A field experiment was conducted during rainy season of 1989 at the Agricultural College, Dharwad to study the appearance of disease, its intensity and rate of infection in eight dates of sowing, and also its relationship with weather conditions like temperature, relative humidity and rainfall. The disease appeared 56 days after sowing in the first date of sowing (8-6-1989) but early in later dates of sowing. The per cent disease index was significantly lower (30.82) on first sowing date than on later sowings (32.66 - 78,76). The grain yield was maximum (9.13 q/ha) on first sowing date than in later sowings (0.7.53 q/ha). The mean minimum temperature (19.33° - 19.74° C), mean relative humidity (87.04 -88.22%) and total rainfall (46.20 - 65.40 mm) favoured the development of the disease at faster rate and caused heavy infection at early stage in late sown crop. The disease first appeared on 3rd August in the first 3 dates of sowing and subsequently on 5th, 8th, 12th and 28th August in later dates of sowing respectively. The favourable conditions for the disease development appeared to be prevalent in August. The rate of spread per unit per day was high (upto 0.2478) in the initial stages of the disease but later there was gradual decrease (upto 0.0538) in spread till the maturity of the crop