue, which must then be treated with suitable fungicides.

• Improve soil drainage to prevent waterlogging.
• Keep the root flare free of soil and mulch.
• Ensure proper spacing for air circulation.
• Disinfect tools after working on affected trees.