How would the public's perception of genetically engineered crops be different if nonprofit agencies or governmental organizations had taken the lead instead?
Pamela : Look at papaya, for example. In the 1990s, there was an infestation of papaya in Hawaii with something called ring spot virus. It completely obliterated papaya production on the island of Oahu, so growers moved production to the island of Hawaii. Plant pathologists predicted that eventually the virus would arrive on Hawaii, too, and eventually it did. But before it had, Dennis Gonsalves, a former plant virologist at Cornell who is now with the U.S. Department of Agriculture, developed a genetically engineered papaya variety that was completely resistant. He was working with a small USDA grant, and the genetically engineered papaya was distributed freely to growers. His GE papaya, it turned out, yielded 20 times more than the previous variety, and the industry completely rebounded. It's a great example of genetic engineering benefiting local farmers. Many groups oppose genetically engineered crops on the grounds that they're unsafe. What exactly are they worried about, and is the concern justified?
Raoul: BT [ Bacillus thuringiensis ] protein is one example. The gene for BT comes from bacteria and is integrated into some genetically engineered crops. Some people are concerned about the idea of eating that protein over long periods of time, even though it is present only in trace amounts. As an organic farmer, I've applied BT protein, which is approved for use in organic farming, many times. The protein affects a relatively small range of butterflies and moths but is nontoxic to humans and other animals, which is one reason it is a favorite tool of organic farmers. You mentioned that some genetically modified plants require less insecticide. That seems like something that organic farmers would embrace.
Pamela: Yes, I think the public is not aware that the use of genetically engineered seed has dramatically reduced insecticide use. In China, cotton farmers were able to eliminate 150 million pounds of insecticide in a single year by using genetically engineered varieties. For comparison, in California, we spray about that much every year. Raoul: One interesting part of this story, however, is that those huge gains started to fall off after six or seven years. Those farmers in China have started to see a resurgence of "secondary" pests because they are no longer spraying insecticides. I'm betting that if those farmers had been using crop rotation and biological controls [releasing beneficial insects, for example, or interspersing crops in ways that make it harder for insects to get the upper hand]—the practices that organic farmers use—instead of growing monoculture [one crop in one place], they wouldn't have had such problems with secondary pests.
How common are genetically engineered crops around the world now?
Pamela: Every time a GE crop has been approved for use, farmers have embraced it and the GE acreage for each crop has quickly grown to 50 to 90 percent of the total acreage. According to a recent article in Science magazine, the top producer is currently the United States with 57 million hectares; the next is Argentina with 20 million hectares; and then Brazil with 15 million hectares. These three are followed by Canada, India, China, Paraguay, and South Africa. Globally, are we using the breadth of what's scientifically possible or just focusing on modifying a few specific traits?
Pamela: There are essentially just two traits out there: herbicide resistance and insect resistance. Those two have been put mainly in soybeans, corn, and cotton. We are just at the tip of an enormous iceberg of possibility. Raoul: Flood resistance, drought tolerance, frost tolerance, salt tolerance—all of these could potentially be put into crops to increase yields. I'm particularly interested in crops resistant to nematodes, a class of tiny, cylindrical worms commonly found in soil. There are researchers working at Davis who are working on nematode resistance for tomatoes. They say it would even be fairly easy to put nematode resistance into heirloom tomatoes, such as Brandywine.