Fall webworm
Encyclopedia
Fall webworm, Hyphantria cunea, is a moth
in the family Arctiidae
known principally for its larval stage, which creates the characteristic webbed nests on the tree limbs of a wide variety of hardwoods in the late summer and fall. It is mainly an aesthetic pest
and is not believed to harm otherwise healthy trees. It is well known to commercial tree services and arboriculturists
.
, ranging from Canada to Mexico, and is one of the few insect pests introduced from North America into other continents. Introduced to what was formerly Yugoslavia in the 1940s, it now has occupied probably its entire range in Europe from France to the Caspian Sea in the east, as well as penetrates into Central Asia
: Turkmenistan (from 1990-1993), Uzbekistan (Fergana valley from 1996-1997), Kyrghyzstan, south-eastern Kazakhstan. It was also introduced into Japan in 1945, and has adjusted its number of generations per year since its arrival. It spread into China, southern Mongolia, Korea and southern Primorye
of Russia
. Now is considered holarctic
in distribution.
, with larvae appearing in late summer through early fall. South of an approximate latitude of 40 degrees north
there are two or more generations annually, with webs appearing progressively earlier further south.
s are highly variable in coloration, ranging from a pale yellow, to dark grey, with yellow spots and long and short bristles. There are two cream stripes along the sides. There are two races, one more common in the north, the other in the south, differing in head capsule coloration. Maximum length, 35mm. Webs are progressively enlarged, and much messier looking than those of tent caterpillars
(which occur only in spring and have shorter hairs and very little yellow on their bodies). Larvae feed inside the tents until the late instars. Very young larvae feed only on the upper surfaces of leaves. Later, they consume the whole leaf. The larval stage lasts about 4–6 weeks.
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
in the family Arctiidae
Arctiidae
Arctiidae is a large and diverse family of moths with around 11,000 species found all over the world, including 6,000 neotropical species. This family includes the groups commonly known as tiger moths , which usually have bright colours, footmen , lichen moths and wasp moths...
known principally for its larval stage, which creates the characteristic webbed nests on the tree limbs of a wide variety of hardwoods in the late summer and fall. It is mainly an aesthetic pest
Pest (animal)
A pest is an animal which is detrimental to humans or human concerns. It is a loosely defined term, often overlapping with the related terms vermin, weeds, parasites and pathogens...
and is not believed to harm otherwise healthy trees. It is well known to commercial tree services and arboriculturists
Arboriculture
Arboriculture is the cultivation, management, and study of individual trees, shrubs, vines, and other perennial woody plants. It is both a practice and a science....
.
Range
The moth is native to North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, ranging from Canada to Mexico, and is one of the few insect pests introduced from North America into other continents. Introduced to what was formerly Yugoslavia in the 1940s, it now has occupied probably its entire range in Europe from France to the Caspian Sea in the east, as well as penetrates into Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...
: Turkmenistan (from 1990-1993), Uzbekistan (Fergana valley from 1996-1997), Kyrghyzstan, south-eastern Kazakhstan. It was also introduced into Japan in 1945, and has adjusted its number of generations per year since its arrival. It spread into China, southern Mongolia, Korea and southern Primorye
Primorye
Primorye is the name of several inhabited localities in Russia:*Primorye, Kaliningrad Oblast, an urban locality in Svetlogorsky District of Kaliningrad Oblast...
of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. Now is considered holarctic
Holarctic
The Holarctic ecozone refers to the habitats found throughout the northern continents of the world as a whole. This region is divided into the Palearctic, consisting of Northern Africa and all of Eurasia, with the exception of Southeast Asia and the Indian subcontinent, and the Nearctic,...
in distribution.
Life cycle
One generation per year emerges in the northern part of North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, with larvae appearing in late summer through early fall. South of an approximate latitude of 40 degrees north
40th parallel north
The 40th parallel north is a circle of latitude that is 40 degrees north of the Earth's equatorial plane. It crosses Europe, the Mediterranean Sea, Asia, the Pacific Ocean, North America, and the Atlantic Ocean....
there are two or more generations annually, with webs appearing progressively earlier further south.
Egg
The adult moth lays her eggs on the underside of leaves in 'hair'-covered clusters of a couple of hundred. Eggs hatch in about a week.Larva
The caterpillarCaterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
s are highly variable in coloration, ranging from a pale yellow, to dark grey, with yellow spots and long and short bristles. There are two cream stripes along the sides. There are two races, one more common in the north, the other in the south, differing in head capsule coloration. Maximum length, 35mm. Webs are progressively enlarged, and much messier looking than those of tent caterpillars
Malacosoma
Malacosoma is a genus of Moth in the family Lasiocampidae.-Species:*Malacosoma alpicolum Staudinger, 1870*Malacosoma americanum *Malacosoma californicum *Malacosoma castrense...
(which occur only in spring and have shorter hairs and very little yellow on their bodies). Larvae feed inside the tents until the late instars. Very young larvae feed only on the upper surfaces of leaves. Later, they consume the whole leaf. The larval stage lasts about 4–6 weeks.
Pupa
The pupal stage overwinters in the bark and leaf litter at the base of the trees. It is dark brown and about 10 mm long. They have thin brown cocoons made of silk with bits of detritus interwoven. This stage overwinters.Adult
The adult is mostly white in the north, but in the south it may be marked with black or brown spots on the forewings. It is quite 'hairy', and the front legs have bright yellow or orange patches. The underwings will have less marking than the forewings, and the abdomen often has a sprinkling of brown hairs. Wingspan of 35–42 mm.Food plants
The fall webworm feeds on just about any type of deciduous tree, where leaves are chewed; branches or the entire tree may become defoliated. Worldwide, it has been recorded from 636 species, and is considered to be among the most polyphagous of insects. In the eastern U.S., pecan, walnut, American elm, hickory, fruit trees, and some maples are preferred hosts; in some areas persimmon and sweetgum are also readily eaten. In the west, alder, willow, cottonwood and fruit trees are commonly used.External links
- Bagworm, Fall Webworm or Eastern Tent Caterpillar? August 18, 2001. Sandra Mason, University of Illinois Extension. Accessed May 31, 2010.
- U. Mass site
- U. Georgia site
- Ohio State U. site
- Texas A&M site
- fall webworm on the UFUniversity of FloridaThe University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
/ IFASInstitute of Food and Agricultural SciencesThe University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
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