Fall
Webworm
Every fall Whitehouse residents will notice large webs
enclosing the tips of leafy branches on a wide variety of our shade trees.
These webs are the work of the fall webworm, the larva (immature stage)
of a medium-sized moth.
The fall webworm (scientific name Hyphantria cunea) is native to North America and
Identification and
Life cycle: The adult moth has a
wingspan of about 1.5 inches and is white with bright orange-yellow front leg
bases. Occasional individuals may
have dark wing speckles. It
appears mostly from late May to August and deposits eggs in hair-covered masses
on the underside of leaves of host trees. The
larvae are covered with long silky hair tufts that arise from orange or black
tubercles. Their bodies are pale
greenish with yellow side stripes and a dusky streak down the back.
After hatching they spin a large communal web over the leaves they feed
on; as they grow and feed they enlarge the web to enclose more leaves.
After reaching about an inch in length the larvae leave the host tree and
spin a cocoon just beneath the soil surface.
In our area, fall webworms over-winter in their cocoons and emerge as
adults in late spring, although there may be more than one generation during the
summer.
Damage:
Common hosts for the webworm include ornamental fruit trees (especially
crabapples), hickories, walnuts, American elm, and some maples.
But many other hardwood trees may be used.
Although the webs are unsightly and heavy infestations can cause partial
defoliation of smaller trees, damage to most trees is considered to be
insignificant. The fall
webworm is of only minor importance as a forest pest, and trees generally show
no ill effects from light to moderate infestations.
Lopping off and disposing of infested branches can be practiced to remove
unsightly webs and reduce the impact of the webworm larvae.
For more information visit:
http://www.ag.ohio-state.edu/~ohioline/hyg-fact/2000/2026.html