A toxin discovered in the bacteria family Bacillus thuringiensis was thought to be the solution to the problem of having to treat cotton with pesticides when it was spliced into the genes of cotton in China using genetic modification.

Researchers have found that the new strain of cotton, which has been growing in China now for a few years, has given rise to a new category of pests called mirid bugs which plague both the pest-resistant cotton and other crops, including dates, grapes, apples, peaches, and pears. The researchers first stumbled on the problem in 2004, and have conclusively proven it now. Until the problem can be dealt with, BT cotton requires the use of pesticides, something it was supposed to be tailor-made to prevent.

Researchers point to this as an object lesson for GE crops; even if they think they’ve solved a problem with one strain, they may be creating a whole new set that they haven’t discovered yet; hence why nobody who eats organic wants to eat GE foods.