Back
 AJPS  Vol.5 No.1 , January 2014
Herbicidal Effects of Fungicides on Arable Weeds
Abstract: In the present study, the herbicidal effects of two fungicides with the active ingredients expoxiconazole, fluxapyroxad, pyraclostrobin and fenpropimorph on the two arable weeds Lamium purpureum L. and Chenopodium album L. were investigated. The experiments were conducted in a climate chamber under defined conditions. Sowing pods were prepared and plants at the cotyledon leaf stage were pricked out in test pods. Fungicides were applied at six application rates: 0%, 12.5%, 25%, 50%, 100% and 200% of the maximum registered dose rate in Germany. Seven days after application, the first assessment was conducted, regarding growth stage, quantity of plants and visible plant damage. Fourteen days after application, the second and final assessment was conducted, regarding growth stage, quantity of plants, visible plant damage and the fresh weight of the plants. There were herbicidal effects of the fungicides, which were presumably due to the active ingredient epoxiconazole. Epoxiconazole has effects on enzymes that are dependent on cytochrome P-450 and inhibits sterol biosynthesis and probably gibberellin synthesis. By doing so, these fungicides have similar effects to plant growth regulators. Weed species showed differential sensitivities, contractions and growth inhibition and ED50-values were calculated. Notwithstanding the probably minor relevance of the present results in agricultural practice, some effects on arable weeds might result if fungicides are applied at an early growth stage in the field. In some cases, the crop-weed competition could be shifted to the benefit of the crop. Nevertheless, the results are interesting for the field of weed research and for the assessment of the ecotoxicology of fungicides.
Cite this paper: H. Nordmeyer and T. Koch, "Herbicidal Effects of Fungicides on Arable Weeds," American Journal of Plant Sciences, Vol. 5 No. 1, 2014, pp. 35-41. doi: 10.4236/ajps.2014.51006.
References

[1]   J. M. Benton and A. H. Cobb, “The Plant Growth Regulator Activity of the Fungicides BAS 480F,” Extended Summaries SCI Pesticides Group Symposium Postgraduate Research on Pesticides. Pesticide Science, Vol. 39, No. 4, 1993, pp. 357-369.
http://dx.doi.org/10.1002/ps.2780390417

[2]   J. M. Benton and A. H. Cobb, “The Plant Growth Regulator Activity of the Fungicide, Epoxiconazole, on Galium aparine L. (Cleavers),” Plant Growth Regulation, Vol. 17, No. 2, 1995, pp. 149-155.
http://dx.doi.org/10.1007/BF00024175

[3]   R. T. Kane and R. W. Smiley, “Plant Growth Regulating Effects of Systemic Fungicides Applied to Kentucky Bluegrass,” Agronomy Journal, Vol. 75, No. 3, 1983, pp. 469-473.
http://dx.doi.org/10.2134/agronj1983.00021962007500030013x

[4]   T. A. Watt, “The Fungicide Tridemorph as a Selective Herbicide for the Control of Holcus latus in Ryegrass and of Bromus sterilis in Barley,” Weed Research, Vol. 23, 1983, pp. 267-271.
http://dx.doi.org/10.1111/j.1365-3180.1983.tb00549.x

[5]   B. D. Hanson, C. A. Mallory-Smith, B. D. Brewster, L. A. Wendling and D. C. Thill, “Growth Regulator Effects of Propiconazole on Redroot Pigweed (Amaranthus retroflexus),” Weed Technology, Vol. 17, No. 4, 2003, pp. 777-781. http://dx.doi.org/10.1614/WT02-162

[6]   P. Niemann, “Auswirkungen von Getreidefungiziden auf Einige Ackerunkrautarten—Side-Effects of Cereal Fungicides upon Some Arable Weeds,” Nachrichtenblatt des Deutschen Pflanzenschutzdienstes, Vol. 46, 1994, pp. 126-133.

[7]   M. S. DeFelice, “Henbit and the Deadnettles, Lamium spp. —Archangels or Demons?” Weed Technology, Vol. 19, No. 3, 2005, pp. 768-774.
http://dx.doi.org/10.1614/WT-05-072.1

[8]   I. J. Bassett and C. W. Crompton, “The biology of Canadian Weeds, 32. Chenopodium album L.,” Canadian Journal of Plant Science, Vol. 58, No. 4, 1978, pp. 1061-1072.
http://dx.doi.org/10.4141/cjps78-161

[9]   EPA, “Pesticide Fact Sheet Fluxapyroxad,” United States Environmental Proctection Agency, Office of Chemical Safety and Pollution Prevention, 2012.

[10]   EPA, “Pyraclostrobin Application for Extension of the Exclusive Use Data Under FIFRA 3c(1)(f)(ii)—Part 1 of 2,” United States Environmental Proctection Agency, Office of Pesticide Programs, 2007.

[11]   EPA, “Pesticide Fact Sheet Fenpropimorph,” United States Environmental Proctection Agency, Office of Prevention, Pesticides and Toxic Substances, 2006.

[12]   M. Hess, G. Barralis, H. Bleiholder, L. Buhr, T. H. Eggers, H. Hack and R. Stauss, “Use of the Extended BBCH-Scale—General for the Description of the Growth Stages of Mono- and Dicotyledonous Weed Species,” Weed Research, Vol. 37, No. 6, 1997, pp. 433-441.
http://dx.doi.org/10.1046/j.1365-3180.1997.d01-70.x

[13]   R Core Team, “R: A Language and Environment for Statistical Computing,” R Foundation for Statistical Computing, Vienna, 2012. http://www.R-project.org/

[14]   S. E. Davidson, J. B. Reid and C. A. Helliwell, “Cytochromes P450 in Gibberellin Biosynthesis,” Phytochemistry Reviews, Vol. 5, No. 2-3, 2006, pp. 405-419.
http://dx.doi.org/10.1007/s11101-006-9005-5

[15]   J. E. Graebe, “Gibberellin Biosynthesis and Control,” Annual Review of Plant Physiology, Vol. 38, 1987, pp. 419-465.
http://dx.doi.org/10.1146/annurev.pp.38.060187.002223

[16]   W. Köller, “Isomers of Sterol Synthesis Inhibitors: Fungicidal Effects and Plant Growth Regulator Activities,” Pesticide Science, Vol. 18, No. 2, 1987, pp. 129-147.
http://dx.doi.org/10.1002/ps.2780180206

 
 
Top