A new USDA Forest Service and Colorado State Forest Service survey finds that spruce beetles continue to be the most damaging pest in Rocky Mountain forests.
Survey manager Brian Howell said the mountain pine beetle outbreak peaked around 2010 and has run its course. But now they're seeing a similar problem with the spruce beetle.
"We sort of have some fronts of activity, if you can think of the beetle marching at a far slower pace but not unlike a firefront, sort of moving through the forest," he said. "We've seen just kind of a continuation of that activity in Wyoming and Colorado."
Howell said spruce beetles prefer mature spruce trees, so they are especially damaging to old growth forests. The western spruce budworm is less deadly, but is the most damaging forest defoliator.
"Budworm is a moth and that caterpillar of that moth feeds on the foliage of the tree," he said. "After several years of intense defoliation from budworm, trees can experience mortality."
The moth is spreading across Colorado and has been seen in the Bighorn Mountains of Wyoming.
Howell said monitoring insect activity is important for forest managers to decide where to spend their time and resources.
Have a question about this story? Please contact the reporter, Ashley Piccone, at apiccone@uwyo.edu.