Invasive Caterpillars Chew Through 25,000 Acres Of Fir Trees In One year

Fir trees along Colorado's Front Range are wilting due to black-tusked tussock moth caterpillars that have munched away at 25,000 acres of forest in one year.

The Denver Post reports the U.S. Forest Service and Colorado Springs have launched an effort to combat the bugs by spraying an insecticide on the caterpillars. The $293,000 aerial attack was conducted over a five-day period in June.

The fuzzy green caterpillars, which turn into tussock moths in July, have caused trees near Colorado Springs, Boulder and Larkspur to wilt and turn brown. Defoliated trees are more vulnerable to other invasive insects, such as mountain pine beetles and western spruce budworm.

Colorado State Forest Service data show the bugs spread across 26,000 acres in 2015, up from only 1,000 acres in 2014.