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Another Bite at GM FoodsJennifer Thomson, Head, Microbiology Dept, University of Cape Town, South Africa
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| FICTION | FACT | |
| 1 | A large number of genetically modified crops are commercially available in South Africa. | Cotton and yellow maize, resistant to insects, are commercially available. The latter accounts for about 2% of the total crop. A number of GM crops are undergoing field trials. The 1998 trials of insect resistant cotton in the Makatini Flats region of KwaZulu Natal showed a significant decrease in the use of insecticides and an increase in yield of between 18 and 23%. The highest increase in yield was achieved by the small scale farmers involved in the trial and one woman farmer stated that she has R30 000 in the bank that she hadn't expected. |
| 2 | The sale of herbicide resistant crops will result in a huge increase in the use of the specific herbicide, which will be environmentally damaging. | Herbicide resistant crops will allow farmers to spray either before the crop is planted or when the crop is still young. This will result in the use of less herbicide. Data from the USA show that in addition to decreased use of herbicide there is less soil erosion. When herbicide sensitive crops are planted, fields are tilled, weeds allowed to grow, sprayed and then fields are left for the herbicide to dissipate (during which time rain can wash top soil away), before crops are planted. In the case of herbicide resistance, crops and weeds grow up together, are both sprayed and the dead weeds can act as mulch. |
| 3 | South Africa has no legislation restricting the release of GMOs, which will result in multinationals "dumping" GM food here. | The GMO Act was passed by Parliament in May 1997 and the Regulations in November 1999. The Executive Council, Registrar and Advisory Committee have all been appointed. Contravention of the Act can result in a fine or imprisonment of up to four years. |
| 4 | Farmers, and in particular, small-scale farmers, will be forced to buy GM seeds. | Market forces will prevail. If the GM seeds provide a better yield, farmers will buy them - if not they will buy seed from other companies. |
| 5 | It would be easy to separate engineered from non-engineered foods | Many food items on supermarket shelves contain soybean, from canned soups to baby foods. America is one of the largest suppliers of soybean and some of their exported soybean may have been genetically modified for insect or herbicide resistance. However, all the soybeans are pooled. It is possible, but very expensive to separate the GMOs from the non-GMOs. Obviously, the soybeans will have been cooked during the preparation of the food items, a process which denatures proteins, including the ones produced by the introduced gene(s). |
| 6 | GM insect-resistant crops contain lectins and lectins are known to be potentially toxic to animals and man. | This was particularly worrying as it was said with great conviction by a Greenpeace representative from London on Will Bernard's "Talk at Will" show on SAfm. Indeed, lectins may be toxic to animals and man, and this was precisely the reason behind the tests done by the Rowett Research Institute. But the GM insect-resistant crops produce the Bacillus thuringiensis (bt) toxin which is NOT a lectin and although toxic to certain specific insect species, is NOT toxic to animals or man. |
| 7 | It is easy to detect GM foods in any product on a supermarket shelf. | It is possible to do this but it is a costly exercise. At present this expertise is not widely available in South Africa. |
| 8 | It is easy to label GM foods on supermarket shelves. | As explained above, detection of GM foods in a given commodity is expensive and cannot be done, at present, in South Africa. A general label, such as "This product might contain plant material which may have been subject to genetic modification" is not very helpful. Such labeling will also tend to "demonise" GM foods in the mind of the public whereas it is the opinion of the vast majority of scientists, in South Africa and abroad, that GM foods are safe. |
| 9 | Genes from GM crops can be passed on to other plants resulting in environmental havoc. | Plants can only be pollinated by closely related crops. Therefore the GMO Advisory Committee looks very closely at the potential of GM crops to cross-pollinate other plants, especially weedy relatives. Fortunately major food crops such as maize do not have weedy relatives. |
| 10 | The production of GM crops will result in a decrease in biodiversity. | Hundreds of new varieties of crops are produced every year by conventional breeding. This increases biodiversity. GM crops will simply add to this. |
| 11 | Insects will rapidly develop resistance to the Bt toxin in insect resistant crops, so planting crops containing this gene is a waste of time. In addition, organic farmers who spray their crops with Bt will no longer be able to use this form of biological control. | This is certainly a concern and requires Integrated Pest Management. Whenever a Bt crop is planted farmers should plant a certain % of non-Bt plants to reduce the risk of the development of insect resistance. The best way is to require seed companies to sell a correct mixture of Bt and non-Bt seeds. This is what South African regulators are investigating. |
| 12 | "Terminator" gene technology - which results in seeds produced from a crop being sterile - will force small farmers to continue buying seed from multinationals, rather than being able to plant some of what they produce. | So-called "terminator" technology has been patented, by the US Department of Agriculture and one commercial company. However, it has not yet been perfected, let alone been used anywhere - and may never be used, thanks to public pressure. |
| 13 | Genetically modified foods are inherently allergenic and/or harmful. | There is no evidence whatsoever that GM foods in general are any different to "normal" foods in terms of toxicity or allergenic potential. Many of the genes used to modify plants occur naturally in plants, or the viruses or the microorganisms that infect them or are associated with them, meaning humans have already been exposed to them. |
| 14 | Non-target, beneficial insects will be killed by eating insect resistant plants. | In fact quite the opposite is happening. Because Bt crops are not sprayed, beneficial insects are returning, together with bird species, some of which have not been seen in the area for many years. We are hoping that field analyses will be done in South Africa to establish hard facts in this regard. Data from the USA show an increase in insectivorous insects and a concomitant decrease in pests such as spider mites. |
| 15 |
Non-target insects will be killed by eating pollen containing insect toxins. |
There was a glasshouse study in the USA in which Monarch butterflies were fed pollen from Bt-containing maize. Not unexpectedly they died as they are sensitive to the particular Bt used in the maize. However, the feeding was totally artificial with doses far exceeding those that would be encountered in the field. Field trials have recently been completed and it is clear that even inside maize fields the build-up of Bt pollen would not be sufficient to pose a threat to Monarch butterflies. |
| 16 | There is enough food to feed South Africa and sub-Saharan Africa – it is just a question of distribution. | This is a naïve attitude considering transportation problems on the sub-continent, wars and corruption, to name but a few impediments |
Enter here for last month's article by Prof Jennifer Thomson
Copyright 2001, Janice Limson. All Rights Reserved
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