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Increasing and Decreasing pH to Enhance the Biological Activity of Nicosulfuron

Published online by Cambridge University Press:  20 January 2017

Jerry M. Green  and
Theresa Hale
Jerry M. Green*
Affiliation:
DuPont Crop Protection, Stine-Haskell Research Center Building 210, Newark, DE 19714-0030
Theresa Hale
Affiliation:
DuPont Crop Protection, Stine-Haskell Research Center Building 210, Newark, DE 19714-0030
*
Corresponding author's E-mail: [email protected]
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Abstract

Increasing the pH of the spray water to solubilize the weak acid herbicide nicosulfuron and then decreasing pH below its pKa so that it converts into a neutral form enhances biological activity under some conditions. The water-dispersible granule formulation of nicosulfuron starts as dispersed particles. Adding 1% wt/wt K3PO4 solubilizes nicosulfuron and increases its activity compared to its dispersion without base. The type of buffer and the surfactant HLB or hydrophilic lipophilic balance, a measure of the molecular balance of the hydrophilic and lipophilic groups, altered the activity of nicosulfuron. Adding 1% wt/wt K3PO4 increases the pH, and the optimum HLB ranged from 13 to 17 on large crabgrass. Adding 1% wt/wt H3PO4 reduces the pH and lowers the optimum HLB range from 10 to 14 on large crabgrass. Adding the acidic buffer converts the solubilized nicosulfuron into its neutral form and increases activity under some surfactant conditions. Thus, neutral nicosulfuron is more active with lipophilic surfactants, while ionic nicosulfuron is more active with hydrophilic surfactants. When tested on other species, low HLB surfactants are the most active at low pH. These results support the concept that the physicochemical properties of the herbicide, adjuvants, and weed species should be matched for optimum activity.

Keywords

Common cocklebur, Xanthium strumarium L. # XANSTcommon lambsquarters, Chenopodium album L. # CHEALgiant foxtail, Setaria faberi Herrm. # SETFAlarge crabgrass, Digitaria sanguinalis (L.) Scop. # DIGSApurple nutsedge, Cyperus rotundus L. # CYPROsicklepod, Senna obtusifolia (L.) Irwin and Barneby # CASOBvelvetleaf, Abutilon theophrasti Medicus # ABUTHAcidadjuvantbasebasic blendbufferformulationhydrophilic–lipophilic balancenicosulfuronnonionic surfactantphosphoric acidpotassium phosphatesulfonylureawater-dispersible granuleweak acidHLB, hydrophilic–lipophilic balanceNIS, nonionic surfactantNPE, nonylphenol ethoxylateWDG, water-dispersible granule
Type
Research Article
Information
Weed Technology , Volume 19 , Issue 2 , June 2005 , pp. 468 - 475
Copyright
Copyright © Weed Science Society of America 

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References

Literature Cited

Fahl, G. M., Kreft, L., Altenburger, R., Faust, M., Boedeker, W., and Grimme, L. H. 1995. pH-dependent sorption, bioconcentration and algal toxicity of sulfonylurea herbicide. Aquat. Toxicol. 31:175–187.Google Scholar
Franz, R. E., Mao, M. K., and Sikorski, J. A. 1997. Glyphosate: A Unique Global Pesticide. Washington, DC: American Chemical Society. 653 p.Google Scholar
Green, J. M. 1999. Effect of nonylphenol ethoxylation on the biological activity of three herbicides with different water solubilities. Weed Technol. 13:840–842.Google Scholar
Green, J. M. and Cahill, W. R. 2003a. Enhancing the biological activity of nicosulfuron with silicone adjuvant and pH adjusters. in Volgas, G., Downer, R., and Lopez, H., eds. Pesticide Formulations and Application Systems: Surviving Change in the Agrochemical Industry. Volume 23. West Conshohocken, PA: American Society for Testing Materials. Pp. 115–124.Google Scholar
Green, J. M. and Cahill, W. R. 2003b. Enhancing nicosulfuron activity with pH adjusters. Weed Technol. 17:338–345.Google Scholar
Griffin, W. C. 1954. Calculation of HLB of non-ionic surfactants. J. Soc. Cosmet. Chem. 5:249–258.Google Scholar
Hall, G. J., Hart, C. A., and Jones, C. A. 2000. Plants as sources of cations antagonistic to glyphosate activity. Pest Manag. Sci. 56:351–358.Google Scholar
Harr, J., Guggenheim, R., Schulke, G., and Falk, R. H. 1991. The Leaf Surface of Major Weeds. Sandoz Agro, Ltd. Witerswil, Switzerland: Fricker. 131 p.Google Scholar
Hartzler, R. M. 2003. Absorption of Foliar-Applied Herbicides. Web page: http://www.weeds.iastate.edu/mgmt/2001/absorp.htm. Accessed: October 2, 2003.Google Scholar
Hess, F. D. and Foy, C. L. 2000. Interaction of surfactants with plant cuticles. Weed Technol. 14:807–813.Google Scholar
Holmberg, K., Jönsson, B., Kronberg, B., and Lindman, B. 2003. Surfactants and polymers in aqueous solution. 2nd ed. Chichester, UK: J. Wiley. 545 p.Google Scholar
Liu, Z. Q. 2002. Lower formulation pH does not enhance bentazone uptake into plant foliage. N. Z. Plant Prot. 55:163–167.Google Scholar
Liu, Z. Q. and Gaskin, R. E. 2004. Visualisation of the uptake of two model xenobiotics in bean leaves by confocal laser scanning microscopy: diffusion pathways and implication in phloem translocation. Pest Manag. Sci. 60:434–439.Google Scholar
Liu, Z. Q., Gaskin, R. E., and Zabkiewicz, J. A. 2004. Visualization of the effect of surfactant on the uptake of zenobiotics into plant foliate by confocal laser scanning microscopy. Weed Res. 44:237–243.Google Scholar
Molin, W. T. and Hirase, K. 2004. Comparison of commercial glyphosate formulations for control of prickly side, purple nutsedge, morningglory, and sicklepod. Weed Biol. Manag. 4:136–141.Google Scholar
Muir, R. M. and Hansch, C. 1955. Chemical constitution as related to growth regulator action. Annu. Rev. Plant Physiol. 6:157–176.Google Scholar
Nalewaja, J. D. and Matysiak, R. 2000. Spray deposits from nicosulfuron with salts that affect efficacy. Weed Technol. 14:740–749.Google Scholar
Nalewaja, J. D., Matysiak, R., and Woznica, Z. 1997. Adjuvants for herbicidal compositions. U.S. patent No. 5,658,855.Google Scholar
Parrish, S. K., Beardmore, R. A., and Herold, A. E. 2003. Herbicide compositions comprising compound in acid form and acidifying agent. U.S. patent Appl. No. 153461.Google Scholar
Roberts, J. R., Thomas, J., and Volgas, G. C. 2002. Composition used as herbicide comprises glyphosate in free acid form and acid component e.g. phosphoric acid and/or neutralized organic acid. U.S. patent Appl. No. 039970.Google Scholar
Russell, M. H., Saladini, J. L., and Lichtner, F. 2002. Sulfonylurea herbicides. Pestic. Outlook 13:166–173.Google Scholar
[SAS] Statistical Analysis Systems. 2000. SAS User's Guide. Version 8.1. Cary, NC: Statistical Analysis Systems Institute. 1686 p.Google Scholar
Stirling, T. M. 1994. Mechanisms of herbicide absorption across plant membranes and accumulation in plant cells. Weed Sci. 43:263–276.Google Scholar
Stock, D. J. and Holloway, P. J. 1993. Possible mechanisms for surfactant-induced foliar uptake of agrochemicals. Pestic. Sci. 38:165–177.Google Scholar
Streibig, J. C., Rudemo, M., and Jensen, J. E. 1993. Dose-response curves and statistical models. in Streibig, J. C. and Kudsk, P., eds. Herbicide Bioassays. Boca Raton, FL: CRC. Pp. 30–55.Google Scholar
U.S. Government. 1987. Code of Federal Regulations, Title 40, Subchapter E, Part 180, Subpart D-180.1001. Washington, DC: U.S. Government Printing Office.Google Scholar
Volgas, G. C. and Roberts, J. R. Benefits of a 2,4-D acid formulation. in Lopez, H., Volgas, G., and Salyani, M., eds. Pesticide Formulations and Application Systems. Volume 24. ASTM STP 1483. West Conshohocken, PA: American Society for Testing and Materials. In press.Google Scholar
Woznica, Z., Nalewaja, J. D., and Messersmith, C. G. 2001. Sulfosulfuron efficacy is affected by surfactants, pH of spray mixtures, and salts. in Mueninghoff, J. C., Viets, A. K., and Downer, R. A., eds. Pesticide Formulations and Application Systems: A New Century for Agricultural Formulations. Volume 21. ASTM STP 1414. West Conshohocken, PA: American Society for Testing and Materials. Pp. 11–22.Google Scholar