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KANSAS CITY, Missouri - Questions about the safety of a popular herbicide made by Monsanto Co. have resurfaced in a warning from a U.S. scientist that claims top-selling Roundup may contribute to plant disease and health problems for farm animals.

 

Plant pathologist and retired Purdue University professor Don Huber has written a letter to U.S. Agriculture Secretary Tom Vilsack warning that a newly discovered and widespread "electron microscopic pathogen appears to significantly impact the health of plants, animals, and probably human beings." He said the pathogen appears to be connected to use of glyphosate, the key ingredient in Roundup.

 

Huber coordinates a committee of the American Phytopathological Society as part of the USDA National Plant Disease Recovery System. He is a long-standing critic of biotech crops, such as Monsanto's "Roundup Ready" soybean and corn, which have been genetically altered to withstand treatments of Roundup herbicide.

 

In his letter to the U.S. Department of Agriculture, Huber said the organism has been found in high concentrations of Roundup Ready soybean meal and corn, which are used in livestock feed. He said laboratory tests have confirmed the presence of the organism in pigs, cattle and other livestock that have experienced spontaneous abortions and infertility.

 

The organism is also prolific in corn and soybean crops stricken by disease, according to Huber.

 

"I believe the threat we are facing from this pathogen is unique and of a high risk status," Huber wrote. "In layman's terms, it should be treated as an emergency."

 

Monsanto scoffed at the allegations and said its own research as well as independent field studies and tests by multiple U.S. universities do not corroborate Huber's claims.

 

"Monsanto is not aware of any reliable studies that demonstrate Roundup Ready crops are more susceptible to certain diseases or that the application of glyphosate to Roundup Ready crops increases a plant's susceptibility to diseases," the company said in a statement.

 

Huber said in his January 17 letter to the USDA that the findings were at an "early stage," but it appeared side effects of glyphosate use may have facilitated growth of the pathogen, or allowed it to cause greater harm to weakened plant and animal hosts.

 

He requested USDA participation in an investigation, and he urged a moratorium on approvals of Roundup Ready crops.

 

USDA officials declined to comment about the letter's contents.

 

"We're reviewing it, and will respond directly to Dr. Huber, rather than responding through the media," said USDA spokesman Andre Bell.

 

Roundup has long been a draw for critics, who say the herbicide promotes widespread weed resistance, or "super weeds."

 

"While the evidence is considered preliminary, the potential damage to humans and animals is severe," said Jeffrey Smith, executive director of the Institute for Responsible Technology.

 

There have been other alarms raised about Roundup, including a report last year from Argentine scientists who claimed that Roundup can contribute to birth defects in frogs and chickens.

 

Monsanto says the chemical binds tightly to most types of soil, is not harmful and does not harm the crops. But some scientists say there are indications of increased root fungal disease as well as nutrient deficiencies in Roundup Ready crops. They say manganese deficiency in soybeans in particular appears to be an issue in key U.S. farming areas.

 

The Environmental Protection Agency said last year that it may review glyphosate for any adverse effects as part of a protocol to review products every 15 years.

 

But the agency had no immediate comment Thursday as to whether or not such a review would be undertaken.

 

(Additional reporting by Christopher Doering in Washington)

 

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