Weed Wisdom June 2018

Screening service for glyphosate and/or auxinic herbicide-resistance

by Dr. Charles Geddes

Glyphosate (group 9)-resistant kochia is invading fields in western Canada and preliminary research shows that the incidence of glyphosate-resistance in fields with kochia populations is increasing quickly. Even worse, certain populations of glyphosate-resistant kochia in Saskatchewan have also tested positive for auxinic (group 4) herbicide-resistance. Acetolactate synthase (ALS) inhibitor (group 2)-resistance in kochia has spread across the prairie provinces to the point that all populations are now considered to be resistant to ALS inhibiting herbicides.

Triple herbicide-resistant kochia populations (to groups 2, 4, and 9) will have a large impact on prairie cropping systems and leave minimal options for management with herbicide. To help combat selection for herbicide-resistance in kochia, experts recommend that, in conjunction with a diverse herbicide program, land managers use non-chemical weed management tools such as: greater seeding rates, narrow row spacing, growing winter-annual crops, maintenance of fence lines (to mitigate seed dispersal from this tumbleweed), site-specific management and diligent crop scouting.

To aid in weed scouting efforts, the Weed Ecology and Cropping Systems research program at the AAFC Lethbridge Research and Development Centre will offer a screening service for suspected glyphosate (group 9)-resistant weeds and/or auxinic (group 4) herbicide-resistant kochia in the prairie provinces. Dr. Hugh Beckie, research scientist at the Saskatoon Research and Development Centre previously offered this service, which will transfer to Dr. Charles Geddes (AAFC-Lethbridge) upon Hugh's retirement from AAFC. The service will remain free-of-charge, and grower identification will remain confidential. Growers with suspected cases of glyphosate-resistant weeds or auxinic herbicide-resistant kochia are encouraged to take advantage of this service and get it confirmed. Confirmation of suspected populations will help western Canadian agriculture and its experts understand the distribution and extent of this problem.

Note: the screening process requires seed from the suspected population.

For further information or to submit a sample, please contact:

Charles Geddes
Weed Ecology and Cropping Systems
Research Scientist / Science and Technology Branch
Agriculture and Agri-Food Canada / Government of Canada
[email protected] / Tel: 403-359-6967
Lethbridge Research and Development Centre
5403 ≥ 1^st Avenue South
Lethbridge, Alberta, Canada
T1J 4B1

or

Louis Molnar
Weed Ecology and Cropping Systems
Senior Research Technician / Science and Technology Branch
Agriculture and Agri-Food Canada / Government of Canada
[email protected] / Tel: 403-317-3380
Lethbridge Research and Development Centre
5403 ≥ 1^st Avenue South
Lethbridge, Alberta, Canada
T1J 4B1