Correlation study of individual meteorological parameters and disease severity for prediction of pearl millet blast

Knowledge of epidemiology provides the basic information to develop efficient and workable plant disease control methods. Environmental factors play an important role to disease development. The various weather variables such as temperature (T), relative humidity (RH) and rainfall influence different parameters of infection process and disease development. Interaction between these weather variables (independent variables) and disease development (dependent variables) pave the way for the development of the prediction models. These diseases are being managed through chemical fungicides, but the efficiency of control measures depends upon the interaction between pathogen and host, which is influenced by environmental factors. Correlation studies showed significant and negative correlation with average maximum temperature (r = - 0.647*). In contrast to temperature, the maximum relative humidity and minimum relative humidity showed a significant positive relationship with the disease. The total rainfall showed a significant positive relationship with the disease (r = 0.668*) indicate that the blast severity increases with the increase in total rainfall. Development of pearl millet blast is favoured by temperature 30-35 oC, relative humidity 55-75% with intermittent rains (190-100mm) proved most effective for disease development. For greater efficiency, the disease-forecasting models must be developed by taking into account the crop variety, the prevalence of a particular pathotype and the different climatic factors.