Effect of Weather Parameters on Population Dynamics of Major Sucking Insect-pests and Their Natural Enemies of Soybean [Glycine max (L) Merrill]

Abstract

A two-year field trial was conducted during Kharif seasons of 2021 and 2022 at the Experimental Research Farm of Department of Entomology, School of Agricultural Sciences, Nagaland University, Medziphema campus on soybean variety JS 335 in order to study the population dynamics of major sucking insect-pests and their natural enemies in relation to weather parameters. Randomized Block Design (RBD) with three replications was used for the study. Three major sucking insect-pests namely, aphid (Aphis glycines Matsumura), whitefly (Bemisia tabaci Gennadius) and pod sucking bug (Riptortus pedestris Fabricius) and one coccinellid predator (Coccinella transversalis) were recorded during the various growth stages of the crop. In both the seasons of investigation, the peak population of aphid (23.33 aphids/leaf in 2021 and 24.33 aphids/leaf in 2022), whitefly (23.67 whiteflies/leaf in 2021 and 21.67 whiteflies /leaf in 2022) and pod sucking bug (4.00 adults/mrl in 2021 and 4.33 adults/mrl in 2022) was observed on 35th, 33rd and 38th standard meteorological week (SMW), respectively. The population of ladybird beetle recorded was ranged from 0.22 to 1.75 beetles/mrl during kharif, 2021 and 0.16 to 1.83 beetles/mrl during kharif, 2022. The findings from this investigation gives a brief idea about the peak activity of the insects in a season and also the impact of weather factors on the major sucking insect-pests of soybean.