Vol. 14 No. 2
Effect of epidemiological factors on percent disease index of rose powdery mildew caused by Podosphaera pannosa (Wallr.) de Bary
Author(s): V. KUMAR AND S. CHANDEL
Abstract: The effect of epidemiological factors was studies on severity (disease index) of rose powdery mildew in cultivar Lutin during the years 2015 and 2016. The disease was first noticed in 2nd week of April in both the years and the disease index ranged from 6.92 to 48.76 per cent and 4.77 to 47.93 per cent in the year 2015 and 2016. respectively. There was a progressive increase in the disease severity upto 2nd week of June and was recorded maximum at this period during both years of study when the temperature remained 24.6 °C, cumulative rainfall (25.5 mm), mean relative humidity (61.5%) and total sunshine (4.6 hrs). Simple correlation between per cent disease index, temperature was 0.910, cumulative rainfall (-0.545), average relative humidity (0.616) and total sunshine hours (-0.760). While the partial correlation between per cent disease index, temperature was 0.475, cumulative rainfall (-0.872), average relative humidity (0.072) and total sunshine hours (-0.273). However, multiple regression equation indicated powdery mildew severity was dependent upon meteorological factors about 97.2 per cent for the disease development during both years i.e. 2015 and 2016.
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