Effect of meteorological parameters on incidence of brown leaf spot in rice crop under different planting methods

Abstract

The field experiments were conducted during three kharif seasons 2012, 2013 and 2014 to study the effect of meteorological parameters on brown leaf spot of rice under different transplanting dates, methods and plant population. The experiment was laid out in split-split plot design with two transplanting dates (15th June and 30th June) in main plots, three methods of planting (conventional, SRI and furrow) in sub plots and two plant population (625 and 300 plants per m2) in sub-sub plots with three replications. The brown leaf spot incidence was recorded at weekly interval from the start of its incidence. The incidence of disease (percentage) was higher under conventional planting (58.6 %) followed by SRI (52.3 %) than furrow planting (49.9 %). The disease incidence was 5 per cent higher in high plant population (625 plants m-2) as compared to lower plant population (300 plants m-2) mainly due 4.1 per cent higher relative humidity within canopy. The correlation analysis revealed that minimum temperature and evening relative humidity significantly affected the disease incidence. The regression model developed with 2012 and 2013 data had highly significant R2 values which was validated with 2014 data.

Effect of Agro-Met Conditions on the Progression of Brown Leaf Spot Disease in Basmati-370 Rice

“…In general, weather conditions that prevailed during the months of August, September and October were most favorable for the development of brown leaf spot disease. Multiple regression models were fitted for the prediction of disease severity under the given set of environmental circumstances because simple correlation did not show any significant relation between meteorological variables and disease progression.Similar results were observed by Dhaliwal et al (2018) who reported that relative humidity (morning) was positively correlated with brown spot severity. On the contrary, the temperature and disease severity was found negatively correlated with development of brown spot of rice.…”

Impact of different chemical fungicides on brown leaf spot of rice caused by Bipolaris oryzae and on yield under field condition

“…The fungicides Mancozeb and Zineb recommended earlier have been found insufficient for management of the brown spot disease. The favourable environmental conditions like temperature, relative humidity and rainfall during the rice season aggravate the severity of brown spot disease (Dhaliwal, 2018) [4] . Effective management of brown spot disease may be achieved by using resistant cultivars, fungicides, biological agent and cultural practices.…”