December 7, 2011
US agency seeks stricter supervision of biotech corn
Following reports that corn root worm is no longer susceptible to the plant's toxin, the US Environmental Protection Agency (EPA) is urging Monsanto to take steps to prevent further spread of pest resistance to its GM corn.
At issue is Monsanto's strains of corn that are modified with the bacteria Bacillus thuringiensis (Bt) -- in particular Cry3Bb1 -- which is toxic to most insects, to prevent the need for farmers to use additional pesticides.
But studies released earlier this summer showed growing resistance among the worms -- a target species.
Now EPA is backing the studies recommending the company takes steps to limit the spread of resistance. Monsanto's resistance managing efforts are "inadequate and likely to miss early resistance events," Jeannette Martinez, an ecologist on the Office of Chemical Safety and Pollution Prevention, says in an internal November 22 memo.
"Resistance is suspected in at least some portions of four states in which 'unexpected damage' reports originated (IA, IL, MN, and NE) and recommends that the remedial action plan be implemented for 'suspected resistance.'"
However, Martinez continues, Monsanto's proposed plan is inadequate "due to a sampling trigger in fields with unexpected damage that is too high (and may miss potentially resistant populations) and a sampling regime that collects [corn root worm] beetles too far (1-2 miles away) from problem fields."
EPA and others have raised similar concerns about other biotech crops. Earlier this year, EPA said in response to the USDA's plan to deregulate engineered alfalfa that controls are needed to prevent resistance among weeds and vowed to raise the issue as an agenda topic for the Agricultural Biotechnology Work Group "so that it receives sufficient attention at high levels in the management of the biotech regulatory agencies."
"As developers produce increasing numbers of novel transgenic herbicide tolerant crops, it is becoming increasingly important to give greater consideration to prevention of weed resistance," EPA said.
While the Bt seeds are commonly used in the Midwest to curb Western corn root worm populations, activists have raised concern that the toxins could be harmful to humans in the long term and discourage integrated pest management approaches to farming, which one source with the Union of Concerned Scientists says contributes to the growing resistance problem.
"The bottom line here is that genetic engineering for pest resistance has done nothing to shift agriculture towards general practices that are more sustainable ... you are losing valuable products," the source says, adding that when used properly, Bt crops can prevent the need for more harmful pesticides. However, the source continues, EPA's requirements to prevent resistance are too lenient and as a result "you are losing their efficacy and you are going to have to go back to older nastier products to replace them."
In order to stem the spread of resistance, EPA recommends that Monsanto collect and test insects in adjacent and neighbouring fields to those where resistance is found; begin testing corn worm for resistance at the first sign of damage, or .5 NIS -- which measures signs of pest feeding on Bt crops; and increase its reporting and data collection activities.
Where resistance is already suspected, EPA recommends that "the registrant will instruct growers to, during the present season, use conventional insecticides to control the adult stage of the suspected pest," and "during the following season, use and alternative pest control method to deter establishment of potentially resistant insects." As part of the "alternate control measures," EPA is also warning that the area of corn farmers plant with non-Bt seed -- known as a refuge -- that is designed to prevent resistance, may need to be increased from its current level of 5% because without greater exposure to conventional corn, resistance could grow and "ultimately compromise the second unrelated toxin [found in Monsanto's Bt corn] used to control the pest."