Collar rot: Sclerotium rolfsii

Symptoms

• The disease occasionally occurs in serious form.
• The lower portion of the stem is affected from the soil borne inoculum (sclerotia).
• Decortications is the main symptom.
• Exposure and necrosis of underlying tissues may lead to collapse of the plant.
• Near the ground surface on the stem may be seen the mycelia and sclerotia.
• Lack of plant vigour, accumulation of water around the stem, and mechanical injuries help in development of this disease.

Healthy plant	Collar rot affected plant

Sclerotial growth on collar region	Death of plant

Management

• Seed treatment with 4 g of Trichoderma viride formulation per kg seed will help in reducing the disease.
• Spraying with Mancozeb @ 2g/Litre of water.
• Collection and destruction of diseased parts and portions of the plant.