Survey shows budworm outbreak

IDAHO FALLS (AP) - Federal officials say an outbreak of a little caterpillar known as the western spruce budworm has defoliated more than 500 square miles of the Caribou-Targhee National Forest.

The budworm has chewed through large amounts of conifers throughout the West this year. Joel McMillin, an entomologist with the U.S. Forest Service, says the Boise forest district is getting calls from the public concerned over the dying foliage.

Budworms don't always kill mature trees, but they can cause reduced growth and make the trees more susceptible to other pests, such as the bark beetle. Nearly 36,000 square miles of trees have been attacked by mountain pine beetles in the West since 1996.

This year's budworm attack has affected primarily Douglas fir and subalpine fir trees located in eastern Idaho counties.

McMillin says there is nothing to prevent a budworm infestation. Instead, the agency is waiting on the species population to crash. Outbreaks tend to last anywhere from 10 to 15 years.

"Budworm outbreaks generally crash when populations of their natural enemies catch up, (when) unusually harsh winter temperatures or spring frosts occur, or starvation," a Forest Service news release said.