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Root rot and stem rot in chilli

Chilli root rot and stem rot is a soil-borne disease complex of the main-field crop in India, caused chiefly by oomycetes and Fusarium. It is particularly damaging in waterlogged nurseries and heavy-rain transplant windows, where it produces rapid wilting and seedling collapse.

Identification and symptoms

The disease produces dark stem-base lesions, rapid wilting and seedling collapse, often in expanding patches following monsoon rain. The aerial symptoms can resemble vascular wilt but the collar-base lesion is diagnostic.

Host crops / Life cycle

The principal pathogens are the oomycetes Phytophthora capsici and Pythium species (P. aphanidermatum, P. myriotylum), with Fusarium species also implicated. Pathogen propagules persist in soil; high soil moisture and warm temperatures favour zoospore release and infection. The same pathogen complex underlies nursery-stage damping-off (Chilli Damping Off Nursery Rot).

Damage and economic impact

Losses are concentrated in poorly drained transplant windows and in nurseries lacking raised beds. Severe outbreaks can demand complete replanting of affected blocks.

Management (cultural, biological, chemical)

  • Drainage — raised-bed nurseries 15 cm above ground level (Practice Chilli Nursery Raising)
  • Biocontrol — Trichoderma viride and Pseudomonas fluorescens seed treatment
  • Chemical drench — metalaxyl-mancozeb or cyazofamid or copper oxychloride
  • Resistance breeding — ICAR-IIHR has identified Phytophthora-resistant accessions, including IHR 3575 resistant to the virulent isolate PC-IIHR1, for use as resistance donors and as rootstocks for grafted chilli

These soil-borne pathogens are integrated into the prophylactic phase of the IPM spray schedule (Practice Chilli Spray Schedule).

Chilli Damping Off Nursery Rot, Practice Chilli Nursery Raising, Practice Chilli Spray Schedule

References

  1. Inheritance of resistance in chilli to Phytophthora capsici. Springer (cites ICAR-IIHR).
  2. Integrated management of damping-off in chili. Frontiers in Microbiology, 2024.