Seasonal incidence of key natural enemies of onion thrips, Thrips tabaci L. in relation to weather parameters in the Terai region of Uttarakhand, India

Abstract

Thrips tabaci, Lindeman (Thysanoptera: Thripidae) is the most serious pest on onion causing substantial yield losses. The present study aims to document the population dynamics of thrips and natural enemies in the Terai region of Uttarakhand, India. Observations were recorded during the crop growing seasons, ie. April 2021 and April 2022 and the continued till crop harvest. Spiders, Coccinellids, and Orius bugs exhibited distinct activity peaks. Temperature, rainfall (2021), and sunshine hours (2022) positively influenced spider populations. Conversely, morning and evening relative humidity (RH) during 2022 had a negative impact on the spider population. Coccinellids were positively affected by maximum temperature (second year), minimum temperature, and first-year rainfall, while RH negatively influenced them. Orius bugs responded positively to temperature and sunshine hours but were negatively affected by morning and evening RH.