Kochia that survived pre-seed burnoff needs to be taken out before it drops seed later in the season. The big weeds can produce at least 15,000 seeds per plant – often many more – so letting them set seed and then spreading that seed with the combine can move a herbicide-resistant population across a field very quickly.
Kochia with resistance to both Group 2 and Group 9 herbicides is found all across the Prairies in big numbers. Agriculture and Agri-Food Canada weed scientists have also confirmed kochia populations with resistance to Group 4 and Group 14 herbicides.
The best practice is to control small kochia plants in the pre-seed window with a tank mix of effective herbicides. If kochia is still alive after crop emergence, growers have fewer options in canola fields.
The only in-crop herbicide option that works on Group-2 and Group-9 resistant kochia is an early application of Liberty on Liberty Link canola cultivars. Group-10 glufosinate in Liberty will control all resistant kochia populations as long as plants are not too large to kill at the time of spraying.
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