BT corn was created by scientists by splicing a gene into the corn that kills root worms that can destroy entire crops.<br /><br />The idea worked for nearly a decade but now crops in North America are suffering severe damage where BT-resistant worms have grown more common.<br /><br />More than half of the corn grown in North America and much of the world is BT corn.<br /><br />Critics of genetically modified foods say that people are now left with the worst of both worlds: GM food that has unknown effects on humans that don't work.<br /><br />The growing resistance of bugs to GM foods leads to the possibility of major crop losses and an uncertain future for GM foods.<br /><br />Al Jazeera's John Hendren reports
