Corn Weed Management Options

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There are three newer corn herbicide premixes available:  Acuron GT, Armezon PRO and Resicore. Below are some thoughts on these newer premixes as well as some that have been around for a spell:

Acuron GT  (Dual II Magnum + Callisto +  Bycyclopyrone + Glyphosate)  Rate: 3.75 pts/A
Positives
a. POST only applications.
b.  Good crop safety in our research.                                                                                        Management Considerations:                                                                                                                            a. Tankmix with atrazine for best control of horseweed and Palmer amaranth.                             b. 3.75 pts/A of Acuron GT provides 16 ozs of Dual II Magnum.

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 weed control.
b. Best used as the POST application of a planned PRE/POST program.

Resicore (Acetochlor + Stinger + Mesotrione) Rate: 2.25 to 3 qts/A
Positives
a. We have limited research on this premix. In last year’s studies, it provided 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 plant back is 12 months.

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.

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 morningglory species.
Management Considerations:
a. Atrazine is needed for best control of Palmer pigweed.                                                                      b. Avoid using on corn that has been treated with an OP insecticide.

Capreno (Tembotrione + Thiencarbazone) Rate: 3.0 ozs/A
Positives
a. Thiencarbazone will provide good residual control of morningglory species.
Management Considerations:
a. Atrazine is needed for best control of Palmer pigweed.                                             .                           b. Avoid using on corn that has been treated with an OP insecticide.

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 control of Palmer amaranth and grasses.
b. Provides flexibility as fields can be planted later to soybean if the need arises.
Management Considerations:
a. In short supply this year. Soybean may be planted after a Verdict application at rates of 5 to 10 ozs/A.

Regardless of herbicide premix that is 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 one of the premixes.