Kochia – 2018 Weed of the Year?
Jul 13, 2020
If not “Weed of the Year” in 2018, kochia certainly is a strong contender. With a relatively dry spring and hot dry summer, conditions were ideal for kochia growth. Not only is kochia a very competitive weed, it also has developed widespread resistance to Group 2 herbicides and increasing concern for resistance to glyphosate (Group 9) and auxin-based herbicides (Group 4). In addition, kochia is a very prolific seed producer.
Selecting an effective chemical treatment, especially one based upon multiple modes of action is an important consideration to achieving good kochia control. Use recommended rates with high water volumes for best coverage. Reducing the sprayer speed and lowering the boom height will ensure the proper rate is applied and that weeds and/or soil are well covered. Make certain to practise herbicide rotation to allow for different chemistries and modes of action to be used. This will help delay the onset of weed resistance. Utilize herbicide layering i.e. apply a soil-active herbicide that kills weeds as they emerge followed by a foliar in-crop product that controls growing weeds. Several pre-seed products are also now available that offer a combination of unique modes of action.
Don’t overlook cultural control practices in your battle with kochia. Kochia does very well in alkaline or saline soils where moisture carries salinity to the soil surface. Consider forages in these areas to use up moisture and compete with kochia. Use narrower row spacing for your crop as this will help suppress kochia growth. Try to cut out kochia patches before they produce viable seed. Baling patches after seed becomes viable may result in seed dispersal during manure application.
Please contact your local Shur-Gro agronomist for assistance in developing a strategy for kochia control in your crops.