The effect of fluorescent tracers on droplet spectrum, viscosity, and density of pesticide formulations

Abstract

The most important factor affecting efficacy and drift of pesticide applications is the droplet spectrum. To measure pesticide drift, researchers utilize fluorescent tracers to rapidly quantify spray deposition. Although fluorescent tracers have been used for more than 50 years, no experiments have been performed on the effect they have on the properties of pesticide formulations (density and viscosity) or droplet spectrum, which affect the drift of pesticides. Therefore, we examined the effect of an oil- and water-based tracer on the volume median diameter (VMD), viscosity, and density of oil- and water-based pesticide formulations. In addition, we experimentally fit and demonstrate the utility of using distributions to characterize pesticide droplet spectra. The addition of tracers to both water- and oil-based formulations did not significantly alter the VMD, viscosity, and density. Lognormal distributions provided the best fit for the water- and oil-based formulations with and without tracer. Our results demonstrated that the addition of oil- and water-based tracers do not significantly alter pesticide formulations properties and droplet spectrum, and most likely do not alter the movement of pesticide droplets in the environment.

Keywords:

• Distribution modeling
• droplet spectrum
• fluorescein
• pesticide
• spray drift
• Tinopal OB

Acknowledgments

We thank the Montana Department of Agriculture for providing the DC-III droplet analyzer. This study was funded by a grant from the USDA Western Regional IPM grant program, and by the Montana Agricultural Experiment Station, Montana State University, Bozeman, Montana, USA.

Notes

^a Standard error.

^a Standard error.