Innogen · News · July 26, 2005

Joyce Tait article in Scotsman

Press reports of an unexpected mutation of a 'superweed' serve only to stoke the fire on an already febrile subject, writes Joyce Tait

Debates about GM crops continue, refreshed from time to time by new claims of risks or benefits, sometimes backed up by scientific evidence. In the latest example, an announcement from the Centre for Ecology and Hydrology in Dorset, reported yesterday, led to renewed claims that GM crops have created a 'superweed'.

This idea is neither new nor surprising. I first became involved in such discussions among scientists in the late 1980s when there were heated discussions among scientists about whether GM crops would be fit enough to survive in the natural environment, and whether they would be able to hybridise with wild relatives.

Such questions are best answered by scientifically-based research and the latest development comes from an intitiative involving sixteen projects set up by BBSRC, NERC and DEFRA, looking into Gene Flow in Plants and Micro-organisms. Stakeholders and the wider public were consulted on the scope of the programme before it was set up and the results were reported back to them on 23 June.

The 'superweeds' described here have picked up genes from GM oilseed rape that make them resistant to one or more herbicides. If this herbicide resistance makes them fitter to survive than other members of their species they will be able to multiply and spread widely. But this will only happen on the farms were herbicides are used. Herbicide resistance will not give an advantage to plants in wild areas were herbicides are not used.

The phenomenon of resistance is everywhere, whether natural or brought on by human acitivity. Humans are sometimes able to become resistant or immune to diseases, but in the early 1900s infections killed large numbers of children and adults. The development of chemical anitbiotics greatly reduced the death-toll of several major diseases, but also inevitably set in train the emergence of antibiotic resistant disease organisms. Should we have banned penicillin and streptomycin in the 1950s in case they led to antibiotic resistance?

Insect pests in agriculture also develop resistance to the chemicals we develop to kill them. In fact the history of the pesticide industry has evolved around it. Insect resistance was one factor opening up new markets for more advanced, often less environmentally damaging, insecticides as they emerged from the R&D cycles of the industry.

A side-benefit for the agro-chemical industry was that the new, advanced pesticides could be sold for higher prices than the older ones which were by that time no longer patented, justifying the expensive development of new pesticides. However, at the same time there was also investment in agricultural strategies to delay the onset of resistance to insecticides, as has also been the case with antibiotics.

Resistance is thus an important driver of innovation and contributes to the competitive advantage of companies. In natural ecosystems, including those dominated by humans, it contributes to the competitive advantage of all species. It is a fact of life which we read as positive if it occurs in a species we humans wish to protect, and negative if it occurs in one that harms us.

How big is the problem?

'Superweeds' would clearly be a problem for farmers who would find it difficult to control weeds using herbicides. If it was widespread it would also be a problem for agro-biotehcnology companies in that farmers would stop buying their product. Organic farmers would presumably not suffer if any of these weeds were to stray onto their land as their non-chemical methods of weed control would still be effective. On uncultivated or unmanaged land, herbicides are not used and resistance to herbicides is not an issue - indeed the concept of a weed becomes irrelevant.

However, because GM crops have the potential to reproduce beyond our control we should take such concerns very seriously, as the research programme funded by the UK government has already done. The research has so far drawn attention to several unresolved questions related to our ability to control such 'superweeds' - how frequently will the herbicide resistance genes be transfered to other non-crop species, how fit to survive will the hybrids be and how rapidly will they be able to spread?

What should we do?

So we should indeed take the potential problem of superweeds seriously, but what should we do about it? Those opposed to GM crops use the reseach results to reinforce the case for a continuing ban on the introduction of GM crops in Europe. However, this will continue to deprive Europe of the undoubted benefits of GM crops at a time when subsidies are being withdrawn and they are increasingly having to compete in global markets. The farmers who were involved in the UK GM crop trials would very much like to be able to continue using this technology. It is also becoming increasingly clear from experience in other parts of the world that some GM crops, including herbicide resistant crops, do have environmental and human health benefits in that they can significantly reduce the levels of pesticide use. These benefits should be weighed against the potential risks.

We should be looking to broaden our range of approaches to dealing with the potential, unproven hazards of new technology. We Europeans are capable of being much cleverer than we have been so far in the context of GM crops - there are management techniques that can contribute to minimising negative effects; we can change the way we develop the technology or add to the sophistication of the technology, rather than banning it.

The debate about GM crops may rumble on but it is time it moved on to a higher level of sophistication, rather than reinforcing tired old arguments.