By Dori Modney with files from Alberta Agriculture

Common weeds developing resistance to herbicides in farm fields

Jun 12, 2018 | 2:29 PM

LETHBRIDGE –  It’s been an issue in crop production for decades but, the issue has multiplied, as increasing numbers of weeds are no longer responding to herbicides.
 
Crop specialist with Alberta Agriculture, Harry Brook, says it should serve as a wake-up call to producers about the importance of rotating different herbicide groups when treating problem weeds.

Canada has reported resistance issues in weeds to at least six different herbicide groups.  
 
Glyphosate – commonly known as RoundUp – is found world wide and there is now glyphosate resistance in kochia in southern Alberta and it continues to spread. 
 
Herbicide resistant wild oats can also be found in many fields in the province, and some biotypes are resistant to more than one herbicide group.
 
According to Brook, when a producer uses the same herbicide or products using the same mode of action, they are actually helping select for those plants that are either not affected or affected less by the active ingredient than other plants.
 
“By killing off susceptible plants, you are actually setting the stage for the resistant ones to thrive as all their competition is killed off
Brook says short crop rotations and a lack of crop variety have set up the conditions to encourage weed resistance to emerge. 
 
Farmers can find the entire Herbicide Resistance article on the Alberta Agriculture website.