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Management of Large, Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri) in Corn

  • Whitney D. Crow (a1), Lawrence E. Steckel (a1), Thomas C. Mueller (a2) and Robert M. Hayes (a1)


Palmer amaranth is a very problematic weed that has evolved resistance to several classes of herbicides, including 5-enolypyruvylshikimate-3-phosate synthase–inhibiting herbicides and photosystem II–inhibiting herbicides. In recent years, corn producers have had difficulty controlling large Palmer amaranth (> 20 cm) in corn > 30 cm whether it be due to environmental conditions or management failures. Palmer amaranth management in corn this tall is made even more challenging because atrazine is not labeled POST in corn > 30 cm tall. Therefore, a study was conducted in 2013 and 2014 in Jackson, TN, to evaluate herbicide programs in corn > 30 cm tall for the control of glyphosate-resistant Palmer amaranth > 20 cm tall. Treatments consisted of herbicides applied alone and in mixtures with dicamba plus diflufenzopyr. Herbicides were applied POST to corn between the V5 and V6 growth stages. Dicamba plus diflufenzopyr 28 d after application controlled Palmer amaranth > 87%. The herbicides alone or in combinations applied as tank mixtures did not improve control (< 76%) over dicamba plus diflufenzopyr alone. There were no grain-yield differences among treatments because of Palmer amaranth control. This was likely due to the Palmer amaranth competition having already affected corn yield by the V5 to V6 corn growth stages.

Amaranthus palmeri es una maleza muy problemática que ha evolucionado resistencia a varias clases de herbicidas, incluyendo herbicidas inhibidores de 5-enolpyruvylshikimate-3-phosphate synthase y herbicidas inhibidores del fotosistema II. En años recientes, productores de maíz han tenido dificultades para controlar plantas grandes (>20 cm) de A. palmeri en maíz >30 cm, ya sea debido a condiciones ambientales o a fallas en el manejo. El manejo de A. palmeri en maíz de esta altura se ha hecho más difícil porque atrazine no está registrado para aplicaciones POST en maíz >30 cm de altura. Por esta razón, se realizó un estudio en 2013 y 2014 en Jackson, Tennessee, para evaluar programas de herbicidas en maíz >30 cm de altura para el control de A. palmeri >20 cm resistente a glyphosate. Los tratamientos consistieron de herbicidas aplicados solos y en mezclas con dicamba más diflufenzopyr. Los herbicidas fueron aplicados al maíz POST entre los estadios de crecimiento V5 y V6. Dicamba más diflufenzopyr 28 d después de la aplicación controló A. palmeri >87%. Los herbicidas solos o en combinaciones aplicados como mezclas en tanque no mejoraron el control (<76%) en comparación con solo dicamba más diflufenzopyr. No hubo diferencias en el rendimiento de grano entre tratamientos debido al control de A. palmeri. Este se debió probablemente a que la competencia de A. palmeri ya había afectado el rendimiento del maíz en los estadios de crecimiento V5 y V6.


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Associate Editor for this paper: William Johnson, Purdue University.



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Abendroth, LJ, Elmore, RW, Boyer, MJ, Marlay, SK (2011) Corn Growth and Development. Ames, IA: Iowa State University Extension PMR 1009
Anonymous (2014a) AAtrex 4L herbicide product label. EPA Reg. No. 100-497. Greensboro, NC: Syngenta Crop Protection, Inc. 11 p
Anonymous (2014b) Liberty herbicide product label. EPA Reg. No. 264-829. Research Triangle Park, NC: Bayer CropScience LP. 5 p
Anonymous (2014c) Callisto herbicide product label. EPA Reg. No. 100-1131. Greensboro, NC: Syngenta Crop Protection, Inc. 14 p
Anonymous (2014d) Laudis herbicide product label. EPA Reg. No. 264-960. Research Triangle Park, NC: Bayer CropScience LP. 7 p
Carey, JB, Kells, JJ (1995) Timing of total postemergence herbicide application to maximize weed control and corn (Zea mays) yield. Weed Technol 9: 356361
Carmer, SG, Nyquist, WE, Walker, WM (1989) Least significant differences for combined analysis of experiments with two or three-factor treatment designs. Agron J 81: 665672
Chandi, A, Jordan, DL, York, AC, Lewis, R M, Burton, JD, Culpepper, AS, Whitaker, JA (2013) Interference and control of glyphosate resistant and susceptible Palmer amaranth (Amaranthus palmeri) populations under greenhouse conditions. Weed Sci 64: 259266
Fernandez-Corejo, J, McBride, WD (2000) Genetically Engineered Crops for Pest Management in U.S. Agriculture: Farm Level Effects . Washington, DC: Resource Economics Division, Economic Research Service, U.S. Department of Agriculture. Agricultural Economics Report No. 786. Assessed September 16, 2014
Gower, SA, Loux, MM, Cardina, J, Harrison, SK, Spankle, PL, Probst, NJ, Bauman, TT, Bugg, W, Curran, WS, Currie, RS, Harvey, RG, Johnson, WG, Kells, JJ, Owen, MDK, Regehr, DL, Slack, CH, Spaur, M, Sprague, CL, VanGessel, M, Young, BG (2001) Effect of postemergence glyphosate application timing on weed control and grain yield in glyphosate-resistant corn: results of a 2-yr multistate study. Weed Technol 17: 821828
Gower, SA, Loux, MM, Harrison, SK (2002) Effect of planting date, residual herbicide, and postemergence application timing on weed control and grain yield in glyphosate-tolerant corn (Zea mays). Weed Technol 27: 6371
Hall, MR, Swanton, CJ, Anderson, GW (1992) The critical period of weed control in grain corn (Zea mays). Weed Sci 40: 441447
Heap, IM (2013) International Survey of Herbicide Resistant Weeds. Accessed July 15, 2013
Horak, MJ, Loughin, TM (2000) Growth analysis of four Amaranthus species. Weed Sci 48: 347355
Keeley, PE, Carter, CH, Thullen, RM (1987) Influence of planting date on growth of Palmer amaranth (Amaranthus palmeri) . Weed Sci 35: 199204
Knake, EL, Slife, FW (1969) Effect of time of giant foxtail removal from corn and soybeans. Weeds 10: 2629
Massinga, RA, Currie, RS, Horak, MJ, Boyer, J Jr (2001) Interference of Palmer amaranth in corn. Weed Sci 49: 202208
Massinga, RA, Currie, RS, Troien, TP (2003) Water use and light interception under Palmer amaranth (Amaranthus palmeri) and corn competition. Weed Sci 51: 523531
McClure, AT (2009) Planting Corn for Grain in Tennessee. Accessed July 29, 2014
Myers, MW, Curran, WS, VanGessel, MJ, Majek, BA, Scott, BA, Mortensen, DA, Calvin, DD, Karsten, HD, Roth, GW (2005) The effect of weed density and application timing on weed control and corn grain yield. Weed Technol 19: 102107
[NASS] National Agricultural Statistics Service, U.S. Department of Agriculture (2002) Agricultural Chemical Usage 2001 Field Crops Summary. Assessed March 7, 2015
Norsworthy, JK (2004) Small grain cover crop interaction with glyphosate-resistant corn (Zea mays). Weed Technol 18: 5259
Norsworthy, JK, Griffith, GM, Scott, RC, Smith, KL, Oliver, LR (2008) Confirmation and control of glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in Arkansas. Weed Technol 22: 108113
Norsworthy, JK, Oliveira, MJ (2004) Comparison of the critical period for weed control in wide- and narrow-row corn. Weed Sci 52: 802804
Page, ER, Cerrudo, D, Westra, M, Loux, M, Smith, K, Foresman, C, Wright, H, Swanton, CJ (2012) Why early season weed control is important in maize. Weed Sci 60: 423430
Steckel, LE, Eubank, T, Montgomery, R, Scott, B, Smeda, R, Blinka, E, Mills, A, Stanislav, J, Seifert-Higgins, S, Zabala, F (2013) Palmer amaranth weed control programs for Roundup Ready Xtend soybeans in the mid-south. Page 179 in Proceedings of the 66th Annual Meeting of the Southern Weed Science Society (SWSS). Las Cruces, NM: SWSS
Steckel, LE, Sprague, CL (2004) Common waterhemp (Amaranthus rudis) interference in corn. Weed Sci 52: 359364
Tapia, LS, Bauman, TT, Harvey, RG, Kells, JJ, Kapusta, G, Loux, MM, Lueschen, WE, Owen, MDK, Hageman, LH, Strachan, SD (1997) Postemergence herbicide application timing effects on annual grass control and corn (Zea mays) grain yield. Weed Sci 45: 138143
Webster, TM, Grey, TL. (2015) Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) morphology, growth and seed production in Georgia. Weed Sci 63: 264272
Zimdahl, RL (1988) The concept and application of the critical weed-free period. Pages 145155 in Altieri, MA, Liebman, M, eds. Weed Management in Agroecosystems: Ecological Approaches. Boca Raton, FL: CRC



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