As summer activities ramp up, it's crucial to remember the needs of your lawn. Neglecting your lawn's health can allow pests like Bagworms to decimate your trees and shrubs. At Newell Services, we understand how challenging it can be to eliminate bagworms, which are a significant threat to your lawn, trees, and landscape. Bagworms are some of the most irritating pests that can destroy your beautiful outdoor living space. We pride ourselves on protecting your precious outdoor living area and, as such, have put together a quick guide on how to get rid of bagworms effectively. Additionally, we've included answers to common FAQs about these pests to help you better understand them.
What Are Bagworms?
Bagworms are commonly found on evergreen trees and shrubs, where they create hanging, cocoon-like bags made of silk. Although these bags may seem harmless, they can contain up to 1000 eggs that will hatch in late spring or early summer. After hatching, the larvae will feed on the surrounding green branches, which can cause significant damage to the plant. Therefore, appropriate measures must be taken to control bagworm populations.
The most frequent targets of bagworms in our area are eastern red cedar, junipers, and arborvitae. However, they can also damage other trees and shrubs such as pines, spruce, bald cypress, maple, box elder, sycamore, willow, black locust, oaks, and roses.
Life-Cycle Of A Bagworm
The life cycle of a bagworm consists of four stages - egg, larvae, pupal, and adult. The eggs, which have been overwintered in year-old female bags, begin to hatch in late April or early May. The young larvae, also known as caterpillars, start feeding and constructing bags immediately. As they grow, they continue to add silk to the bag until it reaches its full size of around 2 inches long. The larvae use their silk to attach the bag to a tree or other surface. Pupation occurs inside the bag in August and the adult males emerge as bagworm moths in late August and September. They search for wingless females who are still inside their bags for mating. After mating, the female lays several hundred white eggs inside her old pupal case, drops from the bag, and dies.
Identifying Bagworms
Bag — The 2” brown, cocoon-shaped bag is the most visible evidence of bagworm infestation but once hatched, the bagworm makes several transformations. The “bag” of the bagworm is created from their silk and pieces of tree and then eventually filled with eggs.
Larvae — Larvae emerge as tiny black dots about the size of a pinhead, and light as a feather. These caterpillars can use their silk to “fly” to other trees and build new homes. Once full-grown, the 1” long larvae have a dark brown abdomen and the head and thorax are white, spotted with black.
Adults — The adults are small moths with clear 1” wings and a black, hairy body. Male bagworms are ashy-black. The adult female’s body is soft, yellowish-white, and practically naked except for a circle of woolly hairs at the posterior end of the abdomen. They are wingless and have no functional legs, eyes, or antennae.
What Damage Do Bagworms Cause?
Bagworms are a type of pest with a particular preference for evergreen trees such as juniper, arborvitae, cedar, and spruce. However, they can also attack over 128 species of trees and evergreens. Most damage caused by bagworms occurs during their larval stage, feeding on buds, needles, and other plant material while creating their bags. This can cause the branch tips to turn brown and eventually die. In severe infestations, bagworms can consume more than 80% of the tree, ultimately killing the entire evergreen. On deciduous trees that lose their leaves in winter, bagworms chew small holes in the leaves, which can lead to defoliation. If left uncontrolled, these trees may survive but become weakened, making them more vulnerable to diseases and other pests.
What Do Bagworms Eat?
Bagworm larvae are known to cause the most damage since they eat the most. As caterpillars, they feed on evergreen needles and the leaves of deciduous trees. If your trees are infested with bagworms, you may notice that they leave only the largest veins of leaves behind. Bagworm larvae tend to emerge from their bags only to eat and then return to rest or hide in the sight of danger.
Bagworms eat over 100 different types of trees, although they prefer evergreens such as:
Red cedar
Juniper
Arborvitae
Spruce
Other common victims of the bagworm include:
Pine
Bald cypress
Maple
Boxelder
Sycamore
Willow
Black locust
Oaks
Roses
What Do Bagworms Turn Into?
When you hear the term “bagworms,” you might think of the larvae, which are wingless creatures that reside inside brown silken bags and come out to feed. These caterpillars pupate inside their bags around August. Once they become fully mature, the male bagworms emerge as adult moths. They have small, dark, hairy bodies and clear wings. On the other hand, the female adult bagworms are wingless and don't have legs, eyes, or antennae. Their bodies are light in color and soft to touch. The females have the closest resemblance to a “bag worm” and simply wait for a male to come and fertilize their eggs. Once fertilized, the female lays between 300-1000 eggs inside her old bag and ultimately dies.
How To Eliminate Bagworms
The easiest way to get rid of bagworms is to cut off the bags by hand and destroy them. Lift branches, clip off bagworm egg sacks, and drop them into the bucket of water with dish soap, making sure they are submerged fully. Dump the soaked bagworms into a sealed plastic bag and throw them in your trash. Repeat this procedure every fall, winter, and early spring to reduce bagworm populations before the eggs hatch. If this process doesn’t appeal to you, or your bagworm population is overwhelming, professional help is available!
When should you treat for bagworms?
Protecting your plants from bagworms can be a challenging task, but timing is key. To ensure the best results, it is crucial to spray insecticide while the larvae are actively feeding. This typically occurs between early May and early July, depending on your location. Waiting until later in the season can be less effective since the bagworms eat less as they prepare to pupate into adults. By taking action early and spraying for bagworms while they are still actively feeding, you can safeguard your plants and enjoy a healthy, vibrant landscapre.
What causes bagworm populations to explode?
Bagworms have a unique way of reproducing, as a single egg sack (or bag) can contain between 300-1000 individual eggs. These eggs eventually hatch into tiny black larvae which grow into larger caterpillars. At an early stage of their development, the larvae spread out and use silk threads to “fly” onto other trees from their original nest. They then create their own bag out of the same silk and plant material from the host tree. Once they reach maturity, female bagworms lay their eggs in the same sack where they grew up, and the cycle repeats itself. It's worth noting that other bagworms can also contribute to the problem, as these creatures tend to produce more bagworms.
Can I Prevent Bagworms?
To prevent bagworms, the most effective method is to use insecticide on the affected trees when young larvae are feeding. Some of the most common products on the market for this purpose include carbaryl, malathion, diazinon, bifenthrin, permethrin, or cyfluthrin. Before applying any of these products, always read the instructions carefully and be sure to take into account the stage of plant development, soil type and condition, temperature, moisture, and wind.
If you prefer a natural treatment, you can use products containing Bacillus thuringiensis var. kurstaki, which is a naturally occurring bacteria found in soil. This bacteria causes bagworms to stop eating and die in a few days.
Another way to prevent bagworms is by attracting their natural enemies, such as birds and wasps. You can do this by placing Shasta daisies, Frikart’s asters, birdbaths, and bird feeders near bagworm trees. This will help you control and prevent bagworm populations.