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