Blight in rice caused by Xanthomonas oryzae. Credit: N. Cattlin/FLPA

The US Department of Agriculture (USDA) this month added a rice pathogen to its national security watch list, despite objections from several prominent scientists.

USDA's Animal and Plant Health Inspection Service has listed the bacterium Xanthomonas oryzae pv. oryzae, which causes leaf blight, as a 'select agent' that could be used for bioterrorism.

Several researchers who work with the microbe argued against the listing, saying that it would have difficulty establishing itself in the United States, and that those labs working with it have perfect safety records dating back more than 20 years.

Researchers have until 17 November to notify the government if they possess the pathogen, and until 14 April 2009 to come into full compliance with the regulations.

"That's not a lot of notice," says Pamela Ronald, a rice researcher at University of California, Davis, who opposed the listing. "All the labs are scrambling to find out what it means to their research programmes."