A successful weed control program starts before you can see the weeds. Pre-emergence herbicides form the foundation for season-long weed suppression and help protect yield potential in both corn and soybeans.
Thoughtful planning in the off-season ensures that you choose the right products, rates, and timing for your fields. Some things that you and your agronomist should keep in mind include:
Weed Pressure History
Talk with your agronomist to identify dominant weed species from the past. Some of these pesky weeds may include water hemp, giant ragweed, lambs quarter, bur cucumber and foxtail. These are just a few weeds that are very common in our region to keep in mind when selecting your pre-emerge herbicide.
Layering Multiple Sites of Action (SOA)
Relying on single active ingredients invites resistance. Build a program with at least two or more SOA’s. Many of the pre-mixed herbicides on the market contain multiple SOA’s
Corn: mesotrione (Group 27)+ S-metoachlor (Group 15)+ Clopyralid (Group 4)
Soybeans: Fomosafen (Group 14)+ S-metoachlor(Group 15)+ Metribuzin (Group 5)
This layering approach can help keep the pesky weeds at bay to make it easier to control later in the season.
Timing of Application
Getting pre-emergent herbicides in a timely manner is key. Try to get the herbicide applied just before or just after planting to maximize the residual window. Ensure at least ½ inch of rain fall or very slight incorporation into the soil to get the herbicide down into the weed germination zone.
Plan for Overlap
Even top-notch programs will fade over time. Plan for a second application of a residual herbicide plus a post-emergence herbicide to control emerging weeds to carry you into crop canopy.
A strong pre-emergence herbicide program is an investment that sets you up for success this year. Having a program in place will help optimize nutrient efficiency of crops due to the lack of competition with weeds, which in turn increases your yields and keeps your fields clean. There is a lot to decide when looking at different herbicides, but with your partnership with Premier Cooperative agronomists, we will help you select the best program for your operation. Thank you for working with Premier Cooperative and we look forward to another successful growing season in 2026.
