Majority of corn grown in North America now at risk after losing its ability to fight off pests.

One of the United State’s most widely planted crops, a genetically engineered corn plant that makes its own insecticide, may be at risk from worms that have become resistant to the insecticide gene.

The loss of that protection puts more than half of the corn grown in North America, and much of the rest of the world, at risk.

Al Jazeera’s John Hendren reports from Des Moines, Iowa.