The letter to Agriculture Secretary Tom Vilsack has been posted on dozens of websites ranging from the Huffington Post to obscure gardening and food blogs, generating discussion on message boards about the controversial topic of genetically modified crops and their potential effect on animals and humans.
But other scientists say they have no way to verify professor emeritus Don Huber's claims because he won't provide evidence to back them up.
"People in the scientific community have at times made outlandish claims but it's been based on research that was flawed in some way, but at least the data was provided to be analyzed and critiqued," said Bob Hartzler, an Iowa State University agronomy professor who called the letter "extremely unusual, especially coming from the scientific community."
Huber, 76, wrote the letter to Vilsack in January, warning of a new organism he claims has been found in corn and soybeans modified to resist the weed killer Roundup. Huber wrote that the organism could lead to a "general collapse of our critical agriculture infrastructure" and further approval of Roundup Ready crops "could be a calamity."
He told The Associated Press the organism that concerned him was found in much higher concentrations in corn and soybeans grown from so-called Roundup Ready seeds than in grains grown from conventional seed, although the samples of conventional crops tested were too small to get a reliable result.
Huber believes the pathogen has made genetically modified soybeans more susceptible to sudden death syndrome and corn to Goss' wilt. He also claims it's linked to spontaneous abortions and infertility in livestock that eat feed generated from those crops.
He said he wrote the letter to Vilsack because he thought the U.S. Department of Agriculture needed to take immediate action and provide resources to further research his claims. He said he doesn't know how it reached the Internet.
Huber said he sent the letter through a third party so it could be hand-delivered to Vilsack.
The USDA acknowledged it had received the letter, but it doesn't appear the agency is investigating the matter.
"It has been confirmed that no letter addressed to Secretary Vilsack from Dr. Huber has been received directly by USDA," the agency said in a statement to the AP. "The only copy we received was forwarded by a third party, and we do not respond to third-party letters."
The USDA declined to comment beyond that statement.