Published on Friday, November 5, 2021
Coverage is king with Liberty®. However, when tank-mixed with Enlist One®, how does nozzle type, orifice size, and PSI restriction change our Liberty management? Products like Enlist One are systemic herbicides, so coverage is not as crucial compared to contact herbicides like Liberty. With Liberty, we strive to have medium droplets to ensure proper coverage. However, tank-mixing Liberty with Enlist One will restrict our droplet size from medium droplets to coarse and ultra-coarse droplets. Applications of Enlist One require a specific PSI as well as nozzle. These restrictions result in different management practices vs. applying Liberty by itself, or Liberty with glyphosate. Enlist One + Liberty provides very effective control of glyphosate-resistant waterhemp. It’s key to understand these management practices if planning to utilize this tank-mix. Beck’s Practical Farm Research (PFR)® data has shown an advantage to Enlist One + Liberty over Enlist One + glyphosate for waterhemp control.
CORRECT CARRIER VOLUME
Two-year PFR data has shown an advantage when Enlist One + Liberty is applied at higher carrier volumes. Utilizing a TeeJet® AIXR nozzle at 20 gal./A. resulted in 95% control of waterhemp and 82% control of fall panicum by 28 DAT. Increasing the carrier rate from 10 gal./A., to 15 gal./A. showed an increase in waterhemp control by 21%, whereas 20 gal./A. waterhemp increased control by 23% using an AIXR nozzle. Liberty is weaker on grass, so coverage had a large impact on fall panicum as well. Enlist One is a Group 4 herbicide and will have no grass control. Enlist One + Liberty never resulted in greater than 82% control of fall panicum. However, by increasing carrier volume from 10 gal./A., fall panicum control increased by 13% (15 gal./A.) and 25% (20 gal./A.) using an AIXR nozzle.
CORRECT NOZZLE SELECTION
The Enlist One® label requires specific nozzles and PSI ranges; examples include the TeeJet® AIXR (coarse) and Turbo TeeJet® Induction (TTI™) - (ultra-coarse) nozzles. The plots below received only a post-emergence application to ensure enough weed vegetation was present at the application timing. Enlist One is a systemic herbi cide, and coverage typically is not as crucial, but due to the thicker vegetation, spray coverage was still key. Compared to a TTI nozzle at 10 gal./A., the AIXR nozzle increased waterhemp control by 12% and fall panicum control by 5%. By increasing spray volume to 15 gal./A. and utilizing an AIXR nozzle, Enlist One + Liberty® resulted in greater than 90% waterhemp control. Even at 15 gal./A., we could still see a visual difference between an AIXR and a TTI nozzle. W ith the TTI nozzle and a carrier rate of 15 gal./A., Enlist One + Liberty r esulted in a reduction of both waterhemp and fall panicum control by 10% compared to the AIXR nozzle. A spray volume of 20 gal./A. resulted in the greatest waterhemp and fall panicum control, but we saw less response to nozzle selection. Compared to a TTI nozzle at 20 gal./A., Enlist One + Liberty sprayed with an AIXR nozzle, increased both waterhemp and fall panicum control by 2%.
To maximize the efficacy of Enlist One + Liberty, we must spray at 20 gal./A. Nozzle selection at higher gallons per acre was not impacted because the carrier volume was able to overcome the larger droplets produced by a TTI nozzle. As we lower our carrier volume to 10 and 15 gal./A., we do not have as much coverage. Therefore, we start to see a larger separation in control with a TTI nozzle vs. an AIXR nozzle. For the greatest success, spray Enlist One + Liberty at 20 gal./A. with an AIXR nozzle.
Canopy closure is one of the best defenses to prevent the germination of weeds. Reducing the amount of sunlight reaching the soil will make it much more difficult for weeds to germinate. In regards to row width and a successful herbicide program, the residual needs to last until canopy closure, which may not occur with wider rows. Narrower rows allow faster canopy closure. It’s crucial to make a pre-emerge herbicide application with multiple SOAs in 30 in. rows so that canopy closure can be reached before the residual herbicide begins to break.
Author: Jim Schwartz
Categories: Agronomy, Agronomy Talk
Tags: Agronomy, Herbicide, weed management