In India, with so many difficult agro-ecological conditions and millions of poor farmers,

Bt-transgenic crops are likely to grow unevenly across farms leading to many cases of sub-lethal doses of the Bt toxin and, therefore, resistance might be engendered at an even faster rate.

The Bt toxin contained by the Bt crops is no different from other chemical pesticides. Early on it will cause a temporary reduction of pesticide use (and associated costs), but resistance will eventually develop unless effective countermeasures are taken. Some of those countermeasures are in place as a result of requirements imposed by EPA as the condition of permits. But there are important scientific questions about whether those plans will work. Doubts about the resistance management plans currently in place for Bt-cotton include concerns that pests might develop resistance to Bt, perhaps in as few as three to five years. If that is the case, cotton farmers will soon be back to ground zero looking for yet another pesticide. In the meantime, they may enjoy a temporary reduction in pesticide use as a result of adopting Bt crops, but not necessarily any greater reduction than had someone introduced a new chemical pesticide.

The loss of Bt, if it occurs, will have ramifications far beyond the conventional cotton fields. Bt, because of its natural origin and lack of toxicity for nontarget organisms like fish and mammals, has been widely used by the organic community and other farmers using integrated pest management (IPM) and other sustainable agriculture approaches. Although many of these farmers would never choose to use genetically engineered crops, Bt will become useless for them, too. Through no fault of theirs, a valuable natural pesticide will have been lost.

Even more worrisome than Bt cotton has been the history of StarLink, a transgenic Bt corn containing one of the family of Bt proteins (Cry9C), developed for control of European corn borer and Southwestern corn borer, and for suppression of black cut worm and corn stalk borer.

Cry9C is a protein for which there is no history of human dietary exposure. It has several properties characteristic of food allergens. In August 1997, Plant Genetic Systems (later acquired by AgrEvo, subsequently taken over by Aventis) applied for registration of StarLink corn.

The EPA approved its use in May 1998 only as animal feed and for industrial purposes. In April 1999, AgrEvo again petitioned the EPA to permit use of StarLink for human consumption. The EPA set up a Scientific Advisory Panel (SAP) comprising 16 physicians and independent scientists to advise it on the matter. In its report to the EPA in December 2000, the SAP concluded, "there is a medium likelihood that Cry9C protein is a potential allergen", thus rejecting the use of StarLink corn in human food. The SAP met once again in July 2001 to consider fresh studies by Aventis and others but found no reason to alter its recommendation of banning StarLink from human food. The panel found that Cry9C shows both heat stability and resistance to digestion, the two best available criteria presently known for ascertaining food allergy proteins. Too many questions remained about StarLink causing allergic reactions such as rashes, breathing problems, gastrointestinal upset or even anaphylactic shock.

Indeed, already in September 2000, some of America's favourite taco shells (Taco Bell), sold in grocery stores nationwide, were found to be illegally contaminated with StarLink. Kraft immediately recalled them from the market. Subsequently, nearly 300 other processed foods were also recalled following StarLink contamination. The registration of StarLink was cancelled and future planting of stocks of StarLink was prohibited. The U.S. Department of Agriculture and Aventis made aggressive efforts to remove StarLink from the market, all of which is expected to disappear by 2002.

The most extraordinary twist to this story is that even as the Americans were busy trying to get StarLink out of their system, the Clinton administration decided in October 2000, to lift export restrictions, allowing shipments of previously banned StarLink corn to Latin America, Asia and Europe.