What to consider when you’re selecting a burndown or pre-emergence herbicide

Agronomy

In some parts of the country, winter is finally showing signs of losing its grip, which means early germinating weeds will be arriving soon. Starting clean is critical when your goal is maximizing production. Weed management programs, whether for corn or soybeans, need to be viewed as a season-long project with clear goals in mind.

Weed Management Goals

Your weed management goals may include early springtime cultivation, rolling certain cover crops and/or a herbicide application to achieve a clean seed bed. If cultivation is not possible (no-till system, highly erodible soil, arid regions), then a burndown and pre-emergence herbicide application may be a great alternative.

Keep in mind that burndown and pre-emergence herbicide applications are only one step in the war on weeds. Starting with a clean field, early competition can be minimized allowing for the crop to get off to a good start. Spring burndown, post-emerge applications, fall burndown and in-season tillage also need to be considered in your overall weed management program.

Actively growing weeds that are not stressed from drought, excessive moisture or cold temperatures are typically the easiest weeds to manage. Stress conditions can cause the weed to shut down making it very difficult to manage, and this tends to be true for all application timings throughout the growing season.

Pros and Cons of the Chemistry You Choose

When considering burndown and pre-emergence products, you must understand the pros and cons of the herbicide, such as preplant interval, crop rotation and rain fast. Understanding the application rates of the herbicide along with any adjuvants that will be added will give you the best chance at managing early weed pressure—adjuvants can increase the efficiency of herbicides, but unfortunately not all adjuvants are created equally, and quality matters.

You must ensure that the adjuvant that you are adding to the herbicide mix is compatible by doing a small sample jar compatibility test. Always read and follow label directions for all herbicides and adjuvant mixtures.


Read this next:
Tips for Your Herbicide Mixing Order (2 min read)


Keep Modes of Action Top of Mind

Mode of Action (MOA) must be considered as well when selecting your burndown and pre-emergence herbicide program. Limit the use of the same MOA season after season. The more MOA used the better chances you will have at limiting the development of weed resistance. It is everyone's responsibility to limit the development of resistant weeds.

When selecting MOA, your ultimate goal should be developing a weed management program that accounts for:

  1. Early removal of weeds

  2. Longer lasting residual controls

  3. Documented regionalized weed resistance and weed types

Know Your Herbicide Products and Their Restrictions

There are numerous products on the market that can be used as burndown and pre-emergence products. Some products may apply a planting delay limit, which may range from multiple days to multiple weeks. Other herbicides have restrictions on crop rotation. This can be an important consideration if you have to change crop rotation in the same year. For example, if excessive rain forces you to change from planting corn to soybeans, an unknown restriction from a corn herbicide may not allow soybeans to be planted.

The following is a small sample of products that may be applied as a burndown and/or pre-emergent herbicide in your corn crop weed management program.

  1. 2,4-D (Defy® Amine 4) MOA 4

  2. Dicamba (Alligare Dicamba 4) MOA 4

  3. Glufosinate (Glufosinate 280SL) MOA 10

  4. Glyphosate (AgSaver™ Glyphosate 5.4) MOA 9

  5. Paraquat dichloride (Para-Shot 3.0) MOA 22

  6. Atrazine (Atrazine 4L) MOA 5

  7. Atrazine, Bicyclopyrone, Mesotrione, S-metolachlor (Acuron®) MOA 15, 27, 5

  8. Carfentrazone-ethyl (Aim®) MOA 14

  9. Isoxaflutole, Thiencarbazone-methyl (Corvus®) MOA 2, 27

  10. Atrazine, Mesotrione, S-metolachlor (Lexar® EZ) MOA 5, 27, 15

  11. Fluthiacet-methyl, Pyroxasulfone (Anthem® Maxx) MOA 14, 15

  12. Isoxaflutole (Balance® Flexx) MOA 27


Download:
FBN Conventional Corn Production Guide


The following is a small sample of products that may fit in a soybean crop season as a burndown and/or pre-emergent herbicide in your weed management program.

  1. 2,4-D (Defy® LV-6 Ester) MOA 4

  2. Glufosinate (Glufosinate 280SL) MOA 10

  3. Glyphosate (AgSaver™ Glyphosate 5.4) MOA 9

  4. Paraquat dichloride (Para-Shot 3.0) MOA 22

  5. Glyphosate, Imazethapyr (Extreme®) MOA 2, 9

  6. Glyphosate, Flumioxazin (Glyphosate + Valor®) MOA 9, 14

Scout your fields early so you know the growth stage and types of weeds, and you don’t apply the wrong products or miss the prime application window.

And remember, always read and follow label directions for all herbicides and adjuvant mixtures.

Download the Do-It-Yourself Spray Applications Guide.

own your sprayer chem spraying guide download


Sources:
https://crops.extension.iastate.edu/files/page/files/wc94.pdf
http://extensionpubs.unl.edu/publication/9000016794277/2016-guide-for-weed-disease-and-insect-management-in-nebraska/

ALWAYS READ AND FOLLOW LABEL DIRECTIONS. It is a violation of federal and state/provincial law to use any pesticide product other than in accordance with its label. The distribution, sale and use of an unregistered pesticide is a violation of federal and/or state law and is strictly prohibited. We do not guarantee the accuracy of any information provided on this page or which is provided by us in any form. It is your responsibility to confirm prior to purchase and use that a product is labeled for your specific purposes, including, but not limited to, your target crop or pest and its compatibility with other products in a tank mix.

Acuron is a registered trademark of Syngenta Group Company. AgSaver is a trademark of AgSaver, LLC. Aim is a registered trademark of FMC Corporation. Anthem is a registered trademark of FMC Corporation. Balance is a registered trademark of Bayer Crop Science. Corvus is a registered trademark of Bayer Crop Science. Extreme is a registered trademark of BASF. Defy is a registered trademark of ADAMA Group Company. Lexar is a registered trademark of Syngenta Group Company. Valor is a registered trademark of Valent U.S.A. Corporation.

 

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