Kochia Scouting: When and How to Identify Kochia in Corn and Soybeans

One of the most persistent weeds for Midwest farmers is Bassia scoparia, more commonly known as kochia. This aggressive summer annual is highly competitive, herbicide-resistant, and alarmingly adaptive, with the potential to reduce soybean yields by 52% and corn yields by 68% if left unchecked.¹ Knowing how and when to identify kochia weed in your fields is essential for protecting yields and staying ahead of resistance.

Characteristics of kochia

Kochia is fast-growing, drought-tolerant, and highly adaptive to disturbed areas. It’s often one of the first weeds to emerge in the spring and can quickly establish itself long before your crops have time to close their canopy and choke out weeds. Typically emerging between February and March, kochia’s head start on growth makes it harder for crops to compete throughout the season.
Kochia seeds need only 2–3 hours of moisture to germinate and their germination rate can reach 75% in temperatures between 39 F and 95 F.² Due to this short germination window and high viability rate, kochia is incredibly difficult to manage year after year once established.

If left unmanaged, kochia plants can potentially grow to 6’ with the roots reaching 21’ in diameter, robbing crops of their water and nutrients.³ Each kochia plant can produce upwards of 30,000 seeds, and mature plants break free from their roots, becoming tumbleweeds that scatter seeds across recently tilled or disturbed areas. Even if a farmer is meticulous about field management, this unique seed dispersal strategy can quickly undo that hard work and even fields with little prior weed pressure can quickly become infested.

Because of its ability to produce so many seedlings rapidly, kochia can quickly build up resistance to several herbicidal modes of action, including ALS inhibitors, synthetic auxins, photosystem II inhibitors, and EPSP synthase inhibitors.⁴ Some kochia weeds that are herbicide-resistant are even harder to control and can spread resistance traits across fields.

When and where to scout for kochia

If you’re concerned about kochia weed pressure in your area, begin scouting for this plant as early as possible. This is usually in February and March when soil temperatures start to rise above freezing and seeds begin sprouting.⁵ Continue scouting periodically throughout the season to eliminate later-emerging weeds and prevent new infestations.
Focus scouting efforts on field edges, tilled or disturbed areas, and soils with higher salinity where kochia thrives.

Kochia identification

When scouting for kochia, early detection is key. Catching young plants before they become established gives you the best opportunity for effective control.
Here’s how to identify kochia weeds in different growth stages:

• Seedlings: Small, elliptical cotyledons (first leaves) that are bright green and covered with fine hairs. Some seedlings may show pink or magenta coloring on the undersides. These early-stage plants can easily be mistaken for other broadleaf weeds, like Russian thistle or lambsquarters, so examine texture and hairiness carefully.⁶
• Young plants: Narrow, pointed true leaves and hairy stems begin to appear as kochia matures.
• Mature plants: Shrubby, bush-like structure with a bluish-gray tint during the growing season, turning reddish in the fall. Mature kochia can grow up to 6’ tall with multiple branches. Leaves are alternate, narrow, and heavily pubescent, about 1–2’ long. Stems often show a reddish color. Mature plants eventually break from their taproot to become tumbleweeds.⁷

Because kochia typically establishes first in disturbed areas, be sure to scout along field borders, ditch banks, and fence lines. Kochia often migrates from these edges into fields, making perimeter scouting essential.

How to manage kochia

Here’s a list of things you can do to minimize the pressure from kochia weeds in your fields:

• Target small weeds early as they emerge.
• Plant fall cover crops to suppress early-emerging seedlings.
• Use tillage strategically to disturb kochia root structures and deplete moisture.
• Apply early-season herbicides to burn down emerging weeds using glyphosate; 2,4-D; paraquat or glufosinate. Beware that there is fairly widespread resistance of kochia to glyphosate.

Kochia is a persistent and costly weed that can quickly spiral out of control if not detected early. By understanding its growth habits, knowing when and where to scout, and learning to spot the weed at early stages, farmers can protect their yields and stay ahead of herbicide resistance.

Staying proactive with kochia scouting today will mean fewer problems and better crop performance tomorrow.
Experts are available to help you make your weed management decisions. Reach out to your seed retailer, a nearby extension office agent, or a seed company professional like your regional BASF representative.

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Endnotes

1. Geddes, Charles M., and Shaun M. Sharpe. “Crop Yield Losses Due to Kochia (Bassia scoparia) Interference.” Crop Protection, vol. 157, 2022, article no. 105981, https://doi.org/10.1016/j.cropro.2022.105981.
2. “Kochia.” Cornell CALS Weed Science, Cornell College of Agriculture and Life Sciences, 2024, cals.cornell.edu/weed-science/weed-profiles/Kochia.
3. Peterson, Dallas, Curtis Thompson, and Richard Zollinger. “Kochia Biology and Management.” University of Missouri Extension, Feb. 2021, extension.missouri.edu/media/wysiwyg/Extensiondata/Pub/pdf/miscpubs/mx1135.pdf.
4. Peterson, Thompson, and Zollinger. “Kochia Biology and Management.”
5. Lancaster, Sarah, Jeremie Kouame, and Patrick Geier. “Late-Winter Kochia Control in Fields Going to Corn or Grain Sorghum.” Agronomy eUpdate, Kansas State University Department of Agronomy, 15 Feb. 2024, eupdate.agronomy.ksu.edu/article/late-winter-Kochia-control-in-fields-going-to-corn-or-grain-sorghum-626-1.
6. “Kochia.” Cornell CALS Weed Science.
7. “Kochia.” Cornell CALS Weed Science.