Over the past few years, bagworms have become
an increasing problem in Lancaster County,
Nebraska.
Bagworms can severely defoliate and kill evergreens
like spruce, junipers, eastern red cedars,
and arborvitae.
Bagworms may also feed on ornamental shrubs
like this viburnum, -- fruit trees, shade
and ornamental trees, perennial flowers and
small fruit plants like raspberries.
Since deciduous plants grow new leaves every
year, the defoliation caused by the feeding
usually does not kill them.
But bagworms can quickly kill evergreens.
It's important to inspect your landscape for
bagworms.
Mature bagworms are small - only 1-2 inches
long.
The bags are covered with dead material and
tightly attached to twigs.
The camouflaged bags can be hard to see on
host plants.
Bagworm eggs hatch in May and early June.
The tiny bagworm larvae can be hard to see.
After hatching, the tiny larvae are often
caught by the wind on a strand of silk and
balloon to nearby plants.
Once a host plant is found, the tiny larva
begins to form a new bag around its body.
The bagworm larva is a brown or tan caterpillar
with black markings.
The larva remains in its protective bag sticking
its head out to feed.
Bagworm larvae feed up until late August.
The mature larva attaches it's bag to a branch
with a strong band of silk.
The larvae pupates in the bag.
The adult male bagworms emerge in August.
The adult males are small, furry gray moths
with clear wings.
The adult female pupates into a grub-like
form and never leaves the bag.
She dies in the bag mummified around the egg
mass.
Each overwintering bag contains as many as
300 - 1,000 eggs.
Winter and early spring are good times to
look for bagworm bags.
Removing the bags before the end of May can
help reduce their summer populations.
Look carefully for bags, they can be hard
to see.
Pull the bags off the plants.
Crush the bags or place them in the garbage
in a sealed trash bag.
If bags containing eggs are discarded on the
ground, the larvae may still hatch and return
to the host plants.
Insecticide control must be aimed at young
larvae in mid-to late June.
Feeding by bagworms slows in August so chemical
controls in late summer and fall are not effective.
Effected plants must be thoroughly covered
with insecticide in June.
For more information on bagworms, contact
your local extension office.
 
