Fall Residual

Conventional Soybean Herbicide Programs - Revisiting a Multi-Layered Program

Recommended Programs for Participation in the Calyxt High Oleic Soybean Program

Recently, there has been a renewed interest in conventional soybean production and weed control options for this production system. For many soybean growers, conventional soybeans may not have been planted on their operations for over a decade, and some growers have never planted conventional soybeans. Regardless, when considering conventional soybeans, site selection, effective burndown and pre-emergence weed control programs are the first prerequisites for effective weed management, and these occur before we ever plant a conventional soybean seed. It is extremely difficult to rely on a total post-emergence conventional soybean weed control program. We have very limited effective options for controlling broadleaf weeds in a post-emergence only program with conventional soybeans.

The The following list shows several suggested conventional pre-and post-emergence soybean herbicide programs to consider. These suggestions are consistent with the SDSU Extension 2019 Pest Management Guide- Soybeans. These programs are consistent with production and management in North Dakota as well. The listed pest management programs have been developed and reviewed by Agtegra and reviewed by Calyxt agronomy staff and participating company partners. These are programs we believe will provide the best management opportunities for program acres. However, the programs are not meant to be exclusive. Local agronomic expertise should always be paramount in developing an effective weed management program.


Step 1: Fall

   • Site Selection! Choose fields with lower initial weed pressure
   • Start Clean! Use Fall Burndown and Fall Residual Herbicides
       o Roundup, phenoxy herbicides like 2,4-D or dicamba and Valor are key herbicides.
1. Kochia or Marestail Program:
    a. 32-40 oz Roundup PowerMax + 4 oz/a Valor + NIS or COC/MSO + AMS
    b. Can also add 8 oz/a dicamba or 1 pt 2,4-D, as needed
    c. Add 4 oz metribuzin (for heavy pressure areas)

2. Winter annual mustards program:
a. 32-40 oz Roundup PowerMax + 3-4 oz Valor + 1-1.5 pt 2,4-D + NIS + AMS

Step 2: Pre-Emergence

   • Use Effective Pre-Emergence Programs, with Layered Residuals
   • Start Clean! Roundup + 2,4-D burndown may be needed, if early weed pressure exists or fall burndown and residual was not used
    a. Follow label restrictions for preplant intervals
• Gramoxone (3 pt/a) may also be used instead of Roundup/2,4-D burndown. Gramoxone may be tank mixed with any of the Pre-Emergence programs listed below and applied in a single pass program.

Suggested Programs
1. BroadAxe or Authority Elite (32 oz/a) + metribuzin (4 oz/a dry) (if no MTZ in fall) + COC/MSO + AMS
    a. This program gives ~ 1 pt Dual pre-emergence
2. Authority MTZ (12 oz/a) + 3 pt/a Prowl H2O
    a. This program must be applied pre-plant, not pre-emergence
3. Authority Assist (8 oz/a) + metribuzin (4 oz/a dry) (if no MTZ in fall) + COC/MSO + AMS
4. Fierce Herbicide (3.75 oz/a) + metribuzin (4 oz/a dry) (if no MTZ in fall) + COC/MSO + AMS -OR- Fierce MTZ (16-20 oz/a) (if no MTZ in fall)

Step 3: Post-Emergence

   • Use Effective Post Herbicides with Layered Residuals! Use 15 GPA Application Rate Minimum!

Post Programs- East of US Hwy 281
1. Flexstar Herbicide (12 oz/a) + Dual Herbicide (16 oz/a) + AMS (2.5#/a) + Adjuvant*
2. Avalanche Ultra/ Ultra Blazer Herbicide (12 oz/a) + Dual Herbicide (16 oz/a) + AMS (2.5#/a) + Adjuvant*

Post Program- West of US Hwy 281
1. Avalanche Ultra/ Ultra Blazer Herbicide (12 oz/a) + Dual Herbicide (16 oz/a) + AMS + Adjuvant*
    a. A Section 24(c) Special Local Needs label to expand the geography for Flexstar Herbicide westward to the Missouri              River (including Gregory, Lyman and Tripp counties west river) in South Dakota is being proposed. This label                          expansion is NOT in any way approved to date.
2. Cobra Herbicide (12.5 oz/a) + Dual Herbicide (16 oz/a) + Class Act NG adjuvant may be used, but caution is recommended because of likely crop response

*Adjuvant Options for Flexstar or Avalanche Ultra/ Ultra Blazer programs:
1. Preferred for all weather conditions: COC-Based HSOC, such as SuperB HC (Winfield United) at 0.5% v/v (minimum 8 oz/a adjuvant)
2. Hot and humid conditions (favoring crop response): a blend of AMS + NIS (Class Act NG) may be substituted
3. Dry conditions or heavy weed pressure present: an MSO-based HSOC such as Destiny HC (Winfield United) at 0.5% v/v (minimum 8 oz/a adjuvant) may be substituted

Added Options:
1. Volunteer Corn + Moderate grassy weeds: Add a clethodim product for grassy weed control and volunteer corn control + COC-based HSOC (such as SuperB HC), at 0.5% v/v or 8 oz/a minimum rate
2. Volunteer Corn + Lower grassy weeds: Add Fusilade Herbicide (8 oz/a) + COC-based HSOC (such as SuperB HC) at 0.5% v/v or 8 oz/a minimum rate if volunteer corn only with low grass weed pressure
3. FirstRate (1/3 oz/a) can be added for additional control of weeds like common ragweed, cocklebur, wild sunflowers and marestail
4. Warrant Herbicide (32 oz/a) or Zidua Herbicide (1.5-2 oz/a) can be used instead of Dual, but these require somewhat to significantly more moisture
5. If Warrant Herbicide and clethodim products are combined, 25-33% increased rates of clethodim are required
6. Outlook Herbicide (12 oz/a) is weaker on kochia control, but may be used if pressure is very low