Andreas Späth

Weedkillers, superbugs and killerweeds

2011-09-21 07:27

Andreas Späth

For decades biotech companies like Monsanto and Syngenta have been making billions of dollars in profits by selling us their genetically-modified (GM) agricultural crops as the answer to the world's growing farming and food production problems.

Today, farmers, and increasingly we as consumers, are left with the nasty side-effects of these supposed supercrops. Side-effects that critics of the technology predicted from the start, but which the industry has consistently downplayed, denied and ignored.

Biotech companies have concentrated their efforts almost exclusively on marketing two kinds of GM crops: ones that produce their own insecticide and ones that are resistant to herbicide.

The former contain artificially inserted genes from a soil bacterium called Bacillus thuringiensis – Bt for short – which cause them to express a toxin deadly to crop-destroying insects. The latter is engineered to be resistant to glyphosate, the active ingredient in the world's most widely-used weedkiller, Monsanto's Roundup, allowing farmers to douse their fields with the herbicide to kill weeds but not crops.

In both instances there is mounting evidence that these crops are causing environmental havoc and threatening human health.

In the USA, years of liberal application of glyphosate on herbicide-resistant GM crops has led a number of weeds, including giant ragweed, water hemp, lamb's quarter and velvet weed to develop resistance to the weedkiller. In response to the problem, many farmers simply apply more roundup to their fields until they're eventually forced to use increasing amounts of alternative herbicides as well.

Not only has the overuse of glyphosate been shown to have detrimental effects on beneficial soil micro-organisms while leading to a rise in harmful parasites and fungi, but according to a series of recent studies published in the journal Weed Science, it has resulted in at least 21 weed species becoming resistant to it. These include superweeds that can grow as much as three inches per day. In addition, several weeds have also developed resistance to alternative herbicides.

In the US, the wide-spread use of Bt-crops in industrial-scale monocultures has led to the rise of resistance in pests such as the western corn rootworm which attacks maize plants. This year, these Bt-resistant superbugs have caused significant corn crop losses in Iowa, Illinois and Minnesota, three of the country's main maize producing states. In 2010, bollworm, a pest that targets cotton plants, was acknowledged to have developed resistance to Bt-cotton.

To make matters worse, GM-crops are not only failing to do their job in the field, but there are increasing fears that they may have negative impacts on human health.

Proponents of the technology have long maintained, for instance, that the Bt toxin is harmless to people since it breaks down in the digestive tract. But traces of the substance have been discovered in the gastrointestinal contents of livestock fed on Bt-corn and this year, Canadian scientists found it the blood of women, including pregnant women and their foetuses, suggesting that it can be absorbed by the human body and transferred from mother to unborn child.

Last year, a study revealed that glyphosate-resistant maize caused organ damage in rodents and a number of researchers have raised alarm over higher-than-normal rates of infertility and early-term abortion in livestock fed on these crops, but perhaps the biggest concern relates to the environmental and health impacts of glyphosate itself.

Scientists recently found significant levels of glyphosate in numerous air and stream samples in Mississippi and Iowa. In an intensive farming area of Argentina, airborne crop-dusting with glyphosate has been blamed for toxic effects on amphibian and chicken embryos as well as a spike in cancer rates and malformations in newborns among the human population. A review of existing data on the potential health effects of the herbicide published in June suggests that industry regulators in Europe and America have known for years that glyphosate may cause birth defects, cancer, DNA damage, endocrine disruption and more in laboratory animals.

So what's the answer to this problem?

It’s simple. We need to reconsider our growing reliance on GM-crops, not just because of all the evidence pointing to the negative impacts, but because alternatives that are much healthier for planet and people are readily available. Modern, sustainable and ecological farming techniques that reduce water usage, improve soil fertility and carbon content, protect biodiversity and reduce human health risks, all while increasing yields, make GM-crops an unnecessary folly.

- Andreas has a PhD in geochemistry and manages Lobby Books, the independent book shop at Idasa’s Cape Town Democracy Centre. Follow him on Twitter: @Andreas_Spath

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