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close this bookBiotechnology and the Future of World Agriculture (GRAIN, 1991)
close this folderProviding the inputs
View the document(introduction...)
View the documentThe biased focus: herbicide tolerance
View the documentEroding the options
View the documentArtificial solutions?

The biased focus: herbicide tolerance

Nowhere does the immense discrepancy between potential and actual developments in biotechnology become clearer than with current biotech research on herbicide tolerance. Over the years, the use of herbicides has grown dramatically, as a result of changing agricultural techniques: monocropping, mechanization and non-tillage farming. World sales of herbicides amount to almost $5 billion annually, representing some 40% of total pesticides sales in the world.'ΓΈ Although the industry often claims that the newly developed herbicides harm neither humans nor the environment, recent research has detected several cases of carcinogenicity caused by herbicides and toxic herbicide residues in groundwater. In general, very little is known about the long-term effects of herbicide residues in the environment.

One problem that limits the use of herbicides is the fact that many herbicides not only attack the weeds they are supposed to kill, but also harm the crop they are supposed to protect. This restricts the farmer in the amount of herbicide she or he can use. Also, some herbicides might not harm a specific crop, but linger too long in the soil and damage the crop that is planted the next season.

The first efforts to reduce the damage that herbicides can cause to crops, were undertaken by Ciba-Geigy. Ciba, which had already bought up several seed companies in the 1970s, developed a chemical 'coat' for seeds to protect them against the herbicides produced by them. This 'herbishield' was wrapped around Ciba-Geigy seeds, thus providing the company with a double profit: the farmer buys the Ciba-Geigy seeds packaged with the Ciba-Geigy herbicides. After successfully introducing the package in industrialized countries, Ciba is now trying to penetrate the markets of the South.

With biotechnology, this process is being further sophisticated. Millions of dollars are being pumped into research to genetically alter crops in order to resist higher doses of herbicides. In Table 5.1 some of the current research on herbicide tolerance is listed. The main source of this listing is based on 'Derwent Biotechnology Abstracts'. (11) Derwent scans more than 1,000 scientific publications and patents related to biotechnology and provides indexed abstracts each fortnight, thus providing probably one of the most complete sources on biotech research. Added to the listing were the results of a few recent studies on the matter. At least 93 institutions have been involved in research on herbicide tolerance since the mid-1980s. All major crops are subject to the search for tolerance to a whole range of different weed killers. The substantial involvement of universities and other public institutions seems at a first sight surprising (48 public institutions in total). One reason for this might be that public institutions tend to publish more freely, and are thus over-represented in the table.

What the table does not show are the dollar figures attached to the projects. The US teased 'Biotechnology Working Group' estimates that publicly funded institutions in the United States alone spent $10.5 million on herbicide tolerance in the past few years. (12) But the major work is done in the corporate laboratories. The public institutions listed in the table generally limit their work to one or two herbicides and only a few crops. Rather than aiming for the commercialization of herbicide tolerant varieties, several of them perform this research to upgrade their knowledge on gene transfer technology in general. In contrast, major pesticide producers such as Monsanto and Du Pont each have a whole range of different projects involving many crops and different chemicals and do focus on the commercialization of the technology. Du Pont alone is investing $13 million in research on tolerance to its new sulfonylurea herbicides. (13) Additionally, most of the work by the smaller biotechnology companies such as Calgene and Plant Genetic Systems is under contract to the TNCs. Keith Pike, Marketing and Sales Director at ICI Seeds, thinks that herbicide tolerance technology is concentrated within a dozen corporations. (14)

No biotechnologically engineered herbicide-tolerant crop has yet reached the farmer's field, but many are now being field tested. The early 1990s are generally seen as the time when the first tolerant crops will become commercially available. If these predictions are confirmed, herbicide tolerance is likely to be the first major result of agricultural biotechnology made available to farmers on a large scale. Opinions differ as to how large. Early estimates talk of an annual value of herbicide-tolerant crops of $2.1 billion by the turn of the century, while other - probably more realistic projections range from a low $75 million to a high $320 million annually. (15) But apart from the profit from the seeds themselves, the chemical TNCs are also interested in the resulting increased use of the chemicals that are sold with them. Teweless reports that a main reason for being involved in this field is the 'hope of selling the seed and the chemical as a pair' thus creasing 'e complementary demand for both chemical and seed'. (16)

A case in point is the work on atrazine, an already widely used herbicide in maize, a crop which is naturally tolerant to it. But soybean, which is often sown in rotation with maize, is very sensitive to the herbicide. As atrazine is persistent and lingers long in the soil, its residues can damage such crops as soybean that are planted the year after. Du Pont has now isolated a gene that enables mutant pigweed to withstand atrazine. According to Charles Arntzen, Du Pont's Associate Director for plant science and microbiology, these mutants 'have a trait that says: "I don't care how much chemical you throw at me, it doesn't faze me". (17) Such perspectives don't faze the chemical companies either. Teweless calculates that with the development of atrazine-tolerant soybeans, atrazine sales would increase by about $120 million annually. (18) A study prepared for the European Commission concurs: 'If the predominant varieties of soya bean were resistant to atrazine, about two or three times more atrazine would be used on related crop land."9

Proponents of herbicide tolerance often point out that this would help to eliminate the older persistent and more dangerous class of herbicides in favour of the new and environmentally safe ones. Graph 5.1, which breaks down the data of Table 5.1 by herbicide, shows that this argument does not reflect reality. The old and persistent triazines (including atrazine) are by far the most researched herbicide group: 30 of the 82 groups for which herbicide tolerance is sought. Triazines have been linked to chronic health effects, such as central nervous system disorders. (20) Dangerous concentrations of atrazine were found in 29% of the samples in a US survey on surface-water quality. (21) Another six institutions are working on the old 2,4-D herbicides, suspected of causing cancer, birth defects and mutations. (22) Paraquat, probably the most toxic herbicide around for humans, is being researched for tolerance by five groups. In all, more than half of the groups listed in Table 5.1 have the old class herbicides included as targets for tolerance.


Table 5.1 Research on herbicide tolerance by private and public institutions - Part 1: Industry


Table 5.1 Research on herbicide tolerance by private and public institutions - Part 1: Industry - continued


Part 2: Public institutions


Part 2: Public institutions


Global research on herbicide tolerance - Number of institutions by herbicide type

This does not mean that the newer herbicides are safe for humans and the environment. Du Pont's low-dose wheat herbicide 'Glean' is a chlorosulfuron, belonging to the group of sulfonylureas which are being researched for tolerance by at least 13 groups. Wheat is naturally immune to Glean, but other crops are not. North Dakota farmer John Leppert has experienced the consequences: 'It would be at least four years in North Dakota before a field treated with Glean could be used for some broadleaf crops.' (23) Also, American Cyanamid's new Imidazolines, used on soybean, are persistent and their residues harm other crops that follow in the cultivation cycle. Cyanamid, Du Pont and others are trying to do something about it, not by developing non-chemical weed control strategies, but by developing crops that tolerate the chemicals. Even glyphosate, which according to one Monsanto executive is so kind to the environment that it could have been 'designed by God', (24) may not be completely safe. Sold by Monsanto as 'Roundup', many of the required safety tests on this herbicide in the USA have been invalidated because of submission of misleading data on the results. Consequently, some health and safety data of this chemical are still under review. It might cause health problems due to its formulation with other ingredients, and because of possibly harmful chemical reactions in the human stomach. (25)

Apart from the obvious negative impact on the environment and the risk to human health, the increased use of herbicides can have serious indirect consequences. Research shows that some herbicides can make crops more susceptible to insect pests and diseases by altering the plant's physiology. Several crops are researched by Du Pont for tolerance to the herbicide picloram, which increases the sugar output in the roots of wheat and corn, encouraging sugar-loving fungal pathogens. (26) Another experiment showed that when maize was treated with the recommended doses of herbicide 2,4-D, for which tolerance is also being sought, it became infested with three times as many corn-leaf aphids. The maize also became more susceptible to European corn borers, corn smut disease and Southern corn leaf blight. (27) Herbicide-resistant crop lines could end up requiring more insecticides and fungicides as well, thus binding farmers even more firmly on to the pesticide treadmill.

Extended use of herbicide-tolerant crops themselves is not without risk either. Crop relatives tend to cross with each other, but also with weedy relatives that grow close by. According to crop scientist Jack Harlan, most crops have one or more sexually compatible weed relative with which they can exchange genetic information. (28) Should genetically engineered crops start handing over their herbicide-tolerant genes to weeds, the farmer is in trouble. The same gene that made it possible to use more of the same herbicide on a particular crop would then be the reason for the farmer to use even greater quantities on it, as the weeds also become tolerant.

From the TNC perspective, it is not hard to understand this heavy research emphasis on herbicide resistance. The use of herbicide-resistant crops will substantially increase the total global herbicide market, and thus the total revenues of the TNCs involved. Also an attractive prospect of herbicide-tolerance engineering is that it offers companies the possibility to bind older herbicides that go off-patent to a specific crop, thus extending the time frame of their use. (29) Another reason emerges when the costs of developing seeds and pesticides are compared. It is simply cheaper to adapt a crop to a herbicide than to develop a new herbicide. A report issued by the European Parliament puts it this way:

From the point of view of the industry, herbicide-resistant varieties are, above all, developed for economic reasons, since the development costs of a new herbicide are up to 20 times higher than those for a new variety. (30)

With both sectors often in the hands of the same TNC, the company can choose; and the choice does not seem to be difficult.

From a socio-economic and agronomic perspective, however, it is difficult to understand why scarce human resources and finance are devoted to make crops resistant to pesticides rather than to pests. With biotechnology, a further development of plant sciences could help to design herbicide-free weed control strategies. These could include better crop rotation techniques, mixed cropping systems repressing the growth of weeds, and, possibly, the use of allelopathic crops that produce natural herbicides. Biotechnology could be used together with traditional plant-breeding to help develop crop varieties that cover the soil at an early stage, thus preventing weeds from becoming a major problem. Rather than totally eliminating the weeds, which is the aim of chemical weed control, such integrated strategies focus on weed management where the farmer uses methods at his disposal to keep damage by weeds at acceptable levels.

Especially for developing countries that so desperately need low-input and locally adapted technologies for their farmers, the present priorities for biotechnology do not make much sense. As with Ciba-Geigy's 'herbishield', herbicide-resistant varieties will find their way to the Third World through the extensive distribution infrastructure of governments and TNCs. This Northern technology will, as with the Green Revolution varieties, primarily be adopted by the large farmers, resulting in a further dependence of the Third World on the North for chemical inputs. It will marginalize the rural poor who need a very different type of technology. In chapter 2, it was already explained how increased herbicide use destroys farming practices in which associated weeds are actually useful plants and form an important source of protein in the local diet and provide extra income for the village people.