How to Select the Best Herbicides for Your Farm
By Bryan Olivi
Weeds pose a constant threat to crops by interfering with growth and limiting yield potential. Choosing the right herbicides for your farm will not only help mitigate weeds, but will also set you up for success.
When selecting a proper herbicide program for your farming operation, you must first know your field’s history of weed species. While, cultural and mechanical control are important management tools to combat weeds, chemical application is the most commonly used practice to manage weeds before, during, and after the growing season.
Four important questions to consider when selecting the best herbicide programs for your farm:
- What species of weeds have been present in my fields?
- Which weeds are the most difficult to control?
- Which herbicides can safely control weeds in my fields?
- Which weeds have built up a documented resistance to herbicides in my region?
Controlling and Identifying Troublesome Grasses and Broadleaves
Knowing which weeds are most common in your fields can help you make early management decisions. If grasses are a common concern, selecting the proper herbicides, such as clethodim and fluazifop, to manage early seedling grasses is important. Other herbicides also offer control of grasses such as glyphosate, metribuzin, pendimethalin, mesotrione, fomesafen, metolachlor and atrazine to name a few. Always be aware of herbicide labels and plant-back restrictions when applying herbicides, such as clethodim or fluazifop for grasses in rice, corn or sorghum fields. If broadleaf weeds are more of your issue, there are multiple herbicide programs to control this weed such as 2,4-D, glufosinate, paraquat, atrazine, sulfentrazone and glyphosate. Like with grasses, be aware of plant-back restrictions on broadleaf weeds, especially for non-dicamba, non-2,4-D, non-glyphosate and non-glufosinate tolerant crops.
When both grasses and broadleaf weeds are a concern, herbicides labeled for control of both are recommended and more specifically focus on herbicide premixes or tank mixing herbicides with different modes of action like Villain® or Ravine®. Coupling a proper pre-emergent herbicide with residual control of grasses and broadleaves at planting may control weeds longer and reduce the need for post-emergent herbicide applications. In situations where residual herbicides don’t control emerging weeds, a post-emergent herbicide that is safe for top application is the best option. Choose herbicides with modes of action different from herbicides applied earlier in the season.
Combating Weed Resistance
The key to a weed-free operation is identifying which weeds are troublesome to control in specific fields, as well as documented resistance to herbicides in your region. The population of resistant weeds to different herbicide modes of action is increasing each year. Herbicide-resistant weeds typically develop when the same type of herbicide program is used over the years. Weed resistance can also occur from crop management tools. Simply put, weed resistance will continuously increase when controlled by the same herbicide program. Once this occurs, resistance biotypes can survive and be stored in a field’s seed bank for future growing seasons. This is how most fields go from adequate control of weeds to below acceptable control. Remember, the type of herbicides used does not cause resistance to occur in a population of weed species, it simply filters out susceptible weeds and allows resistant weeds to continue to reproduce seed.
The need to evaluate the sustainability of weed management practices on a universal level as well as on individual fields is vital to successfully battling weeds. Each farmer, agronomist and agriculture scientist should continue to educate themselves on cultural and mechanical controls to incorporate these methods into weed management practices; however, staying current on resistant populations and herbicide chemistry utilization will also help effectively combat weed resistance issues on fields and provide a better return on investment each growing season.
Weeds can do major damage if not treated properly. Farmers must be aware of weed control issues to select the best program to combat them. To learn more about Pinnacle’s weed management solutions contact your local Pinnacle sales representative or Customer Support.
Bryan has worked in the agricultural industry for the past 10 years and has published research. Bryan currently works as a Proprietary Product Agronomist for Pinnacle Agriculture. In this role, Bryan conducts research trials of experimental and commercially released products for Innvictis Crop Care and Mission Seed Solutions to evaluate agronomic characteristics and ensure product performance in the field.