Grain Discoloration

• The grains may be infected by various organisms before or after harvesting causing discolouration, the extend of which varies according to season and locality.
• The infection may be external or internal causing discoloration of the glumes or kernels or both. Dark brown or black spots appear on the grains.
• The discolouration may be red, yellow, orange, pink or black, depending upon the organism involved and the degree of infection.
• This disease is responsible for quantitative and qualitative losses of grains.

Mode of Spread and Survival

• The disease spreads mainly through air-borne conidia and the fungus survives as parasite and saprophyte in the infected grains, plant debris and also on other crop debris.

• - Drechslera oryzae, D. rostratum, D.tetramera, Curvularia lunata, Trichoconis padwickii, Sarocladium oryzae, Alternaria tenuis, Fusarium moniliforme, Cladosporium herbarum, Epicoccum purpurascens, Cephalosporium sp., Phoma sp., Nigrospora sp.

• High humidity and cloudy weather during heading stage.

• Use of disease-free seeds that are selected from healthy crop.
• Seed treatment with carbendazim 2.0g/kg of seeds.
• Control insect pests.
• Removal and proper disposal of infected plant debris.

• In areas where the disease may cause yield loss, applying captan, captafol, fentin hydroxide, and mancozeb can be inhibited conidial germination.
• At tillering and preflowering stages, spraying of carbendazim fungicide and copper base fungicide can effectively control the disease.
• Pre and post-harvest measures should be taken into account for prevention of grain discolouration.
• Spray the crop at bootleaf stage with Mancozeb 1 kg or Iprobenphos 500 ml or Carbendazim 250 g/ha.
• Store the grains with 13.5-14% moisture content.