Forest Tent Caterpillar

What is it?

Forest Tent Caterpillar

The forest tent caterpillar feeds on aspen poplar, green ash, mayday and several other trees and shrubs. In the early stages this caterpillar is black and hairy. When mature, caterpillars are 4 to 5 cm in length and have blue bands running along both sides of the body with white keyhole-shaped markings on the back. Towards the end of the caterpillar stage, they will cluster together on large tree branches or trunks. The caterpillar then makes a cocoon and later in the season turns into an adult brown moth that disperses and lays grey egg bands around small branches.

What can I do?

Although the tree can look unsightly if defoliated, they cause little permanent damage. If you identify forest tent caterpillars on your tree, you can;

  • scrape off and dispose of caterpillar clusters on your tree trunks
  • look for and remove egg bands located on small branches.

For more information please view the Forest Tent Caterpillar (pdf) pages from our Integrated Pest Management Manual.