HOST: Cedar and arborvitae,
occasionally pines and hardwoods.
primarily an enemy of ornamentals, large
populations can build up in stands of
eastern red cedar and Atlantic white cedar.
Complete or repeated defoliation kills the
tree. Under normal conditions, attacks in
natural stands are limited to single trees.
The bagworm is not a major forest pest.
adult male moth has a wingspan of about
one-inch and his wings are almost
transparent. The body is slender, black and
hairy, and the antennae are broadly
feathered. The adult female is wingless,
legless and yellow-white in color. The
larvae are about one-inch when fully-grown,
and dark brown with a yellowish head and
thorax covered with black spots. Pupae are
brownish and enclosed in the bag. Eggs are
small, white and laid in the pupal case.
SIGNS OF ATTACK: The
most noticeable sign of attack is a bag or
case composed of silk, twigs, and other
debris. When infestations are heavy, the
host may be partially or completely
defoliated. The case of mature larvae may be
as long as two inches.
LIFE CYCLE: Male moths
emerge and fly to the female cases to mate
during late summer or early fall. Each
female deposits 800 to l,000 eggs in the bag
and then her shriveled remains drop to the
ground and die. Eggs remain in the bag over
winter. In late spring, eggs hatch and each
larva immediately makes a small case in
which it lives throughout its larval life.
As larvae grow, they enlarge the cases to
accommodate their increasing size. In order
to feed or move about, larvae must partially
emerge so heads and thoracic legs are
exposed. Pupation occurs within bags during
late summer and moths emerge about three
weeks later. There is one generation per
year in Alabama.
parasites, and other natural control factors
usually prevent build up of large
populations. Forest control: Chemical
control not recommended. Shade tree control:
Residential trees may become heavily
infested and require insecticide
applications. Spray foliage with 0.5%
malathion (mix 6 1/2 pints of 57% malathion
E. C. with 100 gal. of water, or 2 T/gal
according to label directions and state
law). Hand picking and burning cases may be
the easiest control method, particularly
when only a few infested trees are involved.
When pulled out of their bags, larvae make
excellent fish bait.
Photo Credit: Robert L. Anderson, USDA
Eastern Forest Environmental Threat
Forest Encyclopedia, USDA Forest Service
Forest Health Protection-USDA