Impact of weather factors on the seasonal incidence of sapota leaf webber, Nephopteryx eugraphella Ragonot

Abstract

Studies on seasonal incidence of leaf webber, Nephopteryx eugraphella Ragonot (Lepidoptera : Pyralidae) were carried out at new orchard, Agriculture College, Dharwad and Saidapur farm, KVK, Dharwad, University of Agricultural Sciences, Dharwad, Karnataka during 2013–2014. Observations were recorded from four sapota genotypes viz., Cricket ball, Kalipatti, DSH-1 and DSH-2. The incidence of pest was high (2.27 to 3.79%) during August to November. Whereas it was low (0.00 to 1.58%) during December to July. The percentage of damaged leaves on four different genotypes of sapota was high (2.17%) on Cricket ball and it was low on DSH-1 (1.35%).The overall mean percentage of damaged leaves irrespective of the genotypes varied from 0.00 (May) to 3.79(October). The correlation studies of leaf webber with weather parameters showed that there was a positive correlation between leaf webber damage and maximum temperature in DSH-2 hybrid similarly minimum temperature had positive correlation in Cricket ball and DSH-2 hybrid. The morning relative humidity had positive and significant correlation with leaf webber incidence in Cricket ball, Kalipatti, DSH-1 and DSH-2. The evening relative humidity showed positive and significant correlation with leaf webber incidence. There was a positive correlation between rainfall and leaf webber incidence in all the genotypes except DSH-2 hybrid grown in new orchard, College of Agriculture, Dharwad.