With its origin in Eurasia, kochia was introduced to Canada as an ornamental. It is a summer annual broadleaf weed that reproduces only by seed and can spread quickly due to its tolerance to drought and salinity, making it an invasive weed and challenge to control.
Did you know?
1. The weed is tolerant to drought and the seeds are high in protein, making the plant a valuable crop for livestock feed, however, due to its nitrous component, too much can be very toxic.
2. The seeds also contain an oviposition pheromone that can be added to mosquito pesticides as a lurel
3. When kochia matures, it breaks off at the base of the plant and becomes a tumbleweed, helping disperse the seeds.
Identification
Rosette leaves: seedlings form a rosette pattern with long hairs on the surface
Cotyledon: the undersides on seedlings are usually a bright pink color
Leaves: stalkless hairy and pale green leaves that often turn purple in autumn
Stem: the main stem is often tinged with red, but may be green depending on age
Flowers: small and green, usually found in clusters in the axils of upper leaves and on short, dense spikes.
Seeds: nearly oval, 1.5 to 2.0 mm long, flattened with a groove on each side and dull brown in color with yellow markings.
Management
Glyphosate-resistant kochia is more complicated to control. With populations of glyphosate resistant Kochia growing in most prairie provinces in Canada, spraying glyphosate herbicides alone may not provide sufficient control and will actually select for more resistant populations in the future.
Since kochia is one of the first weeds to grow in spring, the key to management of the plant is to use herbicides early and rotating herbicide groups to alternate the mode of action.
Legislation
Considered a noxious weed in Manitoba and the Peace River district in BC, kochia is Class 2 in the Weed Seeds Order. Preventing the spread of kochia seeds is crucial to the Noxious Weeds Act.
Check out our Nasty Weeds (Part 1) ProTraining course:
Why are some weeds more aggressive in their growing habits than others?This course will look at how the Western Provinces categorizes their own list of “Nasty Weeds” and the roles and responsibilities for the Provincial Weed Act within BC, AB, SK and MB. Understanding the biology of the nasty weed provides insight in control tactics for that specific weed. The course will look at how weeds spread from their native country to new areas.
This course looks at identification, biology and control strategies for Jimsonweed, Japanese knotweed, Scentless chamomile, Yellow toadflax and Baby’s breath. We will discuss the threat of the invasive weeds species and the impact on the economy, human health and the environment.
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