Evaluation of foliar‐applied post‐emergence corn–soybean herbicides on giant ragweed and waterhemp control in Wisconsin

Giant ragweed (Ambrosia trifida L.) and waterhemp (Amaranthus tuberculatus [Moq.] J.D.Sauer) are highly competitive the most troublesome weeds in corn (Zea mays soybean (Glycine max Merr.) cropping systems Wisconsin. Field experiments were conducted to evaluate efficacy of multiple foliar-applied POST-emergence herbicides on giant at Janesville, WI (2020 2021), groups 2- 9-resistant Brooklyn, (2019 2020), respectively. Several from site action 2, 4, 5, 6, 9, 10, 14, 27 evaluated. Herbicide treatments applied when reached ~10 cm height. (0-100% visual control) was evaluated 14 days after treatment (DAT). Group 2 provided poor (<45%) control DAT. encompassing different sites >90% control. Certain best (74-87%) waterhemp, but no herbicide this study = 90% Weed management programs containing effective PRE- accompanied by non-chemical strategies recommended extend spectrum chemical reduce risk selection further herbicide-resistant biotypes for both Wisconsin beyond.