|
|
|
Bagworm is causing serious damage to
evergreens in southeast Nebraska. Native to the United States and found in
eastern Nebraska, bagworm feeds on the foliage of common evergreen hosts
including Juniper (cedar), arborvitae, pine, and spruce as well as
deciduous trees and shrubs.
Bagworms over-winter as eggs within bags fastened to twigs of the host
tree. Eggs hatch in late May or early June as caterpillars and begin to
spin tiny (1/4 inch) protective cases or bags around themselves. These
bags are made of silk and leaf/needle fragments that grow to two inches in
length by the end of the summer and somewhat resemble Christmas tree
ornaments hanging from a limb. Larvae feed until late August or early
September when the males emerge and mate with the wingless females through
the bag entrance. Female moths deposit their eggs then die, never leaving
the bag. Each female can produce 500-1,000 eggs. About half the bags on a
host plant will contain female bagworms while the other half contain
males.
Heavy infestations of bagworms are capable of completely defoliating an
evergreen that is severely stressed or even killing the tree if control
measures are not taken. Bagworms on evergreens are especially damaging
because destroyed foliage does not regenerate. Infestations on deciduous
trees and shrubs are not as serious since these plants have the ability to
grow new leaves.
On smaller trees and shrubs, bagworm can be controlled by removing or
hand-picking all the bags during the winter and spring prior to the egg
hatch in late May. Bags should be destroyed by crushing or immersing in
soapy water so that the larvae cannot return to the host plant. For larger
plants or infestations, insecticides are effective if applied during early
stages of bagworm development. For most effective control and prevention
of early season damage, apply sprays from mid to late June. Some options
for insecticides include Sevin, Malathion, Diazinon, Orthene, Dipel, and
Dursban. As always, read, understand, and follow label directions before
using. Return
to Trees/Wildlife |
