IMPORTANT NOTICE: No dicamba herbicide has been approved for use in-crop with seed containing Roundup Ready® Xtend Technology for the 2025 spray season at this time.

No dicamba herbicide may be used in-crop with this seed unless and until such use is approved or specifically permitted. For current approval statuses for in-crop dicamba use with this seed, call 1-844-RRXTEND or 1-866-99-BAYER, or contact the U.S. EPA or your state pesticide regulatory agency. Plants that are not tolerant to dicamba may be damaged or killed if exposed to dicamba herbicides.

Weed Watch: Marestail

Marestail

Marestail, also known as horseweed, can follow a winter or summer lifecycle and grows rapidly — and once this troublesome weed grows above 5 inches, it can be difficult to control with herbicides alone.1,2

This annual broadleaf weed is native to North America but can now be found worldwide.3

Failure to rein in its growth early can reduce yield by 40%.4

Young Plants

Up to 90% of fall emerged seedlings can survive winter and “bolt” in spring.5

Mature Plants

Leaves are entirely without petioles, and solid stems can reach 6 feet, while root systems consist of short taproots with fibrous secondary roots.6

Seed Pain Points

Seeds are numerous as each plant can produce up to 200,000 SEEDS, and 80% of these seeds can germinate immediately after falling from the mature plant.7

The evolution of herbicide-resistant and tough-to-control marestail is widespread. Keep weeds from affecting your bottom line by using well-designed best management practices, including a fall and spring burndown treatment, as well as residual herbicides to control weeds after planting. An integrated approach combining different sites and modes of action along with cultural practices can protect fields now and help prevent resistance in the future.

Keys to Managing Marestail1, 2

Rotate crops

to diversify herbicide programs and weed control strategies.

Start clean

with a burndown herbicide or tillage.

Apply a pre-emergence residual application,

using a residual product within 2 weeks before planting or prior to crop emergence.

Apply a postemergence application to target small weeds early,

before weeds grow taller than 4 inches.

Prevent Seed Production.

If weeds escape, use tillage or physically remove them before plants produce seed.

1 Crop Science (June 27, 2019). Keep crops safe from broadleaf weeds. Retrieved from http://www.cropscience.bayer.us
2 Lingenfelter, D., Klood, A., Curran, W. S. Pennsylvania State University Extension (November 13, 2017). Marestail (horseweed) management. Retrieved from http://www.extension.psu.edu
3 University of Wisconsin-Madison Integrated Pest and Crop Management (Sep. 4, 2019). A horseweed population in Wisconsin is confirmed resistant to glyphosate. Retrieved from http://www.ipcm.wisc.edu
4 Klingaman, G. University of Arkansas Division of Agriculture (August 5, 2005). Plant of the week: marestail (horseweed). Retrieved from http://www.uaex.edu
5 Crop Science (Sep. 4, 2019). Fighting glyphosate-resistant marestail? Get the facts. Retrieved from http://www.cropscience.bayer.us
6 University of Missouri Division of Plant Sciences (June 27, 2019). Weed ID Guide, Horseweed. Retrieved from http://www.weedid.missouri.edu
7 Jhala, A., Elmore, R. University of Nebraska — Lincoln Institute of Agriculture and Natural Resources (October 25, 2018). Management of glyphosate-resistant marestail in fall. Retrieved from http://wwww.cropwatch.unl.edu

The System Proven to Fight the Toughest Weeds

Tough-to-control weeds like Marestail can cause significant damage to your yield. See how Roundup Ready® Xtend Technology stacks up against competitors when controlling Marestail and more.

See the Comparison
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