Weed competition can be devastating to a young crop, and the damage starts almost immediately.

We know that weeds compete with crops for limited resources such as sunlight, nutrients and water, and the yield impact is immediate. Consider that in soybeans, for every day that you’re late with a herbicide application beyond the critical early-growth period, you lose 1% of your yield potential.¹

In corn, research has demonstrated that even non-competitive early-season interactions between weeds and corn can significantly affect crop growth, development and yield potential.

The best way to prevent weeds from stealing your yield is to stop them from emerging in the first place. Preemergence residual herbicides build upon the good work started by a burndown herbicide, layering a strong foundation for a weed-free growing season.

Proper application timing is critical for a successful preemergence program. While the ideal timing is before weeds have emerged, the absolute latest to curtail damage from early-season competition is before weeds reach 4” in height.

Here are 4 ways preemergence herbicides protect crops and pave the way for higher yields:

1. Emergence can start as early as March. Many weeds, such as marestail, giant ragweed and common lambsquarters, are especially challenging to manage without preemergence herbicide applications.
2. Preemergence residual herbicides provide a longer window for young corn and soybean plants to establish healthy root systems and strong stands free of weed competition.
3. By controlling weeds early on, a preemergence residual program makes timely post-emergent applications easier, as there should be fewer weed escapes with which to contend.
4. Preemergence programs reduce the number of weeds that are exposed to post-emergent herbicides, decreasing the potential for resistance development.

Herbicide Program Recommendations

There are many residual preemergence herbicide options available from Syngenta, giving you the flexibility to choose the program that best fits your needs, regardless of the trait you plant.

In soybeans, check out our soybean herbicide program planning tool to learn which soybean herbicides are the best fit for your operation to provide a full-season plan of overlapping residuals.

Proven preemergence performers such as Boundary® 6.5 EC, BroadAxe® XC or Prefix® herbicides fit under any trait platform and contain multiple effective sites of action.

• Boundary 6.5 EC offers residual control of up to 5 weeks against 32 broadleaf weeds as well as early-season grass weeds.
• Combining multiple effective sites of action, BroadAxe XC delivers broad-spectrum and residual control of standard tough and resistant weeds, as well as problem weeds specific to the Upper Midwest.
• With a flexible application window, Prefix can be applied as a preemergence herbicide or, if spring weather keeps you out of the field, an early post-emergence herbicide with residual control of up to 5 weeks.

In corn, we recommend Acuron® herbicide. With 4 active ingredients, including the unique component bicycloprone, Acuron provides season-long weed control of more than 70 weeds and grass to help fully protect your corn’s yield potential. When applied preemergence and at full label rates, Acuron lets you discover 5-15 more bushels an acre than any other herbicide because of its combination of powerful weed control, longest-lasting residual and proven crop safety.*

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¹ Based on 1% yield loss per day when application is delayed beyond critical period (up to V3). Bob Hartzler, Iowa State University.

*When applied preemergence and at full label rates. Acuron yield advantage range based on 2016 Syngenta and University trials comparing Acuron to Corvus®, Resicore®, SureStart® II and Verdict®. For more information on Acuron versus an individual product, ask your Syngenta representative.