Bagworms have hatched in central Illinois, so it will be time to
treat for these insects in central Illinois about June 10. This
is 2 to 3 weeks earlier than normal. Now is the proper time to
treat in southern Illinois, where the bagworms would have
hatched a couple of weeks ago. Bagworm eggs overwinter in the
old female’s bag, which is close to 2 inches long and covered
with dried foliage from the host. Newly hatched bagworms emerge
from the old bag and climb upward in the tree. Then they spin
out and hang at the bottom of silk threads that are typically 2
to 3 feet long. This swinging pendulum catches in the breeze,
the top end breaks from the tree, and the young bagworm goes
soaring through the air at the end of its buoyant silk strand.
Caught in updrafts, they may float for very long distances—trips
of many miles are probably common. These newly hatched bagworms
will continue to hatch and migrate for a couple of weeks. As
such, they represent the only major method of dispersal for the
species because the