What are mountain pine beetles?

The mountain pine beetle (Dendroctonus ponderosae) is a native insect that resides beneath the bark of several species of pine trees in Colorado. The beetles are small, about the size of a grain of rice.

Normally, mountain pine beetles play an important role in forest health by attacking old/weak trees and promoting the growth of younger trees. However, unusually dry conditions and generally poor forest health have led to recent infestations of otherwise healthy trees.

Approximately 4 million acres of Colorado’s lodgepole pine (Pinus contorta) forest were affected by a mountain pine beetle epidemic that began in 1996.

The Colorado State Forest Service is currently monitoring potential outbreaks in Gilpin and Clear Creek Counties, as well as increased activity near Colorado Springs (El Paso County). The current outbreak is affecting primarily ponderosa pines (Pinus ponderosa).

You can learn more about Mountain Pine Beetles on the main CSU Extension website. Other resources include:

• Mountain Pine Beetle | Colorado State Forest Service
• 2024 Forest Health Report | Colorado State Forest Service

If you’re concerned that trees on your property in Lake County may be affected by mountain pine beetle, please contact us.