Genetically engineered (GE) plants are created by splicing foreign genetic material into plant genomes, creating new organisms that could never arise in nature. The most common form of gene-splicing is quite similar to the process of viral infection. The gene is first cobbled together with pieces of unstable DNA from disease-causing viruses and bacteria, which are required to "infect" the target plant with the desired gene, overcome the plant’s defense mechanisms against foreign DNA, and force the plant to express the inserted gene. Once inserted, both the gene and its viral helpers are passed on to future generations; they may mutate, recombine with viruses, or be transferred "horizontally" to other organisms, with unknown and largely unstudied consequences. While chemical toxins may be cleaned up, genetic engineering truly gives pollution a life of its own.

Almost two-thirds of genetically engineered crops grown on a commercial basis in the United States have been modified to tolerate certain proprietary herbicides or weedkillers. Crops such as corn, soy and canola have been genetically engineered to withstand otherwise lethal doses of chemical pesticides. Farmers, therefore, can douse their fields with herbicides without having to worry about killing their crops.

Herbicide-tolerant crops contradict the claim that genetic engineering will help the environment. Instead of moving farmers away from their dependence on chemical pesticides, the crops actually encourage pesticide use – a threat to our drinking water, our food and to wildlife. A report by Benbrook Consulting in July 1999, which reviewed more that 8,200 university-run field tests on herbicide-resistant crops, found that farmers planting Roundup Ready soybeans used two to five times more herbicides than conventional soybean farmers.

It has been shown that herbicide-resistance genes can spread to related plants in pollen carried by bees or the wind. Researchers have found evidence for this in the case of canola and sugar beet in Europe. In Canada, volunteer canola resistant to three different herbicides resulted from such uncontrollable cross-breeding between plants resistant to one herbicide each.

These superweeds can be difficult and expensive for farmers to eradicate. They could displace existing species of plants, destroying local ecosystems and threatening biodiversity.

Research in the UK has shown that pollen from GE crops can contaminate fields up to 4 km away, creating serious liability problems for farmers growing crops for the expanding markets in non-GE and organic foods.

Herbicide-resistant crops, themselves, may also become weeds if they grow in places where humans don’t want them. We already have examples of the consequences of intentionally introducing non-native plants into the environment. Kudzu and Johnson grass, for example, were both introduced into the United States and today have become serious weeds.

Second in acreage only to herbicide-resistant crops, pesticide plants are engineered to produce toxin in all their tissues, including the edible grain. Pesticide plants are produced by means of a "gene gun," which is used to "shoot" a toxin-producing gene taken from a soil bacterium – Bacillus thuringiensis (Bt) – directly into the tissue of corn, canola, potatoes and cotton to make the plants poisonous to insects. About 25% of the U.S. corn crop is now planted in Bt varieties. Proponents of genetic engineering argue that Bt crops will reduce the need for insecticides and therefore spare the environment. In fact, the transformation of plants into pesticides is a terribly misguided development with ominous implications for the health of the ecosystem.

¹ Chevre et al, 1998. "Characterisation of Backcross Generations Obtained Under Field Conditions from Oilseed Rape Wild Radish F-1 Interspecific Hybrids: An Assessment