Sunflower Alternaria Blight

Sunflower Alternaria Blight : Alternaria helianthi

  • The disease is a destructive one, widely distributed wherever the crop is grown.
  • Severe reduction in seed and oil yield reported.
  • The most affected components are number of seeds per head and the seed yield per plant.
  • The disease also affects the quality of sunflower seeds by affecting germination and initial vigour of the seedlings.
  • The disease is characterised by the development of dark brown to black, circular to oval spots varying from 0.2 to 5 in diameter.
  • The spots are surrounded by necrotic chlorotic zone with grey white necrotic centre marked with concentric rings.
  • Spots first appear on lower leaves, later spread to middle and upper leaves.
  • At later stages, spots may be formed on petioles, stem and ray florets.
  • Occurrence and severity of the disease depend on the season and planting dates.
  • Mid-September planting of sunflower remains free from the disease.
  • Foliar spray with 0.3 per cent Mancozeb four times at an interval of 10 days controls the disease.



  • TamilNadu Agritech Portal
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