Canada Fleabane

Identify and control glyphosate resistant Canada fleabane in Eastern Canada.


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Canada Fleabane Biology

  • Canada fleabane (Conyza canadensis) is a winter or summer annual with one or more erect, flowering stems and can grow up to 180 cm in height
  • It can be found on all soil types, including organic soils but is most common on coarse textured soils
  • Canada fleabane seeds are 1-2 mm long, almost transparent, and have an attached pappus, or parachute, which carries the seed for long distances
  • The weed has a short taproot, sparsely hairy leaves with smooth or slightly toothed margins
  • Canada fleabane seeds have a short-term seed bank. They can survive for more than a year, but probably not more than 3 years under most conditions
  • The number of seeds produced per plant is proportional to plant height. A plant 0.4 meter tall produces about 2,000 seeds while a plant 1.5 meter tall produces about 230,000 seeds2
     

Weed Interference and Resistance

  • Canada fleabane interference in crops is influenced by time of emergence and density3
  • Canada fleabane at densities of 100-200 plants per square meter can reduce crop yield by 90% and still produce 100,000 seeds per plant1
  • At a density of 100 plants per square meter, Canada fleabane reduced soybean yields by 97%3
  • Glyphosate-resistant Canada fleabane populations have been confirmed in the U.S., Czech Republic, Brazil, China, Spain and in Southwest Ontario
  • Canada fleabane resistance to ALS herbicides (Group 2) is widespread in the U.S.
     

MINIMIZE THE RISK OF WEED RESISTANCE

  • Start clean and control weeds early
  • Use Roundup Ready® technology as your foundation
  • Add other herbicides and cultural practices where appropriate as part of the Roundup Ready cropping system
  • Use the right rate at the right time
  • Control weeds throughout the season and reduce the weed seed bank
     

RATE YOUR RISK, KNOW YOUR OPTIONS

  • Go to www.weedtool.com
  • Answer 10 field-related questions
  • Get your risk rating score
  • Discover how to lower your risk
  • Learn best management practices for reducing your risk of developing glyphosate resistance
     

Recommendations for Control of Glyphosate Resistant Canada Fleabane

Genuity® Roundup Ready 2 Yield® Soybeans

  • Pre-plant: Tank-mix Roundup Transorb® HC with Eragon®, Integrity®, Optill® or Sencor®.

Winter Wheat

  • POST: 2,4-D ester, Estraprop® or Infinity®.

Corn hybrids with Roundup Ready® 2 Technology

  • Pre-emergence: Tank-mix Roundup Transorb HC with Banvel® II, Integrity and Marksman®.
  • Post-emergence: Apply Distinct®, or tank-mix Roundup WeatherMAX® with Banvel II or Marksman.
  • Tillage is also an effective option to control Canada fleabane
  • Scout fields and control weeds throughout the season
  • Proper application timing protects yield, ensures correct use rate for weed size and considers the impact of environmental conditions on performance

The effective use of Roundup® agricultural herbicides and Roundup Ready® crops has continued in areas where glyphosate resistance has occurred. Glyphosate resistant weeds have been effectively managed by including tank mixes, tillage and other cultural methods of weed control.

 

Sources:

1Bruce, J.A., and Kells, J.J. 1990. Horseweed (Conyza Canadensis) Control in No-Tillage soybeans (glycine max) with preplant and preemergence herbicides. Weed Technology. 4:642-647

2 Canada Fleabane Factsheet. Ontario Ministry of Agriculture, Food and Rural Affairs. http://www.omafra.gov.on.ca/english/ crops/facts/02-067.htm

3 Dauer, J.T., Mortensen, D.A., and Vangessel, M.J. 2007. Temporal and special dynamics of long-distance Conyza Canadensis seed dispersal. Journal of Applied Ecology. 44:105-114.