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Evaluation of Aerial Application Rates and Drop Sizes for Control of Thrips on Cotton By D. Lopez, Jr., D.E. Martin, W.C. Hoffmann, B.K. Fritz, Y. Lan Contact: Juan D. Lopez, Jr. email: j-lopez@tamu.edu Summary: Several thrips species can be serious pests of cotton depending on early-season growing conditions. Lower temperatures associated with cloudy conditions that delay plant growth are especially conducive to damage. Feeding by these insects on plant terminals under these conditions can result in delayed and abnormal plant growth. Although in-furrow or seed-applied insecticides may prevent this damage, broadcast insecticide applications are sometimes needed as rescue treatments when below-ground insecticidal activity is inadequate. Aerial insecticide applications are an option when large areas need to be treated over a short period of time or when soil conditions do not allow ground applications. Field evaluations at the lowest recommended rate of spinosad (Tracer®) applied with Micronaire and CP-11TT nozzles at 2 and 5 GPA with small and large drops were conducted in 2005 and 2006 in commercial cotton fields. Insecticide deposition was measured with water sensitive cards, individual plant samples, and Mylar cards while thrips densities were determined by washing individual plants in ethanol and counting immature and adult thrips per plant pre- and post-treatment.
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