ABSTRACT

Three studies were conducted in 2001 and 2002 to evaluate seed treatment insecticides for thrips control on BollGard and non-BT cotton varieties. In-furrow insecticide treatments of aldicarb (Temik 15G) and phorate (Thimet 20G), foliar sprays of acephate (Orthene 97AG) and lambda cyhalothrin (Karate Z), and hopper box seed treatments of acephate (Orthene 75S) were compared to commercial seed treatments of thiamethoxam (Adage in 2001,Cruiser 5FS in 2002) and imidicloprid (Gaucho 600 F). The tobacco thrips, Frankliniella fusca (Hinds), was identified as the primary species in these studies. In 2001 thiamethoxam treated seed gave three weeks of thrips control comparable to the aldicarb in-furrow treated cotton, but residual control declined by 5 weeks after planting. Foliar applications of either acephate or lambda cyhalothrin to the thiamethoxam treatments provided thrips control comparable to the aldicarb treated cotton. All insecticide treated cotton had significantly higher lint cotton yields compared to the untreated cotton. In the 2002 studies, thrips control with the seed treatments suppressed thrips for 3-4 weeks which was equal to the in-furrow treatments of aldicarb. The seed treatments needed one foliar spray of either acephate or lambda cyhalothrin to extend control for an additional three weeks which equaled the control of the in-furrow aldicarb. Because of excessive fall rain and poor harvest conditions, cotton yields in the 2002 studies did not reflect the effects of thrips control.