Onion Pythium root rot: Pythium aphanidermatum, P. debaryanum and P. ultimum
Symptom:
- This disease causes seed rotting, pre-emergence damping off. The disease appears in circular patches in the field here and there.
- All the affected plants get killed. if the disease occurs prior to seed germination, it causes gappiness.
- The seeds or seed materials are killed before their establishment.
- The disease also occurs after the establishment of the crop i.e after 15 to 30 days of sowing or planting. This stage is called post-emergence damping off.
- If the disease occurs very late, it causes stunting of the plant and rotting of the roots.
Identification of pathogen:
- The disease is caused by complex of Pythium aphanidermatum, P. debaryanum and P. ultimum
Management:
- Seed treatment with Thiram or Captan @ 4g/kg. The bulbs may be dipped in Thiram solution 0.25%.
- After sprouting, the root region of the plants along the rows should be given a soil drenching with Copper oxychloride 0.25%.
Source-
- TamilNadu Agritech Portal
