The fall webworm, Hyphantria cunea, is a moth in the family Arctiidae known principally for its larval stage, which creates characteristic webbed nests on the tree limbs of a wide variety of hardwoods in the late summer and fall. The adult is a white or white and black spotted moth with wing span 30mm. Females lay between 300-1000 eggs in batches of about 100; the larvae hatch out and feed together from a inside their web structure, which they build and continually enlarge as they grow. In North America, where it is native, many natural enemies help maintain low-level populations and although their numbers do periodically crest into outbreaks, the fall webworm is mainly an aesthetic pest usually without economic consequence. Healthy trees, although they can become defoliated sometimes two years in a row in outbreaks, usually recover. The fall webworm is among the most polyphagous of insects, feeding on just about any type of deciduous tree. Worldwide, it has been recorded from 636 species. When it entered Europe in the 1940s there was great concern for containing its rapid spread. Currently it is well established across Europe and Asia, and although it is a significant pest of hardwoods orchard and ornamental trees in some Eastern European regions, it is now fully established across these continents, and is considered a static pest responsible for local damage.
Much research energy has been put into biological control of the fall web worm using Bacillus thuringiensis kurstaki, which has been especially effective in containing populations in Korea and Hungary. Sex pheromones have been obtained from female H. cunea and are used in monitoring traps.
(CABI 2011; Global Invasive Species Database 2007; Hyche 1999)
- CABI, 2011. Hyphantria cunea. In: Invasive Species Compendium. Wallingford, UK: CAB International. http://www.cabi.org/isc. Retrieved October 28 2011 from http://www.cabi.org/isc/?compid=5&dsid=28302&loadmodule=datasheet&page=481&site=144
- Global Invasive Species Database, 2007. Hyphantria cunea (insect). Retrieved October 28 2011 from http://www.issg.org/database/species/ecology.asp?si=1201&fr=1&sts=&lang=EN
- Hyche, LL. 1999 "Fall webworm: A Guide to Recognition and Habits in Alabama". Retrieved October 28, 2011 from http://www.ag.auburn.edu/enpl/bulletins/fallwebworm/fallwebworm.htm
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Regularity: Regularly occurring
Type of Residency: Year-round
Life History and Behavior
Molecular Biology and Genetics
Barcode data: Hyphantria cunea
There are 68 barcode sequences available from BOLD and GenBank. Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species. See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Hyphantria cunea
Public Records: 61
Specimens with Barcodes: 185
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
Rounded National Status Rank: N5 - Secure
The 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.
The moth is native to North America, 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 (firstly recorded in 1949), 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, and southeastern 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 Primorsky Krai of Russia, so now is considered holarctic in distribution.
One generation per year emerges in the northern part of North America, with larvae appearing in late summer through early fall. South of an approximate latitude of 40°N there are two or more generations annually, with webs appearing progressively earlier further south.
The caterpillars 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. The two races, one more common in the north, the other in the south, differ in head capsule coloration. The maximum length is 35 mm. 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 whole leaves. The larval stage lasts about four to six weeks.
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. The thin brown cocoon is made of silk with bits of detritus interwoven. This stage overwinters.
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. It has a wingspan of 35–42 mm.
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.
Damage on Acer negundo
Appearances in media
In the video game Metal Gear Solid 2: Sons of Liberty, the AI Colonel, while infected by a computer virus, mentions that he was a North American Fall Webworm in his past life, reminiscing about how "those were the good old days."
- Lopez-Vaamonde, C.; Agassiz, D.; Augustin, S.; De Prins, J.; De Prins, W.; Gomboc, S.; Ivinskis, P.; Karsholt, O. et al. (2010). "Lepidoptera. Chapter 11". BIORISK – Biodiversity and Ecosystem Risk Assessment 4. doi:10.3897/biorisk.4.50.
- Gomi, Takeda (1996). "Changes in life-history traits of Fall Webworm within half a century of introduction into Japan.". Functional Ecology 10:384-389.
- Wagner, DL (2005). Caterpillars of Eastern Forests. Princeton, NJ: Princeton Univ. Press.
- Douce, GK. "The Fall Webworm". Accessed August 21, 2006.
- Hyche, LL. "Fall webworm: A Guide to Recognition and Habits in Alabama". Accessed August 21, 2006.
- Warren, Tadic (1970). The fall webworm, Hyphantria cunea (Drury). Arkansas Agric. Exp.Sta. Bull.
Bat Man, 2003. The fall webworm. http://www.bugwood.org/factsheets/webworm.html . Accessed Aug 21, 2006.
Gomi, T and M Takeda. 1996. Changes in life-history traits of Fall Webworm within half a century of introduction into Japan. Functional ecology 10:384-389.
Hyche, LL, 1999. Fall webworm: A guide to recognition and habits in Alabama. http://www.ag.auburn.edu/enpl/bulletins/fallwebworm/fallwebworm.htm Accessed Aug 21, 2006.
Wagner, DL. 2005. Caterpillars of eastern forests. Princeton Univ. Press.
Warren, LO and M Tadic. 1970. The fall webworm, Hyphantria cunea (Drury). Arkansas Agric. Exp.Sta. Bull. 759.
Names and Taxonomy
Comments: Following Lafontaine and Schmidt (2010), the traditional Arctiidae have been transferred to the family Erebidae as a subfamily (Arctiinae), with former subfamilies such as Lithosiinae now treated as tribes. The circumscription of Arctiinae remains virtually identical to recent circumscriptions of Arctiidae, but circumscriptions of some taxa within the Arctiinae have changed.
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