As part of our Weeds Waking Up series, we are examining the pattern of weed emergence found in many corn and soybean fields across the Midwest to help with weed identification at crucial early stages and help inform management decisions.

Several weeks prior to corn planting, the first signs of common lambsquarters emerge from shallow soil depths. At the cotyledon stage, common lambsquarters can often resemble amaranthus species, such as common waterhemp or Palmer amaranth, but the first true leaves have a dull gray appearance with a white powdery coating on it.

Common lambsquarters can be difficult to manage due to its emergence early in the growing season, which can give it a head start compared to your crop. This weed is very aggressive as it does rob yield from both corn and soybeans. Due to its growth pattern and high seed production, there are usually dense amounts of these plants in fields. If left untreated, it can take up to 25% of soybean yield throughout the growing season. Additionally, it can produce 175,000 seeds in a single season, which can remain viable in the soil for up to 80 years.

The key to successfully managing common lambsquarters is to start clean. As this weed typically emerges early in the growing season, if there is a field infested with common lambsquarters, you can wait and plant that field later to control much of this weed with tillage prior to planting.

Start clean and stay clean throughout the growing season with an application of Acuron® or Acuron Flexi corn herbicides. Acuron has 3 effective sites of action (Groups 5, 15 and 27) and Acuron Flexi has 2 (Groups 15 and 27). Both herbicides contain bicyclopyrone, which is designed to complement the other active ingredients in the premix to deliver broader spectrum, more consistent control of tough weeds other products are missing.

In soybeans, we recommend Boundary® 6.5 EC (Group 5 and 15), BroadAxe® XC, (Group 14 and 15) or Prefix® (Group 14 and 15) herbicide.

If you would like input in developing a herbicide program for 2019 based on the specific weed pressures in your field, contact your Syngenta retailer, local Syngenta sales rep or visit www.ResistanceFighter.com.

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