A complex of thrips species infests seedling stage cotton, Gossypium hirsutum (L.), in the southern United States. Preventive control tactics are recommended to manage early season infestations, but foliar insecticides may be necessary to prevent injury for the duration of seedling development. The objective of this work was to compare efficacy of spinetoram to that of spinosad and current standard products, and to define the minimum effective spinetoram rate for satisfactory control of thrips. Foliar applied insecticides were applied with and without a surfactant against varying thrips infestation levels in field plots. Results demonstrated that infestations comprised primarily of tobacco thrip, Frankliniella fusca (Hinds), were more sensitive to spinetoram than spinosad at equivalent rates of active ingredient. Spinetoram applied at 13.0 to 26.0 g a.i./ha provided control comparable to commercial standards under moderate infestation levels. Consistency and numerical increases in efficacy were observed when applying spinetoram (13.0 g a.i./ha) with a surfactant. Efficacy of spinetoram at 13.0 g a.i./ha in combination with a surfactant was confirmed against onion thrips, Thrips tabaci (Lindeman), and in commercial scale plots. Spinetoram alone was not adequate for managing extremely high (>269 fold greater than a threshold of one thrip per plant) populations of tobacco thrips. These experiments demonstrate that spinetoram, applied at 13.0 to 26.0 g a.i./ha, has utility in the management of thrips infesting cotton seedlings.
