Field Evaluation of Spinosad Aerial Applications for Thrips Control on Cotton1
2007
Martin, D. E. | Lóópez, J. D. | Hoffmann, W. C. | Fritz, B. K. | Lan, Y.
Aerially applied spinosad (Tracer®®) at 154 ml/ha was evaluated in a large-scale field study for thrips control in early season cotton and compared to conventionally applied dicrotophos (Bidrin 8®®) at 292 ml/ha. Larvae and adult thrips counts were significantly less than the untreated control across all sampling dates except for larvae per plant count at 1 DAT with dicrotophos and adult numbers at 7 DAT. The greatest percentage reductions of adult thrips occurred at 1 DAT when all aerial application treatments were significantly lower than the control. At 7 DAT, the three spinosad applications made with CP nozzles showed the greatest control for adults and reduction of larvae. There were increases in adult numbers in the electrostatic and rotary treatments of 41 %% and 10%%, respectively, over the control at 7 DAT. Based on spray droplet deposition data collected and thrips control obtained in this study, the optimum aerial application treatments were conventional hydraulic nozzles (CP-03) with a volume median diameter of 175 μμm at spray rates of 18.7 and 46.8 l/ha with Tracer®® as the active ingredient. The addition of an adjuvant did not have a significant effect on efficacy. Tracer®® provided as good as or better control of larval or adult thrips than the conventional application of dicrotophos.
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