Will the next terrorist attack be against plants, not people? At the urging of the White House, the U.S. Department of Agriculture and the FBI are looking at the threat of agricultural bioterrorism-an assualt on the country's efficient but fragile system of giant single-crop farms.
"The fear is that if some party wanted to, they could damage a major crop-and the economy-by introducing a plant pathogen that doesn't normally exist here," says plant disease expert Larry Madden of Ohio State University. Likely bioweapons include plant-killing fungi, such as soybean rust, or infectious microbes that induce plants to produce toxins. "If the group were sophisticated enough, they could genetically engineer a highly pathogenic strain, produce it in large quantities, and sneak a lot of it in," says Madden.
In wild plants, natural genetic diversity helps limit the spread of disease. "Ninety-nine percent or more of the genes in crops are the same across the United States," Madden says, "and that uniformity makes an epidemic much more likely." Once unleashed here, a superbug could spread like wildfire before researchers identified it and figured out how to keep it in check. Even then, spores could survive and infect the next year's crop. "They could also be spread by the wind, from field to field, or even state to state," Madden says. "It would be a continuing, recurring problem, like a permanent bomb going off."