Plant growth stage: The infections start at late tillering to joint elongation stage and becomes severe at panicle differentiation.

Favorable conditions:

1. Warm temperature 28-32 D.C High humidity 95 percent.
   
2. Use of Nitrogen fertilizers.
3. Canopy (micro climate) formation with semi-dwarf rice varieties.

Pathogen survival: The pathogen is soil-waterborne and can survive as sclerotia (survival structures made of hyphae with stored food inside) for 2-3 years and reinfect rice plants in the subsequent planting. Dormant sclerotia floats on irrigation water travelling long distances leading to greater spread.