The U.S. Environmental Protection Agency has raised concerns over the stewardship of one of Monsanto’s corn hybrids that is designed to ward off certain corn rootworms, the Wall Street Journal reported. EPA sent a memo to Monsanto Nov. 22 saying EPA scientists “conclude that Monsanto needs to expand its monitoring program now that rootworms in portions of four Midwest states are ‘suspected’ of having developed resistance to the plants,” according to the Wall Street Journal.

The EPA regulates the corn plants because they are genetically engineered to make a natural pesticide. The corn in question from Monsanto is a single mode-of-action hybrid that contains the Cry3Bb1 protein.

EPA’s concern was prompted because of reports in August of possible resistance showing up to the Cry3Bb1 protein in Iowa and Illinois fields. Monsanto’s corn reportedly showed “unexpectedly high levels of damage from rootworms.”

This week, Monsanto responded to EPA’s concerns saying it continues to take reports on the performance of its corn rootworm products seriously and remains committed to working with farmers to encourage the adoption of integrated pest management practices.

Monsanto said in a news release that it takes the EPA’s review seriously, but said that scientific confirmation of corn rootworm resistance to Cry3Bb1 had not been demonstrated. However, the company was already working to support the adoption of best management practices for the 2012 season in these specific field situations.

“There is nothing we take more seriously than the stewardship of our products,” said Ty Vaughn, corn product lead at Monsanto. “Even though we see no immediate impact on the products we offer or the refuge options currently available to our farmer customers based on the scientific information available to date, we believe farmers that plant continuous corn should carefully consider a series of best management practices to ensure they stay ahead of this insect.”

The company said it shares the EPA’s recommendations that careful monitoring and stewardship needs to occur in fields with greater than expected rootworm damage, and that dual mode-of-action approaches with an integrated pest management recommendation are critical to the long-term durability of trait technologies.

Importantly, the company also noted that the recommendations outlined by the EPA are consistent with Monsanto’s best management practices that are being implemented for field-specific situations where farmers were faced with high populations of corn rootworms during the 2011 season. These best management practices, which were announced last month, are designed to provide farmers with valuable on-farm recommendations for sound stewardship and the long-term durability of rootworm-protected technologies.

Monsanto has been working with independent researchers to better understand the factors that led to greater than expected rootworm damage to this single mode-of-action technology in these areas, and to recommend specific best management practices to support its farmer customers. More information on these best management practices can be found on Monsanto’s Web site,