How to get rid of bag worms on cedar trees

How to Kill Bagworms on a Cedar Tree | Home Guides

By Maureen Malone Updated August 16, 2021

Cedar trees (Cedrus spp.) are needled evergreens that are often used as specimen plants in the landscape. Unfortunately, these trees sometimes suffer infestations of bagworm species. There are cultural and biological control steps you can take to control the pests, or you can kill bagworms in trees with chemical insecticides. Cedar trees are hardy in U.S. Department of Agriculture plant hardiness zones 5 to 9 depending on the species, according to Missouri Botanical Garden.

Bagworms on Cedar Trees

Bagworms are not a single species of insect but rather the larvae and caterpillar forms of moths, advises the University of Maryland Extension. They make a cocoon and carry it as they feed on the tree. In late summer, the bagworms reach their full size, and the cocoon, or bag, is attached to the tree where the worms pupate and transform into moths.

Bagworms can defoliate and even kill cedar trees if the infestation is severe. Although you can see the pests if you look closely, they are not easily visible, and you may not know about the pests until serious damage has been done to your tree.

The evergreen bagworm (Thyridopteryx ephemeraeformis) is especially common on conifer trees, like cedars, advises Clemson University Cooperative Extension Service. These pests are more likely to be a problem if your cedar tree is stressed from drought or other poor growing conditions. It is important to implement control measures before the bagworm population grows out of control.

How to Control Bagworm Species

The first step when you recognize a bagworm infestation is to handpick the bags from your tree. Be sure to throw out the bags. If you simply drop them in the soil, they may emerge from the cocoon, and the adult moths may lay more eggs that then attack your tree. You can do this any time of year, but ideally, remove the bags in the fall, winter and spring.

If the infestation is small, this may be the only step you need to take to control the pests. However, if the infestation is larger or if there are a number of bagworms that you cannot reach on taller cedar trees, additional control steps may be necessary.

A biological control method to kill bagworms in trees is to spray the tree with Bacillus thuringiensis, or Bt. Bt is a bacteria that eradicates the bagworms after they ingest it. You can spray in the late spring as a preventative measure or in mid-July when the bagworms are actively feeding on the tree.

Chemical Control of Bagworms

In some cases, mechanical and biological control methods are not sufficient to kill bagworms in trees. Insecticides are not effective at eradicating eggs, as it doesn't penetrate the casing. Spray the insecticide in the early summer months while the larvae are actively feeding.

When looking for a chemical treatment, be sure to check the product label to determine the best insecticide for bagworms on your tree. Some active ingredients that can effectively target bagworms include spinosad, pyrethrins, pyrethroids, malathion or acephate.

Be sure to follow all of the instructions and safety warnings indicated on the product label. These chemicals can also harm beneficial pollinators, so spray the tree later in the day when these good insects are less active. You may need to spray some products, such as those containing spinosad, multiple times to fully control the bagworms. Use caution with repeated applications, as these pests may become resistant to some insecticides, such as those containing pyrethrins.

Things You Will Need


  • Missouri Botanical Garden: Plant Finder Results, Genus Cedrus
  • University of Maryland Extension: Bagworms on Trees and Shrubs
  • Clemson University Cooperative Extension Service: Integrated Pest Management (I.P.M.) For Evergreen Bagworms


  • Bagworm bags are made from bits of cedar foliage held together with silk. Newly constructed bags are the same color as the live foliage, making them difficult to find. As the bits of foliage age, they turn orange, yellow and brown so they stand out against the green foliage.


  • Read the entire label before using an insecticide, and follow the instructions for mixing and applying the product exactly. Store unused portions in the original container and out of the reach of children and pets.

Writer Bio

Maureen Malone has been a professional writer since 2010 She is located in Tucson, Arizona where she enjoys hiking, horseback riding and martial arts. She is an outdoor lover who spends her weekends tending her raised garden and small orchard of fruit trees.

How to Get Rid of Bagworms

Photo: via NY State IPM Program at Cornell University

Notice an inexplicable mass destruction, yellowing, or defoliation in your evergreens? A close and careful look through the branches might reveal the culprit in clever camouflage: bagworms.

These destructive insects attack many species of tree or bush but are most often found on conifers like juniper, pine, arborvitae, cyprus, cedar, and spruce. They’re called “bagworms” because after the larvae feed on plants and trees, they encase themselves in cocoon-like “bags” constructed from twigs, leaves, and self-spun silk.

Once in its bag, a female bagworm can lay 500 to 1,000 eggs, escalating your bagworm problem to a serious infestation fast. Each egg will hatch into another bagworm primed to defoliate whatever it’s near. The worst part? Your problem may go unnoticed until too late because these bags assume the appearance of conifer cones.

Should you find yourself with a bad case of bagworms, follow this thorough guide to get rid of them.

Tools & Materials
  • 5-gallon plastic bucket
  • Soap
  • Bacillus thuringiensis
  • Garden sprayer
  • Insecticide for bagworms


Get Rid of Bagworms By Handpicking

If you find just a few bagworms, you may have caught the infestation early enough that you can effectively control the situation by handpicking the bags off the plants and submerging them in a bucket of soapy water to suffocate the larvae.

This will work, however, only if the larvae haven’t yet left the bags to go out to feed. Hatching generally happens in late May to early June, so do your handpicking of bagworms from late fall to early spring.

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Remove Bagworms Through Biological Control

Sometimes it’s not feasible to handpick bagworms, particularly when you’re dealing with tall trees. But if you can harness the power of creatures that feed on bagworms, you may still be able to control your bagworm population.

  • Bacteria: Bt, the bacteria Bacillus thuringiensis, is effective at controlling bagworms if it’s applied as soon as the eggs hatch in the spring. Don’t wait too long—this bacteria won’t be as effective when the larvae have grown large. Follow the application instructions on the product you buy, and apply it with a garden sprayer. Follow up and reapply every seven to 10 days until the bagworms are gone.
  • Birds: Sparrows are predators of bagworms, so you may be able to keep the bagworm population down by attracting sparrows to your yard. To make your property more appealing for the birds, provide water at ground level (a low birdbath) as well as materials and places for nesting (thickets and trees). Sparrows also appreciate shelter to flit between, so brush piles and shrubbery can be assets, as can dusty areas for dust-bathing.

Or, Control Bagworms with Chemicals

An insecticide with malathion, diazinon, or carbaryl (such as Ortho Tree & Shrub Insect Killer, available on Amazon) can rid you of a bagworm problem if applied to bushes and trees when the worms are still young larvae. So, aim to spray in late spring, just after the bagworms have hatched and begun to feed, and always follow the insecticide manufacturer’s instructions.


No matter where or what time of year you find bagworms, don’t wait to start formulating a plan to eradicate them. Left unchecked, they can completely defoliate and kill your yard’s trees, bushes, or hedges.

Photo: via Dick Culbert

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Caterpillar in a case • Vasily Derevianko • Scientific Picture of the Day at Elements • Entomology

In the photo — a pea bagworm caterpillar ( Megalophanes viciella ) is crawling about its business. Bagworms (Psychidae) are a family of butterflies that got its name from the silk cocoon, or cap, that the caterpillar builds around itself and drags on itself all its life. The caterpillar encrusts this cocoon with various improvised materials in order to blend in with the surrounding landscape and not attract the attention of predators.

Caterpillars begin to build their caps as soon as they hatch from their eggs. This matter is ahead of even food in importance and urgency. The basis of the cap is a bag of silk thread - silk is produced by silk glands (modified salivary glands) that open near the jaws. As the caterpillar grows, this bag increases. The cocoon must be smooth and dry from the inside: due to dampness and insufficient ventilation, mold can penetrate inside the cover, which will inevitably lead to the death of the caterpillar. This explains the attraction of bagworms to sunny, well-heated locations - dry pine forests, high river banks, forest edges, steppes, mountain slopes. Also, caterpillars mainly look for food during the day, in sunny weather.

The caterpillar keeps its case clean: excrement, food remains, pieces of skin after molting - all this is immediately thrown away. The cocoon is always dry and clean, at least from the inside. Outside, the cocoon is covered with particles of the environment. To fix them, the caterpillar protrudes the thoracic region from the cocoon, moves them with its paws and fastens them with silk.

The bagworm family includes a little more than 1300 species, which are distributed almost everywhere - in the Palearctic, Africa, South and North America. Bagworms live in a variety of landscapes and encrust their cases with a variety of materials. Caterpillars that live on plants attach dried stems (like the pea bagworm in the main photo), twigs, pieces of leaves and bark, and other available materials to the case. Bagworms living on the soil surface cover the cocoon with grains of sand and the remains of shells of land mollusks (for example, living on the Canary Islands Luffia rebeli ).

Soil and excrement serve as building material for the cover of the psychid snail ( Apterona helicoidella ), which, of course, is reflected in its appearance. The shape of the cap is spiral - it is for this that this pouch received the nickname "snail" in different languages. A caterpillar with such a house behind it really resembles a snail, and because of the shape of the cap, not only does it itself constantly stay in a twisted state, but also its chrysalis has the shape of a spiral.

Cases of different baggers are not limited to a variety of materials for inlay. The shape of the silk bag and the arrangement of materials on its surface also differ. Therefore, caps serve as a good tool for determining the genus or even species of an insect. For example, the moorland bagworm Acanthopsyche atra decorates its home with heather twigs and leaves. And they do not agree to replace heather even with outwardly similar materials planted by the experimenter. In shape, the caps can be cylindrical with varying degrees of cone-likeness, trihedral, spiral-shaped (as in the above-mentioned Apterona helicoidella ). The simplest option is a cigar-shaped one: a soft and, as a rule, not thick case with particles of soil and grains of sand or fragments of bark and leaves woven into it. This is built, for example, by the New Zealand bagworm Liothula omnivore .

Building materials covering the cover can be woven along - in one layer, as in Epichnopterix ardua , or in several layers, consisting of various materials and partially overlapping each other, as in Canephora hirsuta.

Materials can also be woven across the cover. Such styling is characteristic mainly of the highest representatives of the bagworm family, in particular the heroine of the main photo, the pea bagworm and living in Europe Amicta cabrerai , which builds a very even transverse quadrangular structure - almost a teremok (see photo). Some species, such as the European bagworm Sterrhopteryx fusca , prefer to lay the material in concentric circles, expanding from the beginning to the neck of the case, or in a spiral (this is not about the shape of the case, like in a psychid snail, but about the way the branches are laid on a cigar-shaped bag).

But all covers have something in common - this is a soft neck at the entrance. It is never reinforced by external elements and, if necessary, is drawn inward, closing the inlet. Through this hole and neck, the caterpillar protrudes its head and anterior segment with pectoral legs, with the help of which it moves. It must be said that bagworm caterpillars are quite strong: not only do they travel only with their front legs, they also raise their huts above themselves, holding them with their abdominal section, lifted up!

True, bagworms move even without a cap with their abdomen up, which can be observed on caterpillars that have just hatched from eggs.

And the caterpillars have to move a lot due to their food habits and the propensity for food migration inherent in some types. For example, Sterrhopterix fusca in the first year of life feeds on grass, and after wintering it climbs onto shrubs such as alder, hazel and others.

A successfully overwintered caterpillar dedicates the second summer of its life to preparing for the transition to adulthood - to pupation, mating and oviposition. Sometimes, however, the caterpillar survives two or even three winters in its lifetime. It depends on the type and weather conditions. After leaving the pupa, the adult insect (imago) sits on the cover for an hour, spreading and drying its wings.

Butterflies bagworms are small (wingspan from 8 to 50 mm) and inconspicuous - gray, yellowish or black in color, some have translucent or transparent wings. But they have a luxurious feathery mustache.

True, females are rarely winged and mustachioed. In most species of bagworms, the females are the keepers of the "home" cocoon; even after leaving the pupa, they remain worm-like, wingless, often with underdeveloped legs. Such a female does not fly away anywhere, she either crawls out of the case, remaining nearby to lay her eggs in it soon, or even remains sitting in it, waiting for the matchmaking of the mustachioed gentleman who found her. The female signals her readiness for copulation by releasing pheromones. The male does not have much time to search for females by smell: adult males live from several hours to one or two days (females - up to a week). Adult bagworms do not eat anything, and even their mouth organs are reduced. Sometimes males fly to the smell of human sweat, which must be a very annoying waste of time and effort, given the length of their adult lives.

In some species, the female remains inside the cap during mating. For this, the whole family received the name Psychidae - in honor of the heroine of ancient Greek myths, Psyche, who lived in the castle of Eros, but did not have the right to look at it. True, in bagworms, it is the male who does not particularly manage to see his beloved, and not vice versa. Having found a female ready for mating in a case, the male sits on the edge of her case and launches his abdomen with a retractable copulatory apparatus into it. Moreover, it is necessary to get not only into the sheath, but also into the exuvium located in it - the cuticle of the pupa - in which the female sits. In species whose females crawl out of the cap, mating is less intricate.

After mating, the female lays eggs. Very few species lay them openly (for example, on leaves), winged females fly away from the cap and lay their eggs in natural hiding places like crevices in the bark and trunk of a tree or cracks in stones. But most species leave clutch inside the cap, and even inside the exuvia. Dying, the female falls out of the cap, leaving it to future offspring, which will hatch in three to four weeks and will be able to pull the mother's house to the original building material to inlay their caps.

Photo © Helmut Kaiser from

Vasily Derevyanko

How to get rid of evergreen bagworms?

How to get rid of evergreen bagworms? How to get rid of bagworm on thuja, evergreen and other trees? You won't like it, but the easiest way to get rid of pouches is to cut the pouches by hand and destroy them. Remember to also cut off all their silk, because this can suffocate (and kill) the branches later.

What kills bagworms on evergreens? An insecticide with malathion, diazinon, or carbaryl (such as Ortho Tree & Shrub Insect Killer, available on Amazon) can get rid of bagworm problems if applied to bushes and trees when the worms are still young larvae.

Can an evergreen recover from bagworm? Evergreen trees, on the other hand, are very slow to germinate, shed their leaves, and regenerate. This is likely the case for many bagworm infested evergreens where bagworms were not controlled early or well enough to stop the damage.

How to protect evergreens from bagworms? Products containing Bt (Bacillus thuringiensis) such as DiPel or Worm Whipper are not contact insecticides. They have to be eaten by young caterpillars. To apply, simply spray Bt on the foliage and let bagworms nibble on.

Are evergreen bagworms harmful?

How serious are bagmen? Bagworm larvae grow and feed on trees, causing damage to plants. These pests can be dangerous and costly to landscaping, but they do not pose a threat to human health. Large infestations of these pests can damage or kill trees and shrubs as a result of defoliation.

Is it too late to spray for bagworms?

If the caterpillars are no longer visible and do not feed, if the bags no longer move, then it is too late to treat. Even if caterpillars are still visible, spraying at the end of the season may not be effective. Trees should be protected from bagworm defoliation by spraying in late June to mid-July.

What do you spray against sacks?

Sprays such as Bacillus thuringiensis, spinosad, and any of the pyrethroid insecticides are effective against bagworms, especially early in the season. Late season infestations, when bagworms are larger and harder to kill, are best treated with pyrethroid sprays.

Can a plant be cured of bagworm?

Will thuja be able to recover after being damaged by bagworm? Unfortunately, it may take some time for the thuja to recover from bagworm damage. Brown spots may or may not recover. A good way to say this is if you use your fingernail to look for green tissue inside the branches.

When should you spray against bagworms?

Early summer is usually the best time to treat this pest. If you miss this opportunity, the effectiveness of control will be greatly reduced. If you have bagworms this year, schedule a re-spray next year (mid-May) to catch young caterpillars that will hatch next season.

How do sackers start?

In spring, bagworm eggs hatch and each larva leaves the pouch, releasing a thin silk thread and swimming down from the pouch. The wind will then carry it to another host plant, where it will attach itself and start creating its own bag. The larvae pupate in September.

How to get rid of pouchers?

How to get rid of bagworm on arborvitae, evergreens and other trees? You won't like it, but the easiest way to get rid of pouches is to cut the pouches by hand and destroy them. Remember to also cut off all their silk, because this can suffocate (and kill) the branches later.

Are marsupials good for anything?

These are the bagmen's houses. The worm-like immature stages of these insects feed on over a hundred varieties of plants. The flowers help attract beneficial insects to the plants and help control bagworm populations. Remove the bags when they are found.

How do you control bagmen?

Collecting bagworms by hand: to get rid of bagworms in the garden, collect or cut off their limbs and destroy them by throwing the bags into a bucket of hot soapy water. The baggers should be collected before the eggs hatch in June. When too many plants are involved, use sprayers.

What are the stages of bagworm?

The bagworm, like all moths, undergoes a complete metamorphosis in four stages. Egg: At the end of summer and autumn, the female lays up to 1000 eggs in a case. She then leaves her bag and falls to the ground; eggs hibernate. Larvae: In late spring, the larvae hatch and disperse along the silk threads.

Do pouchers spread?

Sacs spread slowly because the female does not fly. However, the wind can carry the worms from plant to plant, which is quite effective in dispersing bagworms.

What do evergreen bagworms turn into?

Adult males turn into butterflies in four weeks to look for females to mate with. The female never leaves the cocoon, requiring the male to mate with her through the open end at the back of the body.

How do you know if the bagmen are dead?

Because baggers add plant materials to the top of the bag, the freshest and greenest material is at the top of the bag. When you see a completely brown bag, the insect inside has stopped feeding or is dead.

How to get rid of bagworms in summer?

Pick up the branches, cut off bagworm egg sacs and drop them into a bucket of soapy water. Make sure they are completely submerged in water. Empty the soaked baggies into an airtight plastic bag and throw them in the trash can. Repeat this procedure every fall, winter, and early spring to reduce bagworm populations before the eggs hatch.

Is Sevin useful from baggers?

The GardenTech® brand offers highly effective controls that kill feeding bagworms on contact and keep foliage protected for up to three months. Sevin® Insect Killer Concentrate is an easy and economical way to provide extensive coverage of small trees and shrubs.

Where do bagworms lay their eggs?

The bagworm (T. ephemeraeformis), found on most evergreens, is found in east-central Texas, from the Oklahoma border to the Gulf Coast. This species has one generation per year. Eggs are laid in autumn and hatch in spring.

How long do bagworms live?

From start to finish, the lifespan of a bagworm is approximately one year. Typically one generation per year. The eggs of most species overwinter in bags before starting their destructive behavior again.

Can trees survive baggies?

A: If an evergreen tree is heavily infested with bagworms, they can indeed kill the tree if the defoliation is severe. Bagworms can also be a problem for deciduous trees, but they don't usually kill them.

Where are the bagmen?

Bagworm is a native defoliator found throughout the eastern half of the United States, commonly found in Kansas and Nebraska, and occasionally reported in South Dakota. primarily a pest of arborvitae and eastern red cedar.

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