Where Are Eastern Tent Caterpillars Found

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 change from year to year, with epidemics happening every few years or even more often. 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 dots 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 rear. In order to consume the leaves, the larvae enlarge the web, which eventually grows to be a foot or more in length. They are fully developed 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 construct a cocoon on their own. Approximately 1 inch long and formed of tightly woven white or yellowish silk, the cocoon is linked to other items by a few coarser strands 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.

  • A typical eating pattern for the larvae is to focus their feeding on a single branch at a time.
  • In comparison to the eastern tent caterpillar, this caterpillar is differentiated by the keyhole-shaped markings that run along its back.
  • Larvae are about the size of a pea.
  • 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.
  • 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. The pesticide should be administered in the evening or early morning when the insects are in the nest.
  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 copyrighted photos.
  9. Any commercial or other usage of the photographs requires explicit permission of the SFIWC and the individual photographer or organization.
See also:  Tent Where Food Is Prepared In Military Encampment

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 often placed such that the broadest wall faces southeast, allowing it to benefit from the early sunlight. It is customary for the caterpillars to attach silk to the surface of the building at the beginning of each of their daily activity periods. After a period of time, the silk is placed down with a tiny amount of strain, which finally causes the newly spun layer of silk to split from the next one.

  • They will be able to enter and depart the tent through the apertures.
  • Light has a significant impact on the caterpillars’ ability to spin silk, and they spend the bulk of their time spinning silk on the face of the tent that is the most lighted.
  • Caterpillars continue to grow and enlarge their tent until they reach the end of their larval stage of development.
  • The tents may be used for a variety of purposes.
  • The increased humidity within the tent may aid in the process of molting.
  • Because the weather in the early spring is frequently chilly, 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.
  • 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 little greenhouses, capturing and retaining the warmth of the morning light, helping 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.

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.

After three weeks, Malacosoma americanummoths are able to break away from their cocoons. They lack the vibrant colors of many other moths and look nearly dull in comparison. When examined closely, two parallel lines of cream may be seen across the wings, which are tan or reddish brown in color.


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.
  • 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.

The eastern tent caterpillar may be found across the eastern United States, as far west as the Rocky Mountains, and as far south as southern Canada. 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

Get Rid of Eastern Tent Caterpillar Moths: Life Cycle, etc.

The color of adult moths ranges from brown to tan. They have two white or yellowish lines on the inside of their front wings that go from one side of the wing to the other side. The adult’s wing span ranges from around 1-1/4 to almost two inches in width. The female moth lays eggs in straight rows approximately the diameter of a pencil on twigs. The eggs that have accumulated around the twig are frequently encircled. Upon fertilization, the female excretes a frothy material that, once dried, gives the impression of being glossy and black on top of the egg mass.

While forest tent caterpillar webs are occasionally confused with eastern tent caterpillar webs, there are several significant distinctions between the two types of caterpillars that should be noted.

Eastern tent caterpillar webs are constructed in the crotch and forks of the host plant’s branches by the caterpillars themselves.


Malacosoma americanum overwinters as an egg mass, then it emerges as a larvae in the spring. After hatching and developing into larvae, they begin to construct their web tent and eat for around six to eight weeks until pupating. Once the larvae have reached full maturity, they go to safe havens where they weave their unique cocoons for protection. As a result of this, larvae do not eat within their webs; instead, they travel out from the web and feed elsewhere on the host before returning to the web for safety.

Larvae, in their penultimate stage as caterpillars and shortly before becoming pupae (cocoons), alter their eating habits such that they only feed at night during this time.

In addition, the larvae of the eastern tent caterpillar infest ornamental shrubs and trees on a regular basis.


In most cases, mating and egg laying take place on the same day that moths emerge from their cocoons. In each egg mass deposited by a female moth, there are around 150-400 eggs.

Signs of Infestation

The presence of eastern tent caterpillars is indicated by their web-like “tents” erected in the forks and crotches of tree trunks.


Eastern tent caterpillars may be found across the eastern United States, as far west as the Rocky Mountains and as far north as southern Canada. They are also found in parts of Canada. In fact, these insects are indigenous to the United States and do not constitute an invading 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.

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

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: Insect & Disease Fact Sheets: Forest Health & Monitoring: Maine Forest Service: Maine DACF

The Eastern Tent Caterpillar in PDF format Photo courtesy of the Maine Forest Service’s Forest Health Monitoring Photographic Archive.

Eastern Tent Caterpillar,Malacosoma americanum(F.)

During the month of May, the eastern tent caterpillar may be found in the crotches of wild cherry and apple trees along roadsides, hedgerows, and the borders of fields, where it will spin webbings or tents. In early May, when the baby caterpillars hatch and the buds begin to open, these tents become visible for the first time. As the larvae develop, these tents become larger, and the backs of the caterpillars are coated with light brown hairs, with a row of oval, pale blue dots on either side of the caterpillar’s body.

The eggs will stay in this stage until the next spring.

Larger webbing on the extremities of hardwood tree branches in July and August is created by distinct caterpillars known as the autumn webworm, which feeds inside a tent on the ends of the branches of the trees.

Forest Tent Caterpillar, Malacosoma disstria(Hubner)

Caterpillars of the Forest Tent Photo courtesy of the Maine Forest Service’s Forest Health Monitoring Photographic Archive. The forest tent caterpillar has a life cycle that is similar to that of the eastern variety, but it does not build a tent. It is often found in wooded areas on oak, poplar, maple, or birch trees, where it may be a significant problem. Mature larvae are distinguished by a row of white keyhole marks on their backs, but otherwise resemble the eastern tent caterpillar in appearance and behavior.

Control *

The tents of the eastern tent caterpillars can be removed and destroyed by hand in small trees where they are found. Forked sticks or sticks with nails in them can be used to enter into bigger webs and twist them off of the branch by twisting the stick in two directions. It is better to complete this task early in the season before the tents become very enormous. Controlling eastern tent caterpillars on apple trees can be accomplished with the use of a fruit tree spray. The application of Bacillus thuringiensis (Bt), a microbial product, or carbaryl at the appropriate period can effectively control both the eastern and forest tent caterpillars.

  • Sevin should not be used in places where honey bees are kept as a pest control measure.
  • If you want the greatest results in central Maine, you should apply controls about May 20.
  • Before using any pesticide, make sure you read the label.
  • Use extreme caution while applying pesticides, both for your personal safety and the preservation of the environment.

Maine’s Department of Agriculture, Conservation, and Forestry (MAINE DEPARTMENT OF AGRICULTURE, CONSERVATION, AND FORESTRY) april 2000 – Maine Forest Service – Forest Health and Monitoring Division More information may be found at: PestAlertBugWood: Eastern Tent Caterpillar (USFS PestAlertBugWood) BugWood: Caterpillar of the Forest Tent

Tent Caterpillars

Caterpillars on the stump of a forest tent James SolomonUSDA Forest Service,Eastern tent caterpillars on a “tent” by James Solomon Forest tent caterpillars (Malacosoma disstria) and eastern tent caterpillars (Malacosoma americanum) are native to the state of New York, as is the forest tent caterpillar (FTC). A variation in population numbers has occurred over time, ranging from very few and hardly perceptible to many and very visible defoliation of trees. In spite of the fact that it favours fruit trees such as ornamental crabapples and pears, the ETC is not a significant forest danger; rather, it is a nuisance in urban and suburban regions as well as orchards.

How Caterpillars Damage Trees

In the spring, tent caterpillars and gypsy moths feed on the leaves. In most cases, deciduous trees (trees that lose their leaves each fall) can sprout a new set of leaves by July, and they can generally resist defoliation (the loss of leaves) for up to 2-3 consecutive years without succumbing to death. Defoliation, on the other hand, has the effect of reducing the vitality and resilience of the tree, making it more susceptible to pests and diseases. It is possible for trees to die if they are subjected to other pressures in the same year, such as disease or other insect outbreaks.

As opposed to deciduous trees, evergreens can not recover their leaves as readily and might die as a result of full defoliation.

Healthy deciduous trees may withstand defoliation for up to three years in a row without succumbing.

Insect Identification and Look-Alikes

Forest tent caterpillars, eastern tent caterpillars, and orgypsy moths are all possible causes of black hairy caterpillars devouring the leaves on your trees. Please refer to theComparison Chartfor information on the unique traits and images of these three species. The markings on the backs of these caterpillars are the most distinguishing feature between them. The gypsy moth caterpillar has five pairs of blue dots on its back, followed by six pairs of red spots on the rear of its wings. The eastern tent caterpillar is distinguished by a white line running down its back and light blue and black markings on either side of the caterpillar.

The fall webworm is another caterpillar that is frequently mistaken with the eastern tent caterpillar because it, like the eastern tent caterpillar, builds tents in trees and consumes leaves.

  • It is usually the case that a fall webworm tent will begin at the tips of branches and will progressively expand down each branch toward the trunk. Fall webworms feed on the leaves within the tent throughout the cooler months. Eastern tent caterpillars construct their tents in the forks of branches and feed on the leaves that grow outside the tent. In the fall, the webworm is hairy, pale green or yellow in color, with black or reddish markings down its back
  • There is frequently more than one generation each year of this species. Fall webworms construct their tents during the months of July and August, whereas eastern tent caterpillars construct their tents throughout the spring.

Fall webworms are generally not thought to be hazardous to trees, with the exception of the aesthetic aspect of the tents they create.

During the spring and summer, fall webworms may be a nuisance because they feed on the regeneration of trees that have been defoliated earlier in the season by other caterpillars.

Harmless to Humans

With a few exceptions, coming into contact with these insects is not dangerous in most cases. People who come into touch with gypsy moth hairs, especially those on the exterior of egg masses, may have skin rashes or irritations as a result of the encounter. Researchers have discovered that pregnant horses who consume eastern tent caterpillars are more likely to miscarry than non-pregnant horses (mare reproductive loss syndrome). Humans or other animals have not been shown to be harmed by the consumption of eastern tent caterpillars, according to available research.

Control Options

The first option to consider for homeowners is to do absolutely nothing. Deciduous trees in good health will generally recover from defoliation and will produce a second set of leaves in July. Natural management of these species occurs on a continuous basis and includes birds, rodents, parasites, and illnesses, among other things. Extremes in temperature can also have a negative impact on population growth. When controlling individual trees, manual control may include hand removal of egg masses, occupied tents, and pupae, as well as the application of adhesive tree wraps on trunks to trap caterpillars as they migrate up and down the tree.

It is not recommended to attempt to burn tents while they are still attached to trees.

Insecticide Treatment Options

Tent caterpillars are a native and natural element of our environment, and gypsy moths have become established in our forest ecosystems as a result of “naturalization.” These caterpillars will always be there, albeit in small and inconspicuous numbers at times. Spraying may be necessary if high concentrations of tent or gypsy moth caterpillars are causing a loss in the health of the trees or endangering an economically valuable resource such as a sugar cane crop. A gypsy moth is seen dining on a branch.

  1. Generally speaking, insecticides may be split into two categories: microbial/biological and chemical.
  2. They are especially effective on caterpillars that are tiny and young.
  3. Bacillus thuringiensis is the most often encountered microbial and biological pesticide (Bt).
  4. It is completely innocuous to humans, animals, and plants, however it does have an adverse effect on early moth and butterfly larvae.
  5. Chemical pesticides are toxins that come into contact with the skin.
  6. Licensed pesticide applicators may be discovered in the yellow pages under Tree Service, where they can be found.
  7. For a list of certified pesticide applicators in New York State, visit the link below.
  8. Maple syrup producers may be interested in aerial spraying as severe defoliations can affect maple syrup yield.
  9. Nesting birds, beneficial insects, and other creatures might be threatened by usage of chemical pesticides.

There is presently no State program in New York to spray for tent caterpillars of gypsy moths on State or private land. There are no State funds available to property owners for managing tent caterpillars or gypsy moths.

Woodlot Recommendations

After an epidemic, we propose postponing wood harvesting in defoliated regions for two or three years in order to reduce the amount of additional stress placed on trees. Time will also allow you to determine which trees are still in good health and make adjustments to your harvesting plans if needed. (See the link to the New York State Department of Environmental Conservation’s Forest Tent Caterpillar Defoliator Report 2005.)

Predicting Future Defoliations

Caterpillars from the forest tent defoliate a tree. James Solomon, the USDA Forest Service, the Federal Trade Commission, and the Environmental Technology Center are all natural components of our native forest ecosystem and will be there for a long time. In general, their populations vary; after a few years of high numbers, their populations begin to decline. Tent caterpillar populations that are very big and persistent often develop once every 10 years and endure for two to three years. Sample procedure is supplied if you are interested in sampling your woodlot or forest to evaluate the possibility of defoliation by FTC during the following growing season (see important links).

The following addresses are for sending or emailing sampling data:NYSDECDivision of Lands and Forests, Bureau of Invasive Species and Ecosystem Health625 BroadwayAlbany, NY 12233-4253Telephone: 518-402-9425, Fax: 518-402-9425NYSDECDivision of Lands and Forests, Bureau of Invasive Species and Ecosystem Health Send a message to the Forest Health team through email.

More about Tent Caterpillars:

  • Comparing the properties of Forest tent caterpillars, Eastern tent caterpillars, and Gypsy moths is depicted in the Caterpillar Comparison Chart

Eastern Tent Caterpillar, Malacosoma americanum

In the early spring, the tents of the eastern tent caterpillar are a striking sight to see. A common sight in early spring in Wisconsin is the eastern tent caterpillar (Malacosoma americanum), also known as the tent caterpillar. A colony of caterpillars builds the white mounds in the forks of tree branches that you see in the photo. They are protected by the tent from predators such as birds as well as from excessive temperatures. They emerge out of their silken webs to eat in the early morning, late afternoon, or early evening when the temperature is not too low.

As the caterpillars increase in size, the nest grows in size as well.

This species is more common later in the season; it feeds on almost all shade and fruit trees with the exception of conifers; its nests are located at the ends of branches rather than in branch crotches; and its loosely woven webs enclose foliage in contrast to the eastern tent caterpillar’s tight-woven tents.

  1. Shiny egg masses are wrapped around twigs to create a beautiful display (top).
  2. The eastern tent caterpillar overwinters as an egg.
  3. It is around the time of bud break that the larvae — caterpillars – hatch.
  4. In a colony, caterpillars from the same egg mass will stay together; in a big colony, caterpillars from two or more egg masses will join together to form a single enormous colony.
  5. As soon as they have finished eating, they leave the nest and weave a white or yellowish silk cocoon in a safe location like as tree trunks, fences, or buildings.
  6. When the ladies have finished mating, they lay their eggs on little branches that survive until the next spring.
  7. It is estimated that the population of this native North American pest fluctuates from year to year, with epidemics happening every few years.

Fruit trees, such as apple, cherry, blooming crabapple, plum, and chokecherry, are the most typically afflicted, with apple, cherry, and flowering crabapple being the most prevalent.

However, while severe infestations can result in significant defoliation, eastern tent caterpillars are seldom known to kill trees, with the exception of those that have already been compromised by disease, climate change, or other environmental pressures.

When it comes to tree health, the eastern tent caterpillar is more of an inconvenience than a danger.

Most trees will leaf out again within two or three weeks even if they have been entirely defoliated, because caterpillar feeding normally ceases during periods of high leafing activity.

It is also possible that the nests will become a nuisance in the landscape, particularly if they are exposed as a result of extensive defoliation.

When fully developed, the hairy caterpillars measure around 2 inches in length and have a prominent white line running down the back of their bodies.

When they are mistakenly squished on roads, driveways, sidewalks, and patios, they cause quite a commotion. It is easy to eliminate this insect issue when it is discovered early in the season.

  • During the winter, egg masses should be removed and destroyed. They may be removed from a branch by pruning or crushing it. Dormant oil sprays, when applied to huge trees with numerous egg masses, are extremely effective at suffocating the eggs and preventing them from hatching. Small tents should be removed by hand (while wearing gloves) in the early spring. Larger webs should be removed with a broom or a stick, and the webs should be disposed of with the caterpillars (crush, burn or bury them). To avoid re-establishing their colony, wait until the caterpillars have entered the nest before doing this. It is not recommended to attempt to burn tents on plants since this might cause more damage to the tree than the caterpillars themselves. Unless the caterpillars are more than one inch in length, you should only use a certified pesticide. Caterpillars beyond a certain size are less susceptible to insecticides since they have already completed the majority of their eating. Avoid using any treatments that might harm pollinating bees while the tree is in bloom – instead, use Bacillus thuringiensis (BT), which only affects caterpillars.

– Susan Mahr, University of Wisconsin – Madison– Phil Pellitteri, Department of Entomology, University of Wisconsin – Madison, took all of the photographs.

Leave a Comment

Your email address will not be published. Required fields are marked *