Published on Tuesday, November 10, 2020
Enlist One® or Enlist Duo® 2,4-D choline are both very effective on glyphosate-resistant (GR) marestail, giant ragweed, and waterhemp. Just like glyphosate, Enlist One is a systemic herbicide, meaning coverage is not as crucial as it is with a contact herbicide. One approved tank-mix partner for Enlist One is Liberty®. The addition of Liberty provides two effective SOAs for GR marestail, giant ragweed, and waterhemp. When spraying Liberty alone, Beck’s Practical Farm Research (PFR)® data has shown a 12% increase in control when using a carrier volume of 20 GPA vs. 15 GPA. When Liberty is used with a systemic herbicide, PFR data has shown a 14% increase in waterhemp control when Liberty + glyphosate carrier rate was increased from 15 GPA to 20 GPA. This showcases how critical carrier rate is, even when Liberty is tank-mixed with a systemic herbicide. In this example, the waterhemp population was suspected to be resistant to glyphosate, resulting in limited control from the systemic herbicide. The results below detail what happens to carrier rate if Liberty is tank-mixed with an effective systemic herbicide, such as Enlist One.
The two systemic herbicides (Enlist One + glyphosate) resulted in less variation across the spray rates and were not as impacted by spray coverage. At greater spray volumes, Enlist One® + Liberty® helped increase Liberty coverage. Yet, at lower spray volumes, waterhemp control was less with Enlist One + Liberty than with Enlist One + glyphosate. Why? Liberty performs better with smaller droplets, but Enlist One requires nozzles with spray tips that create larger droplets and maintain a specified pressure range. Therefore, TTI nozzles, which produce large droplets, were used in the demonstration plots. Spraying Liberty at 10 GPA with a TTI nozzle is going to result in poor control.
Enlist One + Liberty control was lower than Enlist One + glyphosate at 10 GPA. This could be due to how quickly Liberty works in the plant compared to Enlist One or glyphosate. In theory, the larger droplets at 10 GPA burned the leaves and never allowed the full concentration of Enlist One to enter the plant. By increasing the spray volume, Liberty is more effective with the Enlist One even when using larger droplets. The 2,4-D choline in Enlist One has no activity on grass, so adding Liberty or glyphosate to the tank mix is critical for grass control. Note, Liberty grass control will be lower compared to glyphosate. Just like Liberty alone, spray volume will play an important part when spraying Enlist One + Liberty.
Author: Joe Bolte
Categories: Agronomy, Agronomy Talk