Genetically modified crops' results raise concern

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2012/04/30/MN1O1O5SS0.DTL
Washington -- Biotechnology's promise to feed the world did not anticipate "Trojan corn," "super weeds" and the disappearance of monarch butterflies.
But in the Midwest and South - blanketed by more than 170 million acres of genetically engineered corn, soybeans and cotton - an experiment begun in 1996 with approval of the first commercial genetically modified organisms is producing questionable results.
Those results include vast increases in herbicide use that have created impervious weeds now infesting millions of acres of cropland, while decimating other plants, such as milkweeds that sustain the monarch butterflies. Food manufacturers are worried that a new corn made for ethanol could damage an array of packaged food on supermarket shelves.
Some farm groups have joined environmentalists in an attempt to slow down approvals of genetically modified organisms, or GMOs, as a newly engineered corn, resistant to another potent herbicide, stands on the brink of approval.
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