Now is the time to finalize plans for kochia control. In western Kansas, kochia is among the first summer annual weeds to emerge in the spring. Recent research suggests that kochia can begin emerging in early February, with most kochia emerging by late April. Kochia seedlings have been observed as early as February 7 in southwest Kansas.
Good control of the first dense flush of kochia is essential for obtaining a good crop yield. Early-emerging seedlings use the limited spring soil moisture in dryland production fields. Kochia seedlings emerge in dense populations, making adequate herbicide coverage difficult. In addition, glyphosate-resistant kochia is prevalent across western Kansas, making kochia control even more challenging. For these reasons, it is important to apply preemergence herbicides in late winter or early spring to control kochia before it emerges.
Herbicide program components to effectively manage kochia at germination. To successfully manage kochia, an herbicide program needs two components:
1. a very soluble and effective herbicide that can be incorporated with very little precipitation, such as dicamba; and
2. an herbicide that has longer residual activity, which will require perhaps 0.75 inches or more precipitation for adequate incorporation, such as atrazine.
Precipitation events during late winter are often too small to activate longer-lasting residual herbicides, but dicamba may control kochia for 4 to 6 weeks until atrazine is incorporated.
The best time to apply herbicides for kochia control is prior to kochia emergence, generally January through the first week of March, but this depends on weather conditions. Later applications, for example, at the time of burndown, are more likely to occur after kochia emergence, which increases the risk of control failure. Fall-applied treatments can help ensure timely application; however, they are not likely to control later flushes of kochia effectively.
Other herbicides with good preemergence kochia activity include: mesotrione (Callisto, others), metribuzin (Sencor, others), saflufenacil (Sharpen), sulfentrazone (Spartan, others). Be sure to check product labels for crop-specific planting intervals. For example, sulfentrazone requires a 10 to 18-month rotation interval to corn.
The use of trade names is for clarity to readers and does not imply endorsement of a particular product, nor does exclusion imply non-approval. Always consult the herbicide label for the most current use requirements.
For more information on controlling kochia, see the 2026 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland, K-State publication SRP1194.
Stacy Campbell is a Crop Production Extension agent in the Cottonwood District (which includes Barton and Ellis counties) for K-State Research and Extension. You can contact him by e-mail at scampbel@ksu.edu or by calling 785-628-9430