Scientists are expressing alarm about the relationship between the application of a common weed killer to food crops and the resultant proliferation of potentially toxic fungal moulds in the harvest. Monsanto’s popular product Roundup, which contains a chemical called glyphosate is alleged to increase the size of colonies of the fungus Fusarium, a genus of often very toxic moulds that occurs naturally in soils and occasionally invades crops, but usually held in check by other microbes. If true, these allegations not only call into question the world’s number one weed killer, but they also jeopardize the world’s acceptance of Monsanto’s flagship line of genetically-engineered "Roundup Ready" crops.
"Glyphosate-treated wheat appeared to have higher levels of Fusarium head blight (a toxic fungal disease) than wheat fields where no glyphosate had been applied." said Scientist Myriam Fernandez of the Semiarid Prairie Agricultural Research Centre in Swift Current, Saskatchewan in a recent interview. Fernandez added "We have not finished analysing the four years of data yet or written up the study." While Fernandez’s research recently made headlines throughout Canada, it was not the first to discuss the relationship between glyphosate-containing weed killer formulations and the enhancement of potentially toxic fungi, but it was the first to report on the possibility of potentially toxic crop damage caused by the link in wheat and barley, two of Canada’s most important crops.
According to Dr. Harvey Glick, head of Monsanto’s Scientific Affairs, who remains critical: "It appears to be that Dr. Fernandez did a field survey looking at levels of Fusarium and then the factors that might be related. 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 was there was Roundup used in those fields the previous year.
Maybe, but, 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 reporting the results of their work through the hidden world of academic journals. The result of all of this work, is "just under 50 scientific papers," says Robert Kremer PhD., a soil scientist at the University of Missouri. This body work shows an increase in Fusarium or other microbes after the application of glyphosate.
Monsanto’s Dr. Harvey Glick disagrees: "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."
Dr. Kremer’s ongoing research deals with the effect of glyphosate-fusarium relationship on soybeans, not just regular soybeans, but "Roundup Ready" soybeans also. Monsanto has been producing a series of genetically-engineered "Roundup Ready" seed stock for various crops including, cotton, soybean, wheat and corn to be used exclusively with their successful glyphosate weedkiller Roundup. "Roundup Ready" crops are themselves unaffected by the Roundup weedkiller, which will kill all any competing plants such as weeds in the same area. Because they are genetically-engineered, they have not found easy acceptance in many countries outside the US, and they are still banned in Canada and Europe.
Dr. Kremer found that in his "Roundup Ready" soybean experiments that "Glyphosate seems to stimulate Fusarium in the roots area of the plants," to such a degree that he considers the elevation of Fusarium levels to be glyphosate’s "secondary mode of action." While he found enhanced Fusarium colonies in the roots of his plants, which could potentially reduce the harvest, he did not find it in the harvested soybeans themselves. Even so, he expressed concern about what this accumulation of Fusarium in the soil could lead to.
Dr. Kremer also noted: "We didn’t see enhancement of Fusarium when other herbicides were used." However, in the case of "Roundup Ready" crops, Roundup is to be used exclusively or in combination with other chemicals as a weed killer. To use other weed killers alone would be a violation of contract.
Thus, if Roundup increases Fusarium levels, then "Roundup Ready" crops that use Roundup as a weed killer could become potential disasters, increasing Fusarium levels in the soil to such critical levels it could produce an epidemic and move from field to field throughout a wide area.
In a recent article titled "GM cotton blamed for disease," the Farm Weekly, an Australian publication, predicted that "up to 90 percent of Australia’s cotton belt could be inundated by the soil borne pathogen Fusarium wilt 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 Dr. Fernandez is studying in Saskatchewan has been responsible for serious crop losses. About a fifth of the wheat crop in Europe every year is lost to FHB and in Michigan during 2002 it was estimated that 30-40% of the crops were destroyed by the infestation. When the mould passes into the food-chain undetected, Fusarium epidemics on cereals can have even worse effects: a Fusarium epidemic of cereals was considered responsible for thousands of deaths in Russia during the 1940s and more recently in 2001, it caused a series of deadly birth defects among tortilla-eating Mexican-Americans in Brownsville, Texas.
When cultured on Petri dishes, Fusarium can display various colours, often ranging from orange to salmon-coloured, and it has a varying appearance on different cereals and at different stages of its life cycle. On wheat and rye it can appear as a chalky white colour; on barley it can appear as a black rust, and on oats it can be black and reddish-orange coloured. Small amounts of contamination of grains are invisible to the human eye, and chemical tests have to be done to detect it. Since such tests are at the expense of the farmer, minute amounts 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 and not death, to the more lethal compounds which include fumonisin, which can cause cancer and birth defects to the very lethal chemical warfare agent fusariotoxin, more often referred to as T2 toxin.
During 2000, the US Congress planned to use the fungus Fusarium as a biological control agent to kill coca crops in Colombia and another fungus to kill opium poppies in Afghanistan, but these plans were dropped by then-president Clinton who was concerned that the unilateral use of a biological agent would be perceived by the rest of the world as biological warfare. The Andean nations, including Colombia, where it was to be used in the drug war against coca cultivation banned its use throughout the region. Sanho Tree, the director of the Institute for Policy Studies Drug Policy Project commented about using a chemical that produces a banned micro-organism: "The US has supplied tens of thousands of gallons Roundup to the Colombian government for use in aerial fumigation of coca crops. We have 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. 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 Amazon basin. The drug war has tried in vain to keep cocaine out of people’s noses, but could result instead in scorching the lungs of the earth."
Because of the glyphosate-Fusarium link, Canada’s National Farmers Union is already opposing the introduction of genetically-engineered "Roundup Ready" wheat, and this issue shows no signs of going away. Time will only tell if Monsanto will be able to "fix" the problems of their "Roundup Ready" crops with more genetic engineering- this time to control Fusarium–or will their top weed killer and flagship line of "Roundup Ready" crops be rejected by today’s farmers?
JEREMY BIGWOOD is a freelance writer and investigator specializing in Latin America. A shorter version of this story was published by IPS.