Role of date of seeding, soil moisture, temperature and pH in the incidence of downy mildew of Sorghum

Of the different dates of seeding tried, the last week of June proved to be the best time to avoid the incidence of downy mildew of Sorghum. The reduction in the yield of grain and fodder is directly proportional to the severity of the disease. The disease is suppressed considerably by an available soil moisture (ASM) of 76 to 79 per cent but favoured by an ASM of 44 to 47 per cent during the period of 16 days after seeding. Soil temperature of 26.6°C during this period appears to be the optimum for the disease expression. The pH of the soil is not altered by the incidence of the disease or by the growth of the crop.