By Larry Steckel, Extension Weed Specialist
Judging by phone calls we’ve received, it seems there is a good number of questions on some relatively new corn herbicide premixes. The three newer corn herbicide premixes are Acuron, Armezon PRO and Resicore. Below is some information to compare the three.
Acuron (Dual II Magnum + Callisto + Atrazine + bycyclopyrone)
Rate: 2.5 quarts per acre
- Very good resistance management product with three modes of action for control of many broadleaf weeds.
- All three herbicides can provide good glyphosate-resistant horseweed and Palmer amaranth control.
- The best way to use this herbicide is to apply it at 1.25 quarts per acre pre-emergence and then follow with a planned post application of a herbicide premix like Halex GT or Capreno.
- A 2.5-quart-per-acre rate of Acuron provides 0.65 pounds active ingredient of atrazine.
Armezon PRO (Armezon + Outlook)
Rate: 14-24 ounces per acre
- Typically used post at a rate of 18 ounces per acre.
- Provides good all-around weed control with good crop safety.
- Add 1.5 pounds of atrazine and/or glyphosate to provide more consistent control.
- Best used as the post application of a planned pre/post program.
Resicore (Acetochlor + Python + Stinger + Mesotrione)
Rate: 2.25-3 quarts per acre
- We have limited research on this premix. In last year’s research it provided good residual control of grasses and Palmer amaranth.
- Sequential applications of Resicore at 1.25 quarts pre followed by 1.25 quarts post worked very well in last year’s research.
- Cotton and tobacco plant back is 18 months.
Bicep (Dual II Magnum + Atrazine)
Rate: 1.6- 2.6 quarts per acre
- Has been used on more corn acres than any other corn premix.
- Provides good all around weed control with good crop safety.
- 2 quarts-per-acre rate provides 1.55 pounds active ingredient of atrazine.
Corvus (Balance + Thiencarbazone)
Rate: 5.6 ounces per acre
- Balance will provide residual control of Palmer amaranth and horseweed.
- Thiencarbazone will provide good residual control of many weeds, particularly morninglory species.
- Atrazine is needed for best control of Palmer pigweed.
Harness Xtra 5.6, Degree Xtra, Breakfree ATZ (Acetochlor + Atrazine)
Rate: 1.7-3 quarts per acre for Harness Xtra or 2.9-3.7 for Degree Xtra or 2.2-3 quarts per acre for Breakfree ATZ.
- The non-encapsulated acetochlor formulations Harness and Breakfree have provided comparable pigweed and grass control to Dual II Magnum.
- Degree Xtra is an encapsulated formulation that releases slowly over time. Limited research has shown about a week longer residual control of pigweeds than other acetochlor formulations.
- 2.1 quarts-per-acre rate of Harness Xtra provides 1.3 pounds active ingredient of atrazine or 3.5 quarts per acre of Degree Xtra provides 1.17 pounds active ingredient of atrazine or 2.5 quarts per acre of Breakfree provides 1.4 pounds active ingredient of atrazine.
Verdict (Outlook + Sharpen)
Rate: 10-18 ounces per acre
- Will provide good residual of Palmer amaranth and grasses.
- Provides flexibility as can be planted later to soybean if the need arises.
- Corn and soybean may be planted after a Verdict application at rates of 5-10 ounces per acre.
Regardless of herbicide premix selected the best overall weed control will most often be achieved with some kind of two-pass program. One reason this works best is due to being able to apply more atrazine in two passes (2.5 pounds per acre) compared to all in one application (2 pounds per acre). A good approach is to either use Gramoxone Inteon or glyphosate mixed with 16-32 ounces per acre of atrazine for burndown. Then follow early post emergence (up to 12-inch corn) with glyphosate plus atrazine, or even better with one of the post-emergence premixes.