Fall webworm appears late in the season and is usually not difficult to control or detrimental to the plant.
“While they can destroy leaves it’s rare for them to do any significant damage to established trees,” Daniel Frank, WVU Extension Service entomology specialist, said.
Fall webworm larvae form a web or tent around themselves and their food the tree foliage. As the larvae grow, so do their webs and the destruction that they cause.
Because the larvae feed in groups, they can skeletonize leaves, eventually consuming entire leaves as they reach maturity.
Gardeners and growers often mistake fall webworms with the eastern tent caterpillar despite their different appearances.
Fall webworms form loose, silken webs around the ends of branches; the larvae feed on the foliage within the web.
Conversely, the eastern tent caterpillar forms dense webs in the forks and crotches of trees; the larvae leave their web to feed but congregate there at night and during inclement weather. Eastern tent caterpillar larvae occur in the spring.
Since fall webworm feed on leaves late in the season and their webs are generally concentrated in limited areas, they cause minimal damage to the tree. However, the nests often look unsightly and can be controlled by pruning and destroying infested branches if the webs are within reach.
According to Frank, bacterial and synthetic insecticides are also effective against fall webworm. Sprays should be applied to the foliage closest to the web mass, as spraying the web itself will not give good contact to the larvae inside.
For more information on agriculture programs in your community, contact your local county office of the WVU Extension Service, or visit www.ext.wvu.edu.
CONTACT: Cassie Waugh, WVU Extension Service
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