Seasonal variation in major insect pests incidence on rice and impact of various abiotic factors on their incidence under Varanasi conditions

Abstract

An experiment was carried out under field conditions at the Agricultural Research farm of Institute of Agricultural Sciences, Banaras Hindu University, Varanasi to study the seasonal abundance of major insect pests of rice, during kharif, 2014-15. Incidence of yellow stem borer was started from last of July with its peak during second week of October and showed a positive significant correlation with evening and average humidity and a positive non-significant correlation with morning humidity and rainfall. BPH appeared in rice crop during first week of August and reached at highest level during 2nd week of October. Later on the population decreased as the crop reached the harvesting stage. The correlation analysis of Brown plant hopper revealed a positive non-significant correlation with rainfall, temperature and relative humidity. The incidence of leaf folder infestation was commenced during first fort night of August and the larval population increased gradually till 38th week with 10 larvae/ 10 hills. Gundhi bug was first observed during 2nd week of September and showed a positive non-significant correlation with morning RH and negative non-significant correlation with temperature.