What Eats Bagworms

What Eats Bagworms: Friendly Predators in Your Garden

Bagworms are notorious pests known to damage several plant species, particularly junipers, conifers, and other needle-bearing evergreens. You might be curious about which natural predators can help control their population and protect your plants.

As a gardener or an enthusiast looking to explore beneficial insects or animals to curb the infestation of bagworms, you’re certainly in the right place to get an insight into what eats these voracious feeders. In the upcoming sections, we’ll delve into the critters that could be your garden’s natural defense line against bagworms.

A Bagworm on a Leaf
A Bagworm on a Leaf

Understanding the feeding habits and life cycles of these creatures can aid you in strategically employing them to reduce bagworm populations, helping your plants thrive in a harmonious, eco-friendly environment. So, let’s jump in and explore the natural predators of bagworms!

What Are Bagworms

Bagworms are a type of moth with a peculiar way of protecting themselves. They create silken cases or “bags” to live in, decorated with fragments of leaves and twigs from their surroundings. These bags not only provide camouflage but also secure the bagworms as they feed and grow.

You may be wondering about the appearance of these creatures. The bagworm caterpillar lives its entire life inside the protective case mentioned earlier. With its head and legs sticking out, it can continue feeding as the bag enlarges throughout the summer months.

Bagworms aren’t picky eaters. The evergreen bagworm or Thyridopteryx ephemeraeformis can be found on over 50 types of deciduous and evergreen trees and shrubs. Their presence can sometimes cause damage to the plants’ health and aesthetics.

Here are some characteristics of bagworms:

  • The larvae of a small, black male moth and a wingless gray female
  • Hatches from eggs in late April or early May
  • Often found on junipers and other conifers, but can also be found on certain deciduous trees and shrubs.

In summary, bagworms are an intriguing type of moth that uses its surrounding vegetation to construct a unique, camouflaged home. These curious creatures can be found on numerous plant species and may affect their health if infestation occurs.

Bagworm Lifecycle


Bagworms start their life as eggs laid by female adults. These eggs are protected within the female’s bag, ensuring their safety. Once they hatch, they emerge as larvae ready to build their protective cases out of materials from their surroundings, such as leaves, twigs, and bark.


As the larvae grow, they continue to construct and expand their bags around themselves. This allows them to stay protected from predators during their development. You might notice caterpillar-like creatures carrying little bags around on your plants – these are bagworm larvae.

Bagworm Lifecycle Stages:

  • Eggs
  • Larva
  • Caterpillar
  • Pupation
  • Adult


The bagworm caterpillar phase is the most apparent stage. In this stage, the larvae actively feed on your plants, moving between the leaves and branches. They also continue to grow and integrate their bags, increasing their size and providing more protection.


Eventually, the bagworm caterpillars reach their pupation stage, where they transform into the adult phase. During this time, they secure their bags to a stable structure and discard their larvae’s bag-making materials. This process allows them to develop into adults within their protective enclosures.


Once they’ve reached adulthood, the bagworms are fully developed and ready to reproduce. The adult males will leave their bags to find females to mate with, while the females often remain stationary inside their bags. After fertilizing the eggs, the male passes away, and the female soon follows suit after laying her eggs in her bag.

By understanding the bagworm lifecycle, you can better manage their growth and know when to take action if they become destructive pests on your property. Keep an eye out for the various stages and address any issues that arise as you maintain your plants and trees.

Bagworms Hanging on Branches
Bagworms Hanging on Branches

Damage Caused by Bagworms

Bagworms can cause significant harm to various plants, particularly trees and shrubs. These caterpillars are known to primarily target arborvitae, juniper, pine, and spruce trees1. They feed on the leaves and needles, which can lead to defoliation if infestations are left uncontrolled2.

You may notice that a bagworm infestation impacts the health of your plants as they continue to consume the foliage. In severe cases, bagworm damage can lead to complete defoliation, which may even kill arborvitae and juniper trees3.

Aside from the damage to the foliage, you might also spot the bag-like structures created by these pests. The bagworms use bits of leaves and silk to build spindle-shaped bags that protect them from predators4. These bags can also make your plants look unsightly.

Since bagworm infestations can harm various plants and trees, it is essential to keep an eye on your vegetation and implement control measures if you notice signs of bagworms. By doing so, you can minimize the damage to your arborvitae, juniper, pine, and spruce trees and keep your plants healthy and attractive.

Common Plants Affected By Bagworms

Bagworms are known to attack a wide range of plants. Some common examples include arborvitae, cedars, cypress, evergreen trees, and junipers. They can also affect deciduous trees such as maple, oak, poplar, sweetgum, and black locust. Even pine trees and conifers are not immune to these pests. Here’s a compilation of plants that are most commonly impacted by bagworms:

  • Arborvitae
  • Fir
  • Evergreens
  • Maple
  • Oak
  • Junipers
  • Deciduous trees
  • Evergreen trees
  • Sweetgum
  • Black locust
  • Conifers
  • Poplar
  • Cedars
  • Cypress
  • Pine trees

Bagworms prefer to feed on evergreen species, causing serious damage to their foliage. Moreover, they can heavily impact conifers like arborvitae, cedar, juniper, and pine. However, they do not spare deciduous trees and shrubs either. For instance, they have been known to attack black locust, honeylocust, and sycamore trees.

The damage inflicted by these pests varies across different plants. Some plants may lose foliage and turn brown, while others might suffer from a decline in overall health. It’s crucial to keep an eye on these susceptible plants in your garden or landscape and take timely measures to control bagworm infestations.

Controlling Bagworms

Controlling bagworms can be done through various methods depending on the size of the infestation and the type of plant being affected. You can use physical methods such as handpicking and natural predators or chemical methods involving insecticides and bacterium.

Handpicking bagworms, although labor-intensive, is an effective method to control small infestations. Be sure to remove all bags and dispose of them properly to prevent reinfestation. Taking advantage of natural predators, like birds and beneficial insects, can also help control bagworm populations.

However, if handpicking is not feasible, you can resort to chemical control. For instance, Bacillus thuringiensis (Bt) is a popular biological insecticide that targets caterpillars, including bagworms. Other effective insecticides include spinosad, acephate, and cyfluthrin. But remember to always follow the label instructions when applying these products.

Here’s a comparison table to help guide you:

Method Pros Cons Examples
Handpicking Eco-friendly, no chemicals Labor-intensive, time-consuming N/A
Biological Specifically targets pests Takes time to see results Bacillus thuringiensis (Bt)
Chemical Fast results, wide range of coverage Potential harm to beneficial insects Spinosad, acephate, cyfluthrin

No matter which method you choose, the key is to act promptly. The sooner you begin controlling bagworms, the less damage they can cause to your plants. Maintain a close eye on your trees and shrubs to catch infestations early on and take the appropriate measures to safeguard your garden.

Natural Predators of Bagworms

Bagworms are invasive pests that can cause significant damage to trees and shrubs. Although they can be challenging to control, there are several natural predators that can help keep their populations in check.

Birds like sparrows, chickadees, nuthatches, titmice, and woodpeckers are known to feed on bagworms. These avian predators are attracted to areas with diverse foliage, so maintaining a healthy ecosystem encourages their presence.

In addition to birds, various insects prey on bagworms. One notable example is parasitic wasps, which lay their eggs inside bagworms, eventually killing them as the larvae develop. Other insects such as predatory beetles also eat bagworms, providing some control.

  • Birds: Sparrows, Chickadees, Nuthatches, Titmice, Woodpeckers
  • Insects: Parasitic Wasps, Predatory Beetles

To encourage these natural predators in your area, consider planting native plants and providing nesting areas for birds. Avoid using broad-spectrum insecticides, as they can also harm beneficial insects like bees and parasitic wasps.

Remember that while these natural predators play a vital role in controlling bagworm populations, their presence alone may not be enough to totally prevent bagworm infestations. Always monitor your plants for signs of damage and take additional measures, like hand-picking, if needed.

Bagworms and their Camouflage Mechanisms

Bagworms are fascinating creatures due to their unique ability to camouflage themselves in their environment. These caterpillars create protective bag-like cocoons made of silk, which they carry along as they feed on foliage. They incorporate materials like twigs and stems from their host plants into their bags, allowing them to blend in seamlessly.

For example, when feeding on coniferous trees like spruce and juniper, the bagworms’ cocoons can resemble small pine cones. This makes it difficult for predators to detect them. In addition, they have legs and transparent wings, making them even more inconspicuous as they move about.

Some of the key features of a bagworm’s camouflage mechanisms include:

  • Bag-like cocoons made of silk and plant materials
  • Incorporation of twigs and stems from host plants
  • Resemblance to pine cones
  • Legs and transparent wings for inconspicuous movement

This incredible use of camouflage allows bagworms to evade predators and increase their chances of survival. So, as you observe trees and plants around you, pay special attention to details, and you might just spot one of these well-disguised caterpillars.

Specifics of Bagworms Species

The bagworm family includes several species, but one of the most common and troublesome for North American gardeners is the Thyridopteryx ephemeraeformis, also known as the evergreen bagworm. In this section, you’ll learn about the typical characteristics and behavior of evergreen bagworms.

Appearance and Feeding Habits:

  • Larvae resemble small caterpillars and are responsible for most of the damage to host plants.
  • Adult males are small, hairy, black moths, whereas females are wingless and gray.

Evergreen bagworms are commonly found on junipers and other conifers. However, they can sometimes attack broadleaf trees and shrubs, such as maples, oaks, Indian hawthorn, and hollies. This variety of host plants allows them to be quite widespread and difficult to control.

A Bagworm on a Tree Branch What Eats Bagworms
A Bagworm on a Tree Branch What Eats Bagworms

Life Cycle:

  • Eggs hatch in late April or early May, and young larvae begin feeding on host plants.
  • They mature in late August or early September, at which point they become less vulnerable to pesticides.

The evergreen bagworm not only causes damage to plants but also creates an unsightly appearance in gardens due to its feeding habits. Here are some key factors that make this species troublesome for North American gardeners:

  • Bagworms can cause defoliation in host plants, leaving plants with a less attractive look and sometimes necessitating their replacement.
  • The species is able to spread widely, thanks to factors such as wind-aided larval dispersal, unintended human movement, and its wide host range.

Understanding Threat by Bagworms

Bagworms are known for defoliating trees and shrubs, especially those with pine needles. They can be quite a nuisance as garden pests, damaging the aesthetics and health of your host plants.

As you take care of your landscape, it’s important to be aware of the threat these caterpillars pose. One primary concern is their penchant for feeding on various types of host plants. In fact, the evergreen bagworm, Thyridopteryx ephemeraeformis, is known to feed on over 128 plant species. Some of the most commonly attacked host plants include:

  • Arborvitae
  • Red cedar
  • Junipers
  • Black locust
  • Maple
  • Sycamore

It’s crucial to monitor your plants for signs of bagworm activity, such as bagworm eggs, since a severe infestation can lead to total defoliation. For example, bagworms are the leading insect pests of evergreens like juniper and arborvitae.

To better understand the threat of bagworms, let’s compare them to another common garden pest:

Pest Infestation Signs Damage Control Methods
Bagworms Silk bags, defoliation, bagworm eggs Aesthetic and health impact on plants Pesticides, handpicking, natural predators
Aphids Sticky residue, curled leaves Stunting and malformation Insecticidal soap, ladybugs

By understanding the threat of bagworms and staying vigilant in your garden, you can better protect your beautiful plants and ensure their growth is not hindered by these persistent pests.

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