Evergreen bagworm
Encyclopedia
The Evergreen Bagworm (Thyridopteryx ephemeraeformis), commonly known as bagworm,
eastern bagworm, common bagworm, common basket worm, or North American bagworm, is a moth
that spins its cocoon in its larva
l life, decorating it with bits of plant
material from the tree
s on which it feeds.
The evergreen bagworm's case grows to a length of over 6 cm, tapered and open on both ends. Newborn larva are blackish and turn brown to tan as they grow, mottled with black. The heads and thorax
develop a yellow tint as they grow to a full length of 24 to 32 mm. Adult males resemble bees, having a 25 mm wingspan with transparent wings (Greek
thuris window + pterux wing) and black furry bodies. Adult females are maggot
-like with yellowish-white soft bodies 19 to 23 mm long and small tufts of hair near the end of the abdomen
. The cream colored eggs are 0.75 mm in diameter.
The evergreen bagworm thrives in the eastern United States
as far west as Nebraska
, north into New England
and bordering the Gulf of Mexico
south throughout Texas
. Large populations in forested areas are rare. With scarce predators in urban areas, evergreen bagworms often thrive in urban habitats. When disturbed, the larva will retract its head into its case and hold the front opening closed. Mature larva may remain in the host tree or drag its case nearby before attaching itself for the pupa
stage.
Arborvitae and red cedar
are the favored host trees of the evergreen bagworm, but cypress
, juniper
, pine
, spruce
, apple
, birch
, black locust
, elm
, maple
, poplar
, oak
, sycamore
, willow
, and over 100 other species are also attacked. Leaves and buds are both fair game for food.
Bagworms are commonly parasitized by ichneumonid wasps
, notably Itoplectis conquisitor. Predators include vespid wasps
and hornet
s. Woodpecker
s and sapsucker
s can feed on the larva from their cases.
Eggs hatch from early April to early June (earlier in the south) and larvae emerge from the carcass of their mother in her case. Newborn larva emerge from the bottom of the hanging case and drop down on a strand of silk. The wind often blows the larva to nearby plants where it begins its new case from silk and fecal material before beginning to add leaves and twigs from its host. When mature in mid-August, the larva wraps silk
around a branch, hangs from it, and pupa
tes head down. The silk is so strong that it can strangle and kill the branch it hangs from over the course of several years as the branch grows. Adult males transform into moths in four weeks to seek out females for mating. The female never leaves the cocoon, requiring that the male mate with her through the open end at the back of the case. She has no eyes, legs, wings, antennae, and can't eat, but she emits a strong pheromone
to attract a mate. After her death with hundreds to several thousand eggs still inside, her offspring hatch and pass through her body, pupal shell and case over several months emerging to start their own cases. Later, her pupal case can be found, full of the yellow remains of eggshells.
The bagworm has a voracious appetite and is considered a serious pest. Host trees develop damaged foliage that will kill the tree if left unchecked. If caught early enough in an infestation, the cases from the previous year can be picked off by hand before the end of May. They are easiest to detect in the fall after their cases have turned brown, especially on evergreen trees. Various bacterial sprays such as Bt
/Spinosad
and stomach insecticide
s such as carbaryl
(Sevin) are used to control infestations.
eastern bagworm, common bagworm, common basket worm, or North American bagworm, is a moth
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...
that spins its cocoon in its larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
l life, decorating it with bits of plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
material from the tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s on which it feeds.
The evergreen bagworm's case grows to a length of over 6 cm, tapered and open on both ends. Newborn larva are blackish and turn brown to tan as they grow, mottled with black. The heads and thorax
Thorax (insect anatomy)
The thorax is the mid section of the insect body. It holds the head, legs, wings and abdomen. It is also called mesosoma in other arthropods....
develop a yellow tint as they grow to a full length of 24 to 32 mm. Adult males resemble bees, having a 25 mm wingspan with transparent wings (Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
thuris window + pterux wing) and black furry bodies. Adult females are maggot
Maggot
In everyday speech the word maggot means the larva of a fly ; it is applied in particular to the larvae of Brachyceran flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and Crane flies...
-like with yellowish-white soft bodies 19 to 23 mm long and small tufts of hair near the end of the abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
. The cream colored eggs are 0.75 mm in diameter.
The evergreen bagworm thrives in the eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
as far west as Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....
, north into New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
and bordering the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
south throughout Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
. Large populations in forested areas are rare. With scarce predators in urban areas, evergreen bagworms often thrive in urban habitats. When disturbed, the larva will retract its head into its case and hold the front opening closed. Mature larva may remain in the host tree or drag its case nearby before attaching itself for the pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
stage.
Arborvitae and red cedar
Juniperus virginiana
Juniperus virginiana is a species of juniper native to eastern North America, from southeastern Canada to the Gulf of Mexico, east of the Great Plains...
are the favored host trees of the evergreen bagworm, but cypress
Cupressaceae
The Cupressaceae or cypress family is a conifer family with worldwide distribution. The family includes 27 to 30 genera , which include the junipers and redwoods, with about 130-140 species in total. They are monoecious, subdioecious or dioecious trees and shrubs from 1-116 m tall...
, juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
, pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
, spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
, apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...
, birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...
, black locust
Black locust
Robinia pseudoacacia, commonly known as the Black Locust, is a tree in the subfamily Faboideae of the pea family Fabaceae. It is native to the southeastern United States, but has been widely planted and naturalized elsewhere in temperate North America, Europe, Southern Africa and Asia and is...
, elm
Elm
Elms are deciduous and semi-deciduous trees comprising the genus Ulmus in the plant family Ulmaceae. The dozens of species are found in temperate and tropical-montane regions of North America and Eurasia, ranging southward into Indonesia. Elms are components of many kinds of natural forests...
, maple
Maple
Acer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
, poplar
Poplar
Populus is a genus of 25–35 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar , aspen, and cottonwood....
, oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
, sycamore
Sycamore
Sycamore is a name which is applied at various times and places to three very different types of trees, but with somewhat similar leaf forms....
, willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...
, and over 100 other species are also attacked. Leaves and buds are both fair game for food.
Bagworms are commonly parasitized by ichneumonid wasps
Ichneumon wasp
The Ichneumonoidea are insects classified in the hymenopteran suborder Apocrita. The superfamily is made up of the ichneumon wasps and the braconids...
, notably Itoplectis conquisitor. Predators include vespid wasps
Vespid
The Vespidae are a large , diverse, cosmopolitan family of wasps, including nearly all the known eusocial wasps and many solitary wasps. Each social wasp colony includes a queen and a number of female workers with varying degrees of sterility relative to the queen. In temperate social species,...
and hornet
Hornet
Hornets are the largest eusocial wasps; some species can reach up to in length. The true hornets make up the genus Vespa and are distinguished from other vespines by the width of the vertex , which is proportionally larger in Vespa and by the anteriorly rounded gasters .- Life cycle :In...
s. Woodpecker
Woodpecker
Woodpeckers are near passerine birds of the order Piciformes. They are one subfamily in the family Picidae, which also includes the piculets and wrynecks. They are found worldwide and include about 180 species....
s and sapsucker
Sapsucker
The Sapsuckers form the genus Sphyrapicus within the woodpecker family Picidae. All are found in North America.As their name implies, sapsuckers feed primarily on the sap of trees, moving among different tree and shrub species on a seasonal basis...
s can feed on the larva from their cases.
Eggs hatch from early April to early June (earlier in the south) and larvae emerge from the carcass of their mother in her case. Newborn larva emerge from the bottom of the hanging case and drop down on a strand of silk. The wind often blows the larva to nearby plants where it begins its new case from silk and fecal material before beginning to add leaves and twigs from its host. When mature in mid-August, the larva wraps silk
Silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...
around a branch, hangs from it, and pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
tes head down. The silk is so strong that it can strangle and kill the branch it hangs from over the course of several years as the branch grows. Adult males transform into moths in four weeks to seek out females for mating. The female never leaves the cocoon, requiring that the male mate with her through the open end at the back of the case. She has no eyes, legs, wings, antennae, and can't eat, but she emits a strong pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
to attract a mate. After her death with hundreds to several thousand eggs still inside, her offspring hatch and pass through her body, pupal shell and case over several months emerging to start their own cases. Later, her pupal case can be found, full of the yellow remains of eggshells.
The bagworm has a voracious appetite and is considered a serious pest. Host trees develop damaged foliage that will kill the tree if left unchecked. If caught early enough in an infestation, the cases from the previous year can be picked off by hand before the end of May. They are easiest to detect in the fall after their cases have turned brown, especially on evergreen trees. Various bacterial sprays such as Bt
Bacillus thuringiensis
Bacillus thuringiensis is a Gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide; alternatively, the Cry toxin may be extracted and used as a pesticide. B...
/Spinosad
Spinosad
Spinosad is a new chemical class of insecticides that are registered by the United States Environmental Protection Agency to control a variety of insects...
and stomach insecticide
Insecticide
An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
s such as carbaryl
Carbaryl
Carbaryl is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid commonly sold under the brand name Sevin, a trademark of the Bayer Company. Union Carbide discovered carbaryl and introduced it commercially in 1958...
(Sevin) are used to control infestations.
Sources
- University of Minnesota Department of Entomology: Bagworm Information
- Forest Pests: Evergreen Bagworm
- Ohio State University: Bagworm and Its Control