(Editor’s note: This is the fifth in a series of articles about nine of the most troublesome weeds and tips for eradicating them from your no-till operation.)
With high genetic diversity as well as tolerance to heat, cold and saline soils, kochia is a weed that plagues a large area of the Great Plains and western Canada.
It’s also one of the first summer annual weeds to germinate in the spring and can continue germinating into the summer across a wide range of temperatures.
But even this weed has some weaknesses if no-tillers take a multifaceted approach for control.
Kochia plants are competitive with crops and problematic in fallow periods between crops. Early-emerging kochia can reduce crop yields by 70% or more and can also interfere with harvest.
It can self-pollinate, but cross-pollination is common because the stigma is receptive to pollen several days before pollen is produced on the same plant. Cross pollination helps contribute to its high degree of genetic diversity and plant variability, as well as the spread of herbicide resistance.
Kochia also produces up to 30,000 seeds per plant and germination and establishment is optimized when seeds are at or near the soil surface. Seeds initiate germination within 2-3 hours under favorable conditions and seedlings establish quickly.
But it has minimal seed dormancy and seed life in the soil is short-lived, with less than 5% persisting more than 1 year, and less than 1% persisting longer than 2 years.
Early season kochia densities can…