Science in Society Archive

Round-up Ready Sudden Death Syndrome

Prof. Joe Cummins finds evidence that Roundup Ready causes sudden death and other diseases by boosting fusarium in the soil.

For several years, investigations have been carried out on the impact of herbicides, particularly glyphosate (Round-up) on soil microbial communities. These investigations revealed increased colonization of the roots of Round-up Ready (RR) soya with the fungus Fusarium in midwestern fields during 1997 to 2000 [1,2]. At the same time, large scale cropping with herbicide-tolerant cultivars was found to increase soil-borne plant pathogens [3]; Brazilian soils showed increased microbial activity for several seasons [4]. There is clear evidence that repeated glyphosate applications over several seasons increases soil-borne pathogens.

During the first year of glyphosate application on RR soya, a severe sudden death syndrome epidemic occurred in several RR cultivars. The RR cultivars were susceptible to sudden death from infection by the fungus Fusarium solani [5]. Sudden death syndrome of soya is a disease of economic importance in North America. Follow-up studies showed that different cultivars of soya showed different levels of resistance to the sudden death fungus and suggest that glyphosate tolerant and non-tolerant cultivars responded similarly to infection by Fusarium solani [6,7].

According to Jeremy Bigwood (, a scientist from Agriculture Canada, Myriam Fernadez, had reported as yet unpublished studies showing that wheat fields that had been treated with glyphosate had elevated levels fusarium head blight, a serious disease of wheat.

Andy Coghlan of the New Scientist further reported:

"The potential problem was spotted a few years ago by Myriam Fernandez of the Semiarid Prairie Agricultural Research Centre run by Agriculture and Agri-Food Canada in Swift Current, Saskatchewan. She noticed that in some fields where glyphosate had been applied the previous year, wheat appeared to be worse affected by fusarium head blight - a devastating fungal disease that damages grain and turns it pink. In Europe alone, fusarium head blight destroys a fifth of wheat harvests. The fungi that cause the disease also produce toxins that can kill humans and animals. In a follow-up study, Fernandez measured levels of the blight in wheat fields. "We found higher levels of blight within each tillage category when glyphosate had been used in the previous year," says her colleague Keith Hanson. And his lab study showed that Fusarium graminearum and F. avenaceum, the fungi that cause head blight, grow faster when glyphosate-based weedkillers are added to the nutrient medium." [9].

Unfortunately, Agriculture Canada has not fast tracked publication of such important results when they are advocating registration of RR wheat.

In conclusion, there seems to be a clear link between the use of herbicide and accumulation of pathogenic fungi in the soil. The RR soya cultivars fared poorly under the impact of the sudden death fungus. Wheat fields treated with Round-up appear to be sensitive to the head blight disease. Such findings should have triggered prompt and extensive reviews on the use of Roundup and Roundup tolerant GM crops by our North American regulators. Instead of which, the two governments of North America appear to be advocating registration of RR wheat.

Article first published 30/11/03


  1. KremerR, Donald P, Keaster A and Minor H. Herbicide impact on Fusarium spp. and Soybean Cyst nematode in Glyphosate tolerant Soybean. American Society of Agronomy abstracts 2000, s03-104
  2. Editors Glyphosate wed killer benefits soil fungus. Progresive Farmer
  3. Termorshuizen A. and Lotz A. Does large scale cropping of herbicide-resistant cultivars increase soil born pathogens. Outlook on Agriculture 2002 31,51-4.
  4. Araujo A, Monteiro R. and Abarkeli R. Effects of glyphosate on the microbial activity of two Brazilian soils. Chemosphere 2003 , 52,799–804
  5. Njiti V, Myers O, Schroeder D and Lightfoot D. Glyphosate effects on Fusarium solani root colonization and sudden death syndrome. Agron. J. 2003, 95, 1140-5
  6. Sanogo S,Yang X and Sherm H. Effects of herbicide on Fusarium solani f. sp glycines and development of sudden death syndrome in glyphosate-tolerant soybean" 2000 ,90,57-66.
  7. 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.
  8. Bigwood J. Glyphosate-Fusarium story. 2003
  9. CropChoice News "Glyphosate may encourage wheat blight" 2003

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