Population dynamics of insect pests in rice ecosystem

Abstract

Investigations on major insect pests in rice was carried out at the Agricultural Research Farm, Banaras Hindu University, Varanasi during kharif 2017-18 and 2018-19. Observations on Scirpophaga incertulas incidence revealed that deadhearts and white ears were observed to be maximum during 1st week of October (40thSMW) and 3rd week of November (47th SMW), respectively. Likewise, Cnaphalocrocis medinalis was observed during 1st week of August (31st SMW) with maximum incidence being in the 1st week of October (40th SMW) with 11.39% damaged leaves/ 10 hills. Nilapravata lugens appeared from 2nd week of August (33rd SMW) and attained its peak in 1st week of October (40th SMW) as 17.33/ 10 hills. The maximum incidence of Nephotettix virescens was observed in the 4th week of October (43rd SMW)-15.67 insects/ 10 hills. The activity of Leptocorisa acuta commenced from 3rd week of October (42nd SMW) and reached its peak during 3rd week of November (47th SMW-14.67/ 10 sweeps in nets). Correlation analysis revealed that the rainfall and evening RH exhibited a negative impact on S. incertulas, C. medinalis, N. lugens, N. virescens and L. acuta; minimum and maximum temperature, and morning RH, showed both positive and a negative impact on these insect pests of rice. © 2021, The Entomological Society of India. All rights reserved.