Damping off

Disease of nursery beds and young seedlings resulting in reduced seed germination and poor stand of seedlings. Very high seedling mortality 25-75%

Causal organism : Pythium aphanidermatum (Edson) Fitzp

Damage symptoms:

• Disease of nursery beds and young seedlings resulting in reduced seed germination and poor stand of seedlings. Very high seedling mortality 25-75%

• Pre-emergence damping off: Seedlings disintegrate before they come out of soil surface leading to poor seed germination


• Post-emergence damping off is characterised by development of disease after seedlings have emerged out of soil but before the stems are lignified


• Water soaked lesion formation at collar region


• Infected areas turn brown and rot


• Plants shrivel and collapse as a result of softening of tissues


• In Rhizoctonia solani attack infected stems become hard, thin (wire stem symptoms) and infected seedlings topple Disease appear in patches both in nursery and field beds.

Survival and spread:

• Primary: Oospores in soil in case of Pythium Sclerotia in soil in case of Rhizoctonia


• Secondary: Zoospores through irrigation water in case of Pythium. Mycelial growth in soil and sclerotia through irrigation water in case of Rhizoctonia.

Favourable conditions:

• Heavy rainfall, excessive and frequent irrigation, poorly drained soil and close spacing, high soil moisture with temp around 25-30 °C


• For Rhizoctonia: High soil moisture with temp around 30 – 35 °C.