INFLUENCE OF WEATHER VARIABLES AND AGE OF PLANT ON COTTON LEAF CURL DISEASE (CLCuD)

Abstract

The behaviour of cotton leaf curl disease (CLCuD) and weather variables were studied using three genotypes, planted each year at15 days intervals during 15th to 23rd standard (std.), week of 2010-2012. Three genotypes viz. CIM-573, CIM-496 and CIM-608 (2010) and CIM-554, CIM-591 and CIM-608 (2011) and CIM-591, CIM-612 and CIM-573 (2012) respectively, were planted in split plot. Weather parameters such as maximum, minimum temperatures and relative humidity were recorded. On an average basis of cultivars, the 15thstd. week planting showed significantly less disease incidence than all other sowing dates. The incidence increased as the sowing was delayed up to 23rdstd. week. Among the sowing dates, regardless of genotypes, disease incidence differed significantly. The CLCuD boost up during 25th to 27thstd. (2010) and 27th to 31st std. (2011& 2012) weeks of the year, regardless of sowing date and genotypes. Averaged across sowing dates, minimum disease incidence was observed in CIM-608 (2010 & 2011) and CIM-612 (2012) which was lower than all other strains. All other interactions were non-significant statistically. The disease increased sharply during 2010 and gradually during 2011 and 2012. Disease incidence was low during 2011 and 2012 as compared to 2010. Average maximum, (34.8~39.8°C, minimum (27.7~28.9°C) temperature and relative humidity (51~79%) favored CLCuD progression.