Bagworm Treatment in St. Louis County

What Do Bagworms Look Like?

In most cases, you won’t be able to see the bagworm on its own, but the cocoons that bagworms make are highly visible and can grow up to two inches long. Throughout the fall, you may see these large bags made with parts of the tree and silk, each of which can contain as many as 1,000 eggs.

By late spring or during the early summer months, the eggs hatch, and small black larvae emerge. Each larva is only around two millimeters long and can travel easily on silk threads to other trees and shrubs, spreading the bagworm infestation on your property.

The bagworm larvae will then spend the rest of the summer months in their bags until late in the season or early fall. At this time, you may be able to see adult males leaving their bags for mating season. Unlike larvae, adult bagworm moths are easy to spot at around an inch long and will appear ashy and black. Their transparent wings also stand apart from the opaque wings of other moth species.

Signs of a Bagworm Infestation and the Damage They Cause

If you’re noticing unusual changes in your trees and shrubs, you may be dealing with a bagworm infestation. Bagworms are most commonly found on juniper, cedar, arborvitae, and spruce trees, but they can affect many types of deciduous and coniferous trees. Like other common tree pests and diseases, early identification is the key to effective treatment.

One of the first signs of a bagworm problem is the appearance of silken bags hanging from branches, which are often mistaken for pinecones or seed pods. These bags are made from silk and bits of foliage, blending into the tree while concealing hundreds of eggs or developing larvae.

As soon as bagworms begin building their nests, they start to cause damage. Here’s what to watch for:

• On Evergreens: Bagworms feed aggressively on foliage and buds. This causes browning at the branch tips, followed by dieback that can spread throughout the entire tree. If left untreated, the tree may not survive. Severe cases may require tree disease treatment or removal.
• On Deciduous Trees: Bagworms chew through leaves, leading to visible defoliation. While deciduous trees can often recover after shedding their leaves in the fall, early bagworm control is still essential to limit long-term stress.
• On Twigs and Branches: Bagworms cover twigs in dense silk as they build their bags. These wrapped twigs often die off, leading to additional canopy thinning and branch loss. Affected branches may need professional trimming and pruning to restore the tree’s structure.

If you see any of these warning signs, it’s time to act. Omni Tree Service offers expert bagworm treatment in St. Louis County, backed by ISA-certified arborists. We can help identify, contain, and eliminate the infestation before it causes permanent damage.

Bagworm Life Cycle

Bagworm caterpillars tend to emerge from their nests around June, after which they start to feed on nearby plants. They may spread to other trees via silk threads and wind, at which point they will start to build their nest and stay in place for around the next three months until the end of the summer.

During the late summer months, the larvae pupate for a period of seven to ten days. The adult males will eventually emerge to mate as moths, flying from tree to tree in search of females in bags. Unlike the males, female bagworms remain in their bags and never grow wings.

Once bagworm females mate, they can lay as many as 1,000 eggs in the nest before dying. The eggs will develop throughout the winter within the bag before repeating the cycle. Because bagworms can spread rapidly, trees already weakened by other threats like fire blight or oak galls are particularly vulnerable to infestation.

How to Get Rid of Bagworms

Effective bagworm control starts with early detection and prompt action. One method is to handpick the bags and manually destroy them, ensuring all silk is cleared to prevent further damage to twigs.

For larger infestations or hard-to-reach areas, professional treatment is often necessary. Omni Tree Service offers insecticide applications, including tree injections and targeted pest control treatments, for advanced bagworm treatment. Our solutions are designed to stop the spread and protect your trees and shrubs long-term.

For ongoing protection, our plant health care programs include routine monitoring and preventive treatments. Strengthening your trees with deep root fertilization and custom-blended fertilizers can also help trees resist pest damage and recover more quickly after treatment.

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Frequently Asked Questions (FAQs)

When is the best time to treat bagworms?

The most effective time to treat bagworms is in late spring to early summer (late May through mid-June in the St. Louis County area), when the larvae have recently hatched and are still small. Young larvae are much more susceptible to insecticide treatments than mature bagworms inside hardened bags.

Can bagworms kill my tree?

Yes. Evergreen trees are especially vulnerable. A severe bagworm infestation can strip an evergreen of its foliage entirely, and because evergreens do not regenerate needles the way deciduous trees regrow leaves, the damage is often permanent. Deciduous trees are more resilient but can still suffer significant stress from repeated infestations.

Are bagworms harmful to humans or pets?

No. Bagworms are not harmful to people or animals. They do not bite, sting, or carry diseases. The concern is strictly the damage they cause to trees and shrubs on your property.

How do I prevent bagworms from coming back?

Prevention starts with removing and destroying bags during the fall and winter before eggs hatch in the spring. Regular inspections by an ISA-certified arborist can catch early signs of reinfestation. Professional insecticide applications timed to the larval emergence window are the most reliable way to break the cycle. Visit our Tree Care FAQ for more tips on protecting your trees.

Professional Bagworm Treatment in St. Louis County

Omni Tree Service is your trusted local resource for targeted bagworm treatment and tree pest management throughout St. Louis County.

From our convenient location at 415 Old State Road in Ellisville, MO, we serve Ellisville, Wildwood, Chesterfield, Ballwin, and surrounding communities with fast, professional tree care solutions.

Bagworms can quickly damage trees and shrubs if left untreated. Our ISA-certified arborists respond quickly with in-depth inspections and customized treatment plans designed to stop infestations early and prevent long-term harm to your landscape

Whether you’re noticing signs of pest damage or want to be proactive in protecting your property, Omni Tree Service offers expert tree-focused pest treatment and ongoing care, always delivered with local knowledge and timely service.

Contact us today to schedule an estimate and protect your trees from destructive bagworm infestations.

Call or contact us today to schedule your bagworm treatment.