Seasonal incidence of different insect-pests in Kharif maize

Abstract

A field study on population dynamics of different insect-pests of maize viz., maize leaf folder, Marasima trapezalis, maize aphid, Rophalosiphum maidis, maize cob borer, Helicoverpa armigera, pollen feeding beetle, Chiloloba acuta was conducted during Kharif, 2017 at Entomological Research Area of CCS Haryana Agricultural University, Regional Research Station, Uchani, Karnal. Results of the study revealed that M. trapezalis larval population was maximum (0.8 larvae/ plant) during 1st week of August (32th SMW). On the other hand, R. maidis population was maximum during 3rd week of September (38th SMW) with 17.1 aphid per plant. Infestation of H. armigera was first noticed during 35th SMW and attained a peak value of infestation (3.9 %) during 38th SMW. Similarly, C. acuta population was also maximum (1.5 beetle/plant) during 38th SMW. Correlation of insect-pests population with environmental factors and plant age (in days after germination) revealed that larvae of M. trapezalis exhibited significant positive correlation with evening relative humidity, rainfall whereas it was negatively correlated with maximum temperature and plant age. R. maidis, H. armigera and C. acuta population was negatively correlated with minimum temperature, evening relative humidity and rainfall whereas it was positively correlated with plant age (DAG) stating higher infestation in later stages of crop growth.