Say No To GMOs! logo

Weedkiller May Encourage Blight

Andy Coghlan
16th August 2003

The evidence builds that the active ingredient in Roundup may be linked to a devastating fungal disease that has caused tens of millions of dollars of losses for wheat growers in the eastern Prairies in recent years.

A widely used herbicide encourages the growth of toxic fungi that devastate wheat fields, laboratory studies by scientists working for the Canadian government suggest.

If field studies confirm that the herbicide, glyphosate, increases the risk of fungal infections - which are already a huge problem - farmers might be advised to use it less. That could be a major blow for backers of genetically modified wheat in Canada, because the first GM variety up for approval in Canada is modified to be glyphosate-resistant. If it gets the go-ahead, there is likely to be an overall increase in glyphosate use.

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.

But the investigators warn against jumping to conclusions. "We're deferring judgement until we have all the data," says Hanson. His team is now planning field and greenhouse trials.

Hanson stresses that the real issue is whether the fungi leave more spores in the soil. It is also possible that the effect is simply due to herbicides leaving more dead plant matter in the soil for fungi to grow on and is not directly caused by glyphosate. His field studies should provide answers next spring, he says.

Monsanto, the company based in St Louis, Missouri, that sells glyphosate as Roundup, as well as a number of "Roundup Ready" crops modified to be resistant to it, claims that glyphosate is already widely used without causing any apparent problems with fungi. Monsanto applied to the Canadian government last December for approval of its Roundup Ready GM wheat. It says it will be keeping a close watch on Hanson's research.

The team's initial findings are likely to be seized upon by anti-GM activists. But switching to other herbicides could be bad news for the environment: glyphosate is one of the least harmful herbicides, as it quickly breaks down in the soil.

Ironically, Syngenta, another biotech giant, based in Basle, Switzerland, has been developing and testing both genetically modified and conventional wheat strains that are resistant to the fusarium head fungi. "The results have been promising," says a Syngenta spokesman.


Scientists Link GM Crop Weed Killer To Powerful Fungus

Washington (IPS/Jeremy Bigwood)
August 20, 2003

Scientists are expressing alarm after finding elevated amounts of potentially toxic fungal moulds in food crops sprayed with a common weed killer widely used with genetically engineered (GE) plants. Roundup, produced by food-industry giant Monsanto, contains a chemical called glyphosate that researchers are blaming for increased amounts of fusarium head blight, a fungus of often very toxic moulds that occurs naturally in soils and occasionally invades crops, but is usually held in check by other microbes.

If true, the allegations could not only call into question the world's number one weed killer, but they also jeopardise global acceptance of Monsanto's flagship line of genetically engineered Roundup Ready crops, which are themselves unaffected by the Roundup weed killer, which kills all competing plants, such as weeds, in the same area.

Monsanto has been producing a series of GE Roundup Ready seed stock for various crops, including cotton, soybean, wheat and corn, to be used exclusively with their successful glyphosate weed killer Roundup.

But because they are genetically engineered, the crops have not found easy acceptance in many countries outside the US, and they are still banned in Europe.

A four-year study found that wheat treated with glyphosate appeared to have higher levels of fusarium than wheat fields where no glyphosate had been applied, said Myriam Fernandez of the Semi-arid Prairie Agricultural Research Centre in Swift Current, in Canada's Saskatchewan province. "We have not finished analysing the four years of data yet or written up the study," she added in a recent interview with IPS.

While Fernandez' research recently made headlines throughout Canada, it was not the first to discuss the relationship between glyphosate-containing weed killers and increased levels of potentially toxic fungi, but it was the first to report on the possibility of potentially toxic damage in wheat and barley, two of Canada's most important crops.

A Monsanto spokesman was critical of the findings.

"It appears to be that Dr. Fernandez did a field survey looking at levels of Fusarium and then the factors that might be related," Harvey Glick, head of the company's scientific affairs division, told IPS. "So, from what I can gather, that was not a cause and effect. It's just that they saw in the study area some fields that had higher levels of fusarium, for whatever reason, and then they looked at a list of factors that might be related and one of them there was Roundup used in those fields the previous year."

Over the last two decades, several scientists from New Zealand to Africa have noticed and investigated the glyphosate-fusarium relationship through small-scale experiments in the relative obscurity of their labs and reported the results in academic journals.

The result of all of this work is almost 50 scientific papers, says Robert Kremer, a soil scientist at the University of Missouri. Overall, they describe an increase in fusarium or other microbes after the application of glyphosate.

Kremer's ongoing research deals with the glyphosate-fusarium relationship on soybeans, including a Roundup Ready variety. His experiments with Roundup Ready and regular soybeans revealed that glyphosate seems to stimulate fusarium in the plants' roots to such a degree that he considers the elevation of fusarium levels to be glyphosate's secondary effect.

While Kremer found enhanced fusarium colonies in the roots of the plants, which could potentially reduce the harvest, he did not find them in the harvested soybeans themselves. But he said that he still worries that fusarium could accumulate in the soil at such levels so as to produce an epidemic that would move from field to field throughout a wide area. He also noted: "We didn't see enhancement of fusarium when other herbicides were used" without Roundup. But according to contracts, farmers planting Roundup Ready crops must use Roundup weed killer exclusively or in combination with other chemicals.

Monsanto's Glick rejected Kremer's suggestions. "Roundup is almost 30 years old, and scientists have been looking at all aspects of its use for at least that long. So there is a tremendous amount of information available."

"And that is why there is such a high level of confidence that the use of Roundup, based on all of this earlier work, does not have any negative impacts on soil microbes ... And a lot of it has been published."

In a recent article titled 'GM Cotton Blamed for Disease', Australia's 'Farm Weekly' predicted that up to 90% of the country's cotton belt could be inundated by a fusarium epidemic within the next decade due to Roundup Ready cotton. Fusarium contamination of cereals, such as the fusarium head blight (FHB) in wheat and barley that Fernandez is studying, has been responsible for serious crop losses.

About one-fifth of the wheat crop in Europe each year is lost to FHB, and in Michigan during 2002 it was estimated that 30-40% of crops were destroyed by the infestation.

When the mould passes into the food chain undetected, fusarium epidemics on cereals can have even worse impacts: such an epidemic was considered responsible for thousands of deaths in Russia during the 1940s, and in 2001 it caused a series of deadly birth defects among tortilla-eating Mexican-Americans in Brownsville, Texas, after the blight infiltrated corn. Minute amounts of fusarium continually enter commercial food products; it is at the higher levels that it can become a serious problem.

The fusarium fungus can produce a range of toxins that are not destroyed in the cooking process, such as vomitoxin, which as its name suggests, usually produces vomiting but not death. More lethal compounds include fumonisin, which can cause cancer and birth defects, and the very lethal chemical warfare agent fusariotoxin, more often referred to as T2 toxin.

During 2000, the US Congress planned to use fusarium as a biological control agent to kill coca crops in Colombia and another fungus to kill opium poppies in Afghanistan. Those plans were dropped by then-president Bill Clinton, who was concerned that the unilateral use of a biological agent would be perceived by the rest of the world as biological warfare. Andean nations, including Colombia, banned its use throughout the region.

According to Sanho Tree, director of the drug policy project at the Washington-based Institute for Policy Studies, "the US has supplied tens of thousands of gallons of Roundup to the Colombian government for use in aerial fumigation of coca crops." That operation has "been using a fleet of crop dusters to dump unprecedented amounts of high-potency glyphosate over hundreds of thousands of acres in one of the most delicate and bio-diverse ecosystems in the world."

But "this futile effort has done little to reduce the availability of cocaine on our streets, but now we are learning that a possible side-effect of this campaign could be the unleashing of a fusarium epidemic in the Amazon basin."

Because of the glyphosate-fusarium link, Canada's National Farmers Union is already opposing Monsanto's application to introduce GE Roundup Ready wheat into the country. The federal government is expected to make its decision within months.

From SUNS, the South-North Development Monitor edited by Chakravarti Raghavan ( It is reprinted here with the kind permission of the editor.


Fraudulent Conclusion Facts
Found by Inspection of the Safety Assessment of GM Roundup Tolerant Soybean

Masaharu Kawata
Assistant Professor
School of Science
Nagoya University, Japan

Monsanto's Dangerous Logic as seen in the Application Documents submitted to Health Ministry of Japan

What is herbicide resistant soybean by Monsanto?

In growing soybean, well-planned weed and pest control is important to get the desired harvest. If soybean itself had herbicide resistance, low input cultivation would be possible and dust cropping could be much simpler. Monsanto had endeavoured, in vain, till 1990s to achieve this goal by creating soybean mutant that is resistant to their best selling organo-phosphoric herbicide Roundup in which the glyphosate is the active ingredient. The resistant strains created, however, had seriously hampered enzymatic activity of EPSPS (5-enol-pyruvylshikimate-3-phosphate synthase: one of the enzymes work to synthesize aromatic amino acid, Tyrosine, Phenylalanine and Tryptphan) and the soybean failed to thrive.

The genetic engineering technology was becoming popular at the time, and was naturally employed in introducing gene from different organism into soybean. Herbicide resistant bacterium was found in the glyphosate factory sewage of Monsanto USA. This Agrobacterium tumefaciens CP4 strain is a kind of soil bacterium, which could synthesize aromatic amino acid in the presence of glyphosate. The amino acids sequence of the enzyme is largely different from that of any plants and is called class II EPSPS (refered to as CP4EPSPS hereafter).

Inserting the bacterial genes into plant genome generally does not work by itself because genetic switch called promoter for prokaryotes and eukaryote are different. A powerful promoter from "Cauliflower Mosaic virus" called 35S promoter was connected to the gene insert . Then connected is a small protein called "signal peptide" which carries the CP4EPSPS protein to where the enzyme is supposed to function, in this case chloroplast. This signal peptide gene was taken from petunia. A part of plant cancer virus gene called NOS that signals to stop reading the gene is also required. Thus created "Roundup tolerant soybean gene cassette" is a completely artificial one that never existed in natural life kingdom nor could have evolved naturally.

In addition to these modifications of the genetic construct, Monsanto had to change genetic codons for efficient expression of the CP4ESPS gene in soybean plant. The 239 (17.51%) nucleotides out of 1,365 total were manually converted into different bases (though mostly in the third letter) in order for the protein synthetic machinery of soybean cell to decipher the bacterial gene across species barrier. Thus, the Roundup Tolerant soybean came to possess a gene unlike either the prokaryotic or the eukaryotic gene. It is with reason that genetically modified plants are called "the Frankenstein plants" in Europe. Focal point of safety assessment is whether such soybean with artificially modified genes is the same as the conventional non-modified soybean.

The soybeans used for analyses and animal feed tests were grown without herbicide application

The Roundup Ready soybean marketed is usually sprayed with the herbicide Roundup. It was a surprise to find that both the genetically modified soybean 40-3-2 strain and the parent strain A5403 used for feed tests were NOT sprayed with Roundup herbicide in their cultivation. What Monsanto had produced with Roundup application was minimal amount enough to test glyphosate residues in the harvested forage, hay and seed. Several tons of soybean used in safety assessments was not produced with the Roundup. The reason is not stated in the documents.

The data obtained with such samples may not be valid to guarantee the safety of soybean that human and animals consume in the real life, not just because the residual glyphosate is a toxin that kills plants by inhibiting plant enzyme EPSPS but the effects on other metabolic pathways must also be taken into account when such artificial genes are inserted. For consumers, the test results obtained by using different sample other than what is marketed is meaningless.

The protein CP4EPSPS analysed is from E.coli. not from RR soybean!

It is expected that CP4EPSPS protein expressed in the bio-engineered soybean has the same amino acid sequence as the soil bacterium from which the gene was extracted. This can only be verified when soybean produced protein is isolated and the amino acid sequence is determined, because exchanging genes between bacteria and higher organism can sometimes result in partial change of amino acid and/or post-translational modification after expression. It was our presumption before the inspection of the documents that the amino acid sequence of the soybean CP4EPSPS was determined but, to our surprise, it was not.

What Monsanto has sequenced was only 15 amino acids from N-terminal of the protein that was expressed in E.coli. The rest of the sequence was an assumption from the nucleotide sequence of the bacterial DNA. They determined only 3.3% of expected total of 455 amino acids and that the protein is not of soybean! ELISA test described in the documents is the only method to verify antigenic equivalence of proteins. But antigenic similarity itself does not prove that the amino acid sequences are the same. The real sequence of CP4EPSPS protein in the soybean that we are eating is still unknown.

Acute toxicity test on rats is also carried out by using the protein expressed in E.coli CP4EPSPS protein used for acute toxicity test on rats also come from that produced by E.coli harbouring CP4EPSPS plasmid. What Monsanto says in the application document is that extracting large amount of CP4EPSPS protein from soybean is difficult. This is an unacceptable execus because there is a possibility that the inserted gene work differently in soybean than in the original bacterium, therefore the expressed product may be different from that of soybean. Moreover, according to the application document, 0.238mg of CP4ESPS protein is detected in one gram of genetically modified 40-3-2 soybean which is good enough concentration to extract with no difficulty. This again is the typical "for the roundup" approach by Monsanto. This kind of problem could be resolved if all CP4ESPS amino acid sequence in soybean had been sequenced and confirmed equal as the bacterium. The experiment appears to have been conducted on the presumption that the other soybean proteins are the same as the non-GM soybean as long as the CP4EPSPS is not toxic. If so, this is too easy and one-sided approach. The core of this problem is whether or not the soybean gene gets affected by insertion of foreign gene. The series of experiments described are fundamentally invalid.

Insufficient feeding experiments and intentional neglect of "inappropriate" data

Animal feeding test is important for safety assessment. Monsanto conducted these experiments on such animals as rat, cow, chicken, catfish and quail. However, the scale of experiment is much less than adequate. For example, in rat experiments, raw and toasted soybean both genetically modified and non-modified were fed to only 10 rats each group and feeding period is only 28 days. Toxicity across generation or chronic toxicity will not be measured by these limited experiments.

Even with these far from satisfactory experiments, the data for body and organ weight of lever, kidney and testicles show obvious difference in the male rats between both groups, wild strain A5403 and bio-engineered strain 40-3-2 soybean.

Raw soybean fed group showed no difference. But toasted soybean 40-3-2 fed male group weighed 6.7% less body weight than A5403 fed group and 13% less than commercial feed mix fed group at the end of test period of 28 days. Though this difference is described as statistically significant in the data sheet, the conclusion ignores these results and states that "no statistical significance is observed."

The experiments are far from satisfactory in its samples and the statistic method used. Our group transcribed all raw data and redid statistical analysis using Turkey multiple method. The result again showed the apparent growth obstacle for the body and kidney weight in male rats group fed with toasted 40-3-2 soybean. I wondered why there is no such difference in female rats group. The answer to this question seemed to be the amount of the feed intake where male took 25-30g/day, female rats took only 18-20g (approx. 70% of male)/day. It is highly possible that female rats also showed significant growth difference if experiment is conducted in much larger scale and with longer feeding period.

Misinterpretation, false conclusion and disregard of data

Chemical analysis of the components from both normal and genetically modified is important to certify so called substantial equivalence.

We found a highly intentional misinterpretation by ignoring obvious difference between A5403 and 40-3-2 hybrid in the documents. Raw soybeans showed no difference in the analysis between genes modified 30-4-2 and non-modified A5403 soybean. Difference is observed in toasted soybeans. Besides such main components like water, protein, fat, fibre and ash, trypsin-inhibitor, lectin and urease which are called harmful physiologically active substance as feed are detected in the analysis. Urease is used as an indicator of protein denaturation by heat treatment.

Obvious difference appeared after toasting at actual feed processing condition (108 degrees celcius, 30min). While the concentration of total protein and potassium were not changed, the concentration of trypsin-inhibitor, urease, and lectin are significantly higher in the toasted glyphosate-tolerant bean 30-4-2 compared to that of A5403 normal bean. These physiologically active substances remained active even after heat treatment in the genetically modified soybean, though those of herbicide sensitive normal bean were easily denatured and inactivated. The high activity of these elements does not usually satisfy as feed.

Monsanto took this result as "the modified soybeans are not toasted sufficiently in the experiment" and returned and asked for re-treatment of the sample to Texas A & M laboratory who processed the beans. Monsanto ordered the condition of re-toast at 220 degrees celcius for 25min, which is considerably higher than normal processing of 100 degrees celcius, 10 minutes. However re-toasting further widened the difference in the activity between the two strains. The hybrid 61-67-1,which is another genetically modified soybean inserted with bacterial CP4EPSPS, showed high heat resistant property.

Scientist would usually conclude in such case that there is substantial difference between the two. But Monsanto dared to challenge this common practice and concluded again the second toasting was still not enough. In the end, they toasted twice further and got the result they wanted, i.e. all proteins were denatured and inactivated. With this result, they concluded that genetically modified and non-modified soybeans have equivalent properties.

No protein can withstand repeated heat treatment and stay active. This is a common knowledge of protein chemistry. The argument at normal feed processing condition is required and no more, no less. Monsanto based their argument on their presumption that "they can't be different" and their need that "they shouldn't be different". Their translation of the experiment is based on "the conclusion is safe" attitude and not at all scientific. The English data volume did not show analysis data of third and fourth heat treatment, but the summary volume in Japanese, as if there were data, has a graph showing after loss of activity and stated that "the data from insufficient heat treatment is not adopted" and "No substantial difference observed." If you review only summary volume in Japanese and not look into English data volume, you would be ushered to the conclusion of "Safe."

However we could found in the first and the second analyses data of toasted soybean a fact indicative of regular heat treatment. Granulated soybean, when heated, loses weight as water and other volatile components evaporate, and as the result, relative concentration of non-volatile substance such as total protein and ash increases. The data shows clearly that the gene modified 40-3-6 and 61-67-1 and non-modified A5403 gone through same level of heat treatment. The decrease of water content also certifies this fact.

Monsanto requested slackened herbicide residue level

Monsanto's concluded that the residual herbicide in crop increases, therefore the safety standard should be slackened.

Adopting the Roundup tolerant soybean would increase the herbicide concentration in the soybean plants and seeds, because the herbicide is directly sprayed on the plant by postemergence application before harvest. The Monsanto studied in detail what would be the results by changing factors like spraying times, concentration of the active ingredient glyphosate, duration of harvest after spraying and growing locations. The data show clearly that the concentration of glyphosate and AMPA (a degraded substance of glyphosate) in forage and hay increase greatly by postemergence application of the herbicide compared to that of conventional preemergence application, although the residual concentration in the plant differed from place to place. The largest value of the combined glyphosate and AMPA was 40.187 ppm in forage which is higher than the US safety standard of 15 ppm in forage and hay in 1994 when FDA and USDA accepted the application documents. The maximum combined concentration of glyphosate and AMPA in soybean seed was 13.178 ppm, which is less than 20 ppm of the US standard at that time. The concentration residual glyphosate increased in accordance with the application increased from twice to three times. Then cultivating Roundup ready soybean may sometimes violates the US safety standard. We found a surprising description in the document to dissolve the problem.

In final conclusion, Monsanto say that "the maximum combined glyphosate and AMPA residue level of approximately 40 ppm in soybean forage resulting from these new uses exceeds the currently established tolerance of 15 ppm. Therefore, an increase in the combined glyphosate and AMPA tolerance for residues in soybean forage will be requested." They know very well that adoption of herbicide tolerance crop needs slackened safety standards. In effect, the US tolerance standard of combined glyphosate and AMPA in soybean forage was changed to 100 ppm after they approved the genetically engineered soybean.

As to Japanese government, they revised the safety standard of combined glyphosate and AMPA in soybean seed to 20ppm in April 2000 from what used to be 6 ppm according to the request of US government. Japan could import soybean from USA without violation of the law by this decision.

Thus, Monsanto, in their rush to verify safety, patch worked the results of experiments and analyses that are full of voids like a puzzle and asserted safe with manipulation of the results. They requested even the revision of safety standard. We have managed to find facts showing inadequate and incomplete safety assessment described above in the application document by Monsanto even in our limited work under difficult situation. The process of genetic recombination and the results of other animal experiments remained uninspected by us.

Monsanto informed US soybean importing countries in May 2000 that they found Roundup resistant soybean has two extra fragments of the CP4EPSPS gene in the genome. They were there since the first FDA approval in 1992, and all the GM soybeans supplied worldwide contain this gene fragments. Monsanto asserts that these fragmented genes do not create unknown protein since they have any open reading frame or termination signal around them.

But such basic facts comes to light 8 years after the approval is a sure indication of how incomplete the genetic recombination of crop is, and how dangerous safety assessment can be to rely only on company's information and data. We doubt it very much if at all government experts in charge at the Japanese Ministry of Health and Welfare for safety assessment had a good sense to have concluded as safe on the basis of such incomplete application.

top of page