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[SANET-MG] glyphosate and fusarium crop death

September 24, 2005

Prof. Joe Cummins

Glyphosate and Fusarium Crop Death

Last year I wrote about the glyphosate and the Fusarium fungus causing sudden death syndrome in soy and wheat. In that article I quoted an article from the New Scientist magazine describing unpublished studies by Myriam Fernandez and co-worlers from Agriculture Canada (1). Dr. Fernandez and her co-workers completed and published the study recently (2). Glyphosate application in combination with no till (crop seeds are drilled into fields were prepared by herbicide treatment alone) had significantly increased fusarium head blight in spring wheat. The Fusarium infection not only effected wheat production but also increaded the risk of having mycotoxins harmful to humans and farm animals alike. The study did not determine whether the impact of glyphosate treatment was due to over-wintering and culture of pathogens in the crop residues left after herbicide treatment or whether it was due to some feature of glyphosate treatment.

Sudden crop death following Fusarium infection is also a problem in soybean production. In growth chamber and greenhouse experiments glyphosate treatment caused significant increases in disease severity and infection of roots (3). In field experiments with soy there was increase in Fusarium disease after glyphosate preparation of soil but the disease incidence did not differ between glyphosate tolerant and sensitive cultivars (4,). During 1997 a severe epidemic of soy sudden death syndrome that severally effected several Roundup Ready cultivars. A follow up study found that sudden death syndrome on Roundup-Ready cultivars is influenced by the genetic background of the cultivars (5).

Fusarium based sudden crop death is clearly influenced by the use of glyphosate. Presently, it is not yet clear whether the effect is due to the residues of plant material in the soil resulting form herbicide use or whether the fungus itself is effected by glyphosate.

Roundup-Ready crops have been sold commercially since 1996. Following that introduction several fundamental flaws in the use of that genetic technology have appeared. There has been little or no effort to correct the fundamental flaws in the technology, Glyphosate is rapidly translocated to accumulated in roots and reproductive tissue. Such accumulation results in reduced pollen production and viability, or increased fruit abortion. Glyphosate treatments effect the relationship between Roundup-Ready crops , plant pathogens , plant pests and symbiotic microorganisms . In some cases nitrogen fixation or accumulation has been effected(6) In spite of these adverse effects Roundup-Ready crops are widely sold. The effect may be like the sale of cigarettes, where public relations have prevailed over rationality.


  1. Cummins,J. Round-up Ready sudden death syndrome Science in Society
     2004 ,21.24
  2. Fernandez,M,Selles,F,Gehl,D,DePauw,R. and Zentner,R.  Crop
     production factors associated with Fusarium head blight in spring
     wheat in Eastern Saskatchewan  Crop Science 2005,45,1908-16
  3. Sanogo,S,Yang,X. and Scherm,H. Effects of Herbicides on Fusarium
     solani f. sp. glycines. and Development of Sudden Death Syndrome.
     in Glyphosate-Tolerant Soybean Phytopathology 2000 90,57-66
  4. Sanogo,S,Yang,X and Lundeen,P. Field response of
     glyphosate-tolerant soybean to herbicides and sudden death
     syndrome  Plant Disease 2001 ,85,773-9
  5. Njiti,V,Myers,O,Schroeder,D. and Lightfoot,D.  Roundup ready
     soybean glyphosate effects on Fusarium solani root colonization
     and sudden death syndrome  2003 Agron J. 2003,95,1140-5
  6. Pline-Smic,W. Technical performance of some commercial
     glyphosate-resistant crops  Pest Manag Sci 2005,61,225-34

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