Brown Spot or Sesame leaf spot : Causal organism:Helminthosporium oryzae

(Sexual stage: Cochliobolus miyabeanus)

Symptoms

• The fungus attacks the crop from seedling to milky stage in main field
• Symptoms appear as minute spots on the coleoptile, leaf blade, leaf sheath, and glume, being most prominent on the leaf blade and glumes.
• The spots become cylindrical or oval, dark brown with yellow halo.
• The several spots coalesce and the leaf dries up.
• The seedlings die and affected nurseries can be often recognised from a distance by scorched appearance.
• Dark brown or black spots also appear on glumes leading to grain discoloration.
• It causes failure of seed germination, seedling mortality and reduces the grain quality and weight.