Eye spot

Causal organism: Helminthosporium sacchari

• Usually a crop of 6 - 7 months is more susceptible to the disease.
• Fungus penetrates the host tissue either through stomata, bulliform cells or directly through the cuticle.
• Cloudy weather, high humidity with drizzle coupled with low night temperatures, wetting of leaves either through precipitation or dew greatly enhance disease development.
• Water logging, high fertility status and excess nitrogen fertilization also favour the spread of the disease.

Symptoms:

Lesions first appear as small water soaked spots, darker than the surrounding tissues. The spot becomes more elongated, resembling the shape of an eye and turns straw coloured within a few days. Finally, the central portion becomes reddish brown surrounded by straw coloured tissues. Then reddish brown streaks of a runner develop extending from the lesions towards the leaf tip along the veins. Later the spots and streaks coalesce to form large patches and causes drying of leaves.