Management of kochia is vital as it has the potential to produce thousands of seeds per plant and can greatly reduce crop yields. The best time for control is shortly before or after kochia seedlings emerge and are actively growing (Figures 1).1,2 Yet it is not always feasible to apply an effective soil-applied, pre-emergence herbicide or get adequate efficacy in the spring due to weather impacts. A lack of moisture can limit full activation of the herbicide and excessively wet fields can be inaccessible for application. A great option is to apply residual herbicides in the late fall.
Herbicide applications applied before the ground freezes can help to provide residual control into May.1 Flumioxazin, for example, provides control or suppression of kochia and allows rotational flexibility to many crops the following spring. Suppression of kochia should thin the population to enable better herbicide coverage of any burndown application prior to planting.
Fall Herbicide Options for Kochia Control2,3,4
Not all herbicide active ingredients allow for rotational flexibility. Make sure to read and follow label directions. Successful weed control is dependent on spray coverage and volume, adequate herbicide rates, proper adjuvant selection and tank mix partners.
If planting corn, herbicide active ingredients that could be applied in the fall could include atrazine, flumioxazin, flumioxazin + pyroxasulfone, pyroxasulfone, s-metolachlor, acetochlor, or a combination of these (make sure labels allow a combination).
If planting soybean, herbicide active ingredients that could be applied in the fall could include flumioxazin, pendimethalin, s-metolachlor, dimethenamid-p, pyroxasulfone, sulfentrazone, saflufenacil, dimethenamid, or a combination of these products (making sure labels allow a combination).
The most effective management strategy for kochia is the prevention of seed production throughout the year. Fall control of kochia can be an effective option in setting the stage for a clean start in the spring before planting.
1Managing kochia. Agriculture, Proving of Manitoba Agriculture. https://www.gov.mb.ca/agriculture/crops/weeds/print,managing-kochia.html/.
2Werle, R. 2017. Q&A: When is the best time for kochia control? CROPWATCH. University of Nebraska-Lincoln. https://cropwatch.unl.edu/2017/qa-when-best-time-kochia-control/.
3Ikley, Joe, et.al., 2022. North Dakota Weed Control Guide, W253-22. North Dakota State University. https://www.ndsu.edu/agriculture/ag-hub/publications/north-dakota-weed-control-guide/.
3,4Shaffer, Gared, 2022 (updated). The fall advantage of kochia control. South Dakota State University Extension. https://extension.sdstate.edu/fall-advantage-kochia-control/.
Web sites verified 9/25/22.
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Performance may vary, from location to location and from year to year, as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible and should consider the impacts of these conditions on the grower’s fields.
Tank mixtures: The applicable labeling for each product must be in the possession of the user at the time of application. Follow applicable use instructions, including application rates, precautions and restrictions of each product used in the tank mixture. Not all tank mix product formulations have been tested for compatibility or performance other than specifically listed by brand name. Always predetermine the compatibility of tank mixtures by mixing small proportional quantities in advance. Channel® and the Arrow Design® and Seedsmanship At Work® are registered trademarks of Channel Bio, LLC. Bayer and Bayer Cross are registered trademarks of Bayer Group. All other trademarks are the property of their respective owners. ©2022 Bayer Group. All rights reserved.