- Fall webworm
Taxobox
name = Fall Webworm
regnum =Animal ia
phylum =Arthropod a
classis =Insect a
ordo =Lepidoptera
familia =Arctiidae
genus = "Hyphantria "
species = "H. cunea"
binomial = "Hyphantria cunea"
binomial_authority = Drury,1773 Fall webworm, "Hyphantria cunea", is a
moth in the familyArctiidae known principally for its larval stage, where it creates the characteristic webbed nests on the tree limbs of a wide variety ofhardwoods 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.Range
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, it now has occupied probably its entire range in Europe from France to the Caspian Sea in the east. It was also introduced into Japan in 1945, and has adjusted its number of generations per year since its arrival. [cite journal | last = Gomi | first = Takeda | title = Changes in life-history traits of Fall Webworm within half a century of introduction into Japan. | journal = Functional Ecology | volume = 10:384-389 | date = 1996] It spread into Korea and China and now is consideredHolarctic in distribution.Life cycle
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 degrees north there are two or more generations annually, with webs appearing progressively earlier further south. [cite book|author=DL Wagner|last=Wagner |first=DL |title=Caterpillars of Eastern Forests |publisher=Princeton Univ. Press | location=Princeton, NJ | year=2005]Egg
The adult moth lays her eggs on the underside of leaves in 'hair'-covered clusters of a couple of hundred.Douce, GK. [http://www.bugwood.org/factsheets/webworm.html "The Fall Webworm"] . Accessed August 21 2006. ] Eggs hatch in about a week.Hyche, LL. [http://www.ag.auburn.edu/enpl/bulletins/fallwebworm/fallwebworm.htm "Fall webworm: A Guide to Recognition and Habits in Alabama"] . Accessed August 21 2006. ]
Larva
The larvae are highly variable in coloration, ranging from a pale yellow, to dark grey, with yellow spots and long and short bristles. [cite book|author=DL Wagner|last=Wagner |first=DL |title=Caterpillars of Eastern Forests |publisher=Princeton Univ. Press | location=Princeton, NJ | year=2005] 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.Hyche, LL. [http://www.ag.auburn.edu/enpl/bulletins/fallwebworm/fallwebworm.htm "Fall webworm: A Guide to Recognition and Habits in Alabama"] . Accessed August 21 2006. ] 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.Hyche, LL. [http://www.ag.auburn.edu/enpl/bulletins/fallwebworm/fallwebworm.htm "Fall webworm: A Guide to Recognition and Habits in Alabama"] . Accessed August 21 2006. ]
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.Hyche, LL. [http://www.ag.auburn.edu/enpl/bulletins/fallwebworm/fallwebworm.htm "Fall webworm: A Guide to Recognition and Habits in Alabama"] . Accessed August 21 2006. ] 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.Hyche, LL. [http://www.ag.auburn.edu/enpl/bulletins/fallwebworm/fallwebworm.htm "Fall webworm: A Guide to Recognition and Habits in Alabama"] . Accessed August 21 2006. ] Douce, GK. [http://www.bugwood.org/factsheets/webworm.html "The Fall Webworm"] . Accessed August 21 2006. ] 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. Worldwide, it has been recorded from 636 species, [cite book|author=Warren, LO and M Tadic|last=Warren |first=Tadic |title=The fall webworm, Hyphantria cunea (Drury) |publisher=Arkansas Agric. Exp.Sta. Bull | year=1970] 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.Douce, GK. [http://www.bugwood.org/factsheets/webworm.html "The Fall Webworm"] . Accessed August 21 2006. ]
Notes
References
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.
ources
* [http://www.umassgreeninfo.org/fact_sheets/defoliators/fall_webworm.html U. Mass site]
* [http://www.bugwood.org/factsheets/webworm.html U. Georgia site]
* [http://ohioline.osu.edu/hyg-fact/2000/2026.html Ohio State U. site]
* [http://bexar-tx.tamu.edu/HomeHort/F1Column/2004Articles/MAR21.htm Texas A&M site]
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