Using weather information to identify pearl millet downy mildew risk environments in India

The relationship between prevalent weather and downy mildew (Sclerospora graminicola) incidence on pearl millet (Pennisetum glaucum; cultivars BJ 104, NHB 3, 5141B and J 104S) was determined using 3-5 years of weather data from Rajasthan, Karnataka, Gujarat, Andhra Pradesh and Maharashtra, India. The mean disease incidence in the pearl millet cultivars examined ranged from 40 to 82% across location and years. Cultivar NHB 3 recorded the highest disease risk percentage (77%), whereas cv. BJ 104 recorded the lowest (44%). Positive relationship was recorded for relative humidity and disease incidence 30 days after seedling emergence of BJ 104 in Karnataka and Rajasthan. However, the relationship was not consistent across genotypes over the different environments and years. The correlation between temperature and disease incidence were not significant for any location or year.