Biotech, African Corn, and the Vampire Weed.

• Author: Halweil, Brian
• Position: Scrophulariaceae weed

A parasitic weed is sucking the life out of East African corn. One way to deal with it would be to engineer corn for herbicide resistance, so that herbicide could be sprayed on the corn to kill the parasite-even though the corn seed and the herbicide would probably be too expensive for poor farmers, the herbicide would pollute, and the weed would likely become resistant. Another way would be to improve soil health. Tough call.

I was hot on the trail of the infamous Striga weed. Though I'd never confronted a live specimen, the in various panel discussions on biotechnology, I have plant had been hounding me in absentia, and often in public, for several years. Again and again, listened to my debating opponents hold up Striga as proof that genetic engineering could one day eradicate hunger and poverty in the Third World. The particulars varied, of course, but I had heard the same basic Striga argument from biotech executives, from industry-funded scientists, and from the industry's advocates in academia and government.

Striga hermonthica is a member of the Scrophulariaceae family, a widespread group of about 4,000 plant species that includes a couple of "heirloom" garden favorites, foxglove and snapdragon. But it also includes several important Old World plant parasites-plants that live off other plants. S. hermonthica is one of these. It's common in East Africa, where it's called "witchweed" or in Swahili, "buda." It looks innocent enough, standing about 15 centimeters (around 6 inches) tall, and bearing little lance-shaped, pale-green leaves that make a pleasing contrast with its pink-purple flowers. But below ground, the plant is a monster. Its root-like organs, called haustoria, seek out the roots of nearby crops, then rob them of water, nutrients, and life. And those pretty flowers can set as many as 20,000 seeds per plant. The seeds are easily dispersed and can lie dormant in a range of soil conditions for decades.

In a badly infested field, Striga can destroy most of the harvest, perpetuating not only poverty and hunger, but also gender inequity, since it's usually women who must undertake the largely futile task of disentangling Striga from the crop. Throughout East Africa, Striga causes several billion dollars in losses each year.

The solution, according to the biotech advocates, is to engineer varieties of African staple crops to resist herbicides, so that farmers can spray their infested fields-and kill the Striga without killing the crop. This is an extension of agricultural biotech's dominant commercial application: the engineering of soybeans, corn, cotton, and canola by Monsanto to withstand the company's best-selling herbicide, glyphosate ("Roundup").

An anti-Striga niche would make it easier to claim the moral high ground for herbicide-tolerant crops. Such products might eventually seem as humanitarian as the industry's "golden rice"-the beta-carotene enhanced rice variety that is being developed to combat vitamin A deficiency. Beta-carotene is the precursor of vitamin A, an especially important nutrient for children. Worldwide, nearly 134 million children suffer some degree of vitamin A deficiency, a condition that can suppress immune system function, cause blindness, and in extreme cases, even kill. Little wonder that golden rice has become the emotionally compelling hook for a $50 million public relations campaign launched by the Biotechnology Trade Organization. (It's true that not everyone is sold on this idea. Some nutritionists argue that it would make more sense to help poor people grow green vegetables, which produce more beta-carotene than golden rice--along with various other nutrients completely lacking in rice, golden or otherwise.)

But in any case, I decided that the time had come for me to get a first-hand sense of this expanding moral high ground. From a political point of view, the Striga issue looked especially interesting because Striga, unlike vitamin A deficiency, is almost exclusively an African problem, and Africa is ground-zero in the global food debate. Although hunger is sorely persistent throughout much of...