Scientists reported recently that monarch butterflies are not in danger from genetically modified corn pollen as earlier feared. This is good news for those farmers who want to use the so-called Bt corn, which is modified with a protein from the soil, bacterium Bacillus thuringiensis .
Bt corn is resistant to the corn borer, a pest that can devastate corn crops.
By sheer numbers, Monarch populations would be appear to be far from endangered. Mexico's environmental protection agency reported recently that more than 5 million of the south-migrating butterflies have already arrived in Mexico, and 180 million more are expected this winter. Current methods determine the total concentration of compounds, not the amounts that are actually available to do harm. Current tests now measure the total amounts of DDT, and its derivatives DDE and DDD, in soil. The Cornell study suggests that the age of the chemicals in the soil may make them less likely to be absorbed by living organisms.