Image: World Wildlife Fund, Canada
ENDANGERED MONARCHS. Scientists say the larvae of these butterflies die when they eat milkweed leaves onto which pollen from genetically modified corn has drifted.
It looks just like a midwestern corn field is supposed to look this time of year; lush and richly green, stretching to the horizon. Maybe even a little bit better--there seems to be less pest damage to the leaves, and fewer weeds grow between the rows. The same is true for the fields of soybeans and the potatoes growing in Idaho.

Yet appearances can be deceiving. Indeed, there are quite a few people who would like to rip these super-ordinary looking plants out by their roots. These crops, being embraced by big agriculture in the U.S., carry genes that imbue them with resistance to herbicides and lace their tissues with a bacterial toxin harmless to humans but fatal to pests that may try to feed on them. For corporate farmers, the promise of such genetically modified crops seems clear--higher yields, superior quality, better nutrition and less need for spraying highly toxic and expensive pesticides.

Since the first genetically modified seeds were sold to farmers just a few years ago, the amount of acreage planted has grown exponentially. By the 1998 growing season, it was estimated that genetically altered crops planted in the U.S.--including tomatoes, squash, cotton, canola, corn, soybeans, rapeseed and potatoes--covered an area the size of Scotland. Corn alone, then in its first season after winning regulatory approval, accounted for some 15 million acres. The percentage of genetically modified seed, some experts estimate, is now approaching 40 to 60 percent of all U.S. plantings. More designer seeds are wending their way through the review and approval processes of the Department of Agriculture, the Food and Drug Administration and the Environmental Protection Agency, which regulates pesticides.

It is almost a certainty that practically everyone living in the U.S. has eaten some food that contained the produce of a gene-spliced plant. That's enough to make some people gag.

Do the risks of genetically modified crops outweigh the benefits?

Read what other readers say.

When genetic engineers began modifying bacteria to produce a new generation of drugs, such as human insulin, there was little outcry. But people seem to be far more finicky about what they put in their mouths for nutrition. As soon as plant scientists began tinkering with foodstuffs, controversy raged. Developers of modified seeds, among them Monsanto, Cargill, Novartis, Du Pont and a small horde of agbiotech startups, became the targets of demonstrations--and sometimes open warfare. Experimental plots were vandalized; protesters tried to block the loading of ships with genetically altered crops.

On the front lines of the controversy these days is Monsanto Inc. The agrochemical giant has developed a line of seeds that are resistant to its multi-billion dollar a year herbicide, Roundup, and carry a gene from a soil bacterium called Bacillus thuringiensis. The organism produces a toxin that makes plants the last repast of common insect pests.

In theory, at least, Monsanto's scheme would appear to be a boon to humanity. The gene conferring resistance to Roundup, a chemical known as glyphosate, allows farmers to spray fields with a broad-spectrum herbicide that will spare only the selected crop. And this ability in turn lets farmers optimize their use of "no-till" agriculture, a tactic that can reduce soil erosion by an estimated 70 percent.

Meanwhile, the bacterial toxin, a protein called CryIA(b), is highly specific to certain insect pests, such as the European corn borer and the spruce budworm. When it was discovered, it was hailed as an ecologically friendly, natural pesticide free of the dangers posed by potent, but indiscriminate, organophosphate insecticides. In the form of killed bacteria, it was sprayed on millions of acres. Simply incorporating the gene, known as Bt, into a plant gives it resistance to pests, without requiring periodic spraying by the farmer.

Monsanto's insistence that its elegant double whammy is far more ecologically benign than the products it replaces has done little to put fears about genetically modified crops to rest. Nor did the EPA's encouraging 1996 statement, which came after a decade of testing, quell critics. The report stated that "there is a reasonable certainty that no harm will result from aggregate exposure to the United States population, including infants and children, to the CryIA(b) protein and the genetic material necessary for its production. This includes all anticipated dietary exposures and all other exposures for which there is reliable information."

Opponents now refer to the new crops as "frankenfood." Last August a report from British researcher Arpad Puztai indicated that rats fed on genetically modified potatoes for 110 days, the equivalent to 10 years in human terms, showed signs of stunted growth and increased vulnerability to disease. An immediate outcry ensued. Criticism that rats are not notably fond of potatoes and that a human, fed only the tubers for a decade, would not likely be in such great shape either, had little effect.

The most recent fly in Monsanto's ointment is the beautiful Monarch butterfly. In a brief letter published in the May 20 issue of Nature, Cornell University entomologists led by John E. Losey reported that Monarch larvae fed milkweed leaves dusted with pollen from Bt-modified corn died in a laboratory experiment. Almost half of the tested lavae, which ate less than control butterflies fed their normal milkweed diet, died. The Monarchs migrate from Mexico to northern North American, where they spend the summer breeding; the larvae eat a diet exclusively of milkweed.

It was quickly pointed out that large concentrations of pollen on milkweed leaves were unlikely more than a few feet from flowering corn--and that pollen is readily blown off by the wind and washed away by rain. It was also noted that while the butterflies breed all season, corn pollinates once. Others commented that the larvae wouldn't be very healthy either if they were in a corn field sprayed with conventional agricultural chemicals.

Even so, in Europe, where resistance to genetically modified crops is even more determined than in the U.S., the report drew immediate action. The European Union's executive commission decided to halt the approvals procedure for gentically altered crops. France, which, like Britain, has had a moratorium on planting genetically modified rapeseed to produce cooking oil since 1998, appointed a commission to determine if a similar moratorium on the corn was warranted. In Asia, the Japanese Ministry of Agriculture, Forestry and Fisheries announced in late June that it was suspending approval of Bt crops for agricutural purposes, pending the establishment of criteria by a special committee on genetically modified organisms.

So far U.S. growers and food processors have been able to fend off efforts to segregate and label genetically altered foods. Their view is also supported by the Codex Alimentarius, a United Nations Food and Agriculture Organization committee seeking uniform international standards for food. But the butterfly findings seem to have also speeded a move by European food processors, who are bowing to perceived consumer pressure by shying away from genetically modified ingredients.

In Britain, for example, a recent study showed that 30 of the leading food processors had either stopped, or were going to stop, using genetically modified ingredients. The latest among them is Northern Foods, one of the largest producers of fresh food products in the U.K. Meanwhile, Paris-based Groupe Danone, the third biggest food processor in Europe, announced that it wouldn't use genetically modified ingredients. And both Unilever, the Anglo-Dutch company, and Switzerland's Nestle stated that they would limit or ban the use of genetically modified ingredients in selected countries.

The Case for Genetically Modified Crops

The advent of plant biotechnology was hailed as the engine of a Second Green Revolution, capable of providing farmers with the hardier, higher-yielding, disease-resistant and more nutritious crops needed to sustain a burgeoning world population. Plant scientists argue that modification is really nothing new; using tools such as selective breeding and hybridization, humans have been influencing the genetics of food crops for millennia. Indeed, present varieties of corn, they say, bear little resemblance to their historical progenitors. The contribution of biotechnology is that the process can be sped up enormously and new traits incorporated from virtually any species. These proponents insist that their new varieties have been more extensively tested than any in history and that their safety as foodstuffs and in the environment is well proven.

The Case Against Genetically Modified Crops

Opposition to genetically modified plants comes from many fronts. It ranges from those like biotechnology gadfly Jeremy Rifkin, who oppose gene splicing on religious and moral grounds; to environmental and consumer rights groups, including Greenpeace and the Union of Concerned Scientists, that fear unexpected consequences to the environment; to health and pure food advocates, who see the new products as adulterated; and to small farmers and organic growers, who see the products as a sign of big chemical makers, seed merchants and commercial farmers trying to force them into buying these goods or going out of business. These groups charge that there has been insufficient testing, that the benefits have not been adequately demonstrated and that there is a clear potential for ecological disaster. Moreover, they argue that the same forces that stymied earlier crops, such as acquired resistance to pesticides by insects, will also triumph over the laboratory feats of the gene splicers.