Efficacy of Neonicotinoid Seed Treatments in Cotton on THRIPS And THRIPS Community Composition in Cotton in Texas

Seed treatments are common and effective pest control methods in many crop systems. Cotton seed treatments are often used for control of in ground and early season pests. A market shift in seed treatments to neonicotinoid formulations followed the phasing out of aldicarb (Temik®). Imidacloprid and thiamethoxam (Cruiser®) are two commonly used insecticide cotton seed treatments, but concern lies with the possibility of varying degrees of efficacy of these seed treatments on the different thrips species. 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), each of which exhibit different degrees of susceptibility to various insecticide formulations. To improve the use of neonicotinoid seed treatments against thrips in Texas cotton, it is necessary for us to better understand the thrips species composition across the state, as well as the impact of imidacloprid and thiamethoxam and seed treatments on those species. The evaluated locations include: Chillicothe, College Station, Corpus Christi, Halfway, Kress, Lamesa, Levelland, La Feria, Mercedes, Port Lavaca, Victoria, and Wall, Texas. These are representative samples of cotton growing areas of the high plains, rolling plains, and central Texas regions. Thrips populations were low in 2014 in Chillicothe, Lamesa, and Wall, but there were fewer thrips on plants grown from treated seeds for most sampling dates in College Station, Halfway, and Kress. Imidacloprid treated seed had a greater yield than the control in College Station, which was the only harvested location with thrips populations exceeding the economic threshold of one visible thrips per true leaf. Greenhouse evaluations of the thiamethoxam and imidacloprid seed treatments efficacy against western flower thrips were also conducted to lend a more controlled view of how well the insecticides work