An epidemiological experiment was conducted on four varieties of mustard viz., RH-9801, RH-9304, RH-8113, and RH-30 sown on three staggering dates with an interval of 7–10 days. The analysis of disease progression with corresponding weather parameters revealed that disease progression was maximum during mid of March on all the four varieties in all the three staggering dates of sowing when weather parameters were Temp. (Max.) 32.5°C, Temp. (Min.) 12.7°C, RH (M) 94.5 per cent, RH (E) 38.5 per cent, Avp. (M) 12.30mm, Avp. (E) 14.30 mm, wind speed 2km/hr and sunshine 8.80 hrs. Disease intensity and AUDPC increased from 48 to 74 per cent and 326 to 440, respectively with delay in date of sowing. The apparent infection rate was also higher during mid of March on all the four varieties in first and second dates of sowing.
Weather parameters, rapeseed-mustard, powdery mildew progression, disease intensity, apparent infection rate, AUDPC
