The corn drift barriers were effective in reducing particle drift from applications with the ER11004 and the TTI11004 nozzles (Fine and Ultra Coarse spray classifications, respectively). The corn drift barrier had appropriate porosity and width as the airborne spray was captured within its canopy instead of deflecting up and over it. © 2018 Society of Chemical Industry.

The introduction of 2,4-D–resistant soybean and cotton provided growers a new POST active ingredient to include in weed management programs. The technology raises concerns regarding potential 2,4-D off-target movement to sensitive vegetation, and spray droplet size is the primary management factor focused on to reduce spray particle drift. The objective of this study was to investigate the droplet size distribution, droplet velocity, and particle drift potential of glyphosate plus 2,4-D choline pre-mixture (Enlist Duo®) applications with two commonly used venturi nozzles in a low-speed wind tunnel. Applications with the TDXL11004 nozzle had larger DV0.1 (291 µm), DV0.5 (544 µm), and DV0.9 (825 µm) values compared with the AIXR11004 nozzle (250, 464, and 709 µm, respectively), and slower average droplet velocity (8.1 m s−1) compared with the AIXR11004 nozzle (9.1 m s−1). Nozzle type had no influence on drift deposition (P = 0.65), drift coverage (P = 0.84), and soybean biomass reduction (P = 0.76). Although the TDXL11004 nozzle had larger spray droplet size, the slower spray droplet velocity could have influenced the nozzle particle drift potential. As a result, both TDXL11004 and AIXR11004 nozzles had similar spray drift potential. Further studies are necessary to understand the impact of droplet velocity on drift potential at field scale and test how different tank solutions, sprayer configurations, and environmental conditions could influence the droplet size and velocity dynamics and consequent drift potential in pesticide applications.

Improper or suboptimal application techniques can cause decreased weed control and increased environmental contamination. Droplet size is a key factor in pesticide applications in regard to both drift and efficacy. Droplet size can be altered by several application parameters, such as nozzle type, pressure, orifice size, and spray solution. The objective of this study was to evaluate the influence of nozzle type, application speed, and pressure when using glyphosate, dicamba, or glyphosate plus dicamba on droplet size and control of common lambsquarters, velvetleaf, kochia, and grain sorghum. The study was conducted with two herbicides, glyphosate at 0.77 kg ae ha−1 and dicamba at 0.56 kg ae ha−1, tested alone and in combination. The application rate was 94 L ha−1 at three different speeds (8, 16, and 24 kph), and the pressures used were low, medium, and high for each speed and orifice size combination. The pressures were combined with the appropriate orifice size to deliver a fixed spray volume. An XR, AIXR, and TTI nozzle were used (two of which are venturi nozzle designs). The droplet size ranged from 219 to 232 µm for the XR nozzle across the three solutions, 440 to 482 µm for the AIXR nozzle, and 740 to 828 µm for the TTI nozzle. Solutions using dicamba resulted in the largest droplet size, followed by glyphosate and then the combination. There were no significant interactions for nozzle × herbicide across all species.