(AP) -- The widespread Internet posting of a letter by a retired Purdue University researcher who says he has linked genetically modified corn and soybeans to crop diseases and abortions and infertility in livestock has raised concern among scientists that the public will believe his unsupported claim is true.
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.
Monsanto, the St. Louis-based company that developed Roundup resistant seeds, said in a statement it was "not aware of any reliable studies that demonstrate Roundup Ready crops are more susceptible to certain diseases. GM crops have undergone a rigorous safety assessment following internationally accepted guidelines, and no verifiable cases of harm to human or animal health have occurred."
Huber's letter identifies himself as a retired Purdue professor, and it has left the Indiana university known for its agriculture programs in the uncomfortable position of being linked to research it can't verify.
"This is not Purdue research being carried on by people at Purdue University," said Peter Goldsbrough, director of the university's plant pathology department.
Goldsbrough said Huber declined to provide evidence supporting his claims or the names of his research partners.
"If someone is making a new discovery, they normally want someone to know about it and if this was an important environmental or agricultural problem, you would want to engage other people in finding what the causes of the problems are," he said. "I don't know what would be gained by not sharing."
Goldsbrough said nothing is being done to strip Huber of his association with Purdue.
Huber, who now lives in Melba, Idaho, said he started his research at Purdue and continued it in collaboration with other scientists in the Midwest, Florida, Brazil and Canada after retiring in 2006. He declined to name the other scientists, saying they asked to remain anonymous because the attention would distract from the research.
He acknowledged he was taking an unusual approach by not submitting his finding for other scientists to review.
"The information on the new organism was new enough that there wasn't time for peer-reviewed papers and that it was serious enough I felt it was very important the secretary know what the situation was and that they exercise some caution before moving forward," Huber said.
The USDA, meanwhile, has moved ahead with an expansion of biotech crops.
In January, the USDA deregulated alfalfa and in February it partially deregulated sugar beets that have been genetically modified to withstand Roundup, which contains a chemical called glyphosate.
Paul Vincelli, a plant pathology professor at the University of Kentucky, said he talked with Huber last fall after he was asked to review a Kentucky researcher's work on the same topic. Vincelli declined to identify the Kentucky researcher, saying his review was a private consultation, but he said he has seen no evidence to support Huber's claims linking a new pathogen to crop diseases or animal fertility.
Vincelli said while research has shown the use of glyphosate may make some plants more susceptible to disease, he is not aware of evidence of a new pathogen that increases that risk as Huber claims.
Vincelli said Huber is highly distinguished and well respected in the scientific community but said his recent work was "highly speculative."
"I'm not saying the claims are true or false. What we need is really good science on this issue," Vincelli said. "We're talking about extraordinary claims, and we need at least ordinary evidence in support of these claims."
Explore further: How does enzymatic pretreatment affect the nanostructure and reaction space of lignocellulosic biomass?