The era of genetic engineering begins this spring for Minnesota's largest cash crop. Some farmers will plant corn that contains a built-in pesticide, a gene deadly to the european corn borer. The new corn is expected to account for about 1% of the nations crop this year... buts thats expected to grow rapidly in coming years. Insects are very resilient, and researchers worry the borer will develop a resistance to the new corn...possibly in as little as five years. If that happens it would destroy years of research into one of the most effective tools ever developed to fight the pest.