There are many different types of insect infestation. From bark beetles to defoliators we can help you prevent or isolate potentially devastating outbreaks.

Bark Beetles

Mountain Pine BeetleMountain Pine Beetles have been in the spotlight recently, but they aren’t the only type of bark beetle that can potentially harm forest health.

Mountain Pine Beetle or MPB (Dentroctonous ponderosae)

  • MPB attacks Lodgepole pine, Ponderosa pine, Limber pine, and Bristlecone pine.
  • Native species of beetle usually present in low population levels in pine forests.
  • Epidemic infestations occur in forests with older, less vigorous trees or where other stress factors such as long-term drought are present.
  • Management treatments such as thinning have been effective in reducing moderate infestations.
  • Pheremone applications have shown promise in low to moderate cases.
  • Large-scale infestations are currently happening in forests across the Rocky Mountains ranging from northern New Mexico to British Columbia in Canada.

Spruce Beetle (Dentroctonous ruffipennis)

Spruce beetle attack

  • Spruce beetles attack Engleman spruce, Blue Spruce and White Spruce.
  • Infestations usually occur in older (250 years and up) low-vigor stands.
  • Infestations often start in scattered blowdown and can build to landscape-level epidemics.
  • Large-scale infestations are currently happening in Colorado and Wyoming.

Ips Engraver Beetles (Ips spp.)

  • Two species out of eleven species found in Colorado that are of the greatest concern, Ips pini in Ponderosa and Lodgepole pine and Ips confusus in Piñon pine.
  • Ips beetles are generally secondary pests and attack trees under stress or damaged by other causes.
  • Management actions include prompt removal of tops, branches, and trees removed in thinning or construction as well as protection of trees from construction damage and root compaction.

Douglas Fir Beetle (Dentroctonous psudotsugae)

  • Attacks Douglas fir and occasionally spruce and western larch.
  • Older trees are the usual targets but higher beetle populations pose risks to healthy trees as well.
  • Management actions include thinning of forests to maintain tree vigor and prompt removal of infested trees.
  • Pheromone placement has shown to be effective in protecting large high-risk individual trees.


Several types of insects defoliate trees. Single-year defoliators are usually not serious, but multi-year defoliators can kill trees.

Western Spruce Budworm (Choristoneura occidentalis)

  • The caterpillar stage can defoliate both large and small trees.
  • Understories of true firs (subalpine fir, white fir, and grand fir) are particularly suceptible to major damage or death.
  • Infestations can be minimized by maintaining even-sized groups of trees rather than multiple stories in one place and keeping stand densities at moderate levels by periodic thinning.


Douglas-fir Tussock Moth (Orgyia psuedotsugata)

  • Attacks Douglas fir, spruces and true firs.
  • Continual defoliation can cause top dieback or tree death
  • Maintaining tree vigor through thinning helps control tussock moths.


Western Tent Caterpillar (Malacosoma californicums)

  • Attacks Aspen, mountain-mohogany and domestic fruit trees
  • Can kill trees with repeated defoliations or if other stresses like drought are present. Controls are limited.

Short forestry can answer any questions or concerns you may have about insect infestations on your lands. Bruce Short has more than 35 years of experience in dealing with insects and forest health.