Kannada Name: Kandu Chukke Roga

            Brown spot is a fungal disease that can infect both seedlings and mature plants. This disease is more severe in areas of poor management.

Period of occurrence: Seedling to maturity

Extent of yield loss: 50-90% in extreme cases

Collateral hosts: Digitaria sanguinalis, Leersia hexandra, Echinochloa colona, Pennisetum typhoides, Setaria italica, Cynodon dactylon.   

Favorable conditions for the pathogen

• Temperature of 25-30°C
• Relative humidity (>90%)
• Heavy and late north-east monsoon
• Cloudy days
• High doses of N

Mode of transmission/ dissemination: wind

Sources of inoculum: Seed, Collateral hosts, Rice straw or Stubble

Symptoms:

• On seedlings - Small, slightly elongated or circular brown lesions are observed on coleoptiles and black discoloration of the roots cause distorted seedlings.
• On leaves - Spots appear as circular to oval reddish brown lesions often surrounded by a yellow or gold halo.
• On glumes - Black or brown spots appear and in severe cases the greater portion of the glume may be covered by these spots causing black discoloration.  This reduces the market value.

Preventive measures:

• Use of resistant varieties - Rasi, IR 36, Jagannath.
• Proper crop nutrition
• Avoid water stress
• Clean cultivation

Chemical control: Seed treatment with Mancozeb 75WP @ 2.5 g or Iprodione 50 WP @ 2 g per kg of seeds

Control measures:

Chemical control

Recommended fungicides

 Note : Spraying is to be avoided during the period of flowering.