Asian beetle destroys N.American trees

Over the next two years, grounds crews in St. Louis will cut down nearly one out of every five trees, altering the US city's leafy landscape for at least a generation.

St. Louis is the latest victim of the Emerald Ash Borer, an Asian beetle smaller than a penny, which emigrated from China via shipping materials and is destroying millions of trees in North America.

The insect targets the Ash tree - a common variety in Midwestern cities, where the tree can survive cramped sidewalks, harsh winters and road salts used to keep streets clear of ice and snow.