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Defining the Rate Requirements for Synergism Between Mesotrione and Atrazine in Redroot Pigweed (Amaranthus retroflexus)

  • Josie A. Hugie (a1), German A. Bollero (a1), Patrick J. Tranel (a1) and Dean E. Riechers (a1)


Joint action of the effects of atrazine and mesotrione can lead to synergistic herbicidal activity in broadleaf weed species. The objective of these experiments was to determine if specific rates are required to provide synergistic joint activity between mesotrione and atrazine in both triazine-sensitive (TS) and triazine-resistant (TR) redroot pigweed. Herbicide rates were evaluated in TS and TR redroot pigweed in two experiments: a dose response of mesotrione alone and in mixture with a constant rate of atrazine and a dose response of atrazine alone and in mixture with a constant rate of mesotrione. Results from these experiments revealed that synergism was detected in the TS pigweed when 56 g ai ha−1 mesotrione was mixed with 126 g ai ha−1 atrazine. In the TR pigweed, synergism was detected when mesotrione rate at 10 to 56 g ha−1 was mixed with a constant rate of atrazine at 126 g ha−1. Additionally, when mesotrione was held constant at 10 g ha−1, synergism was detected in mixture with atrazine from 31 to 3556 g ha−1 in TR pigweed. Furthermore, in TR pigweed, analysis of slope deviation across the dose-response curves of mesotrione with and without atrazine revealed a divergence that increased in magnitude as the rate of mesotrione increased. In other words, increased synergism was observed with increased mesotrione rate in the TR pigweed, which was also supported by biomass reduction and atrazine-like injury to the leaves. An additional experiment investigated synergism between mesotrione and bromoxynil in both TS and TR pigweed. Mesotrione at 10 g ha−1 was synergistic when paired with bromoxynil from 70 to 210 g ha−1 in both the TS and the TR pigweed.


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Abendroth, J. A., Martin, A. R., and Roeth, F. W. 2006. Plant response to combinations of mesotrione and photosystem II inhibitors. Weed Technol. 20:267274.
Anonymous 2006a. Callisto® Herbicide Label. Greensboro, NC Syngenta Crop Protection. 14. p.
Anonymous 2006b. AAtrex Nine-O® Herbicide Label. Greensboro, NC Syngenta Crop Protection. 16. p.
Anonymous 2006c. Buctril® 4EC Label. Research Triangle Park, NC Bayer CropScience. 36. p.
Burnet, M. W. M., Hildebrand, O. B., Holtum, J. A. M., and Powles, S. B. 1991. Amitrole, triazine, substituted urea, and metribuzin resistance in a biotype of rigid ryegrass (Lolium rigidum). Weed Sci. 39:317323.
Colby, S. R. 1967. Calculating synergistic and antagonistic responses of herbicide combinations. Weeds. 15:2022.
Corbett, J. L., Askew, S. D., Thomas, W. E., and Wilcut, J. W. 2004. Weed efficacy evaluations for bromoxynil, glufosinate, glyphosate, pyrithiobac, and sulfosate. Weed Technol. 18:443453.
Devine, M. D. and Preston, C. 2000. The molecular basis of herbicide resistance. Pages 72104. in Cobb, A. H. and Kirkwood, R. C. Herbicides and their mechanisms of action. Sheffield, England, UK Sheffield Academic.
Diggle, A. J., Neve, P. B., and Smith, F. P. 2003. Herbicides used in combination can reduce the probability of herbicide resistance in finite weed populations. Weed Res. 43:371382.
Duke, S. O., Dayan, F. E., Romagni, J. G., and Rimando, A. M. 2000. Natural products as sources of herbicides: current status and future trends. Weed Res. 40:99111.
Flint, J. L., Cornelius, P. L., and Barrett, M. 1988. Analyzing herbicide interactions: a statistical treatment of Colby's method. Weed Technol. 2:304309.
Foes, M. J., Liu, J., Tranel, P. J., Wax, L. M., and Stoller, E. W. 1998. A biotype of common waterhemp (Amaranthus rudis) resistant to triazine and ALS herbicides. Weed Sci. 46:514520.
Gowing, D. P. 1960. Comments on tests of herbicide mixtures. Weeds. 8:379391.
Green, J. M., Jensen, J. E., and Streibig, J. C. 1997. Defining and characterizing synergism and antagonism for xenobiotic mixtures. Pages 263274. in Hatzios, K. K. Regulation of Enzymatic Systems Detoxifying Xenobiotics in Plants. City, The Netherlands Kluwer Academic.
Heap, I. 2007. The International Survey of Herbicide Resistant Weeds. Accessed: September 5, 2007.
Kelly, T. L. W. and Chapman, P. F. 1995. The design and analysis of mixture experiments to meet different objectives: a practical summary. Aspects Appl. Biol. 41:5159.
Kudsk, P. and Mathiassen, S. K. 2004. Joint action of amino acid biosynthesis-inhibiting herbicides. Weed. Res. 44:313322.
Lee, D. L., Knudsen, C. G., Michaely, W. J., Chin, H. L., Nguyen, N. H., Carter, C. G., Cromartie, T. H., Lake, B. H., Schribbs, J. M., and Fraser, T. 1998. The structure-activity relationships of the triketone class of HPPD herbicides. Pestic. Sci. 54:377384.
Mitchell, G., Bartlett, D. W., Fraser, T. E. M., Hawkes, T. R., Holt, D. C., Townson, J. K., and Wichert, R. A. 2001. Mesotrione: a new selective herbicide for use in maize. Pest. Manag. Sci. 57:120128.
Patzoldt, W. L., Tranel, P. J., and Hager, A. G. 2005. A waterhemp (Amaranthus tuberculatus) biotype with multiple resistance across three herbicide sites of action. Weed Sci. 53:3036.
[R] R Development Core Team 2005. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL
Ritz, C. and Streibig, J. C. 2005. Bioassay analysis using R. J. Stat. Softw. 12 (5):122.
[SAS] SAS Institute Inc 2004. SAS/STAT® 9.1 User's Guide. Cary, NC SAS Institute Inc. 5136. p.
Seefeldt, S. S., Jensen, J. E., and Fuerst, E. P. 1995. Log-logistic analysis of herbicide dose-response relationships. Weed Technol. 9:218227.
Streibig, J. C. and Jensen, J. E. 2000. Actions of herbicides in mixtures. Pages 153180. in Cobb, A. H. and Kirkwood, R. C. Herbicides and Their Mechanisms of Action. Sheffield, England, UK Sheffield Academic.
Streibig, J. C., Kudsk, P., and Jensen, J. E. 1998. A general joint action model for herbicide mixtures. Pestic. Sci. 53:2128.
Sutton, P., Richards, C., Buren, L., and Glasgow, L. 2002. Activity of mesotrione on resistant weeds in maize. Pest Manag. Sci. 58:981984.
Zhu, X., Govindjee, , Baker, N. R., deSturler, E., Ort, D. R., and Long, S. P. 2005. Chlorophyll a fluorescence induction kinetics in leaves predicted from a model describing each discrete step of excitation energy and electron transfer associated with photosystem II. Planta. 223:114133.
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Weed Science
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