With fewer agrichemical compounds and molecules being discovered by private industry, innovative ways of using current modes of action and application technologies are not only necessary but imperative to maintain and improve pest management strategies. This research was conducted during 2019 and 2020 at the Edisto Research and Education Center in Blackville, SC. The objective was to determine if sprayer droplet size (150-900 μm) had an impact on the efficacy of a standard insecticide used to control tobacco thrips, Frankliniella fusca (Hinds), in cotton, Gossypium hirsutum (L.). Three separate fields were used where 1- to 2-leaf cotton was sprayed with Orthene 97SG (acephate) applied at a rate of 197 g ai ha-1 to control thrips. Treatments consisted of droplet diameters of 150, 300, 450, 600, 750, and 900 μm. In 2019, acephate applied at a droplet size of 450 μm resulted in the greatest number of thrips on cotton 3 days after application (DAA) when compared with all other droplet sizes. Visual injury ratings at 3 DAA were greater on cotton where acephate was applied at 300-μm droplets when compared with other droplet sizes. In 2020, acephate applied at a droplet size of 150 μm resulted in the lowest number of thrips on cotton at 14 DAA when compared with all other droplet sizes. Based on these results, South Carolina cotton farmers might have more flexibility in nozzle selection and droplet size ranges when using acephate to effectively control thrips in cotton than previously hypothesized.
