Check out this agronomy update from Austin Scott, Field Agronomist and Herbicide Specialist, to see how Beck’s 15 in. row population study is progressing at the PFR research plot in Murray Kentucky!

Aaron Brooker, Beck’s Hybrids Field Sales Agronomist, discusses late planting wheat management decisions for mid-November.

Applying Enlist One® + glyphosate at 10 gal./A. never resulted in greater than 70% (waterhemp) and 75% (fall panicum) control. However, by upping our spray volume from 10 to 15 gal./A., waterhemp control increased by 17%, and fall panicum control increased by 20%. Why did two systemic herbicides, Enlist One and glyphosate, have such a large response to carrier rate? Even though complete coverage is not as crucial, the herbicide must still reach each plant. Putting the Power in the Pre™ generally leads to reduced weed pressure and greater control; therefore, a pre-emerge was withheld from these demonstration plots to ensure enough vegetation was present at the time of the post-emerge treatment. When increasing from 15 to 20 gal./A., we saw less response with Enlist One + glyphosate vs. Enlist One + Liberty®. When Enlist One + glyphosate was applied at 20 gal./A. (compared to 15 gal./A.), waterhemp control only increased by 3% and fall panicum control by 1%. Note that in heavy vegetation scenarios, 20 gal./A. may still be needed with Enlist One + glyphosate.

XtendFlex® provides farmers the opportunity to utilize an approved dicamba formulation such as XtendiMax® or Engenia®, as well as Liberty® and glyphosate. Though some of our problematic weeds are resistant to glyphosate, there are several that glyphosate remains highly effective against. Glyphosate is also strong on many of the weeds that Liberty is weak on, such as cocklebur, velvetleaf, and grasses. Growth regulators such as Engenia or XtendiMax will be highly effective on broadleaf weeds but have no activity on grasses. The XtendFlex system allows farmers the opportunity to utilize Engenia or XtendiMax in the pre-emerge or early post-emergence application, providing short-term residual with no potential crop response. An additional option could include applying Liberty, separately, in-season to control any escaped weeds.

The Enlist™ system provides farmers the opportunity to utilize 2,4-D choline, Liberty®, and glyphosate. Beck’s Practical Farm Research (PFR)® data shows that utilizing multiple, effective SOAs in the pre-emerge resulted in less waterhemp for the post-emergence application to control. In 2021, Beck’s PFR set out to determine how the pre-emergence application impacted the post-emergence application and, conversely, how the post-emergence application impacted the preemergence application in Enlist E3® soybeans. The study was designed to evaluate various programs in the Enlist system targeting heavy, medium, and low waterhemp pressure.

The more we add to the tank, the more chances antagonism can occur, especially when we tank-mix contact and systemic herbicides together. The larger weeds become, the greater the chance antagonism will occur. Grass or volunteer corn herbicides like clethodim can have antagonism, especially when mixed with certain Group 15 herbicides. One way to overcome the antagonism is to increase the clethodim rate to 12 oz. (2 lb. ai. product)/A. Products such as Enlist One® and Liberty® are very effective on glyphosate-resistant weeds like waterhemp and giant ragweed. However, Enlist One + Liberty will be weaker on grasses compared to Enlist One + glyphosate. One solution would be to add clethodim, but antagonism can occur when tank-mixed with Enlist One.

Replant is always a difficult decision to make, but what is the best option to terminate a failed corn stand? One option could be tillage, but depending on the type of tillage and the growth stage of the corn, it may take two passes to achieve 100% control. The benefits of tillage would be not having a plant-back restriction compared to some chemical options that require plant-back restrictions. One disadvantage of tillage would be the impact on the residual herbicide. Pre-emerge herbicides act as a blanket, reducing weed emergence, but tillage can destroy this barrier.

Beck’s Practical Farm Research (PFR)® data suggests 60 lb. to 90 lb./A. of cereal rye can effectively suppress waterhemp compared to the untreated check. In addition to knowing the proper rate to seed cereal rye, we need to determine how to terminate it. Crimping can lay the cover crop down, creating a mat, resulting in effective weed control. The timing and growth of the cereal rye will impact the success of the crimping. For the best results, wait for the cereal rye to head out. If terminated too soon, the crimper will not be successful because the cover crop will recover and continue to grow. Using glyphosate for chemical termination opens the window to earlier applications but will not get the mat of cover as with a crimper. Both methods can be utilized. Spraying the cereal rye and waiting 24 hours to crimp will allow for herbicide uptake to occur before the leaves are damaged with a crimper.

Enlist E3® soybeans allow the opportunity to utilize 2,4-D choline, Liberty and glyphosate in-season. With so many options, what is the best tank mix? Liberty is very effective on glyphosate-resistant (GR) weeds such as waterhemp. However, Liberty will be very weak on grasses and Enlist One will have no grass activity. With today herbicide systems with multiple traits we should target our problematic weeds. For instance, the problematic weed in this plot is GR waterhemp. Therefore, we should utlize Enlist One + Liberty to provide two effective SOA’s on this GR waterhemp population. We know we will sacrifice grass control but glyphosate or clethodim can be utilized in a later application to control any grass escapes.

Jonathan Perkins, Beck’s Practical Farm Research (PFR®) Location Lead/PFR Agronomist, discusses post-emergence options for Enlist E3® soybean systems.