Bagworms feed on over 128 plant species. The most commonly attacked plants are arborvitae, red cedar, and other juniper species. The principle harm done by the insect is the destruction of foliage by the caterpillars. Plants usually are partially defoliated, weakened, and rendered unsightly.
Complete defoliation can occur.
The most notable sign of bagworm infestation is the presence of protective bags attached to a branch. The bags incorporate bits of twigs and leaves from the host plant. They are approximately 30-50mm long and resemble Christmas tree ornaments hanging from the limbs. Almost immediately after emerging, a larvae starts to produce its own protective bag. The bag is constructed such that the larvae's head and legs are free.