Weed Control: A Million to 1

zero tolerance

You already use Capreno® herbicide, so odds are that you’re already familiar with the importance of controlling weeds early and throughout the season. In fact, maybe you started using Capreno because you started to see it was becoming more and more difficult to keep weeds at bay season-long.


1 pigweed can product 500,000 to a million seedsThis difficulty is largely due to weed shifts that are becoming common in corn fields across the country. Weeds once dominant in fields didn’t disappear, but the likes of waterhemp and Palmer amaranth seem to be taking over. 

Many blame such weed shifts on mismanagement of glyphosate, because key weeds developing herbicide resistance often cause the shifts.

Waterhemp and Palmer amaranth are two of the most commonly discussed weeds when it comes to weed shifts and resistance because they reproduce rapidly and prolifically. A single plant can produce hundreds of thousands of seeds.

“These are two very aggressive weed species in terms of growth habitat and seed production,” said Mark Waddington, product development manager, Bayer. “If left alone and untreated, a single Palmer amaranth plant can produce up to a million seeds. That single weed can be responsible for generations of weeds in the same growing season.”

That long germination window means no chemistry will last long enough to control the entire season of flushes of waterhemp and Palmer amaranth.

“You really need to use multiple products with multiple sites of action and rely on multiple herbicide application timings,” Waddington said. “You can’t let those weeds get big enough to reproduce.”

Not only are herbicide choices one way to manage tough-to-control weeds, but stewardship and tillage practices come into play too.

“Even equipment use and practices can contribute to the spread of weeds and weed shifts,” Waddington said. “For example, people can run the combine through one field in which waterhemp or Palmer amaranth were present during the season. The seeds are still in the soil that clings to the combine tires, and might transfer to the next field.

That next field may not have had waterhemp or Palmer amaranth previously, but one or both will likely show up in those fields the next year.”

The number of factors that could play into the spread and management of these weeds might overwhelm some growers. However, you can turn the odds in your favor with one philosophy: Zero Tolerance.

“If you have, or end up with, fields with waterhemp or Palmer amaranth, the best thing you can do is not even give those weeds a chance,” explained Jason Manz, selective herbicides product manager, Bayer. “Weeds can grow so quickly from one day to the next. You might scout one day and think you have a window of one or two more days to spray. Those two days can easily be disrupted and before you know it, the weeds are well above the maximum height for best control.”

Turning the Odds in Your Favor

That one simple philosophy – ZERO TOLERANCE – means the odds of you against waterhemp and Palmer amaranth aren’t as daunting as they seem. With proper weed management, you can keep these weed populations under control. Stop the weeds – and their seeds – before they outnumber you.

In addition to Capreno, following are a few herbicide choices available to growers:

Pre-Emergence Herbicides


Corvus® is a pre-emergence residual herbicide that has overlapping sites of action to control early season problem weeds. It is the only corn herbicide to offer burndown, residual and reactivation. Residual activity prevents new weeds, while reactivation controls late weeds.

Balance Flexx

Balance® Flexx is best suited for certain soil types or fields that rotate to certain specialty crops. Follow a pre-emergent application of Balance Flexx with a postemergence herbicide, such as Capreno, Laudis or DiFlexx, to control multiple weed flushes.


DiFlexx® herbicide is dicamba with a superior safener. It’s also a great tankmix partner, adding an additional site of action to your tank.

Postemergence Herbicides


Capreno® herbicide offers multiple sites of action and provides the longest-lasting residual of any post product on the market.


DiFlexx® herbicide is dicamba with a superior safener. It’s also a great tankmix partner, adding an additional site of action to your tank.


Laudis® herbicide has the power to control weeds safely in with corn. Laudis provides powerful residual weed control with unsurpassed crop safety in all types of corn. If using Laudis following an application of Corvus, add another effective herbicide with a different site of action, such as DiFlexx or Liberty®.


Liberty herbicide for corn provides simply better weed control on tough-to-control weeds and can be coupled with the high performing genetics of the LibertyLink® trait for high yields that deliver.

Fall-Applied Herbicide

Autumn Super

Autumn™ Super herbicide takes down the toughest fall and early spring weeds and keeps them down prior to planting. Autumn Super also controls winter annuals that can attract pests that emerge in the spring.

For more information about waterhemp, Palmer amaranth and their management, visit www.CropScience.Bayer.us, call 1-866-99-BAYER (1-866-992-21937) or talk with your local sales representative.

Learn how Capreno® herbicide delivers an amazing end-of-season clean at an ultra-low use rate.// more
Evaluate your corn herbicide options and determine the best weed management solutions for your farm.// Get Started
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