Where Do Tent Caterpillars Come From

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.

  • 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.

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 the buds begin to open, usually in early March. These insects are social; caterpillars from one egg mass stay together and spin a silken tent in a crotch of a tree.

Caterpillars from two or more egg masses may unite to form one large colony. During the heat of the day or rainy weather, the caterpillars remain within the tent. They emerge to feed on leaves in the early morning, evening, or at night when it is not too cold.

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.

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.

See also:  How To Make A Tent Cool

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.

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

Fall Webworm

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

  1. They can have either a red or a black head on their bodies.
  2. A frail web will be formed by the blackheaded larvae, but a huge and thick web will be formed by the redheaded larvae.
  3. The moths begin to emerge between the middle of March and the middle of late April.
  4. Female moths lay their eggs on the underside of leaves in masses ranging from 200 to 500 eggs in size after mating.
  5. 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.

The return of tent caterpillars: What’s it means for your yard?

Bud break does not just herald the advent of flowers and foliage; it also heralds the emergence of tent caterpillars from their cocoons. Troops of these caterpillars may completely cover tree branches with their silk tents in as little as a few weeks. Is it necessary for you to be concerned about them? Continue reading to find out! Caterpillar tents are a common type of western tent. These tents are commonly found in the bends of large branches on trees and medium-sized bushes, although they can also be seen on the ground.

  • There are three species of tent caterpillar that may be found in Indiana: the Forest tent caterpillar (Malacosoma disstria), the Western tent caterpillar (Malacosoma californicum), and the eastern tent caterpillar (Malacosoma elatior) (M.
  • All three species dwell in groups of anything from 40 to 200 individuals, and they remain together until just before they pupate, at which point they split off.
  • They are not particularly gregarious, although they will leave pheromone trails leading to trees that have rich food sources.
  • Below you’ll find a few of ways for distinguishing them from other species.
  • If a tent caterpillar’s body is coated in fuzzy hairs, it is not a tent caterpillar; if it is smooth or spikey, it is not a tent caterpillar.
  • These tufts are absent in tent caterpillars.
  • If the caterpillar you’re looking at doesn’t exhibit any of these characteristics, it’s most likely not a tent caterpillar at all.

slate blue with a pair of black stripes, and C.



Elizabeth Barnes.

Hoff, C.

Hoff What exactly do they eat?

They are particularly fond of plants belonging to the Rosaceae family, such as cherry, apple, and chokecherry, among others.

What kind of harm do they cause?

Tent caterpillars typically defoliate only a few branches and are only actively feeding for a few weeks at a time.

However, if the tree is defoliated for a number of years in a row or is subjected to another stressor such as drought, it may suffer branch loss or even death.

If you decide that you want to get rid of tent caterpillars from your trees, you have a variety of choices to choose from.

Wait until the majority of the caterpillars have gathered in their tent before removing the tent from the tree and placing it in a bag to be frozen for later use.

Because their hairs might create an allergic response in some people, you may wish to use gloves when removing them off their tree.

If you believe you’ve discovered tent caterpillars but aren’t sure, please contact the author or post your find oniNaturalistorBugGuidefor ID assistance!

How to Get Rid of Tent Caterpillars

Tent caterpillars are the larvae of various moth and butterfly species (mentioned below), which are referred to as a group by their common name. These caterpillars, which are found throughout most of the United States and Canada, reproduce quickly and have the ability to defoliate a significant number of deciduous trees and shrubs in a short period of time. These pests are frequently seen on wayside trees and in abandoned orchards. Aside from defoliation, the larvae build big unattractive webs, or tents, in the crotches of tree limbs, which are difficult to remove.

Despite the fact that tent damage is ugly, infestations of insects seldom endanger the life of trees.


The Eastern Tent Caterpillar (Malacosoma americanum) is a species of caterpillar that may be found east of the Rocky Mountains and north into southern Canada. In their full developed state, caterpillars are sparsely hairy and black in appearance, with a row of pale blue markings on either side of their bodies. They may be distinguished by a white stripe running down the middle of their backs, which helps to identify them. Adults are reddish brown moths that are 1-1/2 inches in length and have two white stripes running diagonally across each forewing.

  1. The Western Tent Caterpillar (Malacosoma californicum) is a pest that may be found in the northern and western regions of the United States as well as in adjacent Canadian territory.
  2. Approximately 1-1/2 inches in length, adult moths are orange-brown in color with two faint yellow lines on the underside of the wings.
  3. Malocsoma disstria is a forest tent caterpillar that may be found across the United States and Canada anywhere hardwoods can be found in the forest.
  4. americanum are similar in appearance to the adult, but instead of a solid line running down their back, they have a series of keyhole-shaped white dots.
  5. Wild cherry, aspen, maple, oak, and hawthorn are among the plants that serve as hosts.
  6. Webworms are known to feed on over 85 different types of trees and are found across North America and Mexico.
  7. One-inch-long caterpillars are coated with long hairs and range in color from yellow to green, with a black stripe along the back and a yellow stripe on each side of the body.

The color of their heads is either red or black. Adult moths (1 inch in length) are pure white in color with black markings on the wings, which are characteristic of the species.

Life Cycle

The egg stage is where the majority of tent caterpillar species overwinter. Egg masses ranging in color from dark brown to gray and holding 150 to 400 eggs are adhered to the short twigs of trees and bushes. Hatching takes occur around the time when leaf buds begin to open, which is normally in the early spring months. They are social creatures who quickly build silken tents, which they use as a haven during the early morning and evening hours, as well as during rainy spells, to protect themselves from the elements.

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The larvae reach full maturity around six weeks after hatching and five instars following that time period (up to 2 inches long, sparsely hairy).

Adult moths emerge around two weeks later and deposit the overwintering eggs within a short period of time.

Note: When larvae begin to travel to sheltered regions in order to pupate, they can become a nuisance.

How to Control

  1. Prevent the larvae from starting to eat by scraping off and discarding overwintering egg masses and tearing the protective tents out by hand before they start to feed. With this method, you may restrict caterpillar mobility and deny them access to eating locations. Sticky Tree Bands or Tree Tanglefoot Pest Barrier are two options for preventing pest infestations. The naturally occurring soil-dwelling bacteriumBacillus thuringiensis, often known as Bt-kurstaki, is highly powerful against all species of inch worms. At the first indication of damage, use a spray that is simple to apply to knock out the worms and safeguard the foliage. It is safe to use BTKsprays near dogs and children since they do not damage honey bees or birds
  2. Spinosad, a biological substance developed from fermentation, is also extremely useful in a variety of applications. In fact, it’s the active ingredient in Monterey Garden Insect Spray, a product that has been classified as organic by the United States Department of Agriculture’s National Organic Program and listed for organic use by the Organic Materials Review Institute
  3. AzaMaxcontains azadirachtin, which is the key insecticidal ingredient found in neem oil. This very powerful spray interferes with the growth and development of nuisance insects while also acting as a repellant and anti-feedant. In addition to being non-toxic to honey bees and many other helpful insects, it should only be used as a last resort for dealing with bug infestations. Natural pesticides, which are derived from plants that contain insecticidal qualities, have less adverse side effects than synthetic chemicals and degrade more quickly in the environment.

Note: Although more than 80 species of predators and parasites have been identified in the United States, none of them are now available for purchase on the market. During the majority of the year, these insects serve a crucial role in keeping pest populations under control. As a result, extreme caution must be exercised while spraying pesticides in order to avoid causing harm to these important species.

Where did all these caterpillars come from?

Important to note: Despite the fact that more than 80 species of predators and parasites have been found in the United States, none of them are now available for purchase. During the majority of the year, these insects play a critical role in sustaining pest populations. This means that while spraying pesticides, caution must be exercised in order to ensure that these beneficial species are not negatively affected.

6 Fascinating Facts About Tent Caterpillars

It is possible that homeowners who are concerned about the health of their beloved cherry trees would be disappointed to see silk tents sprout in the branches each spring. Tentcaterpillars have the ability to consume practically every leaf on a tree when they congregate in sufficient numbers. However, if you spend a few minutes observing the tent caterpillars in action, you will quickly realize that they are very smart insects. Tent caterpillars are a frequent pest, but these ten intriguing facts about them may make you reconsider your position on them.

Tent caterpillars are gregarious

Tent caterpillars are known to congregate in large groups. Ed Reschke/Getty Images/PhotoLibrary/Getty Images A group of tent caterpillars congregates in a shared silk tent for no reason other than convenience. Tent caterpillars are extremely gregarious creatures! Within the genus Malacosoma, there are 26 species of tent caterpillars that have been identified, and all of them are known to display social activities.

The female moth lays 150-250 eggs in a single mass, which is most typically found on the south side of a cherry tree limb, according to the species. During the 6-8 weeks that they are caterpillars, these siblings will live, feed, and develop in close proximity to one another.

The tent caterpillars’ tent serves as their home base

The caterpillars are more protected from predators such as birds when they are in the tent. Photograph courtesy of Getty Images/PhotoLibrary/Johann Schumacher Not allMalacosomacaterpillars construct huge, permanent tents, but those that do do so use their family tent as a base of operations throughout the larval stage of their development. Choosing a spot to build their house is where eastern tent caterpillars begin living their lives. A tree crotch that receives early sun attracts the tiny caterpillars, who subsequently spin silk to contribute to the construction of their tent, which takes many days.

The caterpillars repair and maintain their habitat in preparation for each foraging expedition.

Tent caterpillars use pheromones to mark trails on their host tree

Caterpillar of the eastern tent. John Macgregor/Getty Images/PhotoLibrary/Getty Images Many insects communicate with one another through the use of chemical markers. In order to communicate with their siblings, eastern tent caterpillars use pheromone trails, which they accomplish in a rather complex manner. They employ a variety of pheromones to distinguish between exploring tracks and recruiting paths. When a travelling caterpillar comes across an exploratory pheromone trail, it understands that another caterpillar is already investigating that branch for food, and it turns away from the trail to choose another path.

If you spend enough time monitoring eastern tent caterpillars, you’ll observe that when a caterpillar gets close to the crotch of a tree limb, it stops and “sniffs,” as if it’s trying to figure out which direction to move.

Tent caterpillars keep each other warm

Eastern tent caterpillars congregate to soak up the rays of the sun. Photograph courtesy of Getty Images/PhotoLibrary/Johann Schumacher During the early spring, when the warm weather hasn’t completely taken hold, eastern tent caterpillars are most active. Temperatures are likely to vary, and evenings can be quite chilly. In order to regulate their body temperature, eastern tent caterpillars engage in behavioral thermoregulation, in which they work together to take active steps. Eastern tent caterpillars may warm themselves by basking in the sunlight on the exterior of their tents if they need to.

When it becomes particularly cold, the eastern tent caterpillars will all huddle together in their silk tent for protection.

In contrast, if the temperature within the tent becomes too high, the caterpillars will go to the shady side of the tent and suspend themselves independently, allowing air to pass between them.

Eastern tent caterpillars can cause abortions in pregnant mares

Tent caterpillars can cause a mare to miscarry her late-term foal if she consumes them. Photographer’s Choice/Bread and Butter courtesy of Getty Images When eastern tent caterpillars are present in the spring grasses, grazing mares can quickly become unwell, causing serious problems for horse owners. However, although being typically innocuous, eastern tent caterpillars are coated in minute hairs known as setae, which may pierce the walls of a mare’s digestive tract, including her intestines.

MRS (mare reproductive loss syndrome) is a disorder in which pregnant mares spontaneously abort their late-term embryos after devouring eastern tent caterpillars (or other caterpillars) (MRLS).

Kentucky horse owners lost more than one-third of their foal pregnancies to MRLS in 2001, according to the Kentucky Horse Council.

Mules and donkeys can also have their developing offspring aborted if they consume tent caterpillars while they are pregnant.

Tent caterpillar outbreaks are cyclical

Tent caterpillar epidemics occur in cycles, with some years being more severe than others. Photograph by Johann Schumacher for Getty Images These caterpillars, which are endemic to our forests and have voracious appetites, can do significant harm to our forest trees, but our plants are typically able to recover from the damage they cause. When it comes to caterpillar infestations, some years are unquestionably worse than others. Every 9-16 years, the tent caterpillar population reaches a critical mass, causing substantial harm to the trees along their path.

Don’t be alarmed if your favorite cherry or apple tree has suffered a setback this year.


“Horse owners should be on the lookout for the eastern tent caterpillar,” according to the University of Missouri Extension, published on May 17, 2013. accessed on the internet on the 15th of August, 2017. “Tent Caterpillars, Malacsoma spp.,” by Terrence D. Fitzgerald, in Encyclopedia of Entomology, 2nd edition, edited by John L. Capinera and published by John L. Capinera.

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.

In addition, the communal larvae of that species do not construct tents as they do in other species. 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.

Winnipeg’s forest tent caterpillars invasion: 5 things to know

In Winnipeg, forest tent caterpillars are chomping their way through our leafy canopy of trees, consuming the leaves as they go. According to entomologist Taz Stuart, 500 million moths might emerge in July. Tent caterpillars cling on the trunk of a tree at a park in Winnipeg. (CBC) Forest tent caterpillars are nibbling their way into the city of Winnipeg, dining on the lush canopy of trees that surrounds them. Caterpillars of the forest tent species infest the city about once every 10 to 15 years, but when an infestation occurs, it can linger for up to two to three years.

  • According to an entomologist, forest tent caterpillars are invading Winnipeg.
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Taz Stuart, an entomologist and director of technical operations at Poulin’s Pest Control Services, believes that there are more of the writhing bug in the city than most people would anticipate. If each tree produces 100 forest tent caterpillars and there are 5 million trees, then 500 million adult moths will emerge in July, according to a tweet he sent out on Monday. How many adult moths will emerge around the middle of July if each tree contains 100 forest tent caterpillars and there are around 5 million trees?

@tdtsca is a Twitter handle.

  • The World Health Organization has concluded that malathion is ‘probably carcinogenic’ to humans. In Winnipeg, the supply of malathion will not be replenished after this year.

His knowledge of the creepy crawler included several other fascinating tidbits.

Caterpillars relax during the day

Tent caterpillars are not active during the day, despite the fact that this is the period when most people see them. They are most active at night, according to Stuart. According to him, “They graze on leaves and they feed at night.”

Grouping protects them from predators

The tent caterpillars may appear to be having a wonderful time clumping together on the trees, but Stuart emphasized that their clumping serves a more important purpose than simply entertaining themselves. “If they are left alone, a bird, a skunk, a raccoon, or even a squirrel may take advantage of their vulnerability and eat them. When they are gathered together in such a huge group, they are less likely to be bothered “he explained. He went on to say that there are often 100 to 150 caterpillars in each cluster.

(Photo courtesy of the Associated Press/Star Tribune, Joel Koyama) (From the Star Tribune and Joel Koyama of the Associated Press)

They are equal opportunity tree eaters

Despite the fact that they appear little, the caterpillars’ impact on the leaves may be significant. Stuart said that a defoliated tree is weaker and slows down, which means it may not be able to absorb enough glucose to produce leaves the next year as a result. According to him, if a tree is subjected to defoliation for a number of years, it may eventually succumb.

Stuart went on to say that he hasn’t come across a tree that the caterpillar doesn’t like, but that they like attractive trees such as Chokecherry and Ash. Stuart went on to say that he had never seen them in gardens before.

Most of their life is spent as an egg

According to Stuart, the tent caterpillar’s life cycle begins with the laying of an egg, which occurs about in the third week of July. The eggs are kept in storage throughout the winter until the ideal temperatures are reached, which normally occurs in mid-May. “They will emerge as very, very little larvae when they hatch. They will grow in size in stages, and right now you are watching what appears to be the final stage of their development “Stuart shared his thoughts. “After that, it will go into the pupa stage, which is almost like a little cocoon stage that will be in the ground or in locations where they feel safe to be,” says the expert.

Stuart claims that they are fast to begin mating and depositing new egg masses, which “appear to be a small bit of dung on a stick,” according to Stuart.

Forest tent caterpillars invading Winnipeg: Here is what you need to know

Forest tent caterpillars infest the city on average once every 10 to 15 years, according to the USDA. 0:29

They make an easy pet

It is possible that small children will be enticed to carry home the fluffy, squirmy tent caterpillar. According to Stuart, if this is the case, it should be rather simple for a parent to comply. According to him, “if you want to keep them in a lovely small container, you can put a few of leaves from the tree in there and they will feed on them at night and relax during the day.”

Forest tent caterpillars

Throughout Minnesota, forest tent caterpillars prey on a variety of broadleaf trees and plants, including quaking aspens, balsam poplars, basswoods, oaks, ashes, birches, alders, and fruit trees, among others.

  • The feeding damage caused by these caterpillars causes the development rate of deciduous trees to slow down. When forest tent caterpillars defoliate their target trees, they may cause damage to other adjacent plants as well. On vegetables, fruit trees and other tiny fruits, as well as nursery crops, there is evidence of damage
  • When they are discovered in close proximity to buildings or on roads, they become a nuisance.

The forest tent caterpillar (Malacosoma disstria) may be found throughout most of the United States and Canada, where hardwood trees can be found in dense stands of foliage. Red maple and conifers, such as pine and spruce, are among the plants on which this caterpillar is less likely to feed. Larvae of the forest tent caterpillar

How to identify forest tent caterpillars

  • Two inches long, primarily blue and black in color, with a row of white, footprint-shaped marks on the back and a dense covering of hairs along the edges of their bodies.

Adult moths

  • Moths are nocturnal and drawn to lights at night
  • They emerge from their cocoons around two weeks later, in mid-July
  • And they have a short lifespan.

Caterpillar egg mass in a forest tent

Life cycle of forest tent caterpillars

Aspen leaves begin to open in early to mid-May, which coincides with the emergence of larvae (caterpillars) from egg masses on the aspen tree.

  • Over a period of five to six weeks, aggressively feed on aspen and other broadleaf trees a silken mat that is hardly discernible where caterpillars congregate on the tree’s trunk and branches

As the month of June approaches, older larvae begin to roam about trees and other vegetation in search of food, causing harm to adjacent plants.

  • By the end of June, fully grown caterpillars are searching for safe havens to spin silky cocoons
  • By the middle of July, adults have emerged from their cocoons
  • Adults live for about five days and lay 100 to 350 eggs in gray, cylindrical masses surrounding small twigs
  • By the end of August, the caterpillars have hatched.

The eggs survive the winter, and the larvae that emerge from the eggs the following spring. Every year, just one generation is produced. The forest tent caterpillar is responsible for some defoliation.

Damage caused by forest tent caterpillars

Generally, feeding by forest tent caterpillars does not cause deciduous trees to die since they may develop another set of leaves during the same season in which they were fed. Healthy trees may withstand two to three years of intensive defoliation in a row if they are in good condition. Trees may be felled for the following reasons:

  • If the same tree has been significantly defoliated for four or more years, it is considered to be diseased. When trees are under stress, such as during a drought, they might die.

It is considered substantially defoliated if the same tree has been severely defoliated for four or more years; The condition of trees when they are under stress, such as during a drought

Forest tent caterpillars as a nuisance

Maturity larvae can be seen on buildings and in yards when they are searching for a safe haven to lay their eggs.

  • They do not bite or hurt people, animals, or property
  • Instead, they are peaceful. There are several difficulties in removing their cocoons from the exterior of buildings, and they are a nuisance. If forest tent caterpillars on city roadways are mistakenly squashed, the resulting oily and slippery surface can be dangerous.

They do not bite or injure humans, animals, or property; instead, they are harmless. There are several difficulties in removing their cocoons from the walls of buildings, and they are a nuisance; Forest tent caterpillars on city streets can cause oily and slippery surfaces if they are mistakenly crushed; this is especially true if they are accidently crushed while walking.

How to protect your trees from forest tent caterpillars

  • The population of forest tent caterpillars is reduced by a cold or damp spring, hunger, and viral illness. In order to destroy caterpillar eggs, larvae, and pupae in a forest tent, wasps and flies must be allowed to flourish within the tent. A good example is the giant gray fly, Sarcophaga aldrichi, which is endemic to Minnesota and is considered a pest.

Remove eggs and caterpillars as you see them

  • Remove and destroy egg masses that have accumulated on the limbs of tiny trees before the eggs hatch the following spring. With a stiff brush, remove caterpillars and cocoons from the outside of houses, picnic tables, and decks. Using a water spray, knock caterpillars from their perches. Care should be taken not to crush too many caterpillars as this might cause smearing and marking on some paints.

Using pesticides

Pesticides, in addition to physical measures, may be effective in the control of larvae. Pesticides should be used while larvae are little (1 inch or less in length), which is often in early to mid-May. Larger larvae are more difficult to destroy, and they can continue to defoliate trees even after insecticides have taken their toll. Some of the choices that are accessible are as follows:

  • Bacillus thuringiensis (commonly known as BT), a microbial pesticide derived from a bacterium, is both efficient and friendly to the environment. Additionally, insecticidal soap, spinosad (a microbiological pesticide), and azadirachtin (a botanical pesticide) are among the pesticides that help to conserve beneficial insects. A number of chemical insecticides, including acephate, bifenthrin, carbaryl, cyfluthrin, esfenvalerate, fluvalinate, lambda-cyhalothrin, malathion, permethrin, and phosmet, have been developed to combat these pests.

When selecting a pesticide, take sure to read the label carefully because the active components are written in small type.

Forest tent caterpillars in wood lots

Birds, rodents, and even bears consume the caterpillar larvae of the forest tent caterpillar in wooded areas. Control actions should only be performed in the event of severe defoliation over a period of several years. In wooded regions, resort areas, and campsites where huge areas may require treatment, the following procedures should be followed:

  • Aerial pesticide spraying by aircraft is the most efficient, effective, and cost-effective approach available
  • Nevertheless, spraying should be avoided where gusts threaten to carry the pesticide over open water or other sensitive locations. Treatment of an extra strip about 400 feet wide next to the region should be performed when spraying in residential or recreational areas. The presence of this barrier strip prevents caterpillars from migrating.

The pesticide BT is recommended because it is non-toxic to humans, birds, or beneficial insects, and it is typically used first in aerial spray programs because of this property. Diflubenzuron should not be used near wetlands or bodies of water since the pesticide has the potential to harm aquatic insects and other arthropods. 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.

In 2018, a review was conducted.

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