Role of Weather Parameters on Development of Early Blight of Tomato Caused by Alternaria solani

The field experiment as conducted to study on the influence of weather parameters on the intensity and development of early blight of tomato during Rabi, 2018–19 and 2019–20 at Agriculture Research Station, Gunjevu, Holenarasipur taluk, Hassan district. The epidemiological studies clearly revealed that per cent disease index (PDI) progressing at a linear rate as the growth of the plant advances and weather parameters like minimum temperature, evening relative humidity, morning relative humidity rainfall, number of rainy days found significant and in negative correlation with disease development. The multiple linear regression analysis clearly revealed that coefficient of multiple determinants (R²) was 0.94 indicating that these weather factors responsible up to an extent of 94.00 per cent for early blight diseasedevelopment. The regression equation also reveals that increase in 1 per cent of morning relative humidity the PDI increased by 0.446%. While, when there was increase in 1° C of minimum temperature the per cent disease severity decreased by 12.606 per cent.