Argentine Fleabane (Conyza bonariensis)


Resistance status in Switzerland

For Argentine Fleabane, only one mode of action has resulted in a case of resistance.

A first case of glyphosate resistance (HRAC 9) was confirmed in Valais in 2020. Bearing in mind this species’ ability to develop resistance in other countries and the difficulty of treating all the plants at the optimal stage, careful monitoring of the reaction of Conyza species to herbicides is recommended.

Plant characteristics

Argentine Fleabane (Conyza bonariensis)

Biennial autumn dicot of the Asteraceae family

Colonised crops

All types of crops but mainly perennial crops, wasteland, field margins and roadsides

Favourable conditions
for development

Low-diversity rotations, infrequent ploughing. Sunny, warm locations

Preferred soils

Light, slightly saline, basic-pH soils

Germination window



Mainly by self-pollination but also by wind cross-pollination

EPPO code



Resistance Map