New Threat to Butterflies
from Bt Corn
According to a Reuters news article, the Environmental Protection Agency (EPA) has been urged by experts on biotech crops and monarch butterflies to at least limit Bt corn registration renewals to one year and to investigate a newly found risk that the pesticide-laden plant may pose to the butterflies.
Bt corn is genetically engineered to produce the pesticide bacillus thuringiensis, which supposedly will protect the growing corn plants from destructive pests. It was originally thought that windblown pollen from the corn may pose a threat to the butterflies, but now scientists have raised the question of whether there is danger from a plant tissue called corn anther.
"The presence of anthers on mild weeds is of considerable importance because of the higher concentrations of Bt toxins that they contain," said John Losey, an entomologist at Cornell.
Unpublished field studies conducted in Iowa cornfields last summer showed a 50 percent lower survival rate for monarch caterpillars that ate a mixture of Bt pollen and anther. The four scientists from Iowa State University, Cornell University and the University of Minnesota were among the more than a dozen others who recently authored papers about the risk to monarch caterpillars of windblown pollen from genetically engineered Bt corn for the National Academy of Science.
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