Corn Herbicide Premixes

Author: Larry Steckel, Extension Weed Specialist Comments Off on Corn Herbicide Premixes

Corn Herbicide Premixes. Judging by phone calls over the last week 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.

Acuron (Dual II Magnum + Callisto + Atrazine + bycyclopyrone) Rate: 2.5 qts/A
Positives
a. Very good resistance management product with three modes of action for control of many broadleaf weeds.
b. All three herbicides can provide good glyphosate-resistant horseweed and Palmer amaranth control.
Management Considerations
a. Best way to use this herbicide is to apply it at 1.25 qts/A PRE and then follow with a planned POST application of a herbicide premix like Halex GT or Capreno.
b. 2.5 qts/A rate of Acuron provides 0.65 lbs ai of atrazine.

Armezon PRO (Armezon + Outlook) Rate: 14 to 24 ozs/A
Positives
a. Typically used POST at a rate of 18 ozs/A.
b. Provides good all-around weed control with good crop safety.
Management Considerations
a. Add 1.5 lbs of atrazine and/or glyphosate to provide more consistent control.
b. Best used as the post application of a planned PRE/POST program.

Resicore (Acetochlor + Python + Stinger + Mesotrione) Rate: 2.25 to 3 qts/A
Positives
a. We have limited research on this premix. In last year’s research it provide good residual control of grasses and Palmer amaranth.
Management Considerations
a. Sequential applications of Resicore at 1.25 qts PRE followed by 1.25 qts POST worked very well in last year’s research.
b. Cotton and tobacco plant back is 18 months.

Bicep (Dual II Magnum + Atrazine) Rate: 1.6 to 2.6 qts/A
Positives
a. Has been used on more corn acres than any other corn premix.
b. Provides good all around weed control with good crop safety.
Management Considerations
a. 2 qts/A rate provides 1.55 lbs ai of atrazine.

Corvus (Balance + Thiencarbazone) Rate: 5.6 ozs/A
Positives
a. Balance will provide residual control of Palmer amaranth and horseweed.
b. Thiencarbazone will provide good residual control of many weeds particularly morninglory species.
Management Considerations
a. Atrazine is needed for best control of Palmer pigweed.

Harness Xtra 5.6, Degree Xtra, Breakfree ATZ (Acetochlor + Atrazine) Rate: 1.7 to 3 qts/A for Harness Xtra or 2.9-3.7 for Degree Xtra or 2.2 to 3 qts/A for Breakfree ATZ.
Positives
a. The non-encapsulated acetochlor formulations Harness and Breakfree have provided comparable pigweed and grass control to Dual II Magnum.
b. 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.
Management Considerations
a. 2.1 qts/A rate of Harness Xtra provides 1.3 lbs ai of atrazine or 3.5 qts/A of Degree Xtra provides 1.17 lbs ai of atrazine or 2.5 qts/A of Breakfree provides 1.4 lbs ai of atrazine.

Verdict (Outlook + Sharpen) Rate: 10 to 18 ozs/A
Positives
a. Will provide good residual of Palmer amaranth and grasses.
b. Provides flexibility as can be planted later to soybean if the need arises.
Management Considerations
a. Corn and soybean may be planted after a Verdict application at rates of 5 to 10 ozs/A.

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 lbs/A) compared to all in one application (2 lbs/A). A good approach is to either use Gramoxone Inteon or glyphosate mixed with 16 to 32 ozs/A of atrazine for burndown. Then follow early post emergence (up to 12” corn) with glyphosate plus atrazine or even better with one of the post emergence premixes.

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