Mary Clare Jalonick and Jo Dee Black

Associated Press and Great Falls Tribune

Unregulated genetically modified wheat has popped up in a second location in the United States, this time in Montana, the Agriculture Department said Friday.

No genetically engineered wheat has been approved for U.S. farming, and the discovery of unapproved varieties can pose a potential threat to U.S. trade with countries that have concerns about genetically modified foods.

USDA said Friday that the incident is on a smaller scale than a similar finding in Oregon last year that prompted several Asian countries to temporarily ban U.S. wheat imports.

The herbicide-resistant wheat was found on one to three acres in Montana, while the GMO plants found in Oregon were spread over more than 100 acres. And the plants were found at a university research center in Huntley, Montana, where GMO wheat was legally tested by seed giant Monsanto 11 years ago. The plants in Oregon were found in a field that had never conducted such tests, prompting questions about how it got there.

The department said it is investigating the discovery of the Montana wheat. USDA has said the wheat would be safe to eat but that none of it ever entered commerce.

"We are aware of the situation and working with both USDA, Animal and Plant Health Inspection Service and Montana State University," said Jayson O'Neill, spokesman for the Montana Department of Agriculture. "The voluntary GE Wheat was discovered on a regulated field located within the Southeast Agriculture Research Center, and as such, is being treated as a regulatory compliance issue. SARC is located in a primarily sugar beet and barley production area. The department will continue to monitor the investigation in order to protect producers, consumers and trade partners."

In Montana the volunteer wheat was found in two small areas kept free of unwanted plants through the application of herbicides. When the wheat plants did not die after repeated applications of herbicide, MSU contacted the USDA.

MSU researchers grew genetically engineered wheat supplied by Monsanto as part of field trials between 2000 and 2003. Those field tests were conducted under the regulatory approval of the USDA's Animal and Plant Health Inspection Service and met all post-research regulatory requirements as well, said Tracy Ellig, director of communications for MSU.

Since 2006, the research test sites have been used to grow commercial sugar beets and malt barley.

Testing of the samples from Montana by a USDA laboratory confirmed that the wheat is genetically engineered to resist the herbicide Roundup. Further genetic testing shows that the genetically engineered wheat collected from the field in Montana was not the source of the genetically wheat found growing in a single field in Oregon in 2013.

The wheat volunteers in Montana were in the boot stage of development, which is prior to pollination and kernel development, said Ellig.

"The reserach farm near Huntley where the wheat volunteers were found is located in an area that is primarily devoted to sugar beet production," he said. "It is surrounded on three sides by sugar beet fields; the fourth side has residential development and the Interstate."

After the volunteer wheat was reported and collected, MSU Agricultural Research Center personnel fallowed the field mechanically, as directed by the USDA, said Ellig.

In a final report also released Friday, USDA said it believes the GMO wheat in Oregon was an isolated incident and that there is no evidence of that wheat in commerce. The report says the government still doesn't know how the modified seeds got into the fields.

"The development of new and improved wheat varieties is a critical component of advancing the wheat industry in Montana," said Lola Raska, executive vice president of the Montana Grain Growers Association. "MGGA supports continued research on new wheat varieties including those using biotech traits. We are confident that appropriate protocols have been followed at SARC in accordance with USDA compliance requirements and that no biotech wheat has entered commercial channels."

The discovery of the GMO wheat in Oregon prompted Japan and South Korea to temporarily suspend some wheat orders, and the European Union called for more rigorous testing of U.S. shipments.

"Given that the correct AHPIS protocols were followed in reporting the discovery of this volunteer wheat and those protocols are well understood by mills and millers both domestically and internationally, any impacts on the markets for Montana's wheat, both domestically and internationally, are likely to minimized," said Dr. Vincent Smith, professor at Montana State University in the Agricultural Economics and Economics Department. "None of the wheat entered the marketing chain, so it should not create a problem in that domain."

Monsanto Co. suggested last year that some of the company's detractors may have intentionally planted the seeds. Robb Fraley, Monsanto's executive vice president and chief technology officer, said in June 2013 that sabotage is the most likely scenario, partly because the modified wheat was not distributed evenly throughout the field and was found in patches.

"It's fair to say there are folks who don't like biotechnology and would use this to create problems," he said then.

Bernadette Juarez, who oversees investigative and enforcement efforts for USDA's Animal and Plant Health Inspection Service, said the department wasn't able to prove any such scenarios.

"Ultimately, we weren't able to make a determination of how it happened," she said.

Most of the corn and soybeans grown in the United States are already modified, or genetically altered, to resist certain herbicides. But the country's wheat crop is not, as many wheat farmers have shown reluctance to use genetically engineered seeds since their product is usually consumed directly by people. Much of the corn and soybean crop is used as feed for animals.

There has been little evidence to show that foods grown from engineered seeds are less safe than their conventional counterparts, but several states have considered laws that would require them to be labeled so consumers know what they are eating. Vermont became the first state to enact such a law this year.