SEASONAL INCIDENCE OF MAJOR LEPIDOPTEROUS INSECT PESTS OFRICE (oryza sativa L.)

摘要

A field experiment was carried out to investigate the population dynamics and impact of major lepidopterous insect pests of rice ecosystem under unprotected conditions of Varanasi region. The results revealed that the incidence of yellow stem borer ranged from 0.8% (last week of June, 2016) to 9.11% (Last week of August, 2016)/ per 10 hills. The peak incidence in leaf folder population was noticed during third week of September, 2016 (15 lervae per 10 hills). Among the weather parameters, mean temperature showed a significant positive correlation with dead heart, significantly negative correlation with white ear head and negative correlation with leaf folder. Relative humidity showed a significantly positive correlation with dead heart. Rainfall showed a positive correlation with dead heart and leaf folder. The statistically significant values indicated that occurrence of insect pests population was due to the prevailing favourable ecological conditions. Thus the management of yellow stem borer andrice leaf folder during kharif sown rice should be initiated from third week of July onwards using an integrated approach.