Role of Meteorological Parameters on Sheath Blight of Rice under different Planting Methods

Abstract

The field experiments were conducted during kharif 2012 and 2013 to study the incidence and severity of sheath blight (Rhizoctonia solani) in relation to meteorological parameters under different planting methods. The experiments comprise of three dates of transplanting (15th June, 30th June and 15th July), two rice varieties (PR-118 and PR-116) and two planting methods (furrow planting and conventional planting). Sheath blight incidence and severity were significantly lower in 15th June transplanted crop followed by 30th June table and 15th July during both the crop seasons and were significantly more in variety PR-116 as compared to variety PR-118. It was more in conventional transplanted crop as compared to bed transplanted crop. Correlation analysis showed that among all the meteorological parameters considered, maximum air temperature and morning relative humidity were key factors to govern this disease in the field. A maximum temperature around 34°C and a minimum temperature around 26°C were found to be favourable for the spread of sheath blight after its establishment in the field. High relative humidity (more than 90%) facilitates the spread of this disease. The disease incidence and severity were negatively correlated with maximum temperature, minimum temperature, evening relative humidity and rainfall and positively correlated with morning relative humidity and sunshine hours during both the crop growing seasons. Sheath blight incidence can be reduced by 8–9% by bed planting method.