Spray Mix Adjuvants for Spray Drift Mitigation

Numerous drift reduction adjuvants and spray deposition aids are available to applicators of crop production and protection chemicals. Performance of many of the newly introduced drift control adjuvants has not been well documented for aerial application. Since there are no product labeling or efficacy regulations for these adjuvants, applicators must rely on experience or information in the technical literature for evaluating their performance. Twelve new drift control adjuvants were selected for atomization studies in a wind tunnel to document their performance as applicable to aerial application. Spray droplet size is the primary factor that applicators can control to influence spray drift. Atomization performance of spray adjuvants in a wind tunnel is closely related to their performance under field conditions. The adjuvants were mixed in a blank emulsifiable concentrate tank mix at their maximum recommended label rate for aerial application. Atomization data were collected with a laser spectrometer on the first and eighth passes through a gear pump. The eighth pass simulates any effect of shear breakdown and loss of effectiveness of the adjuvant from bypass and recirculation in the spray tank during application. Most of the adjuvants move the droplet spectra classification from fine to medium. The most effective adjuvant moved the droplet spectra classification from fine to coarse. This performance information will aid aerial applicators in selecting drift reduction agents to meet the drift mitigation criterion for a given application.