Effect of abiotic factors on incidence of leaf folder, Cnaphalocrocis medinalis (Linnaeus) in rice ecosystem of Varanasi region

The present investigation was conducted on submergence rice variety Swarna sub-1 to study the effect of abiotic factors on the incidence of leaf folder, Cnaphalocrocis medinalis (Linnaeus) during Kharif season of 2016-17 and 2017-18 at Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi. The infestation of leaf folder was noticed in the field from 31st SMW to 41st SMW during both years of investigation. The maximum leaf damage was recorded in 41st standard meteorological week (SMW) (11.76 %) during Kharif 2016. And 11.10 per cent leaf damage was recorded in 39th standard meteorological week (SMW) during Kharif 2017. The relationship between the population of leaf folder and weather parameters showed a significant positive correlation with maximum temperature (r= 0.549*) i.e. with an increase in temperature the population of leaf folder also increased and highly significant negative correlation with rainfall (r= -0.620**). Other parameters showed a non-significant positive and negative relationship with the leaf folder population.