INFLUENCE OF WEATHER PARAMETERS ON THE INCIDENCE OF ROOT ROT (MACROPHOMINA PHASEOLINA) DISEASE IN MULBERRY

Root rot disease caused by M. is the major disease in mulberry. The study was conducted in 50 mulberry gardens covering 15 villages during the year 2012-13 by adopting random sampling method. The present survey was taken up in the viz., Coimbatore, Erode, , , , and to assess the incidence of root diseases. The environmental factors that most seriously affect the initiation and development of infectious plant disease are temperature and humidity of the air, amount of rainfall, soil temperature, moisture and fertility. These factors affect disease development through their influence on the growth and susceptibility of the host, on the multiplication and activity of the pathogen or on the interaction of host and pathogen relates to the severity of symptom development. Correlation studies have revealed that average temperature plays the key role in disease incidence invariably in all the locations studied except district, which had no correlation with any of the weather variables, studied. root rot incidence attained peak during a particular period of a month where weather parameters like Temperature, Relative Humidity, Rainfall, Soil Moisture, and Soil Temperature were favorable. The root rot incidence will be minimum if all these conditions are unfavorable. Seasonal analysis revealed that South West Monsoon season was the predominant season for root rot incidence in mulberry. All the locations had peak incidence during SWM season only. The least occurrence had no specific season as it occurs in all the remaining three seasons.