Efficacy of neonicotinoid seed treatments on thrips in cotton

            Following the discontinuation of the popular aldicarb insecticide (Temik^®), neonicotinoid seed treatments are the choice for management of thrips and any early season insect pests in cotton. Currently, imidacloprid and thiamethoxam are two commonly used neonicotinoid insecticide seed treatments commercially available in cotton. The common thrips species that infest cotton seedlings are tobacco thrips (Frankliniella fusca), flower thrips (Frankliniella tritici), western flower thrips (Frankliniella occidentalis), and onion thrips (Thrips tabaci), and each of these species exhibits different degrees of susceptibility to insecticide formulations. It is necessary to evaluate the thrips species composition in Texas cotton, as well as the impact of imidacloprid and thiamethoxam seed treatments on the thrips populations. A total of eight replicated trials have been planted across different regions of Texas to evaluate the efficacy of imidacloprid and thiamethoxam seed treatments along with the application of acephate at economic threshold. The overall objective is to compare the efficacy among the treatments and estimate economic value for each of the treatments in terms of lint yield production. Parameters such as damage rating, number of adult and immature thrips and delay in crop development will indicate the efficacy of seed treatment chemicals and resultant response of plants to thrips injury. Documenting species composition would partially explain if there is any difference in efficacy of the two seed treatments, especially given the report of thiamethoxam tolerant thrips populations in mid-south cotton production region.