Ozonium wilt and collar rot

Ozonium wilt and collar rot is a destructive fungal disease caused by the soil-borne pathogen Ozonium texanum. This fungus exists primarily as a saprophyte in soil, but it becomes a serious parasite when environmental conditions favor the development of its mycelial growth and infection processes.

The pathogen has a wide host range, with chickpea being one of the most susceptible crops. Other hosts include cotton and various legumes. The fungus can persist in the soil for several years by forming dormant structures, which makes the disease extremely persistent in fields.

The initial symptoms are characterized by sudden wilting of the plants, particularly during hot days. As the disease progresses, the collar region (the junction of the stem and root) shows signs of necrosis, and the roots may become covered with thick, white mycelial strands, leading to the collapse of the vascular system.

Favorable conditions for the pathogen's development include high soil temperatures and sufficient moisture levels. The fungus spreads rapidly through the movement of infested soil particles, contaminated irrigation water, and the use of non-sanitized farm machinery during field operations.

Effective management requires an integrated approach to minimize the survival of the fungus in the field.

• Implementation of long-term crop rotation using non-host crops.
• Improvement of soil drainage to prevent moisture accumulation.
• Seed treatment with systemic fungicides to protect germinating seedlings.
• Deep tillage to bury and destroy pathogen-infested debris.