INFLUENCE OF ENVIRONMENTAL FACTORS ON DEVELOPMENT OF DOWNY MILDEW (SCLEROSPORA GRAMINICOLA) IN PEARL MILLET

The present study was undertaken during kharif, 2022 to find out the effect of different weather variables on the development of downy mildew in pearl millet. The data of downy mildew incidence for consecutive one year revealed that the mean weekly disease incidence in 7042 S ranged from 5.45 to 81.82 per cent indicating the highly susceptible response. The second fortnight of August to the first fortnight of September can be considered as window period for downy mildew incidence. The disease incidence in cultivar 7042 S was correlated highly significantly and positive correlation with maximum temperature (r = 0.753**), highly significantly and negative correlation with total rainfall (r = -0.744**). Evening relative humidity (r = -0.602*), morning relative humidity (r = -0.625*) and rainy days (r =-0.624*) was significant and negatively correlated with downy mildew incidence. The minimum temperature showed non-significant and negative correlation (-0.309) with downy mildew disease incidence. It has been observed that multiple correlation (R) value 0.941 indicating a strong association between per cent disease incidence and weather parameters. The co-efficient of determination (R2 ) of 0.886 proved the significance of overall regression model accuracy. Predict the occurrence of downy mildew with R2 = 0.886, indicating that all weather parameters contributed 88.6 per cent towards disease development.