Ah the irony. The Western rootworm beetle has been found to be munching on Monsanto GB Corn plants that were thought to be resistant to the beetle. And I mean munching, according to the recent paper published July 29th 2011, by Aaron Gassman, states that
In all cases, fields experiencing severe rootworm feeding
These are the first cases of the field resistance, these are not laboratory tests, these are reports by farmers that their fields of Monsanto GM Corn are being infested with beetles that eat the roots of the corn.
Rootworm larvae feed on thin hair like roots, working their way to larger roots, in numbers large enough they will prune back enough roots to prevent the corn plant from getting enough water. The Adults like to eat the corn silk and pollen, and in large enough numbers the adults can cause pollination problems.
From Aaron Gasmanns paper
This is the first report of field-evolved resistance to a Bt toxin by the western corn rootworm and by any species of Coleoptera. Insufficient planting of refuges and non-recessive inheritance of resistance may have contributed to resistance. These results suggest that improvements in resistance management and a more integrated approach to the use of Bt crops may be necessary.
http://www.ncbi.nlm.nih.gov/...
WSJ via gmwatch:
According to Dr. Gassmann, the Iowa fields in which he found rootworms resistant to the Cry3Bb1 toxin had been producing Monsanto's Bt-expressing corn continuously for at least three years. Dr. Gassmann collected rootworm beetles from four Iowa cornfields with plant damage in 2009. Their larvae were then fed corn containing Monsanto's Cry3Bb1 toxin. They had a survival rate three times that of control larvae that ate the same corn.
http://www.gmwatch.org/...
Monsanto stock during August dropped from 73.48 to 69.47, a 5.46% drop since the news of DR Gassmans paper was published.
http://www.google.com/...
The Resistant beetles were found on fields where the Bt Corn was grown for a minimum of 3 three years.