Blog: The Wheat Sheaf

Herbicide Resistance Summit Review

Alberta Wheat Commission recently sponsored the Herbicide Resistance Summit Hosted by Top Crop Manager is Saskatoon. It was an important event to shine further light on the problem of herbicide resistance in Western Canada.

Ian Heap, Director of International Survey of Herbicide Resistant Weeds in Corvallis, Oregon said resistance is a naturally occurring response to selective pressure that can start off as one plant in 10,000,000 and that the economic impact of resistance is now the most important consideration.

The International Survey of Herbicide-Resistant Weeds has 21 years of data online. It is available by clicking here:

He said there are 466 unique resistant biotypes with 249 species of resistant weeds.  Different herbicide groups act on different areas of plants. Wild Oat in Manitoba is now resistant to five herbicide groups.

He reported that North America, Europe and Asia lead the world in resistant weeds, but there are reporting problems in other countries. Wheat has more resistant weeds than any other crop, but not all resistance is due to herbicide pressure.

Hugh Beckie, Weed Scientist with Agriculture and Agri-Food Canada in Saskatoon gave an update on the state of weed resistance in Western Canada. There are one and a half new cases in Canada every year. There are just over 60 in Canada now. There are 23 biotypes in Alberta, 19 in Saskatchewan and 21 in Manitoba. Cleaver resistance has increased the fastest in Western Canada and over 50 per cent of fields in Western Canada have herbicide resistant weeds. The cost to agriculture is now over $1 billion annually.

There are 100 cases of herbicide resistant kochia in Western Canada.  When it tumbles as many as 100,000 seeds can be released by one kochia plant. Kochia is a cross pollinator so resistance genes spread easily. The next herbicide resistance weed survey in Alberta will be in 2017.

He gave a top 10 list of Best management Practices for herbicide resistance management:

  • Sound record keeping of herbicides and fields using GPS technology.
  • Strategic tillage.
  • Field and site specific weed management – patch management.
  • Weed sanitation.
  • In-crop herbicide rotation.
  • Burn down herbicide rotation.
  • Herbicide mixtures.
  • Pre and post herbicide application scouting.
  • Competitive crops.
  • Crop rotation

Growers need to be very vigilant in Alberta to avoid resistant problems faced by farmers in other areas and need to take an integrated approach to weed management now, before the best tool for weed control ever developed, glyphosate, is lost.



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