Bagworms

Order/Family: Lepidoptera/Ptinidae

Description:

  • This pest is best recognized by the tear-drop shaped bag covered with materials from the plant on which it is feeding. The larvae carries the bag around as it feeds.
  • The larva (caterpillar) is dark brown with a yellow head and black and yellow spots on the body.
  • Male moths are about 3/4-inch long, have a wingspan of approximately 1-inch, and are sooty black and covered with hairs.
  • Rarely seen, females are yellowish, wingless, legless, and maggot-like.

 

Biology and Habits:

  • Females lay 500 to 1,000 eggs in their bag and then die.
  • The eggs are the overwintering sate and hatch in late spring.
  • The young larvae spins a silken cocoon and incorporates plant material in the bag. As the larvae molt, the size of their bag increase.
  • The larvae pupate in late summer, and the adults emerge within 7 to 10 days.
  • The males emerge and fly around seeking females which remain in their bags and mate there.
  • There is one generation per year.
  • Because the females can not readily move from plant to plant, it is very common for a plant to be heavily infested while others close by remain totally unaffected.

 

Plants Attacked:

  • Bagworms prefer junipers, cedars, arborvitae, white pine and other conifers.
  • They also feed on rose, sycamore, maple, elm, boxelder, poplar, maple persimmon, and black locust.

 

Damage:

  • The primary damage is defoliation which can kill the plant.