Aspen Defoliators - Forest Health and Adaptation

 Aspen Defoliators Slide Show{GFX-ESRDx-ForestHealth-AspenDefoliators-Slide2.jpg}{GFX-ESRDx-ForestHealth-AspenDefoliators-Slide3.jpg} Aspen defoliators are a group of common forest insects that include some of the most serious defoliators of trembling aspen throughout Alberta. They are often grouped together because they cause similar damage to trees.
Aspen defoliator caterpillars feed on leaves of broadleaf trees, such as trembling aspen and sometimes balsam popular.

Their damage is difficult to distinguish, especially during aerial surveys. Depending on the time of year, these insects may be in a moth stage (adult) or in a caterpillar (larva) stage.

In Alberta, the most important aspen defoliators include:
  • Bruce spanworm (Operophtera bruceata)
  • Forest tent caterpillar (Malacosoma disstria)
  • Large aspen tortrix (Choristoneura conflictana)
For more information about each of these defoliators, see:
For more information about the content of this document, contact Devon Belanger.
This information published to the web on February 24, 2016.