Eastern Tent Caterpillar What Do They Eat

Eastern Tent Caterpillar

ENTFACT-423: Eastern Tent Caterpillar|Download the PDF version of this fact sheet

by Ric Bessin, Extension Specialist University of Kentucky College of Agriculture

The eastern tent caterpillar, Malacosoma americanum, is a North American insect that is a nuisance to both humans and animals. Populations fluctuate from year to year, with outbreaks occurring every few years or even more frequently. This bug is a nuisance in the late spring and early summer because of the defoliation of trees, the construction of unattractive silken nests in trees, and the presence of roaming caterpillars crawling over plants, sidewalks, and roadways. Eastern tent caterpillar nests are most usually seen on wild cherry, apple, and crabapple trees, but they can also be found on other trees such as hawthorn, maple, cherry, peach, pear, and plum.

Figure 1. An eastern tent caterpillar.

While tent caterpillars may almost completely defoliate a tree when they are in large numbers, the tree will typically rebound and produce a new crop of leaves. Nests, on the other hand, can constitute an eyesore in the landscape, particularly if they are exposed as a result of extensive defoliation. The silken nests, which are formed in the crotches of limbs, can grow to be rather substantial in size. As soon as the larvae begin to roam in search of safe havens to pupate, there is tremendous anxiety.

They are a nuisance and may cause a sloppy mess if they are squished on driveways, sidewalks, and patios, for example.

In general, insecticides are ineffective against fully developed larvae.

Fall webworm nests, in contrast to the tent caterpillar’s, are found at the extremities of branches, and their loosely formed webs include foliage, but the tents of the eastern tent caterpillar do not.


The eastern tent caterpillar overwinters as an egg in a mass of 150 to 400 eggs, which is the size of a grapefruit. In this case, the masses are covered with a glossy, black varnish-like substance and wrap branches that are approximately the size of a pencil or less in diameter.

Figure 2. Eastern tent caterpillar egg masses are wrapped around small twigs.

The caterpillars hatch about the time that the buds begin to open, which is normally in early March, and feed on the buds. These insects are very sociable; caterpillars from a single egg mass will remain together and create a silken tent in the crotch of a tree to protect themselves from predators. Caterpillars from two or more egg masses may congregate to create a single big colony if the conditions are right. They remain within the tent when it is too hot outside or when it is too wet outside.

Figure 3. An eastern tent caterpillar nest.

A row of oval blue spots on the sides of the caterpillars, which are black with a white stripe down the back, brown and yellow lines along the sides, and a black and white stripe down the back. In order to consume the foliage, the larvae enlarge the web, which eventually grows to be a foot or more in length. They are fully grown and 2 to 2-1/2 inches in length after 4 to 6 weeks of development.

At this point, they begin to disperse from the nest in search of safe places in which to spin a cocoon on their own. Approximately 1 inch long and made of tightly woven white or yellowish silk, the cocoon is attached to other objects by a few coarser threads that run through it.

Figure 4. An adult male eastern tent moth.

The adult moth emerges from the cocoon around 3 weeks after the cocoon is laid. In coloration, the moth is reddish-brown with two faint stripes running diagonally across the forewings of each of its wings. Female moths mate and begin to deposit eggs on short branches after mating. The eggs will hatch in the spring of the following year. Every year, just one generation is produced.


  • In most years, natural enemies play a significant role in lowering the population of eastern tent caterpillars on the ground. Caterpillars are regularly parasitized by a variety of small braconid, ichneumonid, and chalcid wasps, which can be found in abundance in the wild. Some predators, as well as a few illnesses, contribute to the control of their populations. This, in part, explains why population levels fluctuate from year to year
  • Prevention and early management are therefore critical. The removal and destruction of egg masses from ornamentals and fruit trees over the winter months helps to significantly lessen the problem the following spring. Small tents may be easily removed and destroyed by hand in the early spring months. It is possible to prune out larger tents that are then destroyed or removed by twisting the nest around the end of a stick. It is not advisable to burn the tents out with a torch because this might cause significant harm to the tree. It is possible to kill young caterpillars by spraying them with a pesticide containing Bacillus thuringiensisvarkurstaki. Carbaryl and malathion are two more pesticides to consider. It is more difficult to destroy larvae under tents because they are shielded beneath the webbing.

Date of last revision: 11/19 CAUTION! The pesticides recommended in this book are only approved for use in Kentucky, United States of America. Some goods may not be legal to use in your state or nation, depending on where you live. It is recommended that you consult with your local county agent or regulatory authority before applying any pesticide listed in this article. As a reminder, ALWAYS READ AND COMPLY WITH LABELED INSTRUCTIONS FOR SAFE USE OF ANY PESTICIDE! Images courtesy of Ric Bessin, University of Kentucky Entomology, with the exception of the tent in the tree shot, which is courtesy of R.

Anderson, USDA Forest Service, copyright 1995.

Tent Caterpillars

ENTFACT-424: Tent Caterpillars|Download the PDF version of this fact sheet

by Joe Collins, Nursery Inspector University of Kentucky College of Agriculture

Tent caterpillars are nocturnal creatures that dwell in groups under a silken tent. The silk is generated by glands in the head, and the tent protects the creature from a variety of natural predators and predatory insects. Tent caterpillars are found in three different species in Kentucky, the United States: the eastern tent caterpillar, the forest tent caterpillar, and the autumn webworm. Each of these pests has a diverse range of natural enemies that, in most cases, prevent caterpillar populations from getting excessively numerous.

During certain years, one or more of the species may, on the other hand, become quite prevalent.

However, excessive feeding within a single year may cause tree development to be stunted, particularly if the tree is subjected to additional pressures such as drought.

Eastern Tent Caterpillar

Larvae of the ETC A native bug, the eastern tent caterpillar was originally described in 1646 and has been around ever since. The appearance of large numbers of this caterpillar is frequently associated with intervals of around 10 years. For a long time before the gypsy moth was unintentionally imported into the United States, the eastern tent caterpillar was thought to be one of the most serious pests of shade trees in our country. Among the fruits that eastern tent caterpillars like are wild cherry, apple, and crabapple.

  • They will also eat The bug hibernates as an egg during the winter.
  • The egg masses are approximately 3/4″ in length and have a varnished appearance.
  • Following the hatching of their eggs, the little caterpillars proceed to create a tent in a nearby branch fork.
  • The larvae crawl out of this tent and into the surrounding vegetation to feed.
  • The larvae are usually black with a white stripe running down the back of their bodies.
  • This insect pupates inside of whitish-colored cocoons that may be seen on tree trunks, fences, and buildings, amongst other places.

The moths are reddish-brown in color with two white lines running across each wing on each of their wings. This bug reproduces just once a year and has only one generation every year. Tent (on the left) and ETC Egg Mass (on the right) (right)

Forest Tent Caterpillar

Larvae of the Federal Trade Commission The woodland tent caterpillar resembles the eastern tent caterpillar in appearance and behavior. The egg masses are laid in a manner identical to that of the eastern tent caterpillar, with the exception that they are square at the ends. When the eggs hatch, the larvae attach themselves to the trunk or limb of a tree and form a loose tent or mat. As a result, they will normally travel to the top of the tree where they will begin feeding on the developing leaves buds.

  1. A typical eating pattern for the larvae is to focus their feeding on a single branch at a time.
  2. In comparison to the eastern tent caterpillar, this caterpillar is differentiated by the keyhole-shaped markings that run along its back.
  3. Larvae are about the size of a pea.
  4. Each of the front wings has two dark brown stripes on each side, and the adult is a tan moth approximately 1-1/2 inches long with two dark brown stripes on each side.
  5. Sweetgum, oak, birch, ash, maple, elm, and basswood are among the trees that have been damaged by this insect.

Fall Webworm

In the United States and Canada, the autumn webworm is a pest that may be found throughout the majority of the country. With the exception of evergreens, it will feed on practically all shade, fruit, and decorative trees. The American elm, maples, hickory, and sweetgum are among the trees that are particularly popular in Kentucky. Larvae of the Fall Webworm When compared to the eastern tent caterpillar and the forest tent caterpillar, the autumn webworm is distinguished by the fact that it always places its tent at the ends of branches and that there is generally more than one generation every year of development.

  • They can have either a red or a black head on their bodies.
  • A frail web will be formed by the blackheaded larvae, but a huge and thick web will be formed by the redheaded larvae.
  • The moths begin to emerge between the middle of March and the middle of late April.
  • Female moths lay their eggs on the underside of leaves in masses ranging from 200 to 500 eggs in size after mating.
  • The first generation of caterpillars begins to feed from the middle of spring through the beginning of summer.

It is during August or September that a second generation of webworms will be spotted, after they have finished eating. Defoliation caused by webworms is often greater in the second generation than in the first generation. Tent for Webworms in the Fall


Essentially the same methods are used to control all three of these pests. It is quite effective to destroy the tents, especially if the tents are tiny, in order to get rid of the caterpillars. If possible, wait until dusk or early morning when the larvae are most active in the tent before doing this. It is best not to burn the tents since the tremendous heat and flames may cause harm to the tree’s roots. It may be necessary to prune egg masses off smaller trees in order to prevent their reproduction.

  1. These caterpillars are resistant to the bacteria Bacillus thuringiensis (Bt) as well as a variety of chemical pesticides.
  2. When the insects are in the nest, it is best to apply the pesticide in the evening or early morning when they are most active.
  3. 1/04 – Date of last revision: CAUTION!
  4. Some goods may not be legal to use in your state or nation, depending on where you live.
  6. The photographs of the Eastern tent caterpillar tent and egg mass, the forest tent caterpillar larva, and the fall webworm tent were taken from the CD: G.K.
  7. I and II, Southern Cooperative Series Bulletin No.
  8. Douce, et al., 1995, Forest Insects and Their Damage Vol These are photos that have been copyrighted.
  9. A signed license from the SFIWC and each individual photographer or organization is required before any commercial or other usage of the photos can be made.
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Food for caterpillars, food for birds: Cherry trees and Eastern tent caterpillars, Malacosoma americanum — Bug of the Week

The eastern tent caterpillar is a stunning creature, with blue stripes and patches on the sides and a white stripe along the middle of the back to distinguish it from its competitors. The return of eastern tent caterpillars is heralded by the blooming of forsythia. Even while the forsythia’s vivid yellow blooms herald the arrival of spring, they also herald the arrival of an outstanding defoliator known as the eastern tent caterpillar. Since last summer, this herbivore has survived by laying eggs in large numbers on the short branches of cherry, apple, and crabapple trees, among other fruit trees.

  1. Thousands of tiny caterpillars were produced from egg masses that looked like Styrofoam and contained as many as 300 eggs apiece.
  2. Larvae construct little silken tents over the egg mass and the surrounding branch to protect themselves from predators.
  3. Pheromones, which are chemical trail markers, are deposited by the caterpillars when they return to their tent after eating.
  4. During the month of April, the larvae’s tents develop in size.
  5. Caterpillars returning to the tent from a meal pass hungry caterpillars on their way to eat fragile leaves along the silk route.
  6. Brothers and sisters from the same egg mass or from neighboring egg masses frequently participate in group activities like as communal foraging and the expansion of their magnificent tent, which they built for themselves.
  7. Besides providing shelter against predatory or parasitic insects, their silken dwellings may also give some protection from the elements.

As soon as the larval feeding is through, the grownup caterpillars begin to travel and seek for safe havens like as cracks in loose bark where they may construct silken cocoons.

The larvae leave the tree and travel the land in search of protective areas beneath logs or leaves or stones, as well as under man-made structures, where they will construct yellowish or white silken cocoons.

They mate and deposit egg masses on the tiny branches of rosaceous trees such as cherry, apple, and crab apple.

What is the best way to tell whether eastern tent caterpillars are a hazard to your trees?

A little stand of wild cherry trees that is constantly plagued with eastern tent caterpillars provided the inspiration for this week’s Bug of the Week photo gallery.

Egg masses resemble rigid foam collars that have been coated with a shiny varnish-like substance and fully wrap twigs and tiny branches, according to the description.

On a chilly or gloomy day (when the caterpillars tend to stay in their nests rather than going out to feed), tents and their inhabitants can be removed with a gloved hand and disposed of in a trash bag.

Flames are extremely harmful to the bark of a tree and should never be used on one.

Another solution may appeal to you if, on the other hand, you want to let Mother Nature take her course and can live with the presence of caterpillars in your garden.

Caterpillars are a vital source of protein for birds in the spring, both during the development of eggs within their bodies and afterwards, when the eggs hatch and the ravenous broods require fresh meat to survive.

If you wish to safeguard your valued trees from defoliation by tent caterpillars while also assisting your local birds, you may simply trim away the afflicted branches, tents and all, and transplant them to a neighboring feral cherry or a nearby wild cherry.

Tent caterpillars are voracious eaters, and they may wreak havoc on small and even huge trees.

While trees may rebound and produce a second flush of leaves, the recurrent defoliation of these trees is certain to have a negative impact on them.

The active components Bacillus thuringiensis(Bt) or spinosad, which are commonly found in pesticides licensed for use against caterpillars, can give good control of these small leaf eaters for those who want to do it themselves.

Take extra precautions if plants are in flower or if helpful pollinators are around.

Naturally occurring predators, parasites, and viruses are generally able to decrease tent caterpillar populations to insignificant levels after only a few years of high caterpillar abundance.

To find out what these fascinating herbivores are up to this week, get out to the garden and take a look around.


This episode was inspired by the fantastic books “The Tent Caterpillars” by Terrence Fitzgerald and “Managing Insects and Mites on Woody Landscape Plants” by John A. Davidson and Michael J. Raupp, both of which can be found on Amazon.com and in libraries everywhere. Visit the following websites for further information about eastern tent caterpillars:

All About Eastern Tent Caterpillars

The eastern tent caterpillar (Malacosoma americanum) may be the only bug that can be identified solely by the structure of its house rather than its appearance. These gregarious caterpillars reside in silk nests that they construct in the crotches of cherry and apple trees, where they may be seen in large numbers. Eastern tent caterpillars are sometimes mistaken for gypsy moths or even the fall webworm.

What Do They Look Like?

Caterpillars of the eastern tent species feast on the leaves of several popular decorative landscape trees, causing their presence to be a source of concern for many homeowners. In reality, they seldom cause enough harm to a healthy plant to cause it to die, and if you’re looking for an intriguing bug to see, this is the one to look for. Several hundred caterpillars live in a communal tent constructed in the crotch of tree branches, where they are protected from the elements. The eastern tent caterpillars, which are models of cooperation, live and work in peace with one another until they are ready to pupate.

They grow to be almost 2 inches long and have noticeable hairs down the sides of their bodies by the time they reach their last instar.

Broken lines of brown and yellow flow along the sides, accented by oval specks of blue in the center of each line.

They lack the vibrant colors of many other moths and look nearly dull in comparison.


Kingdom – Animalia Phylum – Arthropoda Class -InsectaOrder -LepidopteraFamily – Lasiocampidae Genus -MalacosomaSpecies -Malacosoma americanum Kingdom – Animalia Phylum – Arthropoda Class -InsectaOrder -LepidopteraFamily – Lasiocampidae Genus -M

What Do They Eat?

Cherry, apple, plum, peach, and hawthorn trees are among the plants where eastern tent caterpillars dine on the leaves. When the caterpillar species Malacosoma americanum is in abundance, the enormous number of caterpillars can defoliate its host trees completely before moving on to less desirable plants to feed on. Adult moths only survive a few days and do not consume any food.

Life Cycle

Eastern tent caterpillars go through a complete metamorphosis, which includes four phases, as do all butterflies and moths:

  1. Eggs- In the late spring, the female oviposits 200–300 eggs, depending on the species. Caterpillars emerge from the egg mass in a few of weeks, but they stay dormant in the egg mass until the next spring, when new leaves grow. During the sixth instar larval stage, the sixth instar larva creates a silken cocoon in a secluded area and pupates within it. The pupal case is brown in color. Adult- Moths fly around in quest of mates throughout the months of May and June, and they only survive long enough to breed.

Special Adaptations and Defenses

During the early spring months, when temperatures are more volatile, larvae emerge. The caterpillars dwell in large groups in silken tents that are meant to keep them warm during cold spells of weather. On cold or wet days, the broadside of the tent faces the sun, and caterpillars may congregate there to warm themselves. Each of the caterpillars’ three daily feeding expeditions begins with a thorough cleaning and replenishment of silk in their tent. In order to fit their growing size and to get away from the accumulating waste of frass, the caterpillars build additional layers to their body as they mature.

As they move through branches and twigs in search of leaves to eat, they leave behind silk trails and pheromones that attract other insects to the area.

Pheromone signals not only warn other caterpillars to the presence of foliage, but they also convey information about the quality of the food available on a certain branch of a plant.

Whenever they sense a threat, the caterpillars leap to their feet and thrash their bodies about.

The residents of the community respond to these motions by imitating them, resulting in an interesting group spectacle to behold. When the caterpillars need to rest between feedings, they return to the shelter of the tent, which also serves as a protection against predators.

Where Do Eastern Tent Caterpillars Live?

It is possible for eastern tent caterpillars to infest the residential landscape, forming tents in ornamental cherry, plum and apple trees, among other species. It is possible that roadside stands of trees will produce adequate wild cherries and crabapples, and that dozens of caterpillar tents will embellish the forest border in this area. Because these early spring caterpillars need on the warmth of the sun to keep their bodies warm, tents would be unusual, if at all, to be seen in wooded places that were shaded.

Malacosoma americanum is a kind of bug that is indigenous to North America.


  • Caterpillar of the eastern tent. The Texas A&M University tent caterpillar is an Eastern tent caterpillar. T. D. Fitzgerald is at the University of Kentucky Agriculture Department. Stephen A. Marshal’s novel The Tent Caterpillars is set in a tent. Insects: A Natural History and Diversity of the Species

The return of tent caterpillars: What’s it means for your yard?

Bud break does not just herald the advent of flowers and foliage; it also heralds the emergence of tent caterpillars from their cocoons. Troops of these caterpillars may completely cover tree branches with their silk tents in as little as a few weeks. Is it necessary for you to be concerned about them? Continue reading to find out! Caterpillar tents are a common type of western tent. These tents are commonly found in the bends of large branches on trees and medium-sized bushes, although they can also be seen on the ground.

  • There are three species of tent caterpillar that may be found in Indiana: the Forest tent caterpillar (Malacosoma disstria), the Western tent caterpillar (Malacosoma californicum), and the eastern tent caterpillar (Malacosoma elatior) (M.
  • All three species dwell in groups of anything from 40 to 200 individuals, and they remain together until just before they pupate, at which point they split off.
  • They are not particularly gregarious, although they will leave pheromone trails leading to trees that have rich food sources.
  • Below you’ll find a few of ways for distinguishing them from other species.
  • If a tent caterpillar’s body is coated in fuzzy hairs, it is not a tent caterpillar; if it is smooth or spikey, it is not a tent caterpillar.
  • These tufts are absent in tent caterpillars.
  • If the caterpillar you’re looking at doesn’t exhibit any of these characteristics, it’s most likely not a tent caterpillar at all.
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slate blue with a pair of black stripes, and C.



Elizabeth Barnes.

Hoff, C.

Hoff What exactly do they eat?

They are particularly fond of plants belonging to the Rosaceae family, such as cherry, apple, and chokecherry, among others.

What kind of harm do they cause?

Tent caterpillars typically defoliate only a few branches and are only actively feeding for a few weeks at a time.

However, if the tree is defoliated for a number of years in a row or is subjected to another stressor such as drought, it may suffer branch loss or even death.

If you decide that you want to get rid of tent caterpillars from your trees, you have a variety of choices to choose from.

Wait until the majority of the caterpillars have gathered in their tent before removing the tent from the tree and placing it in a bag to be frozen for later use.

Because their hairs might create an allergic response in some people, you may wish to use gloves when removing them off their tree.

If you believe you’ve discovered tent caterpillars but aren’t sure, please contact the author or post your find oniNaturalistorBugGuidefor ID assistance!

Eastern tent caterpillar – Wikipedia

Eastern tent caterpillar
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Lasiocampidae
Genus: Malacosoma
Species: M. americanum
Binomial name
Malacosoma americanum(Fabricius, 1793)
  • Bombyx americana is a species of tree native to North America. Fabricius, 1793
  • Bombyx pensylvanica (Pennsylvania). Guérin-Méneville
  • Clisiocampa decipiensWalker, 1855
  • Bombyx frutetorumBoisduval, 1869
  • Clisiocampa decipiensWalker,

Caterpillar of the Eastern Tent (Malacosoma americana). Caterpillar Moth is a type of moth that caterpillars feed on (Malacosoma americana) The eastern tent caterpillar (Malacosoma americanum) is a species of moth belonging to the familyLasiocampidae, sometimes known as tent caterpillars or lappet moths. It is found in the eastern United States. It is univoltine, meaning that it produces just one generation per year. It’s an atent caterpillar, a sociable species that builds communal nests in the limbs of trees to protect its young.

  1. Most of the time, the moths oviposit on trees in the plant familyRosaceae, mainly cherry (Prunus) and apple (Malus) (Malus).
  2. The blue and white hues are structural colors, which are produced by the selective filtering of light by microtubules that form on the cuticle’s surface.
  3. In late spring or early summer, the mother moth deposits her eggs in a single batch, which is then consumed by the larvae.
  4. In just three weeks, fully grown caterpillars may be seen within the eggs, indicating that embryogenesis has proceeded quickly.
  5. When the caterpillars emerge from their eggs, they immediately begin constructing an asiliketent structure.
  6. Under field conditions, the caterpillars eat three times a day: immediately before dawn, in the middle of the day, and in the evening after sunset, depending on the species.
  7. During the final instar, the caterpillars exclusively feed at night, which is an exception to the general pattern of feeding during this stage.
  8. After reaching the end of their life cycle, the caterpillars scatter and each builds a cocoon in a safe location.
  9. They are exclusively nocturnal, and they begin flying just after dusk, returning to their resting place within a few hours after dawn.
  10. Upon detecting predators or parasitoids, tent caterpillars thrash their bodies rapidly in the anterior section of their bodies, just like many other species of social caterpillars do.
  11. Fortachinid flies, wasps, and other tiny parasitoids that would deposit eggs on or in the body of the caterpillar, such displays serve as a moving target.

A set of caterpillars lying on the surface of the tent’s roof is referred to as anaposematicdisplay. Few birds, with the exception of cuckoos, are attracted to the hairy caterpillars. Cherry leaves contain cyanogenic compounds, and when disturbed, the caterpillars secrete cyanide-laced fluids.

Tents and temperature

The tent constructed by this species is among the biggest ever constructed by a tent caterpillar. It is built in the crotch of the host tree and is typically oriented so that the broadest wall faces southeast, allowing it to benefit from the morning sunlight. It is customary for the caterpillars to attach silk to the surface of the structure at the beginning of each of their daily activity periods. After a period of time, the silk is laid down with a slight amount of tension, which eventually causes the newly spun layer of silk to separate from the next layer.

  1. They will be able to enter and depart the tent through the apertures.
  2. Light has a significant impact on the caterpillars’ ability to spin silk, and they spend the majority of their time spinning silk on the face of the tent that is the most illuminated.
  3. Caterpillars continue to grow and expand their tent until they reach the end of their larval stage of development.
  4. The tents may be used for a variety of purposes.
  5. The increased humidity within the tent may aid in the process of molting.
  6. Because the weather in the early spring is frequently cold, the caterpillars rely on the heat of the sun to raise their body temperatures to levels that allow them to digest their food and grow stronger.
  7. Early instars are dark in color, and their bodies are well-suited for absorbing heat.

Their longsetae also aid in the prevention of convective heat losses.

The tents serve as miniature greenhouses, capturing and retaining the warmth of the morning sun, allowing the caterpillars to warm up more quickly than they would if they were left outside.

Because they are prone to overheating, the aggregation disintegrates once the temperature is reached that is acceptable.

They may also congregate on the outside of the shaded side of the tent and hang from the tips of their abdomens in order to increase convective heat loss and cooling in the structure.

Although there is no radiant heat source present, the temperature in the interior of a tightly packed caterpillar population can be several degrees above ambient temperature even when the caterpillars have been freshly fed.

However, it is not clear whether this small amount of heat gain has a significant impact on the rate of their development.


Tent caterpillars exude silk from their aspinneret wherever they walk, and paths that are regularly traversed eventually become dotted with visible silk tracks. When the caterpillars move about the tree, they tend to stick to the pathways that have been laid out for them. They pull their abdomens down the paths, drawing down pheromones in the process. In addition to constructing recruiting trails, caterpillars that locate food may also overmarkethe exploration paths that they follow back to the tent.

A single successful forager has the ability to attract the entire colony to a food source.

Caterpillars quickly follow the traces left by this chemical, even leaving their own trails in favor of the fake trails created by the chemical in certain cases.

Pest status

Due to its ability to defoliate attractive trees, the eastern tent caterpillar is considered a pest of significant significance. Damaged trees, on the other hand, often recover and refoliate within a few weeks after being struck.


Horses are poisoned by the eastern tent caterpillar, which is found in eastern North America. However, the specific mechanism by which the caterpillar causes abortions in horses has not yet been established. The feeding of eastern tent caterpillars to pregnant mares has been proven to cause them to abort in laboratory tests. The caterpillars of this species frequently feed on the highly cyanogenicblack cherrytree (Prunus serotina), and it was once believed that the mares aborted as a result of the cyanide they drank along with the caterpillars.

That hypothesis, on the other hand, was found to be false.

It was hypothesized that these fragments could facilitate the passage of infectious agents from the horse’s gut into its bloodstream and then onto its placenta, resulting in abortion of the mare.


  • The Tent Caterpillars is a 1995 book written by Terrence D. Fitzgerald. Cornell University Press
  • Fullard, James H
  • Napoleone, Nadia
  • Cornell University Press (2001). “Diel flight periodicity and the development of auditory defenses in the Macrolepidoptera” is the title of a paper published in the journal “Macrolepidoptera” (PDF). 349–368 in Animal Behaviour, volume 62, number 2. The number to cite is 10.1006/anbe.2001.1753.S2CID53182157. On 2007-06-15, a PDF version of this document was made available for download.

External links

  • Bagworm, Fall Webworm, or Eastern Tent Caterpillar: what’s the difference? The date was August 18, 2001. Sandra Mason is a University of Illinois Extension specialist in agriculture. It was accessed on May 31, 2010. Terrence D. Fitzgerald’s work on the eastern tent caterpillar (Malacosoma americanum) is available online.

Eastern Tent Caterpillar Moth

Two light-colored bands cut across the forewing of the adult eastern tent caterpillar moths distinguish them from other moths. The center band between the two lines might be lighter or white in color at times. These moths are similar in size to others in their family, and they have thick, lengthy scales that give them the appearance of being fuzzy. Feathered antennae are found on both males and females. Females are lighter and more golden in color, as well as bigger and more rounded in their wings.

  1. They live in groups in “tents” formed of numerous silken threads in the crotches of host trees, which they construct from the strands.
  2. The inside of the head is dark.
  3. disstria) has black (rather than pale) lines on the forewings, but the forest tent caterpillar (M.
  4. The larvae do not have a continuous line down their backs; instead, there is a light-colored mark on each segment down their backs, with the form of each mark resembling a keyhole, shoeprint, or bowling pin on each segment.

In addition, the communal larvae of that species do not construct tents as they do in other species. Instead, they merely construct silken mats and recommendations on tree trunks and branches to direct them to and from feeding areas and group meeting areas.

Eastern Tent Caterpillar Moth (Malacosoma americanum)

Updated on January 3, 2022; written by a member of the staff; content from www.InsectIdentification.org The Eastern Tent Caterpillar Moth derives its name from the activity of its caterpillars, which is why it is called that. A group of juvenile caterpillars works together to construct a “tent” out of their silk, which they use as a home on the tree or shrub from which they are eating. As they consume their food, the yellow and black meal worm-like caterpillars come and go during the day, returning at night for refuge from the environment and any predators.

  1. The feeding activity causes dead leaves and fruit to become trapped inside the branch, resulting in unattractive branches.
  2. Two thin, but clearly visible white lines cross their forewings in the middle and bottom part, respectively.
  3. The thorax is coated with a thick layer of brown hair.
  4. In the vicinity of roses and fruit trees like as apple, cherry, and peach, where they are most likely to deposit their eggs, they can be observed in large numbers.
  5. Because the caterpillars feed on the leaves of trees that produce fruit that humans consume, they are sometimes referred to be pests.
  6. Malacosoma americanum is the scientific name for this plant.
  7. Furry; uneven; flying are some of the descriptors.

Dimensions (mm): 35.5mm Hi: 41 millimeters Reach Across Territories (A-to-Z) The United States, Canada, and Mexico Territorial Map of the United States, Canada, and Mexico NOTES ON THE MAP: The Eastern Tent Caterpillar Moth is represented by the color red on the territorial heat map above, which shows the states and territories in North America where the moth may be found (but is not limited to).

  • Some insects are naturally restricted by their habitat, weather, mating behaviors, food supplies, and other factors, but others have seen significant growth throughout most of, if not all of, North America, thanks to human intervention.
  • For the most part, insects roam freely, often prompted by changes in nutrition or habitat, as well as mating patterns.
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Eastern Tent Caterpillar

Caterpillar, Malacosoma americanum (Fabricius) (Lepidoptera: Lasciocampidae), tent caterpillar of the eastern hemisphere Drees captured this image. Caterpillar with the common name “Eastern tent caterpillar” Malacosoma americanum is the scientific name for this species (Fabricius) Order:Lepidoptera Description: They are brown and yellowish in color with two diagonal lines on the forewings of the adult tent caterpillar moth, which has a 1-inch wingspread. Caterpillars (larvae) can grow to be more than 1-12 inches in length.

  1. They are distinguished by a solid white line running down the middle of their backs.
  2. At night and during rainy spells, larvae construct a dense silken web, which is commonly found in the crotch of little limbs and which serves as a safe haven for them.
  3. Forest tent caterpillar,M.
  4. It does not build a tent and can be found on a variety of hosts, however oaks are the preferred host in Texas, according to the species.
  5. californicum (Packard), makes huge tents on a variety of trees and plants, including oaks and wild plums, and may be found throughout the western United States.
  6. The Sonoran tent caterpillar, M.
  7. Caterpillars have one black segment on their back, but they do not have any white markings.

Fall webworms construct loose silken webs surrounding the leaves on which they are eating, rather than thick webs in the crotches of branches where they are leaving to feed, as they do in the spring.


took the photograph.

The larvae hatch in the early spring, just as the plants are beginning to leaf out (mid-February to mid-March).

Due to the fact that tent caterpillars only produce one generation each year, all activity is generally completed by May or June.

Caterpillars have mouthparts that are designed for chewing.

Eastern tent caterpillars love the fruits of cherries, plums, peaches, apples, hawthorn, and other similar trees and shrubs.

Leaving their tents to feed on leaves, caterpillars may swiftly defoliate whole parts of a tree in short periods of time.

Adult moths are drawn to lights and can be found in large numbers, although they only live for a few days before dying.

You may also contact your local Texas A M AgriLife Extension Service agent or look for other state Extension offices for further information. Literature citations: Jackman 1988; Metcalfe and colleagues 1962.

Tent Caterpillars – How do I get rid of tent caterpillars?

Wizzie Brown contributed to this article. Tent caterpillars attack a variety of broadleaf trees and shrubs, causing unattractive webs, or tents, to appear on the leaves. When their populations reach a critical mass, the caterpillars can defoliate trees, causing them to develop more slowly. They prey on ornamental and fruit trees, among other things. Early and correct identification of tent caterpillars, knowing their life cycle, and the use of suitable cultural or chemical management strategies are all essential for their eradication from the environment.

The eastern tent caterpillar, Malacosoma americanum, is the most troublesome of the four.

Life Cycle

Female moths lay their egg masses on tree trunks or tiny twigs throughout the late spring to early summer period (Fig. 1). The females of all Texas species, with the exception of the Sonoran tent caterpillar, utilize spumaline, a sticky, foamy substance, to “glue” the eggs to the bark or twigs of trees and shrubs. The spumaline also functions as a protective shell surrounding the egg mass, providing a firm, durable surface. During the majority of the summer, fall, and winter, egg masses linger on the branches of the trees.

  • Eastern and western tent caterpillars begin feeding on these fresh leaves within a few days of their appearance.
  • In most cases, the web is situated in the crotch of tiny limbs (Fig.
  • Because the larvae wander away from their tents to feed on leaves, harm can occur even if the web is located a long distance away from the tents.
  • These enormous, noticeable webs are created by the eastern and western tent caterpillars.
  • The larvae molt, or lose their skin, multiple times throughout their development.
  • The color pattern can also alter from instar to instar depending on the species.
  • 3).
  • Between feedings, dozens of caterpillars may assemble on these mats to wait for their next meal.
  • Protected areas like as the web, under the bark, among dead plant material on the ground, within a curled leaf, or under the eaves of homes are all common locations for spiders to hide.
  • Generally speaking, cocoons are loosely made of silk with a white or yellowish crystalline component dispersed throughout the whole thing.
  • Tent caterpillars in their adult form are brown and yellowish moths with two diagonal patterns on the front wings of their bodies (Fig.

4). Their wingspans are around 1 inch in length. They are drawn to lights, like do other moths. A single generation of tent caterpillars occurs once a year in all species. Adults only survive for a few days, during which time they mate, lay eggs, and do not consume any food.


Tent caterpillars in its infancy are brightly colored and grow to be approximately 134 inches long when fully grown. The only lengthy hairs on their body are found around the sides and on the back. Individual species may be distinguished by the colors and patterns on their larvae. If you come across tents with larvae that do not fit the descriptions in Table 1, it is most likely that they are autumn webworm tents. Fall webworms may construct tents throughout the late summer and fall and can have numerous generations per year, depending on the species.


The degree of defoliation, unattractive webs, and nuisance caused by the caterpillars should be taken into consideration when developing a management strategy. It is possible that you may need to utilize a combination of cultural and chemical procedures to achieve the optimum results. Control over one’s culture. During winter pruning, look for egg masses, which show as swellings on tiny, naked branches and are a sign of infestation. When trees are pruned, the tent caterpillar eggs are frequently removed before they develop.

When you discover spider webs on twigs in the spring, prune them as soon as you notice them.

It is not suggested to burn the web or caterpillars since it is quite dangerous.

Remove the dead caterpillars from the ground and dispose of them.

Beneficial insects can help to lower the number of tent caterpillars.

Trichogramma species prey on the eggs of tent caterpillars.

Control through chemical means.

The use of insecticide is pointless if the tent caterpillars have been allowed to feed and develop to completion.

Tents are weather-resistant and will remain in the tree for an extended period of time until they are removed.

Early morning or late evening applications are recommended in order to concentrate the spray on the tents when the caterpillars cluster.

The species that may be sprayed with these oils will be listed on the label of the product.

Some organically generated goods contain active substances such as Bacillus thuringiensis (Bt)varietykurstaki, spinosad, or insecticidal soap, which are all derived from bacteria.

In order for the Bt kurstaki and spinosad to be taken up and consumed by the caterpillars, spray the plant well before applying the substance to the leaves.

Contact-kill insecticides such as insecticidal soap must be applied directly to the caterpillars in order for them to be killed.

Some of these formulations operate when they come into direct contact with the pest, while others may have an oil-based component that is comparable to horticultural (petroleum-based) oils in their composition.

There are several long-lasting, synthetic pesticide solutions available that give quicker and longer-lasting control than most plant-derived insecticides while also working on all phases of the caterpillar’s life cycle.

Bifenthrin, cyfluthrin, esfenvalerate, fluvalinate, permethrin, lambda-cyhalothrin, indoxacarb, acephate, and carbaryl are all active chemicals to search for in a pesticide formulation.

Pesticide users are accountable for the impact pesticides have on their own plants or home goods, as well as any difficulties that may arise as a result of pesticide drift from their own properties to the properties or plants of their neighbors.

Also prone to change are the regulations governing the use of insecticides and pesticides. Always read and carefully follow the instructions on the product label for the most dependable instructions.


The author would like to express his gratitude to Bart Drees, Glen Moore, and Kim Schofield for their contributions to the review of this article. Bart Drees provided all of the photographs. Download a printer-friendly version of this publication by clicking on the following link: Caterpillars of the Tent »See more details about Gardening and Landscaping» Do you have a question – or do you require the assistance of an expert? Make contact with the appropriate county office.

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