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Control of Glyphosate-Resistant Canada Fleabane (Conyza canadensis) and Waterhemp (Amaranthus tuberculatus var. Rudis) in Glyphosate/Dicamba-Resistant Soybean (Glycine max)

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Title: Control of Glyphosate-Resistant Canada Fleabane (Conyza canadensis) and Waterhemp (Amaranthus tuberculatus var. Rudis) in Glyphosate/Dicamba-Resistant Soybean (Glycine max)
Author: Hedges, Brittany; Hooker, David; Robinson, Darren; Sikkema, Peter
Department: Department of Plant Agriculture
Program: Plant Agriculture
Advisor: Sikkema, Dr. Peter
Abstract: Field studies were conducted in Ontario, Canada on the control of glyphosate-resistant (GR) Canada fleabane and waterhemp in 2016 and 2017. Glyphosate/dicamba was applied to Canada fleabane at 3 postemergent (POST) application timings (5, 15 and 25 cm) and 4 herbicide rates (0, 900, 1350 and 1800 g ae ha-1). An increase in plant height at the application timing, led to a decrease in control of Canada fleabane; an increase in herbicide rate led to an increase in efficacy. There was an interaction between application timing and rate for density and biomass only. This same study was conducted with GR waterhemp, the same trend followed except there was no interaction between application timing and herbicide rate. Control of GR Canada fleabane with several preplant herbicide tankmixes was evaluated; there was no increase in control with the addition of a second-effective site-of-action. Similarly, GR waterhemp control did not increase with the addition of a second-effective mode-of-action. Acceptable control was not obtained with glyphosate/dicamba applied pre-emergent (PRE), therefore, another mode-of-action is needed for effective control of GR waterhemp. A two-pass program of an effective PRE herbicide followed by glyphosate/dicamba provided season-long control of GR waterhemp and was more efficacious than a PRE or POST program alone.
URI: http://hdl.handle.net/10214/12997
Date: 2018-04
Rights: Attribution-ShareAlike 2.5 Canada


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Attribution-ShareAlike 2.5 Canada Except where otherwise noted, this item's license is described as Attribution-ShareAlike 2.5 Canada