Start Clean, Stay Clean

Start Clean, Stay Clean

Using a two-pass herbicide program to fight tough weeds, helps fields start clean and stay clean throughout the growing season.

It is no secret that weeds are problematic and need to be managed. Almost always a constant threat, weeds have the potential to take over fields and greatly reduce yields when left unmanaged.

Herbicide-resistant weeds pose an even greater threat. These weeds are tolerant to at least one site of action and are not usually well controlled by a single herbicide application. Repeatedly using the same site of action contributes to the development of herbicide-resistant weeds. Therefore, it is important to implement an integrated weed management program not only to control weeds, but also to prevent the development and spread of herbicide-resistant weeds.

One of the best ways to manage weeds and prevent development of herbicide-resistant weeds is to keep fields clean and weed-free throughout the entire growing season. This is an integral part of an integrated weed management program.

“Clean fields are weed-free fields,” said Frank Rittemann, selective corn herbicides product manager at Bayer. “Using a two-pass herbicide program with multiple sites of action is essential for fields to start clean and stay clean.”

Start with clean fields

Start off the growing season on the right foot with a pre-emergence herbicide application to ensure that fields are clean from the beginning. Starting clean means getting ahead of weeds before they can compete with crops. A pre-emergence residual herbicide prevents additional weeds from geminating.i

If weeds are not taken out pre-emergence, they will have an advantage over crops. Thus, early season weeds must be managed and controlled. Eliminating early season weeds reduces competition for moisture, nutrients and sunlight. With less competition, corn uses resources for the whole plant, including yield, instead of using all of its energy to grow taller to overshadow weeds.ii

Corvus® is a great pre-emergence residual herbicide with multiple sites of action that delivers early season control for a broad range of grasses and broadleaf weeds,” said Rittemann.  “And with its unique chemistry, Corvus reactivates with as little as a half inch of rain, to continue to fight tough weeds for up to eight weeks.”

Stay clean throughout the growing season

Keeping fields weed-free is the key to a successful season-long weed management program. Once the corn plants begin to emerge, scout fields to recognize and identify potential problem weeds. Then, as part of a two-pass herbicide program, follow up with a postemergence herbicide for continued weed control.iii

DiFlexx® DUO provides powerful postemergence control for a variety of tough-to-control weeds,” said Rittemann. “With two effective sites of action, it has the power to take out tough, glyphosate-resistant weeds, such as Palmer amaranth, waterhemp, ragweed and marestail.”

After the second pass, continue to scout fields weekly for weeds. If weeds are still present after the herbicide application, manually remove them before they go to seed. This is especially important if the weeds are thought to be herbicide-resistant. Removing weeds before they go to seed prevents them from adding to the weed seed bank and causing greater problems for future growing seasons.

Using a two-pass herbicide program, along with weekly scouting, is key to fields starting clean and staying clean. Together, Corvus and DiFlexx DUO work to take a zero tolerance approach to weeds, proactively helping keep fields clean and weed-free throughout the growing season.

©2018 Bayer CropScience LP, 800 North Lindbergh Blvd, St. Louis, MO 63167. Always read and follow label instructions Bayer, the Bayer Cross, Corvus, and DiFlexx are registered trademarks of Bayer. Corvus is a Restricted Use Pesticide. Not all products are registered in all states. For additional product information please call toll-free 1-866-99-BAYER (1-866-992-2937) or visit our website at

Work Cited

i Bechman, T.J. “How to handle clean no-till bean fields.” Indiana Prairie Famer, 2018.

ii Hartzler, B. “Managing weeds to protect crop yields.” Iowa State University Extension and Outreach.

iii Leverich, J. “You’ve got to start with clean no-till fields.” No-Till Farmer, 2010.

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