Efficacy of pesticide seed treatments against wheat aphid and its effect on coccinellid predator and crop yield

Abstract

Field experiment was conducted to evaluate the effect of two neonicotinoid insecticides alone and in combination with fungicide (Tebuconazole) as a seed dressing for the control of aphids and their effect on coccinellids and yield of two wheat cultivars (ARRI-2011, Millat-2011). Results showed that at each observation date staring from January to March, significantly more aphids were present in the plots having control treatment compared to the plots where crop was grown with pesticides treated seed. Imidacloprid and actara alone and in combination with tebuconazole showed non-significant difference from one another in term of management of aphids at each observation date on both varieties. Results also showed that the plots having seed treated with imidacloprid and thiamethoxam have less number of coccinellids compared to those which received imidacloprid and thiamethoxam mixture with tebuconazole at each observation date. Significant more germination of both varieties treated with Hombre (267.67, 272.12 per m-2) and actara + tebuconazole (256.00, 260.44 per m-2) was observed compared to the seeds treated with imidacloprid, actara and control. Seed dressing with Hombre and actara + tebuconazole significantly increases the grains per spike and 1000 grain weight of two cultivars of wheat sown during 2015-2016. The strategy of using Hombre and actara + tebuconazole combinations as a seed treatment allowed easy application of pesticides, gave satisfactory and reliable control of wheat aphids and found to be safer to non-target organisms compared to the foliar application of pesticides.