Grower

GMOs, The Debate Goes On

The anti-GM food lobby had a field-day recently when Dr. John Losey and fellow entomologists at Cornell University published an article in the prestigious scientific journal Nature describing how caterpillars of the monarch butterfly experienced 44% mortality after four days of feeding on milkweed leaves dusted with pollen from genetically modified maize. The GM maize had been engineered to contain the Bt gene and protects the crop from insect pests such as corn borer caterpillars.

Political response across Europe was swift. Although the Bt maize used in the pollen experiments was bred by Novartis, Austria immediately banned the cultivation of a Monsanto Bt maize variety. The European Commission, which has so far allowed commercial crops of Bt maize to be grown in Spain and Germany, has frozen the approval of any more varieties, including one from Pioneer Hi-Bred that was under consideration.

In this heightened political climate many GM trial crops have been vandalised by activists; a GM oilseed rape trial was destroyed at an SAC farm in Aberdeenshire, while at Cereals '99 a trial of GM sugar beet was uprooted. Meanwhile extensive media coverage was given to Wiltshire farmer Captain Fred Barker's decision to destroy his field-scale trial of herbicide-tolerant GM oilseed rape following a Soil Association warning to the farm's Trustee's that it could lose its organic certification status for a crop of beans grown close by.

Such a response begs the question: is a sprinkling of GM pollen onto an entirely unrelated organic crop really as bad as spray drift or deposits of particulate pollutants from vehicle exhaust?

Acts of sabotage like this, of course, leave unanswered the fundamental question that farm-scale field trials are attempting to address, namely, will GM crops threaten the diversity of British wildlife if they become more widely grown?

With more and more GM products in the pipeline, it is essential that the trials go ahead. But with the growing threat of vandalism to field trials, not necessarily restricted to GM crops, and the possibility of falling land prices, fewer farmers are willing to offer their land as trial sites.

Oliver Watson, one of the UK's largest farmer's, however, has put his money where his mouth is. "I will only contemplate using GM varieties if I am reasonably certain that they do no damage to the environment and will also produce as crop that the consumer wants," he says.

"Unless trials are carried out, we will never know the answers. This is why I am inviting any bona-fide plant breeder to use my farm to carry our properly oganised trials."

"Only by doing this," he adds, "will I - and every other farmer - ever hope to know the answers."

And the situation gets more and more complicated with each new study. How for example can a field trial to assess the impact of herbicide resistant oilseed rape be used to predict the impact of Bt-maize? Moreover what happens when new products come on-line? Should the Government, biotech industry, environmental groups and independent scientists be developing a joint strategy for testing each new product?

And what are we comparing the results against? In the USA, the Biotechnology Industry Organisation, which represents more than 850 biotechnology companies, universities and research centers, has stated that the monarch caterpillars study needs further evaluation and context.

"Ongoing monitoring of Bt maize fields by companies since their introduction," it says, "shows that very little pollen lands on adjacent milkweed leaves. It is thus highly unlikely that, in the natural setting, most monarch larvae would never encounter significant amounts of corn pollen."

Dr. John Losey agrees. "Our study was conducted in the laboratory and, while it raises an important issue, it would be inappropriate to draw any conclusions about the risk to monarch populations in the field based solely on these initial results," he says.

Meanwhile, Greenpeace has drawn up a list of UK and European butterfly species identified as potentially at risk as they feed on plants common in field margins and hedgerows during the time that maize is shedding pollen.

"We don't know yet how severe the impact of genetically engineered maize will be on individual butterfly populations, " says a Greenpeace spokesman. "The trouble is, the companies that produced these GMOs, and the government authorities that are supposed to check their safety before approving them, don't know either. They simply ignored the risks."

Some of the 'at-risk' species include the orange tip, Adonis blue and pearl-bordered fritillary, as well as potential pest species such as the large and small whites.

But the GM crops do provide an alternative to insecticides. According to Dr. Chris DiFonzo, an entomologist at Michigan State University: "Bt maize is a much safer method of pest management, and has less detrimental impact on all aspects of the environment - monarchs included - than the use of broad-spectrum insecticides."

Dr. Losey agrees, saying: "I still think the proven benefits of Bt maize outweigh the potential risks."

Among the scientific community there are powerful advocates of continued GM research. Professor Ray Baker, Chief Executive of the UK's Biotechnology and Biological Sciences Research Council, pleads: "Investigating the environmental effects of GM crops is of the utmost importance in helping us to understand how this technology can be safely used to the benefit of agriculture. True environmental conditions cannot be replicated inside a laboratory, and it is therefore important that these trials are allowed to proceed under controlled conditions in the field."