Brown Spot and Its Control

• The brown spot disease is caused by the fungus (Cochliobolus miyabeanus).

• The disease can be infected starting from the seedling stage.

• The lesions on the infected leaves can cause dark spots on the leaves, grains and rice husks, and leading to market losses and also affecting consumption.

Symptom

• The symptom mainly occurs on the grains and the leaves.

• The disease appears with the brown dots as the size of sesame seed on the leaves. First, the spots are brown in color and later, the spots enlarged becoming oval shape with dark brown margin and grayish center.

• The disease spreads also on the rice seeds.

source : Lucid central and IRRI

 

Disease Cycle

• The infected seeds are the main cause of infection.

• Possible infection from the soil because, the infected fungus survives in the infected plant residues and in soil for 2-3 years.

• The disease also spread through the air from the infected fields.

Good Practices for Control

• Use disease-free seed after prior inspection.

• Seed soaking in hot water (53-54°C) for 10-12 minutes may eliminate the seed-borne fungus as first stage.

Chemical Control

• Seed treatment- Use the fungicides such as iprodione, propiconazole, azoxystrobin, trifloxystrobin, and carbendazim as per recommended rate.