Herbicide Resistant Kochia - Challenges and Management

Herbicide resistant kochia has been an increasing concern since glyphosate resistant kochia was identified. Dr. Charles Geddes, research scientist at AAFC Lethbridge, has been studying the integrated management of kochia.

In the most recent The Growing Point podcast, Geddes discussed the observations from the most recent kochia survey, the biology and challenges of managing kochia, and the cultural methods for controlling kochia.

Tune in to the new podcast episode for the most updated info about kochia.

The table above is a summary of the kochia surveys showing a drastic increase in herbicide resistant kochia in the past decade. More detailed information of the 2021 kochia survey can be found at Canadian Agronomist or the original survey report. 

Herbicide resistant kochia poses significant challenges to its management. Integrated weed management (IWM), in this case, is crucial for protecting crop yield and limiting further development of herbicide resistant kochia. For example, in a small plot experiment under a wheat-canola-wheat-lentil rotation, doubling seeding rates of all crops (from 200 to 400 seeds/m² for wheat) and using a smaller row spacing (9” instead of 18”) reduced kochia biomass by 8 per cent. Including a winter wheat in crop rotation also reduced kochia biomass by 64 per cent. These and more potential cultural practices can be included in the toolbox for managing herbicide resistant kochia.