What Do Eastern Tent Moths Eat

Eastern Tent Caterpillar Moth

Two light-colored stripes 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.

They live in groups in “tents” formed of numerous silken threads in the crotches of host trees, which they construct from the strands.

The inside of the head is dark.

disstria) has black (rather than pale) lines on the forewings, but the forest tent caterpillar (M.

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.

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.

  • The feeding activity causes dead leaves and fruit to become trapped inside the branch, resulting in unattractive branches.
  • Two thin, but clearly visible white lines cross their forewings in the middle and bottom part, respectively.
  • The thorax is coated with a thick layer of brown hair.
  • 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.
  • Because the caterpillars feed on the leaves of trees that produce fruit that humans consume, they are sometimes referred to as pests.
  • Malacosoma americanum is the scientific name for this plant.
  • 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).

  1. 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.
  2. 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

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.

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.

  • They are distinguished by a solid white line running down the middle of their backs.
  • 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.
  • Forest tent caterpillar,M.
  • 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.
  • 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.
  • The Sonoran tent caterpillar, M.
  • 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.

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.

  • Thousands of tiny caterpillars were produced from egg masses that looked like Styrofoam and contained as many as 300 eggs apiece.
  • Larvae construct little silken tents over the egg mass and the surrounding branch to protect themselves from predators.
  • Pheromones, which are chemical trail markers, are deposited by the caterpillars when they return to their tent after eating.
  • During the month of April, the larvae’s tents develop in size.
  • Caterpillars returning to the tent from a meal pass hungry caterpillars on their way to eat fragile leaves along the silk route.
  • 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.
  • Besides providing shelter against predatory or parasitic insects, their silken dwellings may also give some protection from the elements.
See also:  What To Take When Camping In A Tent

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 if eastern tent caterpillars are a threat 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.


Throughout this episode, references were drawn from the excellent book “The Tent Caterpillars” by Terrence Fitzgerald and the excellent book “Managing Insects and Mites on Woody Landscape Plants” by John A. Davidson and Michael J. Raupp.For more information on eastern tent caterpillars, visit the following web sites:

Eastern tent caterpillars

  • In the months of May and June, eastern tent caterpillars can be seen on fruit trees such as apple, chokecherry, crabapple, plum, and cherry. The larvae eat on leaves, which can cause trees to become defoliated. The larvae create a visible web or ‘tent’ at the fork of the branches, which is visible to the naked eye. When the caterpillar population is great, the tree is covered with webbing and defoliated
  • Otherwise, the tree remains healthy. The health of the tree is often not harmed by these caterpillars.

How to identify eastern tent caterpillars

  • The larvae are hairy and have blue, black, and orange patterns on their bodies, as well as a white stripe along the back. Most of their bodies are smooth, but they have a sequence of hairs that protrude from the sides of their bodies. When completely developed, they measure two inches in length.

Damage caused by eastern tent caterpillars

Caterpillar tents on a tree that has been defoliated In the day, eastern tent caterpillars graze on tree leaves, but at night and during wet weather, they will stay in their tents to protect themselves. Caterpillars and tent caterpillars of the eastern hemisphere

  • The tents are modest at start, but they will grow in size and become rather conspicuous as time goes on. Healthy, well-established trees can withstand the feeding of the eastern tent caterpillar. Their feeding habits and webs are purely aesthetic problems that have no impact on the trees’ overall look. Young trees, as well as diseased and stressed trees, are more susceptible to injury. are more vulnerable to feeding harm and may require additional safeguards
  • And

How to protect your trees from eastern tent caterpillars

Keep an eye out for the caterpillars returning to their tents at the end of the day or when it starts to rain.

  • Pull off the webbing and the caterpillars at the same time. In order to properly dispose of them, bury or bag them. If it is legal where you reside, you might dispose of them in a fire.

Using pesticides

If you intend to apply insecticides, wait until the caterpillars are less than one inch in length or less. When they reach their full developed size (two inches), it is possible that the pesticides will no longer have any impact. Consider utilizing a pesticide that has a low impact on the environment when making your pesticide selection. The following are examples of items that may be used to manage caterpillars:

  • It is necessary to physically touch the insects when using residual insecticides (Spinosad) or insecticidal soap (insecticidal soap), and it may be necessary to repeat the treatment if there is no residual action. If the tree is in bloom, Bacillus thuringiensisis a suitable choice because it will not hurt visiting honey bees and other pollinators.

DISCLAIMER: The mention of a pesticide or the application of a pesticide label is solely for educational reasons. Always read and follow the pesticide label recommendations that are connected to the pesticide container that you are currently working with. Keep in mind that the label is the law. In 2018, a review was conducted.

Eastern Tent Caterpillar

PDF document that can be printed To see a bigger version of the photographs, click on them. Photograph by Jack Loughrey The eastern tent caterpillar, Malacosoma americanum, is a pest that is endemic to North America and may cause major defoliation to deciduous trees in the Rosaceae family, particularly Cherry (Prunus) and Apple (Malus), among other things (Malus). Because they emerge at comparable dates in the spring, it is sometimes confused with the Gypsy moth caterpillar, as well as the fall webworm (which appears in late summer and fall).

  1. Repeated years of high populations can lead host plants to develop more slowly than they should and may make them more prone to disease.
  2. As opposed to fall webworm egg masses, eastern tent caterpillar egg masses do not encircle foliage as they do in the fall.
  3. Bugwood.org is run by Whitney Cranshaw of Colorado State University.
  4. When the young hatch, they spin a silky tent in the crotch of a limb to protect themselves.
  5. The caterpillars will emerge from their protective tent in the early morning, late afternoon, or even at night to feast on nectar and other nutrients.
  6. Within 4-6 weeks, they will feed on neighboring vegetation, causing the tent to grow in size as a result of their growing numbers.
  7. During the day, the larvae may often be observed traveling around pathways, highways, buildings, and other plants in search of safe areas to spin a 1″ long whitish cocoon and pupate.

There is only one generation every year, and the population will fluctuate from year to year as a result of natural selection.

It forages for food among the leaves of deciduous shade trees such as aspen, birch, elm, oak, and sugar maple, and in the blossoms of blossoming fruit trees such as cherry and plum.

This moth will pupate in a white cocoon that it will construct in the folds of leaves or similar protective spot, emerging three weeks later as an adult moth.

These preventative strategies are comparable to those listed below.

The Eastern tent caterpillar prefers to feed on plants that are members of the Rosaceae family as its host plants.

Measures of Containment

  • During the fall and winter, remove and destroy the glossy egg masses that have formed
  • Tents that have just been created in the spring can be removed by hand and burned. Prior to destroying larger tents, it may be necessary to prune them out or remove them with a long stick. Tents should not be removed with an open flame or a torch. When sprayed to the leaves and consumed, the pesticide Bacillus thuringiensis var. Kurstaki is effective against young larvae
  • However, it is ineffective against adults. On a hot, sunny day, insecticidal soap or Neem oil may also be sprayed, however these may cause foliar damage if applied too frequently. It is also possible to employ contact pesticides, although they are ineffective while the larvae remain within the protective confines of the tent. Caterpillars are susceptible to parasitization by a variety of braconid, ichneumonid, and chalcid wasps, among others. They are also a food source for a variety of animals, including birds, toads, snakes, raccoons, and a variety of insects. Disease has the ability to regulate their population as well.

Pests and illnesses may arise despite the use of excellent cultural practices from time to time. It is only after all other approaches have failed that chemical control should be applied. BEFORE USING ANY PESTICIDES, CHECK THE LABEL ON THE CONTAINER FIRST. Follow the instructions on the label. Pay attention to all warnings and precautions. Children, reckless individuals, and pets should not be allowed to play with pesticides; they should be kept out of reach in their original labeled containers, preferably behind locked doors.

  • Call toll free: 877-486-6271 for pesticide information or for any other inquiries you may have.
  • It was decided to issue the Acts of May 8 and June 30, 1914, in coordination with the U.S.
  • The Connecticut Cooperative Extension System is an equal opportunity employer and supplier of educational programs in the state of Connecticut.
  • The USDA is located at 1400 Independence Avenue, SW in Washington, DC.

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 Caterpillars and Forest Tent Caterpillars on Trees

Crabapple is host to eastern tent caterpillars. Photograph courtesy of David L. Clement of the University of Maryland and Bugwood.org

Key points

  • The eastern tent caterpillar’s webs are a frequent sight in the springtime anywhere wild cherry trees may be found in abundance. The presence of this insect is first detected by the appearance of unattractive webs in the forks of trees. The caterpillars spend the night hiding in the webs and feeding among the leaves during the day. Cherry trees are their preferred host plant, and they are often the beginning point for outbreaks of eastern tent caterpillars in the United States. After the caterpillars have devoured all of the cherry leaves, they will frequently move to other neighboring trees and munch on their leaves as well. Crabapples and hawthorns in bloom are routinely targeted for destruction. In some locations, large outbreaks of peach, plum, witch hazel, rose, beech, birch, willow, and poplar trees may occur every ten years on trees such as peach, plum, witch hazel, rose, beech, birch, willow, and poplar

Egg mass of the eastern tent caterpillar. Photo courtesy of Brian Kunkel of the University of Delaware and Bugwood.org

Life cycle

  • In one inch long, black, gall-like lumps on slender twigs, the overwintering eggs are protected from the elements (see photo above). They are covered with a protective layer that feels similar to styrofoam. In central Maryland, the eggs hatch around the first week of April, depending on the meteorological conditions at the time. Occasionally, this will occur even before the wild cherry buds have opened. Young caterpillars are totally black
  • Older caterpillars are brown. After a few days, they begin to spin the silk tents, which they continue to develop in size. During their development, Eastern tent caterpillars grow an unique white stripe running down the rear of their bodies (see photo below). When forest tent caterpillars reach adulthood, they develop spots on their backs. During the month of May, the huge caterpillars that develop by the end of May do the greatest amount of feeding damage. As soon as they have finished eating, they depart the trees in search of safe havens where they may build protective cocoons. When the little brown moths emerge from their cocoons in the early summer, they mate in order to lay the overwintering eggs. A single generation happens in Maryland each year
  • There are no more.

Eastern tent caterpillar (right) has a white stripe, but forest tent caterpillar (left) has keyhole-shaped white dots on its wings. Photo courtesy of Ronald S. Kelley of the Vermont Department of Forests, Parks, and Recreation and Bugwood.org

Forest tent caterpillar

The forest tent caterpillar differs from the eastern tent caterpillar in that it has a sequence of white dots along the back (as shown in the photo above), rather than a complete white stripe. Unlike wild cherry, it does not build a tent, and favours oak and other shade trees above other types of trees. The life cycle of the western tent caterpillar is quite similar to that of the eastern tent caterpillar.


Instead of the solid white stripe found on the eastern tent caterpillar, the forest tent caterpillar has a succession of white dots along the back (see photo above). It does not form a tent and favors oak and other shade trees over wild cherry trees as a home environment. Similar to the eastern tent caterpillar’s life cycle, the western tent caterpillar has a similar life cycle.

Cultural control

  • As far as is practicable, wild cherry trees should be removed from hedgerows and fields next to properties that contain valuable ornamentals that are vulnerable to tent caterpillar infestation (such as blooming crabapple and cherry trees). The dormant season is the best time to cut away and kill twigs that have egg masses on them. To remove the expanding tents with their caterpillars, strong gloves might be worn by individuals who are not frightened by the prospect of ripping them out.

Biological control

As soon as the silk tents are visible in the early spring, apply Bt (Bacillus thuringiensis) to the crop if spraying is necessary. It is a naturally occurring pesticide that is solely effective against caterpillars. Bt is completely non-toxic to people and animals. It has to be sprayed on the leaves that the caterpillars will be feeding on. Bt must be used in April since only juvenile caterpillars are extremely vulnerable to this pesticide at this time of year. Thuricide is marketed under a variety of brand names, including Dipel, Caterpillar Attack, Biotrol, and others, and is available in several forms.


The use of trade names does not imply sponsorship on the part of the University of Maryland Extension staff.

Forest Tent Caterpillars Resource Page

While searching for food, the forest tent caterpillar (Malacosoma disstriaHübner), sometimes referred to incorrectly as armyworms because of the caterpillar’s habit of crawling in groups across the ground while searching for food, is a significant defoliator of deciduous hardwood trees in the United States. Along with devouring the leaves of desired trees, these insects leave an unpleasant mass of fecal maters behind, which might render one’s backyard unfit for human usage.


  • One of the distinguishing characteristics of forest tent caterpillars is the harm and symptoms they cause: the crowns of strongly infected trees may seem thinner and stripped of their leaves
  • The foliage of heavily infested trees may appear yellow and withered
  • Despite the fact that their name implies otherwise, woodland tent caterpillars do not construct tents. The most common practice is for them to lay silken mats on tree trunks or branches where they travel or rest. Food being limited causes caterpillars to gather on side branches, travel toward the main stem, and then descend downhill and scatter throughout yards, on buildings, and on sidewalks in search of additional food. Forest tent caterpillars will construct cocoons on constructions such as homes, lawn furniture, and other such items. The adult stage of the forest tent caterpillar is a moth, which is drawn to light in order to survive. During the night, moths may become a nuisance, especially if they are located indoors buzzing near light sources.


  • Forest tent caterpillars feature faint bluish stripes down the edges of their brownish bodies when they are mature, and they grow to be around 2 inches in length. Forest tent caterpillars have a row of 10-12 white footprint-shaped marks along the middle of their backs that distinguish them from other caterpillars. The larvae have a faint covering of white hairs on their bodies. A buff-brown moth with darker oblique lines on its wings, the adult moth is a beautiful sight. A thick layer of frothy, dark brown cement covers the egg masses, which range in size from 100 to 350 eggs (USDA Forest Service 1996).

There are a variety of caterpillars that can be confused for forest tent caterpillars, including the following: Caterpillar of the Eastern Tent (Malacosoma americanum)

  • The head is black with a central yellow stripe and little blue patches on the sides.

Gypsy Moth Caterpillar (Lymantria dispar) (Lymantria dispar)

  • Red or blue dots that stand out
  • Head is beige with black markings on it.


Tent caterpillars do not bite or sting, yet some individuals may experience an allergic reaction if they come into contact with them.


  • There is no danger of tent caterpillars biting or stinging, however some individuals may experience an allergic reaction if they come into contact with them.


  • In Minnesota, forest tent caterpillar outbreaks normally occur every 6-16 years, according to the Minnesota Department of Natural Resources. On average, forest tent caterpillar outbreaks persist anywhere from three to seven years. During the height of an epidemic, caterpillars can be found in concentrations ranging from 1 to 4 million per acre. (Minnesota Department of Natural Resources)
  • The last time forest tent caterpillars were seen in the wild was in 2001. (Minnesota Department of Natural Resources)
  • Extreme climatic conditions, such as hard freezes in the middle of winter, freezing temperatures in the early spring, as well as scorching temperatures later in the spring, can cause a large number of forest tent caterpillars to die, decreasing the severity of an epidemic.


  • It is preferred by forest tent caterpillars to feed on the leaves of hardwood trees like the aspen, birch and basswood, as well as the ash and oak trees. Balsam fir, spruce, pine, and red maple are among the trees on which forest tent caterpillars have been seen to feed. Adults do not eat because their mouthparts are siphoning.


  • Every year, a new generation of forest tent caterpillars is produced. When adequate leaves of the host tree is available for the first larval instar feeding activity and the temperature is 50°F or above in the spring, eggs are most likely to hatch
  • However, this is not always the case. According to the weather and location, the time changes. During the following five to six weeks, caterpillars will go through four molts. Towards the end of June, fully-grown tent caterpillars seek for safe havens in the vicinity of buildings, shrubs, and lawns in which to spin their yellowish cocoons and pupate
  • Homeowners may be frustrated by the presence of these difficult-to-remove cocoons. Adult moths emerge around 10 to 45 days later (often by the middle of July). Females will emit a sex pheromone to lure males for mating when they initially emerge from their cocoons. Females who have mated typically lay their eggs in large clusters around little twigs (the eggs have the appearance of a wide gray ring)
  • Each female may lay an average of 150 eggs per egg mass, with each egg mass containing an average of 150 eggs. It is not possible for adult moths to survive for more than two weeks. Forest tent caterpillars hibernate at the egg stage throughout the winter.


  1. Forest tent caterpillars defoliated more than 7.5 million acres of hardwoods in Minnesota in 2001, the highest amount of defoliation ever documented in the state. Only the caterpillar stage has mouthparts that are capable of biting and chewing leaves, and it is this stage that is responsible for the most of the devastation.
See also:  What Do Tent Worms Eat

What Eats Tent Caterpillars?

A gigantic silk nest is constructed among the branches of trees by tent caterpillars. During the day, they leave the nest to eat on leaves, and they return to it at night to rest. They are protected from predators while in the nest, but after they leave the nest, they are preyed upon by a broad range of other creatures, including humans.

Bird Predators

Predators such as birds eat tent caterpillars as they are hatching from their eggs or when they are in the form of moths. Caterpillars are picked off the branches and leaves by songbirds. Tent caterpillars are eaten by a variety of birds, including robins, blue jays, red-winged blackbirds, and cardinals. In addition to ground dwelling birds such as wild turkeys picking off caterpillars when they crawl to the ground to pupate, the caterpillars themselves are preyed upon by a variety of predators.

Most of the time, birds devour them whole.

Insect Predators

Parasitic wasps attack both the egg and larval stages of the eastern and western tent caterpillars, causing them to die. Flesh flies prey on forest tent caterpillars, causing them to die. Depending on where the caterpillar eggs are laid, these parasites may lay eggs on the caterpillars themselves. As soon as the larvae hatch, they begin to devour the eggs or caterpillars from the inside out, as described above. Stink bugs, hornets, and yellow jackets are pests that attack many kinds of animals.

In addition to eating caterpillars directly by grasping them in their teeth, they also sting them and transport them back to their nests where they are devoured by the adults.

Mammal Predators

Caterpillars from tents are eaten by a few species of animals, including humans. While squirrels consume caterpillars that fall from tree branches, foxes and other large mammals (including white-footed mice and chipmunks) devour them as soon as they strike the ground, according to the National Wildlife Federation. The caterpillars and the moths will both be eaten by bats. Some species consume both the caterpillar and the moth in their whole, while others just consume the caterpillar and leave the moth wings behind.

Reptile and Amphibian Predators

Tent caterpillars are preyed upon by a variety of reptiles, including Eastern box turtles, garter snakes, copperheads, and skinks. Snakes and lizards are capable of climbing into trees in order to hunt for tent caterpillars, and they have even been seen to inside tents. It is possible that they will be eaten by water turtles if they fall into water. The tent caterpillar moths are preyed upon by a diverse range of frogs, including the wood frog and the American toad, among others. Tent caterpillar moths and caterpillars are consumed in their whole by reptile and amphibian predators.

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 throughout the structure.

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

However, it is not apparent if this modest amount of heat gain has a major impact on the rate of their development.


Among the largest tent caterpillars in the planet, this species constructs one of the largest tents. It is built in the crotch of the host tree and is normally placed with the broadest wall facing southeast in order to take advantage of the early sunlight. It is customary for the caterpillars to add silk to the surface of the construction at the beginning of each of their daily activity periods. The silk is placed down with a tiny amount of strain, and as a result, it ultimately contracts, causing the newly spun layer of silk to separate from the next layer of the fabric.

  • They will be able to enter and depart the tent through the apertures provided.
  • When the caterpillars are spinning, light has a significant impact on them, and they spend the bulk of their time spinning on the face of the tent that is the most lit.
  • As they near the end of their larval life, caterpillars continue to grow in size and expand their tent even further.
  • All of the tents’ functions can be performed simultaneously.
  • Molting may be facilitated by the increased humidity within the tent.
  • 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 larger.
  • They are dark in color and have a high capacity for heat absorption in their early stages.

Aside from that, their longsetae help to prevent convective heat loss.

They 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 out in the open.

The aggregation breaks apart when the temperature reaches a reasonable level since they are easily overheated.

Furthermore, they may 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.

The temperature in the inside of a mass of freshly fed caterpillars can be several degrees above ambient temperature even in the absence of a radiant heat source when the caterpillars are packed closely together.

It is uncertain if this modest amount of heat gain has a major impact on the rate at which they are expanding.

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.

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