• Mountain pine beetles are the primary insect pest afflicting Colorado's pine forests.

• Older trees and those stressed by drought, fire, mechanical damage, root disease, and other causes are most susceptible. But as the beetle population explodes, younger and healthier trees are increasingly targeted.

• The beetles fly from tree to tree in the summer from July 1 through August, with a few attacks occurring in early September. The they lay their eggs after burrowing into the tree trunk.

• Signs of pine beetle infestation include "pitch tubes" seeping out of the bark, sawdust piles at the base of the trunk, as well as the tell-tale brown needles. When trees are severely drought stressed, pitch tubes may not be produced. However, pitch tubes can also be a sign that the tree successfully eradicated the invading beetles, so one must look under the bark for beetle galleries and for the presence of boring dust accumulating around the base of the tree to determine if the attack was successful.

• Even green trees may be severely infected as it can take up to three years for the needles to turn brown. With lodgepole pine the needles begin to fade the year following attack. Spruce beetle attacks in spruce can take two or three years to fade. 

• By some estimations, the pine beetle infestation has increased four-fold in Summit County from 2002 to 2004.

• The only effective way to combat the pine beetle and protect healthy trees is to spray trees annually before the new beetle flying season. It is recommended that a certified pesticide applicator be used to assure the proper application of a registered insecticide (carbaryl, permethrin or bifenthrin).

Why now? Several factors are at work, including the fact that clear-cut mining 100-120 years ago contributed to a monoculture of lodgepole forest nearing the end of its life span. Drought conditions in recent years have exacerbated the problem further.

Life Cycle