From the beginning, many scientists have had concerns that the release of these new organisms with their engineered DNA could have dire consequences. Those consequences not only affect the natural “wild” environment, but also conventional and organic agriculture.
Companies are also working with the genetic manipulation of trees to produce commercial benefits such as more rapid growth. There are experiments with “pharma-crops,” trying to get plants to “grow” medicines or ingredients for medicines.
Pollen from GM crops and trees can contaminate nearby crops and wild plants of the same type, except for soy, which does not cross-pollinate. In fact, virtually all heritage varieties of corn in Mexico (the origin of all corn) have been found to have some contamination. Canola and cotton also cross-pollinate.
GM sugar beets are a member of the chard family and therefore have even more potential targets for contamination through crosspollination. No one knows what might happen if DNA containing pharmaceutical properties are spread to wild plants.
Studies have shown that pesticide-producing crops contaminate nearby streams, possibly affecting aquatic life. The bt toxin produced by these GM crops are far stronger than any found in nature, and are produced throughout the plant.
They may harm beneficial insects. And, it has been found that previously insignificant insects which are not targeted by the GM varieties develop into pests. Then pesticide spraying resumes, on top of the potential build-up of the extra strong bt toxin in the soil. This has occurred in China, India as well as in the US.
As weeds adapt to herbicides, they develop resistance and evolve into what are called “super weeds.” When that happens, herbicide use increases and the benefits of herbicide resistant crops are diminished, if not lost.
Impact on Sustainable Agriculture
Organic standards do not allow the use of GM seeds and therefore steps are taken to try to prevent contamination. Tests are not required, although some vigilant organic companies require them. According to the organic standards, contamination by cross-pollination is not disallowed, but some companies reject contaminated product above some small amount such as 0.1%.
Organic canola farmers in Canada sued biotech companies, since cross-pollination has made it impossible for them to grow organic, non-GM canola.
GM-free agricultural zones
Using identity preservation (IP), farmers keep crop varieties separate from others to meet purity requirements of their buyers. Contamination is a key challenge to IP growers. Unwanted varieties may cross-pollinate or get mixed up in the seed, harvest equipment, or during storage and transport.
Some farm regions create entire zones that exclude unwanted varieties, where all the farms, and if possible all collection and distribution points, only handle approved grain.
Voters in Mendocino and Marin Counties in California passed ballot initiative to ban GM crops. Officials in Trinity County and Arcata, California have passed ordinances banning the outdoor cultivation of GM crops as well. But since then, a California law was passed prohibiting this type of local initiatives.
In March 2008, voters at the Montville, Maine, annual town meeting overwhelmingly passed a binding ordinance banning the cultivation of GM crops in their community.