Weed Spotlight: Canada Fleabane (Conyza Canadensis)

Identification

Short taproot, sparsely hairy leaves with smooth or slightly toothed margins. One or more erect flowering stems. Canada Fleabane can grow to almost 6 feet in height.

Habitat

Canada Fleabane is a winter or summer annual found throughout Ontario in pastures, grain fields, roadsides and gardens. It can be found in all soil types, but is most common on coarse textured soils. Glyphosate-resistant Canada fleabane populations have been confirmed in the U.S., Czech Republic, Brazil, China, Spain and in Ontario. There are populations of Canada fleabane in Ontario that are resistant to Group 2 and 9 herbicides (multiple resistance).

Reproduction

The number of seeds produced per plant is proportional to plant height. A plant ​1.3 feet tall produces about 2,000 seeds while a plant 5 feet tall produces about 230,000 seeds¹. Canada fleabane seeds have a short-term seed bank and can survive more than a year, but probably not more than three years under most conditions.

Yield Loss

Canada fleabane interference in crops is influenced by time of emergence and density². Canada fleabane at densities of 100-200 plants/m² can reduce crop yield by 90% and still produce 100,000 seeds per plant³. At a density of 100 plants/m², Canada fleabane reduced soybean yields by 97%².

How to Outsmart Canada Fleabane

• Scout early and often.
• Start Clean with a PP/PRE tank mix.
• Apply a residual PP/PRE herbicide for extended control.
• Apply the right rate at the right time.
• Aggressive tillage on small Canada fleabane is also an effective option.