Adult Emerald Ash Borer on a penny.

(Photo: Courtesy of U.S. Forest Service)

Colorado’s ash trees are under threat by the emerald ash borer.

The bright green bug looks like a small grasshopper, about the size of a pencil eraser. But it’s even deadlier than the mountain pine beetle, which has chowed on every national forest in Colorado, devastating millions of acres of trees. That's because the ash borer is not a native species. 

Scientists expect that the insect will ultimately kill almost every unprotected ash tree growing in North America. Scientists say every ash trees along the Front Range could become “beetle kill.” 

A recent survey shows that the Emerald Ash Borer has infested trees in five square miles of central Boulder, Colo. The insect was discovered last September in Longmont, north of Boulder. 

Fifteen percent of trees along the Front Range are ash. Scientists expect that the insect will spread in coming years. It is reasonable to expect that essentially all of northeastern Colorado will be infested within a decade, according to Colorado State University Extension entomology specialist Whitney Cranshaw. 

Emerald ash borer info online: