Spraying Info

Playing the Odds Against
Herbicide Resistant Weeds

The Game:

  • Herbicide Tolerance: ability of a species to survive and reproduce after herbicide treatment 
     - ex. Group 1 on canola
  • Herbicide Resistance: ability of a plant to survive and reproduce after a dose of herbicide that would normally kill it
     - ex. RR/LL Canola

The Players:

  • Target Site System
     - Starve the plant (Groups 1, 2, 8, 9, 10, 13, 15, 20)
     - Build up of toxins (Groups 5, 6, 7, 10, 14, 22)
  • Resistance Mechanisms
     - Target site Mutation: site changes and chemical no longer fits
     - Target site Duplication: more sites and not enough checmical
     - Increased Detoxification: breaks down chemical
     - Reduce Translocation: plant rapidly kills tissues touch by chemical

Herbicide Resistance is a Numbers Game...
Ex. Group 1 Herbicide

   5th application             60.5%                 Weed Control Failure

 

But, I Don't Have a Problem!

  • 2014/2015 Saskatchewan HR survey:
     - 57% of fields has at least 1 HR weed to Group 1 or 2 (10%-31%-57%)
     - 65% of fields with HR wild oat (45% Group 1 and 26% Group 2)
     - Wild Oat Biotype HR to Groups 1,2,8,15 and 25

     - Group 2 HR Weeds
    - BMP: Group 2's no longer work on kochia across Saskatchewan

HR Kochia

  • AB Kochia Survery
     - 40% of samples (300) were positive for glyphosate resistance
     - 8% were Diacam (Group 4) Resistant
     - 10% were Group 2, Dicamba, and glyphosate resistant
  • MB Kochia Survey results available Fall 2019
  • SK Kochia Survey Collection will start Fall 2019

Herbicide Resistance Rehab

  • Admit you have a problem
  • Determine what the problem is (send for testing!)
  • Build a Strategy
    - Documentation
    - Hand-weed escapes
    - Plant perennial cover
    - Integrated Weed Management: Tools in the Toolbox

Beating the Odds

  • Crop Rotation (4 year)
    - Grasses/broadleaf/legume/perennials and competitive/non-competitive
    - time of seeding rate and decrease row space
    - forces herbicide rotations
  • Integrated Weed Management
    - increase sesed rate and decrease row space
    - Fertility Strategy
    - Tillage
  • Sanitation
    - Start with clean seed and clean equipment
    - Compost manure
    - Manage field boundaries and poor crop areas
  • Herbicide Management
    - Herbicide layering
    - Tank-mixing (adding Centurion to Liberty is not a tank mix!)
    - Rotate Herbicides

Google - Sask Herbicide Resistance Testing

 

Andrea De Roo
Crop Intelligence Agronomist 

Derooandrea@southcountry.ca  (639) 906-7066

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