What Kind Of Moths Come From Tent Caterpillars

tent caterpillar moth

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Tent caterpillar – Wikipedia

Tent caterpillars
Eastern tent caterpillar,Malacosoma americanum
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Lasiocampidae
Subfamily: Lasiocampinae
Genus: MalacosomaHübner, 1822
About 26, including:
  • The eastern tent caterpillar (Malacosoma americanum)
  • The western tent caterpillar (Malacosoma californicum)
  • The ground lackey (Malacosoma castrense)
  • And the ground lackey (Malacosoma castrense). Malacosoma disstrium, the forest tent caterpillar
  • Malacosoma neustrium, the lackey moth
  • Malacosoma disstrium, the forest tent caterpillar

Tent caterpillars, sometimes known as moth larvae, are medium-sized caterpillars that belong to the genus Malaco and are members of the family Lasiocampidae. Twenty-six species have been identified, six of which are found in North America and the remaining twenty-six in Europe and Eurasia. Some species are regarded to have subspecies in addition to the main species. Because of their proclivity for defoliating trees, they are frequently referred to as pests. They are among the most gregarious of any caterpillars, and they display a variety of interesting activities.

A single large tent is typically occupied throughout the larval stage by some species, such as the eastern tent cattter,Malacosoma americanum, and the caterpillar of the small eggar moth,Eriogaster lanestris, whereas others construct a series of small tents that are sequentially abandoned by others (for example, the eastern tent caterpillar,Malacosoma americanum).

Life cycle

In the following description of the tent caterpillar life cycle, the eastern tent caterpillar, which is the most well-known species, is used as a model. The specifics of the life cycles of other animals differ only little from one another. It is during the early spring season, when the leaves of their host trees are just beginning to emerge, that tent caterpillars hatch from their eggs. As soon as the caterpillars hatch, they begin to construct their tent. The tent is built in such a way that it is shielded from the light in the early morning.

  • Studies have indicated that digestion cannot take place when the body temperature of a caterpillar is less than around 15 degrees Celsius (59 degrees Fahrenheit).
  • Caterpillars may regulate their internal body temperatures by traveling from one compartment to another within their body.
  • On frigid but sunny spring mornings, it is not uncommon to find that the temperature of the aggregate is as much as 30 degrees Celsius (54 degrees Fahrenheit) higher than the temperature of the surrounding air.
  • Due to the fact that tent caterpillars’ digestive physiology is oriented to young leaves, they must feed multiple times per day in order to finish their larval development before the leaves of their host trees grow too old for them to consume, which forces them to feed several times each day.
  • The caterpillars return to the tent immediately after eating and congregate in the sunshine to aid with the digestive process.
  • The forest tent caterpillar, on the other hand, is a nomadic forager who constructs a succession of temporary resting spots during the course of its larval growth, unlike the other caterpillars.
  • Caterpillars migrate out from the tent in search of food, leaving a pheromone trail behind them as they pass over the branches of the host tree, which they use to find food.

If a caterpillar finds food and consumes it until it reaches full maturity, it will return to the tent, leaving a recruiting trail that will attract other hungry tent mates to the location of the food source.

The chemical recruiting trail of the eastern tent caterpillar is very similar to the pheromone trails used by ants and termites to notify their nest mates to the discovery of food sources in their environment.

Because of this, a colony of caterpillars generates vast volumes of fecal pellets on a regular basis.

The audio illusion of rain is created by fecal pellets falling from trees where caterpillars are feeding, creating the aural illusion of rain.

It is believed that the final instar eats around 80% of the total amount of food consumed by a larva over its entire life cycle.

Caterpillars grow at a quick rate, and their larval development is usually completed in seven to eight weeks on average.

They become fully grown adults around two weeks after that.

Mating normally takes place in the early evening, and the mated female, who is already heavily loaded with eggs, oviposits the whole clutch of eggs later that evening.

Spumaline has a hydrophilic property, which means it protects the eggs from becoming dry.

The female moth dies shortly after laying her eggs, despite the fact that the male can survive for a week or more.

Embryogenesis occurs shortly after the egg mass is implanted in the uterus.

Thesepharatelarvae are kept safe within the shells of the eggs until the next spring, when they hatch.

Because they are very freeze-tolerant, pharate larvae may survive temperatures as low as -40 degrees Celsius (40 degrees Fahrenheit) in northern climates.

The forest tent caterpillar, which is the most well-known of the epidemic species, is responsible for the outbreak.

Despite the fact that these outbreaks do not follow real cycles in the sense that they occur at regular intervals, outbreaks have been observed in some particularly vulnerable places every 10 years or so on average.

Parasitoid infestations and illness are among the factors that put epidemics to a stop.

Trees that have been defoliated by caterpillars will normally refoliate and will not suffer any long-term consequences.

Trees or sections of trees may, in certain situations, be destroyed after multiple seasons of recurrent defoliation, but this is not always the case. This occurred as a result of forest tent caterpillars defoliating sugar maples that were already stressed as a result of the recent drought.

  • Caterpillars of the western tent
  • A bunch of tent caterpillars on their way to feast off a tree
  • Caterpillar tent in the eastern hemisphere
  • A tent caterpillar nest with several caterpillars
  • In the United Kingdom, a tent caterpillar nest was discovered.

See also

  • Fall webworm is a North American moth whose larva weaves webs similar to those of the fall webworm.


  • Terrence D. Fitzgerald is a writer and editor who lives in New York City (1995). The Caterpillars of the Tent Cornell University Press, Ithaca, New York, ISBN 9780801424564
  • Fitzgerald, Terrence D., “Social Caterpillars,” Cornell University Press, Ithaca, New York, ISBN 9780801424564

External links

  • Savela, Markku, “MalacosomaHübner,” in Savela, Markku, “MalacosomaHübner.” Lepidoptera, as well as a few other types of life. retrieved on 1st July, 2019

Eastern Tent Caterpillar

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

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

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

Figure 1. An eastern tent caterpillar.

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

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

In general, insecticides are ineffective against fully developed larvae.

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


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

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

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

Figure 3. An eastern tent caterpillar nest.

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

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

Figure 4. An adult male eastern tent moth.

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


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

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

Anderson, USDA Forest Service, copyright 1995.

Eastern Tent Caterpillar Moth

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

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

Tent Caterpillar And Lappet Moths

Tent caterpillar moths and lappet moths are medium-sized insects with thick, lengthy scales that give them the appearance of being hairy on the outside. It’s common for the abdomen to protrude over the tips of the wings when the wings are folded back over the body. The majority of them are brown, tan, or gray in color, with camouflage patterning to assist them blend in with tree bark or other naturally occurring surfaces like rocks. Feathered antennae are found on both males and females. The fingerlike labial palps on either side of the mouth protrude forward, and the strawlike proboscis is either underdeveloped or absent totally; adults do not eat.

The caterpillars have a lot of hair, are brightly colored, and are striped longitudinally.

They emerge from the tent to feed on the leaves of the host tree or other adjacent trees, which they find delicious.

In appearance, the American lappet moth (Phyllodesma americana) has wavy-edged wings that are gray and rust in color.

It is similar in size to a little dead leaf. Lasiocampids are commonly referred to as “snout moths” due to the fact that their mouthparts extend forward from the skull. For the same reason, crambids and pyralid moths are referred to as “snout moths” as well.

All About Eastern Tent Caterpillars

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

What Do They Look Like?

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

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

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

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


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

What Do They Eat?

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

Life Cycle

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

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

Special Adaptations and Defenses

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

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

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

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

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

Where Do Eastern Tent Caterpillars Live?

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

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


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

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

Malocsoma americanum, the eastern tent caterpillar’s moth, is dark to reddish-brown in color with two faint diagonal lines on the forewing on the forewing. To protect the eggs, they are placed in large groups around twigs and coated with an oily secretion that dries to form a solid, brown shell. After hatching from their eggs, the larvae remain in the egg mass until the next spring. Eastern tent caterpillars are hairy and black in color, with gold, white, and blue patterning on their wings. There is a white stripe running down the back of the shirt.

  1. In length, the cocoon is approximately 1 inch in diameter and is spun from white or yellowish-white silk.
  2. In search of a suitable location to pupate, eastern tent caterpillars crawl about the ground.
  3. Caterpillars of the eastern tent on a tiny apple tree.
  4. The cocoons of eastern tent caterpillars can be found in dry, protected locations.
  5. Eastern tent caterpillars emerge from their egg masses around the same time as the buds on wild cherry, crabapple, and other ornamental plants are beginning to break.
  6. Eastern tent caterpillars construct their silk nests in the crotches of host plants such as wild cherry, crabapple, apple, and other species.
  7. A fresh generation of moths emerges sometime in the late spring to mate and deposit eggs for the next year’s generation of the species.

It is possible that the small caterpillars emerge from the egg masses at the same time the host plant buds burst in spring, causing their host plants to look as if they had never sprouted at all.

Mare reproductive loss syndrome is a term used to describe the phenomena of pregnant mares aborting after ingesting eastern tent caterpillar.

This is successful since eastern tent caterpillars spend the most of their winter within the egg masses.

Sevin and other pesticides are approved for use in the landscape for the control of caterpillars.

Steven Frank is a professor who also works as an extension specialist.

Professor Emeritus of Entomology and Plant Pathology, James Baker Date of publication: April 30, 2013Date of revision: September 18, 2019 Discrimination and harassment are prohibited at North Carolina Cooperative Extension, regardless of age, color, handicap, family and marital status, gender identity, national origin, political opinions, racism, religion, sex (including pregnancy), sexual orientation, or veteran status.

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

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

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

Life Cycle

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

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

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


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


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

  1. When you discover spider webs on twigs in the spring, prune them as soon as you notice them.
  2. It is not suggested to burn the web or caterpillars since it is quite dangerous.
  3. Remove the dead caterpillars from the ground and dispose of them.
  4. Beneficial insects can help to lower the number of tent caterpillars.
  5. Trichogramma species prey on the eggs of tent caterpillars.
  6. Control through chemical means.
  7. 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.

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.

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.

The insects overwinter as egg masses on twigs, and they hatch in April after spending the previous winter as egg masses.

As the larvae grow and mature, more layers of the tent are erected.

The females lay masses of eggs in bands around twigs, which are then eaten by the males.

The larvae of the fall webworm. Photograph courtesy of Ward Upham of Kansas State University. The larvae of the eastern tent caterpillar. Marie-Eve Jacques is credited with this photograph. The larvae of the eastern tent caterpillar. Photograph courtesy of Marie-Eve Jacques.


  • 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.

Tent Caterpillars

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

How Caterpillars Damage Trees

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

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

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

Insect Identification and Look-Alikes

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

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

There are numerous differences between the autumn webworm and the eastern tent caterpillar: A webworm tent at the end of a tree limb in the fall.

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

Fall webworms are generally not thought to be hazardous to trees, with the exception of the aesthetic aspect of the tents they create. During the spring and summer, fall webworms may be a nuisance because they feed on the regeneration of trees that have been defoliated earlier in the season by other caterpillars.

Harmless to Humans

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

Control Options

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

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

Insecticide Treatment Options

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

Generally speaking, insecticides may be split into two categories: microbial/biological and chemical.

They are especially effective on caterpillars that are tiny and young.

Bacillus thuringiensis is the most often encountered microbial and biological pesticide (Bt).

It is completely innocuous to humans, animals, and plants, however it does have an adverse effect on early moth and butterfly larvae.

Chemical pesticides are toxins that come into contact with the skin.

Licensed pesticide applicators may be discovered in the yellow pages under Tree Service, where they can be found.

For a list of certified pesticide applicators in New York State, visit the link below.

Aerial spraying may be of interest to maple syrup producers, as severe defoliation can restrict the amount of maple syrup that can be produced.

It is possible that the use of chemical pesticides would jeopardize nesting birds, beneficial insects, and other wildlife.

In the state of New York, there is presently no state-sponsored program to spray for tent caterpillars of gypsy moths on public or private land. Tent caterpillars and gypsy moths are not managed by the state, and so no payments are provided to property owners.

Woodlot Recommendations

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

Predicting Future Defoliations

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

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

More about Tent Caterpillars:

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

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