Comparison of an insecticide and its alternatives on cotton and soybean plants of two-spotted spider mite Tetranychus urticae in laboratory and field

Abstract

This study used a standardised method for bioassay on cotton and soybean plants to assess the relative toxicity of three chemicals: one known acaricides (Abamectin), one fungal extract (Aspergillus Niger extract), and one plant extract (Neem oil) against the eggs and adult females of two spotted spider mite Tetranychus urticae. The impact of sub lethal doses of these chemicals on some biological and behavioral aspects of the mite was also assessed. Abamectin occupies a unique position in mite chemical control or integrated mite management due to its high toxic effect and toxicity index, whereas neem extract was the least toxic compound to eggs and adult females T. urticae on two host plants. As a result, it could be recommended in IPM programmes. The impact on the mite's biological and behavioral characteristics. The results of the current investigation showed that abamectin was the most efficient chemical against the motile stages, whereas Aspergillus niger extract had a modest effect on T. urticae. The motile stages of the studied pest were less affected by neem extract. During the two seasons 2020-2021, all chemicals were successful in reducing the population density of motile stages of the spider mite, T. urticae, in lab and field trials.