What Time Of The Year Do Eastern Tent Caterpillars Eat

Eastern Tent Caterpillar

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

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

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

Figure 1. An eastern tent caterpillar.

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

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

In general, insecticides are ineffective against fully developed larvae.

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


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

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

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

Figure 3. An eastern tent caterpillar nest.

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

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

Figure 4. An adult male eastern tent moth.

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


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

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

Anderson, USDA Forest Service, copyright 1995.

Tent Caterpillars

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

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

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

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

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

Eastern Tent Caterpillar

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

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

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

Forest Tent Caterpillar

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

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

Fall Webworm

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

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

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


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

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

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

What Do They Look Like?

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

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

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

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


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

What Do They Eat?

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

Life Cycle

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

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

Special Adaptations and Defenses

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

  • As they move through branches and twigs in search of leaves to eat, they leave behind silk trails and pheromones that attract other insects to the area.
  • Pheromone signals not only warn other caterpillars to the presence of foliage, but they also convey information about the quality of the food available on a certain branch of a plant.
  • Whenever they sense a threat, the caterpillars leap to their feet and thrash their bodies about.
  • When the caterpillars need to rest between feedings, they return to the shelter of the tent, which also serves as a protection against predators.

Where Do Eastern Tent Caterpillars Live?

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

The eastern tent caterpillar may be found across the eastern United States, as far west as the Rocky Mountains, and as far south as southern Canada. Malacosoma americanum is a kind of bug that is indigenous to North America.


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

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.

Forest tent caterpillar (left) has keyhole-shaped white spots, Eastern tent caterpillar (right) has a white stripe. Photo: Ronald S. Kelley, Vermont Department of Forests, Parks and Recreation, 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.


Caterpillars have the ability to defoliate whole cherry trees in extreme epidemics. However, defoliation typically happens early enough in the season for wild cherries to replace the eaten leaves with new ones, preventing the trees from succumbing completely. Other tree species, on the other hand, may be destroyed because they do not have enough time to establish a fresh set of leaves for food production and storage, which is necessary for winter survival. The larvae of the eastern tent caterpillar.

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.

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

  • 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.

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

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

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

Life Cycle

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

  1. Eastern and western tent caterpillars begin feeding on these fresh leaves within a few days of their appearance.
  2. In most cases, the web is situated in the crotch of tiny limbs (Fig.
  3. Because the larvae wander away from their tents to feed on leaves, harm can occur even if the web is located a long distance away from the tents.
  4. These enormous, noticeable webs are created by the eastern and western tent caterpillars.
  5. The larvae molt, or lose their skin, multiple times throughout their development.
  6. The color pattern can also alter from instar to instar depending on the species.
  7. 3).
  8. Between feedings, dozens of caterpillars may assemble on these mats to wait for their next meal.
  9. Protected areas like as the web, under the bark, among dead plant material on the ground, within a curled leaf, or under the eaves of homes are all common locations for spiders to hide.
  10. Generally speaking, cocoons are loosely made of silk with a white or yellowish crystalline component dispersed throughout the whole thing.
  11. Tent caterpillars in their adult form are brown and yellowish moths with two diagonal patterns on the front wings of their bodies (Fig.

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


Immature tent caterpillars are colorful and about 1¾ inches long when fully grown. They have a few long hairs on their bodies, mostly along the sides. Individual species are identified by larval coloration and markings. If you find tents with larvae that do not match the descriptions in Table 1, they are probably fall webworms. Fall webworms can have several generations per year and produce tents during late summer and fall. (For more information, see Texas AgriLife Extension Service publication E-233,Fall Webwormsavailable atorg.)


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

  • When you discover spider webs on twigs in the spring, prune them as soon as you notice them.
  • It is not suggested to burn the web or caterpillars since it is quite dangerous.
  • Remove the dead caterpillars from the ground and dispose of them.
  • Beneficial insects can help to lower the number of tent caterpillars.
  • Trichogramma species prey on the eggs of tent caterpillars.
  • Control through chemical means.
  • The use of insecticide is pointless if the tent caterpillars have been allowed to feed and develop to completion.

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

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

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

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

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

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

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

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

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

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

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


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

Controlling Eastern Tent Caterpillars in Your NJ Landscape

You have no idea who is sleeping under your trees’ leaves in silk tents and consuming their whole supply of leaves. The caterpillar in question is most likely the Eastern tent caterpillar. The Eastern tent caterpillar (Malacosoma americanum) is a natural insect in its larval (immature) stage that is easily identified by its silk “tents.” The Eastern tent caterpillar is also known as the tent caterpillar. The mature stage, on the other hand, is usually not something you notice. During the summer, adult moths may be seen in your garden, and they have a limited lifetime compared to the rest of the population of the species.

See also:  How To Set Up A Screen Tent

Thousands of caterpillars might be devouring your trees the next spring as a result of this development.

How to Recognize the Eastern Tent Caterpillar

See if you can find this bug in the trees that it favors. These are mostly apple (Malus) and cherry (Prunus) tree species, and they include the following:

  • Almond, apple and crabapple, apricot, peach, pear, plum, hawthorn, wild cherry, mountain ash (Sorbus), and other trees and shrubs

Look For Egg Masses

Look for eggs on these trees during the fall and winter months. The egg masses deposited by the female moths are tiny, black, and have a glossy appearance, indicating that they are freshly placed. It is common to find them on branches, with the mass of flowers completely around the limb. Because they’re so little, you may have to search for them for quite some time. These masses remain in situ throughout the winter and hatch out in the spring. You may see a picture of an egg mass by clicking here.

Spot Adult Caterpillars

Unlike the larval stage, the adult Eastern tent caterpillar is black and hairy. It features white stripes going down the length of its body, with thinner brown and yellow lines running down the sides, as well as blue patches on its back. When completely developed, it is around 1.5 to 2 inches in length.

Watch Out For Tents

The emergence of eastern tent caterpillars coincides with the emergence of the host tree’s fresh spring leaf growth. You’ll notice them as soon as they begin to form their distinctive “tents” or spun cocoons on branches and in branch crotches, which are easily identifiable. They also increase their tents when they begin to devour the tree’s buds and leaves and develop, which coincides with the growth of the caterpillars. In summer, the adult moths emerge from their cocoons and begin their life cycle all over again.

However, during this point of their development, you will not see the caterpillars eating any leaves and instead will find them traveling over sidewalks, along highways, and up buildings in their hunt for a cocoon location.

If you don’t want to squash them, you should leave them for their natural predators to devour such as birds, snakes, and raccoons.

Tree Damage Caused by Eastern Tent Caterpillars

Trees bring forth fragile, juicy new leaves and buds in the spring, and caterpillars gorge themselves on them. Damage can range from mild to severe depending on the quantity of caterpillars present, as well as the size and condition of your trees. Often, the larvae consume the whole canopy of leaves of a tree. The majority of the time, this type of damage is simply a cosmetic concern. Caterpillar damage of this magnitude often weakens the tree only after three or more years of defoliation more than 50% of the tree’s canopy.

3 Options for Dealing With Tent Caterpillars

Depending on your degree of comfort, you may choose to use a variety of methods to manage or eliminate Eastern tent caterpillars from your trees.

Option 1 – Leave them Alone

If your trees are in good health and the caterpillar population is not overpowering, staying put is typically the best course of action. Once the caterpillars have caused significant spring leaf damage for a month or so, they will cease eating. Your trees will continue to develop throughout their life cycle, with little or no negative impact on their overall health in most cases. Because tent caterpillar populations fluctuate from year to year, you may have many years of low tent caterpillar populations and no leaf damage.

Option 2 – RemoveDispose of Them

If you are unable to leave them in situ, the quickest and most effective methods of removing egg masses or spun tents are to remove them by hand or to cut out the afflicted branches. It is simplest to remove egg masses from deciduous host trees in the winter, when the branches of the host trees are bare. The eggs may be killed by simply removing the eggs off the tree and burning them or soaking them in soapy water. When you notice tents in the spring, you may take them down. This is a simple task that may be completed by hand or with long-handled garden equipment.

  • If you notice Eastern tent caterpillars in your tree, you have a few options for what to do next.
  • To clean up after yourself after removing the nest by hand, simply put it into a bucket of soapy water.
  • The larvae will not survive if they do not have access to light and nourishment.
  • NOTE: If you are apprehensive about handling either eggs or caterpillars, trimming is a preferable alternative than planting.
  • Pruning away an excessive number of branches strains a tree, especially during the warm spring months when the tree is already exerting considerable energy to produce leaves and blossoms.

Also keep in mind that pruning cuts made in the spring are more sensitive to various insects and illnesses that have resurfaced from their winter hibernation.

Option 3 – Spray With Insecticide

Another technique of control is to treat the tree with a pesticide before it blooms or grows. This has the potential to lower the population of caterpillars that are capable of reproducing, hence reducing the caterpillar population the following year. Spraying is effective provided it is done appropriately and at the appropriate time. Non-toxic insecticides, in particular, must be administered at the appropriate stage of an insect’s life cycle and at a time when the sprays would not harm other insects in the vicinity.

Bacillus thuringiensis (B.t.) is the most ecologically friendly biological control approach available, but it must be sprayed in May in order to be successful.

These insecticides, on the other hand, can kill other beneficial insects that you may wish to have in your garden.

What NOT to Do!

Using fire to burn off the caterpillar webs is not recommended. While using a flame torch may be enjoyable, you will only cause damage to your tree by burning the bark. Under addition, in dry circumstances, blazing tents and leaves have the potential to spread fire to other places.

What to Do If Your Tree Has Been Defoliated

If your trees have been defoliated by the Eastern tent caterpillar, we recommend that you water them on a regular basis and treat them with organic fertilizer to help them recover. Consequently, the trees will experience less stress, increasing their chances of recovering fast.

We Can Help

OurPlant Health Care (PHC) program uses organic methods to combat pests and illnesses in our gardens. While we can’t control tent caterpillars and other pests all year, we can keep the beneficial pollinators and predatory insects you want to see around your shrubs and trees all year. Please contact us at 908-309-6611 if you would want us to evaluate your trees for Eastern tent caterpillars or to propose a PHC program for your trees.

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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


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

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