An EAn Evaluation of Insecticide Seed Treatments Against Thrips in Southern Australiavaluation of Insecticide Seed Treatments Against Thrips in Southern Australia
Mar 21, 2019
Thrips (Thrips tabaci and Frankliniella schultzei) are common seedling pests of Australian cotton crops. They are controlled using insecticide seed treatments, soil applied insecticide granules or foliar insecticides. To assess the relative value of these control options, their efficacy was assessed in the field. The yield response of cotton was also assessed to indicate the effect of thrips damage on yield. Cotton protected with thiodicarb, imidacloprid, or a combination of thiodicarb and fipronil, applied as seed treatments was compared with that protected by in-furrow applied aldicarb granules and with untreated seed. Replicated experiments were carried out on commercial cotton farms at 14 sites throughout Australia over 2 seasons. Experiments were unsprayed through the early season, when thrips were present, but after that, insect pests were managed according to best commercial practice. Varieties expressing the Cry 1Ac protein were used to minimize potential confounding effects due to damage by Helicoverpa spp. Aldicarb provided the best control of thrips, followed by imidacloprid, fipronil and thiodicarb. Yield increases were recorded at only 4 of the 13 sites harvested. The magnitude of the yield increase from thrip control appeared to be related to the seasonal abundance of thrips, the growing conditions and treatment efficacy.