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Crop Tolerance and Weed Management Systems in Imidazolinone-Tolerant Corn (Zea mays L.)

Published online by Cambridge University Press:  20 January 2017

Ann M. Thompson
Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77840
Enrique Rosales-Robles*
INIFAP, Campo Experimental Rio Bravo, Mexico 88900
James M. Chandler
Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77840
Paul R. Nester
American Cyanamid Co., The Woodlands, TX 77381
Christopher H. Tingle
Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77840
Corresponding author's E-mail:


Field studies were conducted in 1997 and 1998 to evaluate the efficacy of imidazolinone weed management systems and crop tolerance of imidazolinone-tolerant (IT) corn to imazapic. Imazapic (36 and 72 g/ha) was evaluated when applied PRE; early postemergence (EPOST), when corn was at the two- to three-leaf stage; and late postemergence (LPOST), when corn was at the six- to eight-leaf stage. Imazapyr + imazethapyr EPOST and metolachlor + atrazine followed by (fb) primisulfuron LPOST were evaluated as commercial standards. Imazapic at 36 g/ha EPOST controlled johnsongrass, Texas panicum, smellmelon, and ivyleaf and entireleaf morningglory at least 93% when adequate rainfall occurred. Devil's claw was controlled at least 85% with imazapic EPOST or LPOST at either rate. Imazapic at 36 g/ha EPOST and LPOST controlled eclipta 88 and 91%, respectively. Yellow nutsedge was controlled >91% with imazapic LPOST, which was superior to imazapic applied EPOST. Broadleaf signalgrass was controlled 94% with imazapic at 72 g/ha LPOST, which was significantly higher than other herbicide treatments. Imazapic at 36 and 72 g/ha applied PRE under moisture stress resulted in reduced weed control; but when adequate rainfall occurred, weed control was generally similar to that of EPOST and LPOST applications. Imazapic crop response at 72, 105, 140, and 211 g/ha applied at EPOST and LPOST was evaluated in two IT corn hybrids. Crop response varied with soil and environmental conditions and application timings. Imazapic at 72, 105, and 140 g/ha EPOST resulted in crop injury 33 to 55% at 6 wk after planting (WAP) in a coarse soil; however, crop injury decreased to <20% at 12 WAP. Low crop injury (<9%) was observed at 12 WAP in a clay soil. Imazapic applied LPOST resulted in lower crop injury than EPOST application. Corn plant height and yield were not affected by any imazapic treatment.

Research Article
Copyright © Weed Science Society of America 

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Literature Cited

Alford, J. L., Hayes, R. M., Rhodes, G. N., Steckel, L. E., and Mueller, T. C. 2005. Broadleaf signalgrass (Brachiaria platyphylla) interference in corn. Weed Sci. 53:97100.CrossRefGoogle Scholar
Anderson, W. P. 1996. Weed Science: Principles and Applications. 3rd ed. Minneapolis, MN: West. Pp. 265269.Google Scholar
Bailey, W. A., Wilcut, J. W., Jordan, D. L., Swann, C. W., and Langston, V. B. 1999a. Weed management in peanut (Arachis hypogaea) with diclosulam preemergence. Weed Technol. 13:450456.CrossRefGoogle Scholar
Bailey, W. A., Wilcut, J. W., Jordan, D. L., Swann, C. W., and Langston, V. B. 1999b. Response of peanut (Arachis hypogaea) and selected weeds to diclosulam. Weed Technol. 13:771776.CrossRefGoogle Scholar
Currie, R. S., Kwon, C. S., and Penner, D. 1995. Magnitude of imazethapyr resistance of corn (Zea mays) hybrids with altered acetolactate synthase. Weed Sci. 43:578582.CrossRefGoogle Scholar
Ducar, T. J., Wilcut, J. W., and Richburg, J. S. III. 2004. Weed management in imidazolinone-resistant corn with imazapic. Weed Technol. 18:10181022.CrossRefGoogle Scholar
Ghosheh, H. Z., Holshouser, D. L., and Chandler, J. M. 1996. The critical period of johnsongrass (Sorghum halepense) control in field corn (Zea mays). Weed Sci. 44:944947.CrossRefGoogle Scholar
Goetz, A. J., Wehtje, G., Walker, R. H., and Hajek, B. 1986. Soil solution and mobility characterization of imazaquin. Weed Sci. 34:788793.CrossRefGoogle Scholar
Goetz, A. J., Lavy, T. L., and Gbur, E. E. Jr. 1990. Degradation and field persistence of imazethapyr. Weed Sci. 38:421428.CrossRefGoogle Scholar
Gunsolus, J. L. and Curran, W. S. 1991. Herbicide mode of action and injury symptoms. St. Paul, MN: University of Minnesota, North Central Regional Extension Publication 337. 15 p.Google Scholar
Monks, C. D., Wilcut, J. W., Richburg, J. S., Hatton, J. H., and Patterson, M. G. 1996. Effect of AC 263,222, imazethapyr, and nicosulfuron on weed control and imidazolinone-tolerant corn (Zea mays) yield. Weed Technol. 10:822827.CrossRefGoogle Scholar
Mueller, T. C. and Hayes, R. M. 1997. Effect of tillage and soil-applied herbicides on broadleaf signalgrass (Brachiaria platyphylla) control in corn (Zea mays). Weed Technol. 11:698703.CrossRefGoogle Scholar
Newhouse, K., Wang, T., and Anderson, P. 1991. Imidazolinone-tolerant crops. in Shaner, D. L. and O'Conner, S. L., eds. The Imidazolinone Herbicides. Boca Raton, FL: CRC. Pp. 139150.Google ScholarPubMed
Renner, K. A., Meggit, W. F., and Penner, D. 1988. Effect of soil pH on imazaquin and imazethapyr adsorption to soil and phytotoxicity to corn (Zea mays). Weed Sci. 36:7883.CrossRefGoogle Scholar
Richburg, J. S. III, Wilcut, J. W., and Wehtje, G. R. 1994. Toxicity of AC 263,222 to purple (Cyperus rotundus) and yellow nutsedge (Cyperus esculentus). Weed Sci. 42:398402.CrossRefGoogle Scholar
Sprague, C. L., Stoller, E. W., and Hart, S. E. 1997. Preemergence broadleaf weed control and crop tolerance in imidazolinone-resistant and susceptible corn (Zea mays). Weed Technol. 11:118122.CrossRefGoogle Scholar
Stougaard, R. N., Shea, P. J., and Martin, A. R. 1990. Effect of soil type and pH on adsorption, mobility, and efficacy of imazaquin and imazethapyr. Weed Sci. 38:6773.CrossRefGoogle Scholar
Trotter, D. M., Baril, A., Wong, M. P., and Kent, R. A. 1990. Canadian water quality guidelines for atrazine. Ottawa, ON: Inland Waters Directorate, Environment Canada Scientific Series 168. 106 p.Google Scholar
[USDA-NASS] U.S. Department of Agriculture–National Agricultural Statistics Service. 2004. State Level Data for Field Crops: Grains. Web page: Accessed: October 1, 2004.Google Scholar
[USDA-NASS] U.S. Department of Agriculture–National Agricultural Statistics Service. 2005. Agrichemical Chemical Use Database. Web page: Accessed: March 15, 2005.Google Scholar
Vencill, W. K. ed. 2002. Herbicide Handbook. 8th ed. Lawrence, KS: Weed Science Society of America. Pp. 244258.Google Scholar
Wilcut, J. W., Richburg, J. S. III, Wiley, G. L., and Walls, F. R. Jr. 1996. Postemergence AC 263,222 systems for weed control in peanut (Arachis hypogea). Weed Sci. 44:615621.CrossRefGoogle Scholar
Wilcut, J. W., Richburg, J. S. III, and Walls, R. Jr. 1999. Response of johnsongrass (Sorghum halepense) and imidazolinone-resistant corn (Zea mays) to AC 263,222. Weed Technol. 13:484488.CrossRefGoogle Scholar