Seasonal abundance of leafhopper, Amrasca biguttula biguttula (Ishida) and their relation to weather parameters in cotton

Abstract

In this study, field trial was conducted to determine the effect of ecological factors on the incidence and development of leafhopper, Amrasca biguttula biguttula Ishida of cotton at four different phases of plant protection between October, 2014 and March, 2015 at Agricultural College and Research Institute, Killikulam, Vallanad, Tuticorin district of Tamil Nadu. The overall mean population ranged from 0.90 to 3.79 per three leaves. The contribution of weather parameters to the tune of 47 to 53 per cent on the incidence of leafhopper in SVPR 4 cotton. The pest population was started from first week of November on three weeks old crop and peaked six times (4, 8, 12, 16, 18 and 20 WAS) in unprotected condition; five times during reproductive phase (4, 8, 16, 19 and 22 WAS); four times in vegetative phase protected plants (4, 10, 16 and 21 WAS) followed by three peaks (11, 15 and 20 WAS) on completely protected plants. Among the studied weather factors, only three parameters such as rainfall, evaporation and sunshine hours influenced the population of leafhoppers.