- While 2,4-D is not a new herbicide, its application post emergent to soybeans is relatively new.
- The Enlist E3™ trait confers tolerances for post-emergent applications of glyphosate, 2,4-D Choline and glufosinate, for control of problematic, tough-to-control weeds.
- Enlist™ soybeans are another useful tool with flexibility for in-crop control of herbicide resistant weeds like waterhemp and marestail.
- Following the application stewardship guidelines regarding weed height, spraying techniques, approved tank mix partners and growth stage cutoffs, is paramount to the success of this technology.
The Federal Environmental Protection Agency (EPA) approved the use of Enlist One® and Enlist Duo® in Enlist E3® soybeans through the 2028 growing seasons. This will allow for over-the top use of these products in Enlist E3® soybeans to manage tough-to-control weeds such as waterhemp and marestail. With new federal registrations come some additional restrictions for the upcoming growing seasons. The new label restrictions will ensure a safe and effective application address concerns from previous labels. The labels of Enlist® products have a few additional guidelines regarding weed height, application techniques, and approved tank mix partners and adjuvants.
Two formulated 2,4-D products are approved for use on E3 soybeans; Enlist One® Herbicide with Colex D Technology and Enlist Duo® Herbicide with Colex D Technology. Enlist One® is a straight product containing 2,4-D choline. This is an improved, lower volatility formulation compared to older formulations. Enlist Duo® is a premix of 2,4-D choline and glyphosate. To obtain optimum weed control on herbicide-resistant species like waterhemp and marestail and reduce selection pressure on one herbicide site of action, glufosinate (ex: Liberty®, Legrium™, Interline®) can be tank mixed with Enlist One®. However, glufosinate formulations are not labeled tank mix partners with Enlist Duo®.
Weed height: The labels of Enlist One® and Enlist Duo® herbicides permit spraying weeds up to four inches in height. The smaller the weed, the easier it is to manage. If weeds are taller than four inches, the desired level of control may not be reached. This ultimately may reduce weed control and expedite the evolution of resistance to these new 2,4-D formulations.
Application techniques: One of the biggest goals of all pesticide sprays is to apply the product to the target field and avoid movement to non-target fields/areas. To limit the potential for off-target movement of spray particles, it is extremely important to fully understand the label requirements for Enlist One® or Enlist Duo®. The language regarding buffers, nozzle selection, boom height, wind speed, and environmental conditions must be followed as listed on the herbicide label. By choosing a nozzle that limits fine droplets, keeping the boom low, spraying within the target wind speed, and making applications when a temperature inversion is absent, you will greatly reduce the risk of off-target movement and ultimately acquire greater weed control.
Approved tank mix partners/Rates: Always read the Enlist One® and Enlist Duo® labels to see which products and adjuvants can be mixed. For a product to be approved with Enlist One® or Enlist Duo, it cannot increase particle drift or negatively influence the application in any way. Remember that he Enlist One® use rate is 2 pt/A and the Enlist Duo® use rate is 4.75 pt/A. Check the website for the products and adjuvants you intend to use and only use approved tank mix partners.
Mixing Sequence: The mixing order is crucial to having a homogenous spray solution when mixing Enlist One® with glyphosate or Liberty®. Add each product individually and flush with water prior to adding the next product. If tank-mixing Enlist One® with glyphosate and Liberty®, add each product individually in this order: 1) Enlist One®, 2) flush with water 3) add glyphosate, 4) flush with water 5) add Liberty®. Always remember to sequence mix and not batch mix.
Growth Stage Cutoff: Enlist One® and Enlist Duo® herbicides can be applied post -emergence up through the R1 growth stage (first open flower). When tank-mixing approved tank mix partners, be sure to follow the most restrictive label.
Runoff Mitigation Measures: Applications should take place no less than 48 hours prior to irrigation or predicted rainfall that may result in field runoff. To manage runoff in the most practical manner, mitigation measures created on a credit system based on the soil type are needed to be in place prior to the application of Enlist® products. Examples of mitigation measures are: 1) Residue/tillage management, 2) Cover crops, 3) Contour buffer strips/terraces and 4) Reduction in the number of applications. Each measure is worth a specific number of credits. For example, a sandy clay loam soil will need a minimum of 4 credits. That credit could be achieved by reducing applications from 3 to 2 in a year (2 credits) and having a 30 ft wide vegetative buffer strip on the down slope side of the field (2 credits). See the table below for more information.
Before making any applications, be sure to fully read and understand the herbicide label. By following the label, we help to steward this technology for many years to come. If you have any questions about the Enlist® system or application parameters contact your local FS Crop Specialist.
Enlist Websites:
Enlist One Tank Mix Guide
Enlist Duo Tank Mix Guide
Enlist Application Guide