Skip to main content Accessibility help

Herbicide selection to terminate grass, legume, and brassica cover crop species

  • Kara B. Pittman (a1), Charles W. Cahoon (a2), Kevin W. Bamber (a3), Lucas S. Rector (a4) and Michael L. Flessner (a5)...


Cover crops provide a number of agronomic benefits, including weed suppression, which is important as cases of herbicide resistance continue to rise. To effectively suppress weeds, high cover crop biomass is needed, which necessitates later termination timing. Cover crop termination is important to mitigate potential planting issues and prevent surviving cover crop competition with cash crops. Field studies were conducted in Virginia to determine the most effective herbicide options alone or combined with glyphosate or paraquat to terminate a range of cover crop species. Results revealed that grass cover crop species were controlled (94% to 98%) by glyphosate alone 4 wk after application (WAA). Overall, legume species varied in response to the single active-ingredient treatments, and control increased with the addition of glyphosate or paraquat. Mixes with glyphosate provided better control of crimson clover and hairy vetch by 7% to 8% compared with mixes containing paraquat 4 WAA. Mix partner did not influence control of Austrian winter pea. No treatment adequately controlled rapeseed in this study, with a maximum of 58% control observed with single active-ingredient treatments and 62% control with mixes. Height reduction for all cover crop species supports visible rating data. Rapeseed should be terminated when smaller, which could negate weed suppressive benefits from this cover crop species. Growers should consider herbicide selection and termination timing in their cover crop plan to ensure effective termination.


Corresponding author

Author for correspondence: Michael L. Flessner, School of Plant and Environmental Sciences, Virginia Tech, 675 Old Glade Rd., Blacksburg, VA 24061. Email:


Hide All
Askew, MC, Cahoon, CW Jr, Flessner, ML, VanGessel, MJ, Langston, DB Jr, Ferebee, JH IV (2019) Chemical termination of cover crop rapeseed. Weed Technol 33:686692
Beckie, HJ, Nair, GSH, Warwick, SI, Johnson, E (2004) Multiple herbicide-resistant canola can be controlled by alternative herbicides. Weed Sci 52:152157
Bendig, J, Bolten, A, Bennertz, S, Broscheit, J, Eichfuss, S, Bareth, G (2014) Estimating biomass of barley using crop surface models (CSM) derived from UAV-based RGB imaging. Remote Sens 6:1039510412
Blouin, DC, Webster, EP, Bond, JA (2011) On the analysis of combined experiments. Weed Technol 25:165169
Burket, JZ, Hemphill, DD, Dick, RP (1997) Winter cover crops and nitrogen management in sweet corn and broccoli rotations. HortScience 32:664668
Carmer, SG, Nyquist, WE, Walker, WM (1989) Least significant differences for combined analyses of experiments with two- or three-factor treatment designs. Agron J 81:665672
Clarke, A, ed (2007) Managing Cover Crops Profitably. 3rd edn. College Park, MD: Sustainable Agriculture Research and Education. Pp 933
Cornelius, CD, Bradley, KW (2017) Herbicide programs for the termination of various cover crop species. Weed Technol 31:514522
Crespo, RJ, Wingeyer, AB, Kruger, GR, Riggins, CW, Tranel, PJ, Bernards, ML (2017) Multiple-herbicide resistance in a 2,4-D-resistant waterhemp (Amaranthus tuberculatus) population from Nebraska. Weed Sci 65:743754
[CTIC] Conservation Technology Information Center (2017) Report of the 2016-17 National Cover Crop Survey. Joint publication of the Conservation Technology Information Center, the North Central Region Sustainable Agriculture Research and Education Program, and the American Seed Trade Association. Accessed: March 3, 2019
Culpepper, AS, York, AC, Batts, RB, Jennings, KM (2000) Weed management in glufosinate- and glyphosate-resistant soybean (Glycine max). Weed Technol 14:7788
Curran, WS, Wallace, JM, Mirsky, S, Crockett, B (2015) Effectiveness of herbicides for control of hairy vetch (Vicia villosa) in winter wheat. Weed Technol 29:509518
Dabney, SM, Delgado, JA, Reeves, DW (2001) Using winter cover crops to improve soil and water quality. Commun Soil Sci Plant Anal 32:12211250
Ehlert, D, Horn, HJ, Adamek, R (2008) Measuring crop biomass density by laser triangulation. Comput Electron Agr 61:117125
Frans, R, Talbert, R, Marx, D, Crowley, H (1986) Experimental design and techniques for measuring and analyzing plant responses to weed control practices. Pages 2946 in Camper, ND, ed. Research Methods in Weed Science, 3rd edn. Westminster, CO: Southern Weed Science Society
Heap, I (2019) International survey of herbicide resistant weeds. Accessed: March 3, 2019
Holt, JS, LeBaron, HM (1990) Significance and distribution of herbicide resistance. Weed Technol 4:141149
Kegode, GO, Fronning, BE (2005) Artemisia biennis (biennial wormwood) control is influenced by plant size and weed flora at time of herbicide application. Crop Prot 24:915920
Klingaman, TE, King, CA, Oliver, LR (1992) Effect of application rate, weed species, and weed stage of growth on imazethapyr activity. Weed Sci 40:227232
Lawson, A, Cogger, C, Bary, A, Fortuna, A (2015) Influence of seeding ratio, planting date, and termination date on rye-hairy vetch cover crop mixture performance under organic management. PLoS ONE 10(6):e0129597
McCurdy, JD, McElroy, JS, Flessner, ML (2013) Differential response of four Trifolium species to common broadleaf herbicides: implications for mixed grass-legume swards. Weed Technol 27:123128
Mirsky, SB, Curran, WS, Mortensen, DA, Ryan, MR, Shumway, DL (2009) Control of cereal rye with a roller/crimper as influenced by cover crop phenology. Agron J 101:15891596
Mirsky, SB, Curran, WS, Mortensen, DA, Ryan, MR, Shumway, DL (2011) Timing of cover-crop management effects on weed suppression in no-till planted soybean using a roller crimper. Weed Sci 59:380389
Mirsky, SB, Ryan, MR, Teasdale, JR, Curran, WS, Reberg-Horton, CS, Spargo, JT, Wells, MS, Keene, CL, Moyer, JW (2013) Overcoming weed management challenges in cover crop-based organic rotational no-till soybean production in the Eastern United States. Weed Technol 27:193203
Mischler, R, Duiker, SW, Curran, WS, Wilson, D (2010) Hairy vetch management for no-till organic corn production. Agron J 102:355362
Miville, D, Leroux, GD (2018) Rolled winter rye-hairy vetch cover crops for weed control in no-till pumpkin. Weed Technol 32:251259
Owen, LN, Mueller, TC, Main, CL, Bond, J, Steckel, LE (2011) Evaluating rates and application timings of saflufenacil for control of glyphosate-resistant horseweed (Conyza canadensis) prior to planting no-till cotton. Weed Technol 25:15
Palhano, MG, Norsworthy, JK, Barber, T (2018) Evaluation of chemical termination options for cover crops. Weed Technol 32:227235
Roth, L, Streit, B (2018) Predicting cover crop biomass by lightweight UAS-based RGB and NIR photography: an applied photogrammetric approach. Precis Agric 19:93114
Sellers, BA, Ferrell, JA, MacDonald, GE, Kline, WM (2009) Dogfennel (Eupatorium capillifolium) size at application affects herbicide efficacy. Weed Technol 23:247250
Stephenson, DO, Bond, JA (2012) Evaluation of thiencarbazone-methyl- and isoxaflutole-based herbicide programs in corn. Weed Technol 26:3742
Teasdale, JR (1996) Contribution of cover crops to weed management in sustainable agricultural systems. J Prod Agric 9: 475479
[USDA] U.S. Department of Agriculture (2015) Virginia NRCS Cover Crop Planning Manual 1.0. Accessed: September 13, 2018
[USDA ERS] U.S. Department of Agriculture, Economic Research Service (2012) Distribution of cover crop use in the contiguous U.S., 2012. Accessed: March 3, 2019
Waggoner, BS, Mueller, TC, Bond, JA, Steckel, LE (2011) Control of glyphosate-resistant horseweed (Conyza canadensis) with saflufenacil tank mixtures in no-till cotton. Weed Technol 25:310315
Wallace, J, Lingenfelter, D, VanGessel, M, Johnson, Q, Vollmer, K, Besancon, T, Flessner, M, Chandran, R (2019) 2019 Mid-Atlantic Field Crop Weed Management Guide. University Park, PA: Penn State Agricultural Communications and Marketing. 55 p
Wayman, S, Cogger, C, Benedict, C, Burke, I, Collins, D, Bary, A (2014) The influence of cover crop variety, termination timing and termination method on mulch, weed cover and soil nitrate in reduced-tillage organic systems. Renew Agr Food Syst 30:450460
Westgate, LR, Singer, JW, Kohler, KA (2005) Method and timing of rye control affects soybean development and resource utilization. Agron J 97:806816
Whitaker, JR, York, AC, Jordan, DL, Culpepper, AS (2011) Weed management with glyphosate- and glufosinate-based systems in PHY 485 WRF Cotton. Weed Technol 25:183191
Yu, Q, Powles, S (2014) Metabolism-based herbicide resistance and cross-resistance in crop weeds: a threat to herbicide sustainability and global crop production. Plant Physiol 166:11061118
Zimmer, M, Young, B, Johnson, W (2018a) Herbicide programs utilizing halauxifen-methyl for glyphosate-resistant horseweed (Conyza canadensis) control in soybean. Weed Technol 32:659664
Zimmer, M, Young, B, Johnson, W (2018b) Weed control with halauxifen-methyl applied alone and in mixtures with 2,4-D, dicamba, and glyphosate. Weed Technol 32:597602


Related content

Powered by UNSILO

Herbicide selection to terminate grass, legume, and brassica cover crop species

  • Kara B. Pittman (a1), Charles W. Cahoon (a2), Kevin W. Bamber (a3), Lucas S. Rector (a4) and Michael L. Flessner (a5)...


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.