Control of Glyphosate-Resistant Waterhemp with Two-Pass Weed Control Strategies in Glyphosate/Dicamba-Resistant Soybean
- 1 University of Guelph, Ridgetown Campus, Ridgetown, Canada
- 2 University of Guelph, Ridgetown Campus, Ridgetown, Canada
- 3 University of Guelph, Ridgetown Campus, Ridgetown, Canada
- 4 University of Guelph, Ridgetown Campus, Ridgetown, Canada
- 5 University of Guelph, Ridgetown Campus, Ridgetown, Canada
Abstract
Waterhemp is a small-seeded, dioecious, broadleaf weed that emerges throughout the growing season. If left uncontrolled, waterhemp interference can reduce soybean yield up to 73%. Glyphosate-resistant (GR) waterhemp was first discovered in one county in Ontario in 2014; as of 2017, it has been found in two other counties. Glyphosate/dicamba-resistant soybean can be sprayed with glyphosate and/or dicamba preplant (PP), preemergence (PRE) and/or postemergence (POST). The objective of this study was to determine the control of GR waterhemp in glyphosate/dicamba-resistant soybean with PRE residual herbicides, glyphosate/dicamba applied POST or a two-pass program of a PRE residual herbicide followed by glyphosate/dicamba applied POST. At 8 weeks after application (WAA), pyroxasulfone (150 g ai ha - 1 ), <i> S </i> -metolachlor/metribuzin (1943 g ai ha - 1 ), pyroxasulfone/sulfentrazone (300 g ai ha - 1 ) and flumioxazin/pyroxasulfone (240 g ai ha - 1 ), applied PRE, resulted in 71 % , 85 % , 82 % and 90% GR waterhemp control, respectively. The same PRE herbicides, followed by glyphosate/dicamba (1800 g ae ha - 1 ) POST, improved control to greater than 96%. This study concludes that a two-pass program of an effective soil applied residual herbicide followed by glypho sate/dicamba POST controlled GR waterhemp in glypho sate/dicamba-resistant soybean.
- Franz, J.E., Mao, M.K. and Sikorski, J.A. (1997) Glyphosate: A Unique Global Herbicide. American Chemical Society, Washington DC.
- Hoss, N.E., Al-Khatib, K., Peterson, D.E. and Loughin, T.M. (2003) Efficacy of Glyphosate, Glufosinate, and Imazethapyr on Selected Weed Species. Weed Science, 51, 110-117. https://doi.org/10.1614/0043-1745(2003)051[0110:EOGGAI]2.0.CO;2
- Heap, I. (2018) The International Survey of Herbicide Resistant Weeds. http://www.weedscience.com
- Costea, M. and Tardif, F.J. (2003) Conspectus and Notes on the Genus Amaranthus in Canada. Rhodora, 105, 260-281.
- Schryver, M.G., Soltani, N., Hooker, D.C., Robinson, D.E., Tranel, P.J. and Sikkema, P.H. (2017) Glyphosate-Resistant Waterhemp (Amaranthus tuberculatus var. rudis) in Ontario, Canada. Canadian Journal of Plant Science, 97, 1057-1067. https://doi.org/10.1139/CJPS-2016-0371
- Schryver, M.G., Soltani, N., Hooker, D.C., Robinson, D.E., Tranel, P.J. and Sikkema, P.H. (2017) The Distribution and Control of Glyphosate-Resistant Waterhemp (Amaranthus tuberculatus var. rudis) in Soybean (Glycine max) in Ontario. M.Sc. Thesis, University of Guelph, Guelph, ON, 59-83.
- Schryver, M.G., Soltani, N., Hooker, D.C., Robinson, D.E., Tranel, P.J. and Sikkema, P.H. (2017) Control of Glyphosate-Resistant Common waterhemp (Amaranthus rudis) in Three New Herbicide-Resistant Soybean Varieties in Ontario. Weed Technology, 31, 828-837. https://doi.org/10.1017/wet.2017.81
- Hartzler, R.G., Battles, B.A. and Nordby, D. (2004) Effect of Common Waterhemp (Amaranthus rudis) Emergence Date on Growth and Fecundity in Soybean. Weed Science, 52, 242-245. https://doi.org/10.1614/WS-03-004R
- Vyn, J.D., Swanton, C.J., Weaver, S.E. and Sikkema, P.H. (2007) Control of Herbicide-Resistant Common Waterhemp (Amaranthus tuberculatus var. rudis) with Pre- and Post-Emergence Herbicides in Soybean. Canadian Journal of Plant Science, 87, 175-182. https://doi.org/10.4141/P06-016
- Steckel, L.E., Sprague, C.L., Hager, A.G., Simmons, F.W. and Bollero, G.A. (2003) Effects of Shading on Common Waterhemp (Amaranthus rudis) Growth and Development. Weed Science, 51, 898-903. https://doi.org/10.1614/P2002-139
- Hay, M.M. (2017) Control of Palmer Amaranth (Amaranthus palmeri) and Common Waterhemp (Amaranthus rudis) in Double Crop Soybean and with Very Long Chain Fatty acid Inhibitor Herbicides. M.Sc. Thesis, Kansas State University, Manhattan, KS, 72 p.