Integrated approach to control glyphosate-resistant Ambrosia trifida in North America
Ambrosia trifida (Asteraceae, EPPO List of Invasive Alien Plants) is native to North America and within the EPPO region the species is regarded as mainly transient with populations observed in Austria, Belarus, Belgium, Czech Republic, Denmark, the United Kingdom, Estonia, France, Ireland, Latvia, Lithuania, Moldova, Norway, Poland, Slovakia, Slovenia and the Ukraine. In Israel, the plant was found during summer 2001 and was eradicated with herbicide treatments. Even in the native range, the species is problematic and in the US the species is declared as a noxious weed. In the US, glyphosate resistant A. trifida is a competitive and difficult to control annual broad-leaved weed in several field crops in the Midwestern USA and in Ontario, Canada. Treatments for the control of A. trifida were evaluated in field experiments conducted in 2013 and 2014. Tillage prior to maize sowing resulted in 80-85 % control compared to no tillage. Tillage followed by pre-emergent application of saflufenacil plus dimethenamid-P with or without atrazine resulted in 99 % control compared with 86–96 % control with pre-emergent herbicides alone at 7 and 21 days after application respectively. Tillage alone or post emergent herbicide treatment alone may resulted in 4–14 A. trifida plants per m2, whereas a pre- and post-emergent programme had less than 3 plants per m2. Maize yield was greatest with tillage followed by pre- and post-emergent herbicide application. It is concluded that the combination of tillage with pre- and post-emergent herbicide reduces A. trifida density and biomass accumulation early in the season and provides an integrated approach for effective management.
Sources
Ganie ZA, Lindquist JL, Jugulam M, Kruger GR, Marx DB, Jhala AJ (2017) An
integrated approach to control glyphosate-resistant Ambrosia trifida with tillage and herbicides in glyphosate-resistant maize. Weed Research 57, 112-122.