Douglas-Fir Beetle (Dendroctonus pseudotsugae)

The Douglas-Fir bark beetle is similar to the Mountain Pine Beetle, but attacks Douglas-fir instead of pine. Beetles enter through the bark and lay eggs in the inner cambium layer. Healthy trees can resist attack to some degree by secreting pitch which smothers the beetles. However, if beetles attack in overwhelming numbers, as is the case when major outbreaks occur, a tree will generally be killed within one year. The year after death, the foliage turns a bright red, but the beetles will have matured and flown to other areas by then.

As a general rule, older Douglas-fir trees are more susceptible, especially if under stress due to drought or overcrowding. Beetle populations often build up in windthrown trees, so outbreaks often happen several years after major windthrow events. Infestations in 2004/2005 along the West Arm of Kootenay Lake may have been triggered by a major windthrow event which happened in 2002.

As with the mountain pine beetle, options for control are limited. Use of pheromone (attractant) traps and quick harvest of recently-infested logs can reduce populations, but harvest of susceptible stands is usually the best way to salvage timber value.

The hazard categories on the maps are as follows:

Category Hazard Rating

0 Nil

1 Low

2 Moderate

3 High

4 Very High