Bagworms: Identification, Tree Damage, Eradication (With Pictures of Evergreen Bagworms)

Bagworms infest evergreen and deciduous trees and are a serious garden problem. The little larvae, which are commonly known as evergreen bagworms, are hungry feeders that can consume foliage and kill trees. It’s difficult to detect bagworms. Caterpillars that are small brown or black feed on cocoons hanging from evergreen trees, which resemble seed cones. To get rid of bagworms, you should remove their bags and kill the larvae by burning them.

After the pupal stage, evergreen bagworms transform into black hairy moths. The damage has already occurred before you see the bagworm moths in the autumn. Evergreens like Arborvitae, Junipers, Cedars, and Spruce Trees are commonly infested by bagworms. Bagworms, on the other hand, can destroy deciduous trees like aspen, willow, poplar, and oak. Up to 130 different tree and shrub species can be infested by bagworms.

The damage bagworms may cause will be discussed in this article. You’ll learn how to distinguish these plant-eating worms as well as the cocoons they create. You can learn about natural ways to get rid of evergreen bagworms at the conclusion of the article.

How to Get Rid of Evergreen Bagworms on Trees

Knowing the lifecycle of bagworms is required to get rid of them from cypress, junipers, pine, and deciduous trees. To get rid of the leaf-munching pests in certain situations, pesticides or insecticides are required. The following are a few ways to get rid of bagworm and their nests:

  • Get rid of bagworms by removing their cocoons by hand. In the summer, manually remove cone-shaped cocoons that hang from trees, measuring about an inch (2.5 cm) long. To permanently destroy the bagworms, drop them in a tub of soap.
  • Use biological insecticides to kill evergreen bagworms. Bacillus thuringiensis var. is a natural biological insecticide. When larvae are young, apply kurstaki.
  • Introduce parasitic wasps, which effectively kill young bagworm larvae.
  • Use neem oil spray to treat and control bagworms. Before larvae are more than 1″ (2.5 cm) long, apply a natural neem oil pesticide to the trees.

What Are Bagworms

Larvae of certain moth species damage evergreen and deciduous trees, causing bagworms to appear. Bagworms are known as Thyridopteryx ephemeraeformis in scientific terms. There are approximately 1,300 species of bagworms, and they belong to the flying insect family Psychidae.

The bagworm larvae emerge from bags, hence the name “bagworm.” Eastern bagworms, North American bagworms, and common basket worms are three different names for the same moth caterpillar..

Since the glossy black larvae are only 0.04″ (1 mm) when they begin to feed, bagworms can be difficult to see. The newly emerged larvae begin spinning their own sack almost immediately. The length of mature evergreen bagworm caterpillars may reach 1″ (2.5 cm).

Fur moths with transparent wings, the bagworm moths are a furry black or dark brown color. Because the females remain in the bag-like cocoons and deposit eggs, only male bagworm moths are visible flying in the autumn.

What Do Bagworms Look Like?

Bagworms are shiny black or dark caterpillars that grow up to 1″ (2.5 cm) long and carry their cocoon with them. The body of the black worm-like creatures is segmented, while the head is amber colored and translucent. In late spring and early summer, when evergreen bagworms emerge from their bags or cocoons, they are barely a few millimeters long.

On evergreen trees, bagworms can be difficult to spot. The larvae are only active at feeding time and prefer to remain in their cocoon bags. When they are feeding on different sections of the tree, the black caterpillars also carry their bags.

Bagworm cones (cocoons) dangling from evergreen or deciduous trees are the most common symptom of an infestation. Bagworms make disguised bags by spinning silk and using tree foliage, making it difficult to spot them even then.

Bagworm Cocoon

Bagworm cocoons are the homes where the caterpillars dwell, hanging from trees. Bagworms create their own cocoon nest, which they spend the majority of their lives in. Silk, twigs, and leaf debris make up the bagworm nest. Mature larva bags are 2″ (5 cm) long and 0.5″ (1.2 cm) wide, up to 2″ (5 cm).

A bagworm cocoon resembles a giant, long pointed pine cone. The bagworm’s nest is shaped like a spindle, with the center widest portion tapering to a point at each end. As the black worm-like caterpillars add more foliage to the nest, the cocoon gets larger.

Late in the summer, cocoons hanging from evergreen and deciduous trees are most common. The larvae have reached the pupal stage and are ready to become adults. Depending on the tree, bagworm nests appear differently. Bagworm cocoons, for example, look like pine cones and include parts of pine needles and twigs on pine trees.

A clump of delicate feathery needles dangling from arborvitae branches will resemble bagworm cocoons. Bagworms are the only caterpillars that incorporate plant material into their cocoons, which makes them unusual kinds of crawling insects.

Bagworm Damage

Bagworms have a number of ways to harm trees and shrubs. Tree defoliation can occur as a result of bagworm infestation. Bagworms create strong silk threads that cement cocoons to the tree’s branches. This might eventually lead to the death of the twigs. Unhealthy brown branch tips are the first indication of bagworm damage on deciduous and evergreen trees. Bagworms’ appetite grows as they age, and they begin to consume plant matter. Bagworm infestations may devour a plant’s leaves if they aren’t treated.

Evergreen bagworms are a common name for bagworm caterpillars. Because they harm juniper species (Juniperus) and arborvitae trees (Thuja), this is the reason they cause the most harm. Evergreen trees suffer the most damage since they don’t replace foliage as quickly as deciduous trees. A defoliated conifer tree is generally killed as a result.

Localized bagworm infestation on several trees is not uncommon. Bagworms are most likely to feed on the mother plant. This implies that within a few meters, a massive bagworm infestation of trees and shrubs might take place. Also, it’s not uncommon for the same evergreens to be damaged year after year.

In the autumn, picking off bagworm cocoons by hand is the best way to protect trees from harm. Try to get as many of the cone-like cocoon nests off of afflicted trees as possible. Hundreds or even thousands of bagworm eggs are prevented from hatching the next spring as a result of this.

Bagworm Life Cycle

Bagworms go through four instars (stages) to reach maturity after hatching from an egg in the cocoon nest. In the late summer and fall, a female bagworm deposits up to 1,000 eggs in her cocoon. In the safety of the dangling bagworm nest, the eggs overwinter. The bagworm larvae emerge from the nest in late spring.

Little bagworm larvae are often dispersed on their silken threads by the wind. The same plant or a different host plant is eagerly consumed by the larvae. Bagworm caterpillars make their own bags at this stage. The worms expand the bag’s size by collecting twigs and leaf pieces from the tree while feeding on the plant’s foliage.

Bagworm larvae feed on the dangling bags, remaining inside them and transporting them to different trees. To walk around a tree, the plump bagworm protrudes its head and a portion of its body from the bag. In the late summer, the mature bagworm caterpillar binds the huge bag to a limb in preparation for pupation.

Once the bagworm reaches the pupal stage, it is sealed shut. The females that emerge are wingless, legless, and resemble caterpillars; males become black moths.

Male bagworm moths then go out in search of a female to mate with. The female dies after laying eggs in a bag-like cocoon. The bagworm lifecycle begins anew.

How to Identify Evergreen Bagworms on Trees

Bagworms are spotted on trees in late autumn by their brown cone-shaped bags. The best time to remove the worms is in the fall or winter because they contain hundreds of bagworm eggs. Against evergreen foliage, the brown sac-like cocoons are easy to see.

Emergent, newly developed larvae are just 1 to 2 mm long and virtually undetectable. Little cone-like formations on trees are only noticeable when they appear. The worms increase the size of their bags by consuming part of the foliage they are eating. The identical foliage of the host plant is used to create cone-like structures.

On trees, individual bagworms are difficult to locate. Camouflage sacks are their greatest defense throughout their lifespan. Because their bags resemble naturally developing sections of the tree, extra vigilance is required to identify bagworms.

Where Do Bagworms Come From?

In the Eastern United States, bagworms are most often seen on evergreen and deciduous trees. Most states east of the Mississippi River are home to the caterpillars that destroy trees. Bagworms in cities are usually found near infected trees or bushes in the area. The eggs fall from the hanging nests as they hatch, and the wind transports them to nearby trees and plants. Some larvae drop to the ground and move to a different host plant.

What Do Bagworms Eat?

Bagworms eat plant material, just like other moth caterpillars. Leaves and tree buds make up a bagworm’s diet. The types of trees that the ‘bugs’ prefer to feed on include red cedar (Juniperus virginiana) and arborvitae (Thuja). Bagworms, on the other hand, consume foliage from oaks, sycamores, willows, poplars, birches, elms, and cypresses.

How to Get Rid of Bagworms on Trees such as Evergreens and Arborvitae

It can be difficult to get rid of bagworms. Disrupting the lifecycle of bagworms is the most effective way to eliminate them from evergreen or deciduous trees. Bagworms spend the winter months hanging from tree branches with their furry bags. The eggs are still fertilized during this time.

The ideal time to get rid of all traces of bagworms from trees is usually between October and March. The eggs can be killed off by cutting the evergreen bagworm cocoons from the trees and dropping them into hot, soapy water. The best time to attempt to suppress bagworm populations is usually in the summer.

How to Kill Evergreen Bagworms

The best way to maintain bagworm populations down during their dormant period is through intervention. It is vital to have an integrated pest management system in place to prevent and eliminate bagworms from your property. Handpicking, biological insecticides, and natural controls are examples of methods used. To permanently eliminate bagworms, try one of the following strategies.

Handpick Evergreen Bagworms to Remove them From Trees

The best strategy to get rid of bagworms for good is to handpick them and destroy them. To cut down the dangling cone-like cocoons and remove all of the silk from branches, use a sharp knife. To kill all the eggs and larvae in the cocoon, put the bags in hot soapy water.

Brown or tan-colored cone-like growths dangling from trees can be used to identify bagworm nests. Bagworms can be mistaken for pine seed cones on evergreen trees. Bagworms, which hang from the limbs of deciduous trees like withered leafy masses, appear unusual.

Use Spinosad to Kill Evergreen Bagworms

Spraying the caterpillars with a Spinosad is one way to kill bagworms. Spinosad is a caterpillar-killing soil bacterium that occurs naturally. Natural commercial items including Spinosad may be purchased. Mix with the manufacturer’s instructions to kill bagworms throughout the tree’s foliage. If required, repeat every seven days.

It’s important to keep in mind that pollinators, such as honeybees, may be poisoned by Spinosad. As a result, when bees are less active in the early morning or late evening, it’s preferable to use natural insecticide. Also, on windy days or when rain is predicted, avoid treating the diseased trees.

According to some scientific investigations, Spinosad formulations may be used to kill bagworms. Another research discovered that soil bacteria application protects arborvitae foliage against bagworm damage by decreasing the feeding rate and growth of larvae.

Eradicate Evergreen Bagworms with Bacillus Thuringiensis

Bacillus thuringiensis var. is a great way to spray evergreen trees. Bagworm larvae can be killed off by Kurstaki. A soil bacterium that is harmful to larvae is Bacillus thuringiensis (Bt). The microbe in the plant matter that the caterpillars consume kills Bt. The larvae die as a result of the bacterium’s poison.

Late spring, when the eggs are hatching, is the optimum time to apply Bacillus thuringiensis. To prevent bagworms from destroying your evergreen tree or defoliating deciduous trees, apply every seven to fourteen days.

Parasitic Wasps Can Help to Control Evergreen Bagworms

Using parasitic wasps is one kind of biological control for bagworms. Caterpillars are killed when these tiny flying creatures lay eggs inside them and reproduce. To manage bagworm populations, you may employ parasitic wasps as part of an integrated pest management system.

According to researchers from the Illinois Natural History Survey, bagworm control can be achieved using three parasitoid wasp species: Pimpla disparis, Itoplectis conquisitor, and Gambrus ultimus.

Use Neem Oil Spray to Kill Evergreen Bagworms

When used in conjunction with other pest management techniques, neem oil sprays may help eliminate bagworms. Azadirachtin is a natural pesticide found in neem oil that doesn’t harm beneficial insects. Add 2.5 tablespoons of neem oil and 1 tablespoon of liquid dish soap to every gallon (4 l) of water to make a homemade bagworm spray.

To get rid of bagworms in the summer, liberally spray evergreen foliage every seven days after the bagworm larvae have hatched. Natural control measures may not be enough to manage bagworms in severe bagworm infections. To protect your evergreen and deciduous trees from damage, it may be necessary to use commercial insecticides for bagworms.

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