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Chilli damping-off and seedling collar/root rot

Damping-off and seedling rot is the principal nursery-stage disease of Indian chilli, killing 20-30-day-old seedlings during cloudy rainy spells. It is caused predominantly by oomycetes, with contributions from soil-borne fungi, and is managed through a combination of nursery sanitation, drainage and seed/soil treatments.

Identification and symptoms

Infected seedlings collapse at the soil line ('damping-off'), with watery brown lesions on the collar and root. Patches of dead seedlings expand rapidly under continuous rain and high humidity.

Host crops / Life cycle

The principal pathogens are the oomycetes Pythium aphanidermatum and P. myriotylum, with contributions from Phytophthora, Fusarium and Rhizoctonia. Pathogen propagules persist in soil and on contaminated seed; outbreaks are favoured by saturated nursery beds, low light and high humidity. All Indian chilli varieties — Guntur, Teja and Byadgi types (Chilli Guntur Sannam, Chilli Teja Segment, Chilli Byadgi Segment) — are susceptible at the seedling stage.

Damage and economic impact

The disease causes patchy seedling death in raised-bed nurseries and can necessitate complete re-sowing if sanitation and drainage are not in place; impact on transplant supply for the main field is the primary economic concern.

Management (cultural, biological, chemical)

ICAR-IIHR fertigation guidelines stress nursery sanitation as the primary control. The standard package combines:

  • Cultural — raised beds 15 cm above ground, 50% shade nets, side insect-proof netting (Practice Chilli Nursery Raising)
  • Biocontrol seed treatment — Trichoderma viride 5-10 g/kg or Pseudomonas fluorescens 5-10 ml/kg
  • Chemical seed treatment — thiram 3 g/kg or carbendazim 2 g/kg or metalaxyl-M 31.8% ES 2 ml/kg
  • Drenches — metalaxyl-mancozeb at 2 ml/L, cyazofamid or copper oxychloride at 2.5 g/L at 15-day intervals

The same pathogen complex carries through into main-field collar and stem rot (Disease Chilli Root Stem Rot).

Practice Chilli Nursery Raising, Disease Chilli Root Stem Rot, Practice Chilli Spray Schedule

References

  1. Integrated management of damping-off in chili. Frontiers in Microbiology, 2024.
  2. Chillies — package of practices. vikaspedia.in.