Seedling blight/leaf blight/leaf spot

Seedling blight/leaf blight/leaf spot: Helminthosporium nodulosum

  • The pathogen affects both seedling and the adult plants
  • Minute, oval, light brown lesions on the young leaves and become dark brown
  • Several such lesions coalesce to form large patches of infection on the leaf blade. The affected blades wither prematurely and the seedlings may be killed.
  • Linear oblong and dark brown spots appear on the leaves of grown up plants. The leaves give the blightening appearance.
  • Prominent brown to dark brown discoloration in the neck region  and followed by weakening of neck tissue that causes it to break and the ears hanging down from the plant
  • While nursery infection causes heavy damage due to the seedling blight, neck infection causes heavy chaffiness and severe loss in grain yield.
  • It is seed-borne and primary infection is through seed
  • Secondary infection through airborne conidia and stubbles.
Identification of pathogen:
  • The mycelium is intra and inter-cellular septate and light brown in colour
  • Conidia are erect or curved septate and dark brown. They are borne at the tip of conidiophores
  • Conidiophores are thick walled cylindrical or obcavate straight or curved and light green in color and 3-10 septate
  • The spores germinate either through the stomata or epidermal cells.
  • 11 spores may be formed in one conidiophore

Chemical method:

  • Treat the seeds with Captan or Thiram @4g/Kg
  • Spray Mancozeb @ 1.25Kg/ha
  • Spray 1% Bordeaux mixture or Copper oxychloride or Dithane Z-78 (2g/lit. water).



  • TamilNadu Agritech Portal.


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