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Tips For Managing Waterhemp

February 16, 2018
This agronomic image shows the weed waterhemp.


Waterhemp is a small-seeded broadleaf weed and one of the most common weeds found in corn and soybean fields. Like other small-seeded weeds (marestail, Palmer amaranth), waterhemp is a prolific seed producer. Its small, lightweight seeds tend to thrive in minimum and no-till situations where they can easily germinate near the soil surface or in crop residue.

Unlike large-seeded broadleaf weeds, waterhemp emerges with less plant mass and its close proximity to the soil surface makes it more susceptible to herbicide applications. The sheer number of seeds it produces however, makes it difficult to control. Waterhemp plants that are left to go to seed can quickly populate the soil seedbank with millions of seedlings, spreading resistance and ensuring it remains a costly problem for years to come.

Waterhemp facts:

    • Produces up to 1 million seeds per plant
    • Can grow as much as 1” per day and up to 4 to 5’ in height, with some weeds reaching up to 12’
    • Pollen can travel a half-mile or more, cross-pollinating other waterhemp plants and spreading resistance
    • Early-season competition can reduce corn yield up to 15% by the time weeds are just 6” tall

Learn how to identify and manage waterhemp in this video with Joe Wuerffel, research and development scientist at Syngenta.

Growers can control waterhemp and protect corn yields by employing multiple, effective modes of action that provide residual control and a start-clean, stay-clean approach to weed control. Acuron® corn herbicide has 4 active ingredients and 3 effective modes of action (Groups 5, 15, and 27). Its atrazine-free counterpart, Acuron Flexi corn herbicide, has 3 active ingredients and 2 effective modes of action (Groups 15 and 27). Both contain the active ingredient bicyclopyrone, which complements the other active ingredients to deliver more effective and more consistent waterhemp control than competitive products. For optimal control, these brands should be applied before waterhemp emerges. Acuron and Acuron Flexi can be applied alone or pre-emergence followed by a post-emergence application of Halex® GT corn herbicide (Groups 9, 15 and 27) plus AAtrex® corn herbicide (Group 5).

Syngenta also offers an effective soybean weed control program that starts with pre-emergence, long-last residual control from Boundary® 6.5 EC herbicide (Groups 5 and 15) or BroadAxe® XC (Groups 14 and 15). In addition, a post-emergence application of Flexstar® GT 3.5 delivers 2 different modes of action (Groups 9 and 14) to control glyphosate- and ALS-resistant waterhemp.

Visit ResistanceFighter.com to learn more about weed resistance management in corn, soybeans and wheat.

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