Collar rot shows up right at the base of the cauliflower plant, where the stem meets the soil. It's easy to miss in the early stages, but once the stem tissue starts to rot, the plant can wilt and topple over within days. Catching it early and managing the field correctly makes the difference between losing a few plants and losing patches of the crop.

Symptoms

• Water-soaked, brown lesions at the collar region, where the stem meets the soil line
• Soft, rotted stem tissue that constricts and weakens over time
• Sudden wilting of otherwise healthy-looking plants
• White, cottony fungal growth visible on the affected stem and nearby soil in humid conditions
• Small, round, mustard-seed-like structures (sclerotia) on the rotted tissue as the disease advances
• Plants toppling over or collapsing at the base in severe cases

Causes

• Soil-borne fungal infection that survives in the soil between seasons
• Warm, humid weather, especially after rain or heavy irrigation
• Waterlogging or poor drainage around the plant base
• Excess soil moisture combined with dense planting and poor airflow
• Mechanical injury to the stem near the soil line, which gives the fungus an entry point
• Continuous cauliflower or cole-crop cultivation in the same field without rotation

Management

Chemical Control

Mancozeb 75% WP is a confirmed option for collar rot in cauliflower. It's a contact fungicide that forms a protective layer on the plant surface, stopping fungal spores from establishing before they can infect the stem.

Products recommendation

• Dhanuka M45 Fungicide
• Katyayani KZEB M-45 Fungicide
• Tata M-45 Fungicide
• Exylon Mac 75 Fungicide
• Uthane M-45 Fungicides

Cultural Practices

• Improve field drainage so water doesn't pool around the plant base
• Avoid overwatering, especially during warm, humid spells
• Maintain proper spacing between plants for better airflow around the collar region
• Rotate with a non-cole crop for at least a season in fields with a history of collar rot
• Remove and destroy infected plants and crop debris rather than leaving them in the field
• Avoid injuring the stem near the soil line during weeding or intercultural operations

Conclusion

Collar rot spreads fast once conditions turn warm and humid, so regular field walks to check the base of the plants are worth the time. Good drainage, sensible spacing, and a timely fungicide spray together keep the disease from taking hold and protect the crop through to harvest.