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Fall Webworm (Hyphantria cunea)


Detailing the physical features, habits, territorial reach and other identifying qualities of the Fall Webworm.


 Updated: 3/14/2018; Authored By Staff Writer; Content ¬©www.InsectIdentification.org



  Fall Webworm  
Picture of Fall-Webworm-Moth
Picture of Fall-Webworm-Moth Picture of Fall-Webworm-MothPicture of Fall-Webworm-MothPicture of Fall-Webworm-MothPicture of Fall-Webworm-MothPicture of Fall-Webworm-Moth


The native Fall Webworm produces an active caterpillar that has expanded its geographical range across both oceans into two continents.





The Fall Webworm is a moth that comes in two colors: all white in the north, or white with brown patches (almost like a giraffe) in the south. The thorax is hairy. Legs are white, or orange with brown on them. Part of its name stems from its larval form: a caterpillar that spins a silky web with its newly hatched siblings. These webs can cover twigs, branches or even entire trees. The web is sticky and tough to break into, acting as a barrier, allowing the caterpillars to feed on the leaves of the host plant with a good degree of protection from predators. Both color versions are now present in Europe and Asia. First sightings of them out of their native North American range began in the 1940's.

Females lay a carpet of light green, spherical eggs on the bottoms of leaves. After the caterpillars hatch, they immediately begin eating and building a tent web to cover themselves. The caterpillars, like adults, come in two color forms. In its northern range, it has a black head and hairy yellow body with black dots along the dorsal (back) side. In the southern range, the head is orange. One to four generations each year can be produced depending on the climate. (Warmer climates breed more generations.) They feed on a large variety of tree leaves. Hickory, alder, elm, willow, mulberry, oak, poplar, sweetgum, birch, cherry, apple, and pecan trees are all hosts for Fall Webworms. They do not attack fruit and, though the webs are unsightly, they usually do not permanently damage a tree. They are active in the autumn and consume leaves right before the foliage dries up and falls off anyway. They are considered a pest to ornamental trees only because the purpose of an ornamental is to look attractive and large silk webs deter from those aesthetics. Managment of Fall Webworms is not considered necessary. Certain species of wasps and flies are predators of this caterpillar, so a biological control exists.
Basic Information
Common Name: Fall Webworm
Scientific Name: Hyphantria cunea
Category: Butterfly or Moth


General Identification
Size (Adult; Length): 25mm to 42mm (0.98in to 1.64in)
Colorwheel Graphic
Identifying Colors: white, brown, red, yellow
Additional Descriptors: furry, spots, giraffe, flying, hairy, caterpillar, cluster




Taxonomic Hierarchy
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Erebidae
Genus: Hyphantria
Species: cunea


Butterfly and Moth Anatomy
Graphic showing basic anatomy of a common North American butterfly and moth insect
1
Antennae: Butterflies and Moths have a pair of antennae on the head used as sensors.
2
Head: The head is home to the insect's eyes, antennae, and proboscis.
3
Thorax: Home to the three pairs of legs as well as vital internal organs.
4
Abdomen: Contains vital internal organs such as the heart(s) and reproduction facilities.
5
Forewing: The upper, forward wing pair used for flying.
6
Hindwing: The lower, rearward wing pair used for flying.
NOTE: Butterflies and Moths are part of the Lepidopteran order as they share many similarities.


Territorial Reach (A-to-Z)
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed below as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections below indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Canadian National Flag Graphic
Alberta
British Columbia
Manitoba
New Brunswick
Newfoundland and Labrador
Nova Scotia
Ontario
Prince Edward Island
Quebec
Saskatchewan
Mexican National Flag Graphic
Mexico


Territorial Area Map (Visual Reference Guide)
The map below showcases (in red) the states and territories of North America where the Fall Webworm may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.
Alaska  
Hawaii  
Prince Edward Is.  
State of Alabama graphic
State of Arizona graphic
State of Arkansas graphic
State of California graphic
State of Colorado graphic
State of Delware graphic
State of Florida graphic
State of Georgia graphic
State of Idaho graphic
State of Illinois graphic
State of Indiana graphic
State of Iowa graphic
State of Kansas graphic
State of Kentucky graphic
State of Louisiana graphic
State of Maine graphic
State of Maryland graphic
State of Michigan graphic
State of Minnesota graphic
State of Mississippi graphic
State of Missouri graphic
State of Montana graphic
State of Nebraska graphic
State of Nevada graphic
State of New England graphic
State of New Jersey graphic
State of New Mexico graphic
State of New York graphic
State of North Carolina graphic
State of North Dakota graphic
State of Ohio graphic
State of Oklahoma graphic
State of Oregon graphic
State of Pennsylvania graphic
State of South Carolina graphic
State of South Dakota graphic
State of Tennessee graphic
State of Texas graphic
State of Utah graphic
State of Virginia graphic
State of Washington graphic
State of West Virginia graphic
State of Wisconsin graphic
State of Wyoming graphic
Canadian territory of Alberta graphic
Canadian territory of British Columbia graphic
Canadian territory of Manitoba graphic
Canadian territory of New Brunswick graphic
Canadian territory of Newfoundland and Labrador graphic
Canadian territory of Ontario graphic
Canadian territory of Quebec graphic
Canadian territory of Saskatchewan graphic
Territory map graphic of the country of Mexico
Contiguous United States shape map layer graphic


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