Posted by: Mahdi Ebrahimi | December 15, 2007

GM foods can be dangerous. But you do the research

PLEASE don’t read this and think all genetically modified applications are bad. Please don’t read this and think I am against genetic research. Quite the contrary — I think much good will come from it, particularly in medical research.

Now, if you’ve been following the debate on the lifting of the moratorium on GM crops, you may be bracing yourself for another barrage on how good these crops will be for the economy, farmers, feeding the world, and so on. This is not the case at all. On balance, I have grave reservations about these crops. Farmers are not being told all the risks involved. But you don’t have to take my word for it, you can see for yourself. I’ll show you how in a moment.

When these issues first arose, I looked at the logic behind herbicide-resistant crops and found it compelling. It was every farmer’s answer to weed control.

When Roundup ready soy was released in the United States, a lot of farmers eagerly adopted the new technology. But they were in for a shock. Their crops curled up and died due to an epidemic of sudden death syndrome. This disease is caused by a soil-borne fungus of the Fusarium family.

Robert Kremer, a microbiologist from the US Department of Agriculture, did some tests. He found that every time Roundup was applied to the soil, a spike in the Fusarium population occurred. While he did not find evidence for disease in his trials, every farmer reading this will know the significance of his findings.

Fungal diseases need the right environmental conditions to cause disease. The severity of the disease depends on how much fungus is in the soil — the inoculum. A high inoculum means more severe infection and greater losses. And Roundup causes a higher inoculum.

When Roundup ready canola was first introduced in Canada, a Fusarium-induced wilt caused major damage. In northern NSW and Queensland, Fusarium is devastating cotton at a cost of about $100 million a year.

I wonder how many farmers have been warned of this potential risk? Has there been any testing of local fungal pathogens to find out how they may react? They should find out before they think of planting these crops in March next year. Particularly if we keep having this humid spring weather in the future. They should ask the regulators and advisers if blackleg, for example, has been tested, because we now know that Fusarium is not the only fungus Roundup encourages.

They should also ask about trace elements. Our soils are old, and have poorer levels of trace elements, such as copper, iron and manganese. Don Huber, emeritus professor of botany and plant pathology at Purdue University in Indiana, has been concerned with this emerging problem for some time.

Glyphosate, the active ingredient in Roundup, acts like a pair of tiny chemical tweezers and can prevent the plant from using these trace metals. If plants lack these nutrients, anything that consumes them will also receive less. Huber is looking at the knock-on effects of these deficiencies. He writes: “The impact on animal and human health is emerging from micronutrient deficiency — especially in dairy and pork industries.”

He mentions anaemia, gout, wasting, diarrhoea and young mortality as serious concerns.

So why haven’t our regulatory authorities picked up on these issues? To be fair, the problems with nutrient deficiency have only begun to emerge — an international symposium on glyphosate-disease interactions was held as recently as September. And the Office of the Gene Technology Regulator is reviewing the literature on genetically modified crops. It would be nice if some clearer direction to farmers arrived before the planting season.

It would also be nice if a more reliable estimate of prospective yields were on the table. It is true that in some cases genetically modified crops yield more, but in other cases they yield less than conventional crops. A 2002 report from the USDA says: “Perhaps the biggest issue raised by these results is how to explain the rapid adoption of GE crops when farm financial impacts appear to be mixed or even negative.”

Now, as I said before, you don’t have to take my word for all this. You can Google it. Try, for example, “glyphosate fusarium”, or “yield of GM crops”, or even “use of herbicide in GM crops”. Or how about “GM crops the weed problem”. You’ll find arguments on both sides of the coin, but can refine your searches until you get to the original articles.

And you’ll certainly get plenty of food for thought.

Mitchell Harper is a former scientist with research experience in microbiology and immunology, and has taught biology and genetics for more than 30 years.



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