What Type Of Moth Does An Eastern Tent Caterpillar Produce

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 (ENTFACT-423), which can be downloaded in PDF format.

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.

When the buds begin to open in early March, the caterpillars hatch and begin to feed on the buds. It is social behavior on the part of these insects, since caterpillars from a single egg mass like to stick together and create an elaborate silken tent in the crotch of a tree. Some egg masses may produce enough caterpillars to create a large colony, which may include caterpillars from two or more egg masses.

They remain within the tent when it is too hot outside or when it is too wet to go outside. As long as the weather is not too cold, they emerge to feed on the leaves of plants in the early morning, late afternoon, or at night.

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.


  • Three weeks after the cocoon is formed, the adult moth emerges. Coloration: The forewings of the moth are reddish-brown with two faint stripes running diagonally across them. Female moths begin to deposit eggs on short branches after mating with another female. Those eggs will hatch out in the spring of the following year. Every year, there is just one generation.

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

Bugwood.org is run by Tim Tigner of the Virginia Department of Forestry. Malacosoma americanum is a kind of fungus found in the United States (Fabricius) Since 1646, people have been observing the eastern tent caterpillar in the United States of America. Outbreaks are common at eight- to ten-year intervals, and they can be deadly. Nests or tents formed in the forks and crotches of a tree, which are normally visible in the spring, are usually indicative of the existence of this insect in the area.

However, this was not the case.


Image 1: The Eastern Tent Caterpillar (Malacosoma americanum) in its natural habitat (Fabricius). Egg mass of the eastern tent caterpillar. R.L. Anderson of the USDA Forest Service (UGA0590063b) is credited. Fig. 2: Eastern Tent Caterpillar (Malacosoma americanum), in its natural habitat (Fabricius). The larvae of the eastern tent caterpillar. University of Georgia (UGA0795040b); G.J. Lenhard – Louisiana State University * The University of Georgia, as well as the individual photographers and organizations who created these photographs, have copyright protection for them.

The egg mass may measure nineteen millimeters in diameter.

The size of the tent increases in proportion to the number of larvae.

After reaching maturity (Image 2), the caterpillars will depart the host tree in search of a suitable location to spin their pale yellowish cocoons.

Following mating, the female lays eggs in a mass around little twigs on a host plant, which she later consumes. Caterpillars of the eastern tent, adult stage, image 3.

Life History

This important pest overwinters as a black, shimmering egg mass on twigs that resembles a collar. Every egg mass contains between 150 and 350 eggs. The gregarious larvae begin to build their tents on surrounding branch crotches shortly after hatching from their eggs in the spring, about the time cherry leaves begin to emerge from their buds. These tents, which are constructed of silken layers, serve as safe havens for larvae during their development. A period of six to eight weeks is required for the caterpillars to complete their feeding cycle.

The larva undergoes a transformation into a resting stage known as the pupa while enclosed in the cocoon.

A female lays eggs in a swarm around little twigs throughout the months of June and July, when the adults first emerge.


Cherry, crabapple, and apple trees are the most common hosts of this pest in the United States. The eastern tent caterpillar occasionally infects other deciduous decorative shrubs, shade and forest trees, as well as other deciduous ornamental shrubs. Landscape trees become ugly because to the silky tents woven by the caterpillars, and the caterpillars are a nuisance when hunting for food or a good location to spin their cocoons. Rather than feeding within their webs, the caterpillars concentrate there throughout the night and during wet weather.

Within a three-foot radius of the nest, the leaves on the host tree may be stripped off all of the twigs within that radius (s).


The larvae of the eastern tent caterpillar are prey for a variety of different insects, toads, and birds. Several species of tiny, helpful wasps prey on the eggs, larvae, and pupae of this pest, causing them to die. During bad weather conditions, a large number of caterpillars succumb to illness. From December through March, prune short twigs that contain viable egg masses on them to ensure that the eggs hatch successfully.


Registered pesticides should be used in April, when the caterpillars are at their earliest stage of development. To manage the eastern tent caterpillars, apply registered formulations to the nests as well as around one foot of the surrounding branches or trunk to achieve effective control. Apply the spray before the nests have grown to a diameter of three inches. If at all feasible, apply pesticides first thing in the morning, when the caterpillars are most likely to be within their nests. To get precise information on host plant label clearance, phytotoxicity information, safety precautions, and dose information, read and follow all label requirements carefully.


Pesticides are extremely toxic. Read and adhere to the instructions and safety precautions provided on labels. Precautions should be taken when handling and storing the product in original labeled containers out of the reach of children, pets, and animals Empty containers should be disposed of as soon as possible in a safe manner and location.

Don’t pollute forage, streams, or ponds with chemicals. The following article was written by: Gregory A. Hoover, Sr. Extension AssociateMarch 2002

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.

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

Eastern Tent Caterpillar Moth (Malacosoma americanum)

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

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

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

  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, Malacosoma americanum

In the early spring, the tents of the eastern tent caterpillar are a striking sight to see. A common sight in early April in Wisconsin is the eastern tent caterpillar (Malacosoma americanum), sometimes 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.

  • Shiny egg masses are wrapped around twigs to create a beautiful display (top).
  • The egg stage of the eastern tent caterpillar allows it to survive the winter.
  • It is around the time of bud break that the larvae — caterpillars – hatch.
  • 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.
  • 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.
  • When the ladies have finished mating, they lay their eggs on little branches that survive until the next spring.
  • 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.

Eastern Tent Caterpillar: The Landscape Harbinger of Spring

Throughout all of New Jersey this week, the number of growing degree days (GDD) will continue to rise steadily and consistently. Several regions may reach or surpass 90 GDD by the end of the week, indicating that the eastern tent caterpillars will begin laying their eggs. Not all of the eggs will hatch at the same time because a staggered hatching period may potentially boost survival rates if the weather turns colder again later in the season. Unless otherwise noted, all of the images of the eastern tent caterpillar’s life cycle that appear in this blog were taken at the same location in Freehold, New Jersey, during the spring of 2016.

  • In 2016, central New Jersey witnessed a rather mild early spring, which facilitated the rapid hatching of the earliest eggs.
  • Do you see what I’m talking about?
  • (Photo courtesy of Steven K.
  • The egg mass of the Tent Cat, up close and personal.
  • (Photo courtesy of Steven K.
  • This insect is one of the most destructive defoliators of deciduous shade trees, causing severe defoliation.
  • During outbreak years, which commonly occur at intervals of 8 to 10 years, this pest will also attack pecan, hawthorn, beech, willow, and other shade trees on a sporadic basis.

The eggs on the shaded side of the tree have not yet hatched.

Is it too soon?

(Photo courtesy of Steven K.

A saucer magnolia and a star magnolia are in bloom just a few hundred yards distant from the Tent Cat egg hatch.

Rettke, Rutgers Cooperative Extension.) During the spring months, eastern tent caterpillars build silk nests in the forks of trees, which are immediately distinguishable from other types of nests.

Tree death will be rare as a result of this caterpillar’s defoliation, since trees will re-foliate as a result of the caterpillar’s activity.

During outbreak years, when the caterpillars travel in large numbers across landscapes in search of new food or a suitable location to complete their development, local inhabitants are understandably concerned.

Date: Tuesday, April 2, 2016 (Early webbing).

Many leaf buds have not yet developed into full leaves.

Rettke, Rutgers Cooperative Extension.) Date: Thursday, April 13th, 2016 (Growing tent webbing).

(Photo courtesy of Steven K.

These lustrous brown bands are easily distinguishable and may be easily removed by hand.

More than 10 million egg clusters were destroyed during a first eradication effort in Connecticut in 1913 when the extension service offered a $25 reward to the school child who gathered the most egg clusters, according to historical records.

Consequently, as the larvae emerged in the spring and the silk tents began to form, prize money was granted to schoolchildren in a number of cities for the number of tents they had gathered in the previous year.

These tents were then burnt by fire or ruthlessly trampled upon, generally with tremendous fury and delight.

For example, in 1899, 1350 quarts of cocoons were turned in at Glen Falls, New York, according to historical records.

There is a huge increase in the number of Tent Cats in an established community.

(Photo courtesy of Steven K.

These caterpillars are at their mid-instar stage, and the white racing stripes are plainly evident on them.

(Photo courtesy of Steven K.

While these cultural traditions should be supported in areas where they are feasible, their shortcomings will always be apparent.

Tent Cats will congregate tightly together on top of the nest during the cold early spring mornings, allowing them to warm themselves with the aid of the sun.

Rettke, Rutgers Cooperative Extension.) Date: Thursday, May 14, 2016 (Structural coloration).

(Photo courtesy of Steven K.

The presence of many silk layers inside the nest webbing necessitates the inclusion of entry and exit apertures.

(Photo courtesy of Steven K.

Because tent caterpillars are native to the area, they are preyed upon by a variety of predators (such as spiders, ants, yellow jackets, assassin bugs, birds) and parasitoids (such as braconid wasps, ichneumonid wasps, tachinid flies), but these beneficials do not always arrive in time or in sufficient numbers to effectively control them every season.

  • Yellowjacket wasps are superb caterpillar predators, and they may be found in abundance in the wild.
  • (Photo courtesy of Steven K.
  • (Photo courtesy of Steven K.
  • The caterpillar’s vulnerability to pupal parasitism rises when outbreaks persist for an extended period of time.
  • Egg hatching in the spring is timed to coincide with the growth of the leaves on the trees that they generally feed on, ensuring the best chance of survival.
  • Date: Friday, May 25, 2016 (Late instar).
  • (Photo courtesy of Steven K.

Late instar caterpillars (2.5 inches in length) travel away from the tree in order to find a suitable location to pupate.

Rettke, Rutgers Cooperative Extension.) Sometimes cultural and biological control strategies fail to keep their populations under control in specific areas because of a lack of effective environmental controls.

The bacteria Bacillus thuringiensis is the biological pesticide of choice when dealing with juvenile tent caterpillars that are less than 1 inch in length and breadth (i.e., first 3 instars).

When administered as a spray treatment, it has the ability to cross laminar barriers.

Spinosad (Conserve), which has received approval from the OMRI, completes the list of more biorational forms of insecticides.

Finding a safe environment in which to properly pupate?

(Photo courtesy of Steven K.

The right caterpillar was successful in completing its pupation process, however it was snatched by a predator before it could finish its pupation.

Rettke, Rutgers Cooperative Extension.) When attempting to control a situation, do not use flaming torches.

Using standard contact pesticides, most caterpillar species are quite easy to eradicate from the environment.

The use of expensive tree protection measures to avoid tree damage, on the other hand, is rarely warranted.

The adult Eastern Tent Caterpillar moths emerge from pupation after roughly 2-weeks of development.

This will be the end of the one generation cycle.

It is probable that a predator, such as the assassin insect seen above, preyed on the Tent Cat as it sought to pupate, and killed it.

Cardinals, blue jays, and orioles are just a few of the bird species that have been observed feeding on Tent Cats.

Rettke, Rutgers Cooperative Extension.) Wiley-Interscience Publications (New York) published Forest Entomology–Ecology and Management by R.N.

Witter in 1984.

Fitzgerald’s The Tent Caterpillars was published by Comstock Publishing Associates and Cornell University Press in Ithaca, New York, in 1995.

Hoover and P.R.

Department of Agriculture) 1990. The Eastern Tent Caterpillar is a species of caterpillar that lives in the eastern hemisphere. US Government Printing Office, Washington, DC, including contributions from the Maryland Department of Agriculture and the USDA Forest Service.

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.

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What Do They Look Like?

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

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

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

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


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

What Do They Eat?

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

Life Cycle

Cherry, apple, plum, peach, and hawthorn trees all have leaves that eastern tent caterpillars eat. It is possible that an excessive number of caterpillars will defoliate their host trees completely in years when Malacosoma americanumis prevalent, and that they will then seek food among less desirable plants. In addition to having a short life span, adult moths do not eat.

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

Special Adaptations and Defenses

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

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

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

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

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

Where Do Eastern Tent Caterpillars Live?

Temperature fluctuations cause larvae to emerge in the early spring. They live in groups in silken tents that are meant to keep them warm during periods of chilly weather. On chilly or wet days, caterpillars may congregate on the broad side of the tent, which faces the sun. The caterpillars care to their tent before each of the three daily feeding expeditions, adding silk as required. In order to fit their growing size and to avoid the accumulating waste of frass, the caterpillars develop additional layers to their body.

  1. During their crawling around branches and twigs in search of leaves to eat, they leave behind silk trails and pheromones that attract other insects.
  2. In addition to alerting other caterpillars to the existence of foliage, pheromone signals also convey information about the quality of the food available on a specific branch.
  3. Whenever they sense a threat, the caterpillars leap to their feet and thrash around.
  4. When the caterpillars need to rest between feedings, they return to the shelter of the tent, which also serves as a protection against predators.


  • 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

Comparison of the Eastern Tent Caterpillar, Forest Tent Caterpillar, and Gypsy Moth (E2299)

FILE TO DOWNLOAD Author: Author: Date: May 1, 2001 They are frequently found eating on the leaves of hardwood trees and are readily mistaken with one another because of their similar appearances. The graphics and information provided in this section will assist you in determining which caterpillar is eating on your tree. For additional information on the biology and management of these insects, speak with a representative from your local MSUExtension office or area Department of Natural Resources.

Eastern Tent Caterpillar (Malacosoma americanum) Forest Tent Caterpillar (Malacosoma disstria) Gypsy Moth Caterpillar (Lymantria dispar)
Markings A) Dark headB) Prominent white or yellow stripe down the center of the body;C) small blue spots to the side. A) Blue head;B) Prominent central row of white or yellow markings in keyhole or footprint shape;C) Bluish on sides of body. A) Yellow head with black markings;B) Prominent blue and red spots.
Tents Prominent silk tent in branch junction. They do not spin silk tents; resting sites on leaves may have small silk layer. No silk tents
Egg Mass Dark, spindle-shaped mass wrapped around twigs; rough varnished texture. Similar to eastern tent caterpillar. Tan color; covered with fine hairs; 1 to 3 inches long; usually on tree bark
Preferred Host Trees Black cherry, apple, crabapple. Aspen, sugar maple, oaks, birch, black gum. Oaks, aspens, birch, willow and more than 250 other species.
Populations Native insect; silk tent is unattractive, but feeding rarely harms trees; common pest of ornamental trees in urban settings Native insect; outbreaks occur at roughly 10-year intervals and usually last 2 to 4 years; most common in forests, especially where aspen is abundant. Exotic pest; severe defoliation during outbreaks can occur for 2 to 3 years in urban and forested areas, especially where oaks are abundant.

FILE TO DOWNLOAD The gypsy moth, integrated pest management, Lymantria dispar, and natural resources are some of the terms used to describe pest control.


Deborah McCullough may be reached at [email protected]

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Eastern Tent Caterpillar

Unlike other tent caterpillars, eastern tent caterpillars are black in color, slightly fuzzy, and have lighter stripes along their sides. They congregate in silvery-gray webs, which are commonly seen near the fork of a big branch on a tree or shrub’s main trunk. To see photographs and videos of caterpillars and their tents, please visit this page. The larvae and tent of the eastern tent caterpillar. Tammy Curley captured this image.

Life cycle of eastern tent caterpillars

Eastern tent caterpillars reproduce just once a year, resulting in only one generation. During the summer, the female moth deposits egg masses on the branches of host plants, and the eggs hatch. Eggs do not hatch until the next spring, generally in April, depending on the temperature of the surrounding environment. For 4 to 6 weeks, the caterpillars will feed on the leaf of the host plant. During the day, the caterpillars eat on buds and other plant materials. On gloomy or rainy days, as well as at night, the caterpillars remain within the limits of the tent, where they are safe.

As a result, the tents become increasingly visible in the landscape, orchard, and along roadsides.

Large numbers of roaming caterpillars in close proximity to residences can be a source of anxiety, but they have finished eating and no further control is required at this time.

A few weeks later, adult moths emerge; they mate, and the female moths leave egg masses on trees that will hatch the next year.

Damage caused by eastern tent caterpillars

Carrion caterpillars eat on the buds and leaves of a wide variety of trees and shrubs, but their favorite foods are the fruits of apple, crabapple, wild plum, cherry, and other closely related plants.

Management of eastern tent caterpillars

Tents and caterpillars may be removed and destroyed as soon as they are discovered, hence reducing the amount of damage. It is best to remove the tents in the early morning or late evening, or on chilly, wet days, when the caterpillars are not present in the tents. The caterpillars and silk webbing are completely harmless to humans; there is no danger in pulling down the tent with your bare hands, however many people like to use a paper towel or gloved hands to remove the tent and caterpillars off the ground.

In most cases, insecticides are useless against fully developed caterpillars.

If there are no caterpillars present, the tent is likely to be old and hence does not require treatment.

Caterpillars often confused with the eastern tent caterpillar

In addition to the eastern tent caterpillar, there are many other caterpillar species that are sometimes mistaken with it, including the forest tent caterpillar, the fall webworm, and the bagworm. It is a closely similar but distinct species, theforest tent caterpillar (Malacosoma disstria), that has been known to cause widespread outbreaks, with vast populations significantly defoliating wooded regions, every few years. These outbreaks are more prevalent in northeastern Iowa than anywhere else in the state.

Even though fall webworms (Hyphantria cunea) and other caterpillars are not closely related, the caterpillars eat as a group and weave a silken ‘tent’ or web in the branches of trees.

In addition, fall webworms are active considerably later in the year, and are first observed in August and September.

With the head and legs protruding out of the open top end of the bag, each caterpillar creates a bag that it totes around with it while it feeds.

Do you live in Iowa and have an insect you would like identified?

In addition to the eastern tent caterpillar, there are many other caterpillar species that are sometimes mistaken with it, including the forest tent caterpillar, fall webworm, and bagworm. It is a closely similar but distinct species, theforest tent caterpillar (Malacosoma disstria), that has been known to cause widespread outbreaks, with massive numbers defoliating wooded regions on occasion. It is more frequent for outbreaks to occur in northern Iowa than elsewhere. There is no such thing as a forest tent caterpillar.

Due to the fact that they eat by weaving a web around leaves, fall webworms tend to be found towards the extremities of branches and are bigger in size.

See also:  How To Light Up A Tent

During its whole existence, the bagworm moth larva (Thyridopteryx ephemeraeformis) is enclosed in a robust protective casing comprised of silk and camouflaged fragments of vegetation.

As the caterpillar consumes and develops, the bag rises in size, and by the end of the summer, what began as small pods just one-quarter inch long would have grown to over two inches in length.

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).

  • Repeated years of high populations can lead host plants to develop more slowly than they should and may make them more prone to disease.
  • As opposed to fall webworm egg masses, eastern tent caterpillar egg masses do not encircle foliage as they do in the fall.
  • Bugwood.org is run by Whitney Cranshaw of Colorado State University.
  • When the young hatch, they spin a silky tent in the crotch of a limb to protect themselves.
  • 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.
  • Within 4-6 weeks, they will feed on neighboring vegetation, causing the tent to grow in size as a result of their growing numbers.
  • 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

  • PDF document that you may print off To see a bigger version of the photographs, click on the images. Jack Loughrey created the image above. A pest endemic to North America, the eastern tent caterpillar (Malacosoma americanum) may cause major defoliation to deciduous trees in the Rosaceae family, particularly Cherry (Prunus) and Apple (Malus), causing them to die (Malus). Because they emerge at comparable periods in the spring, it is sometimes mistaken for the Gypsy moth caterpillar, as is the fall webworm (which appears in late summer and fall). Eastern tent caterpillars can defoliate a tree, however trees are typically able to recover after one or two years of harm from the caterpillars’ presence. Host plants may have reduced development as a result of successive years of high populations, making them more vulnerable to disease. The Life Cycle of a Product or Service During the summer, the adult moth will deposit 150-300 eggs, which will overwinter in glossy, varnished-looking, black masses that will be encircled by a branch or limb in the fall. In contrast to fall webworm egg masses, eastern tent caterpillar egg masses do not encircle vegetation. Particularly noticeable during the winter months when the trees are devoid of leaves, the egg mounds are easy to identify. Colorado State University’s Whitney Cranshaw maintains the Bugwood.org website. They are most noticeable during the month of March, when the eggs hatch. They spin a silky tent in the crotch of a limb as soon as they emerge from their cocoons. The freshly hatched caterpillars will stick together, perhaps merging with the young from a neighboring egg mass to establish a huge colony of caterpillars in one location. When the caterpillars need to eat, they will emerge from their protective tent in the early morning, late afternoon, or even at night. In the heat of the day, when it is pouring, or when it is too chilly, they will remain within their cage. During the following 4-6 weeks, they will feed on adjacent vegetation, extending the size of the tent to meet their growing size as they grow. After reaching a length of 2 12″ to 2 12″ in length, the black caterpillar with a white stripe down its back that is bordered by blue will cease feeding and will exit the tent. 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-inch long white cocoon and pupate. It will take 3 weeks after that for the reddish-brown adult moth to emerge, mate, and lay its eggs on little branches, which will hatch the next spring. A new generation is born once a year, and the number of people living in the world will fluctuate year after year. It is similar in appearance to the Eastern tent caterpillar (Malacosoma disstria), except that it bears white dots along the back instead of a stripe as the Eastern tent caterpillar does. 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 peach. While other species in the Malacosoma genus make tents for their larvae to cluster in, this species spins silken sheets on which the larvae aggregate in large numbers. It will pupate in a white cocoon that it will construct in the folds of leaves or another protective location, emerging three weeks later as an adult. Like the Eastern tent moth, it also contains an egg mass that it uses to overwinter. Control measures are comparable to those outlined below in the table below. Linda SpoerlHosts provided the image. When it comes to host plants, the Eastern tent caterpillar prefers plants of the Rosaceae family. Within this family, there are several genera that include the fruits almond, apricot, cherry, crabapple, peach, plum, and quince, the genus Cotoneaster, which contains the fruits hawthorn and rowan tree, as well as the genus Sorbus, which comprises mountain-ash and service tree. Measures to Maintain Control

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.

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

Fall webworm & Eastern Tent Caterpillar [fact sheet]

Obtaining a Downloadable Resource In addition to fruit, the autumn webworm (Hyphantriacunea) and the Eastern tent caterpillar (Malacosomaamericanum) eat on trees in woodlands and shadows. Orchards that are frequently treated with pesticide to combat codling moths and other pests have little need for them in terms of economic value. They can, however, be regarded a serious pest in nurseries and landscaping due to the unattractive webs they create. A common misconception is that the fall webworm is the same as the Eastern tent caterpillar.

For its part, the Eastern tent caterpillar’s web is densely packed into the forks and crotches of trees; the larvae do not feed within their webs, but instead cluster there at night and during wet weather.

Caterpillars of the eastern tent Image courtesy of Marie-Eve Jacques


Fall Webworm: When fully developed, the larvae measure around 1 1/2″ in length. Depending on the species, they may be yellow with dark stripes and dots or a drab blue black without any yellow. Their bodies are covered with hair, and their heads are dark in color. Adult moths have a wing span of around 1 1/2 inches. Their hue is almost completely white. The Eastern Tent Caterpillar has scant hairs and grows to be around 2 inches long when fully developed.

A white stripe runs down the middle of the back of the animal, and it is painted black with white and blue patterns. Adult moths are reddish-brown in color with two white lines running obliquely across each forewing on each forewing.

Life Cycle

Each year, a new generation of fall webworm is produced, but it is not particularly synchronized. The insects hibernate as pupae in the soil during the winter. The adult moths emerge from the earth throughout the months of June and July. In July, the females begin laying their massive clutches of eggs. The eggs begin to hatch towards the middle of July. The larvae eat within the web for a month or more before crawling down the tree and constructing a cocoon, where they will eventually pupate.

  1. The insects overwinter as egg masses on twigs, and they hatch in April after spending the previous winter as egg masses.
  2. As the larvae grow and mature, more layers of the tent are erected.
  3. The females lay masses of eggs in bands around twigs, which are then eaten by the males.
  4. The larvae of the fall webworm.
  5. The larvae of the eastern tent caterpillar.
  6. The larvae of the eastern tent caterpillar.


  • It is possible to limit the requirement for therapy by monitoring for and eliminating tent caterpillar egg masses. It is critical to discover webs of either insect as soon as possible in order to avoid significant defoliation. Destroy nests by trimming or removing them manually (a stick can be placed into huge webs and then twisted to remove the webs). Biological Control – A variety of natural enemies, including birds, small animals, insect predators, spiders, and parasitic wasps, keep the numbers of both the autumn webworm and the Eastern tent caterpillar under control. When the humidity and temperatures are just right, a naturally existing virus and a fungus can multiply to the point where they kill large numbers of caterpillars of both species. When dealing with either pest, biological pesticides based on the Bacillus thuringiensis (Bt) bacteria should be employed, and they should be administered as soon as the tents are spotted while the larvae are still young. Chemical Control – Use pesticides to control infestations that are difficult to reach or when populations are large. In order to receive particular pesticide recommendations, contact your county’s Agricultural Field Specialist.

Egg mass of the eastern tent caterpillar. Photograph courtesy of Alan T. Eaton. The Eastern tent caterpillar is responsible for the defoliation. Photograph courtesy of Marie-Eve Jacques. Stop! Ensure that you thoroughly read the label on every pesticide bottle before to utilizing the item. Pesticides must only be used in the manner specified on the label in order to be in conformity with the law. The continuous registration of all pesticides described in this book is conditional on their ongoing use.

New Hampshire rules require that empty containers be disposed of in an appropriate manner.

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