• Thick white strands of fungus appear at the collar region of the stem and roots
• White fungal hyphae grow on the tubers which later start rotting and covered by fruiting bodies

• Fungi produced silky white mycelium
• Septate and branched hyphae
• Globose, smooth surfaced sclerotia

Mode of spread and survival :

• Mycelium and sclerotia subsists in soil
• Infected soil, in running water & on farm implements

Epidemiology :

• Temp - 30-35°C
• Thrives in sandy or loamy soil which are acidic
• Alternate wet & dry soil conditions favour the disease development

• Application of ammonium nitrate to the soil
• Seed tuber treatment - PCNB@ 15 kg/ha
• Resistant clones - S. acaule, S. multiinerruptum, S. infundibuliformae