Epidemiological Study of Myrothecium Leaf Blight Disease of Cotton

Cotton is one of the most important commercial crops which is mostly valued for its natural fiber. The diseases of cotton of common occurrence in Odisha have been identified as Angular leaf spot or Black arm, grey mildew, Alternaria leaf spot, Root rot and Myrothecium leaf blight. The incidence of Myrothecium leaf blight is growing consistently throughout the country among all the foliar diseases. In a survey conducted, across different locations of Odisha, Myrothecium leaf blight had the highest incidence in Bhawanipatna at 16.0%, surpassing Anthracnose and Bacterial blight. In contrast, Rayagada recorded the lowest Myrothecium leaf blight incidence at 6.5%. The diseases caused by Myrothecium roridum are generally thought to be associated most frequently with warmer environments during wet conditions. The disease increased progressively from 35th meteorological week and reached its peak during 41st Standard Meteorological Week with a maximum Percent disease Incidence of 46%. The meteorological parameters such as Temperature(maximum), relative humidity(morning), number of rainy days and bright sun shine hours showed highly significant positive correlation with PDI.