Check Your Evergreens: Bagworm Season is Here

Every summer, bagworms begin appearing throughout southwest Missouri, especially on evergreens like arborvitae, junipers, and cedars. Right now, many are still small—around ½ inch long—which makes this one of the best times to catch them before they can cause significant damage.

What Are Bagworms?

Bagworms are caterpillars that build protective bags around themselves using silk and pieces of the plant they're feeding on. These bags help camouflage them, making them easy to overlook until damage becomes noticeable.

Right now, many of the bags we're seeing are only about ½ inch long, which means the caterpillars are still young.

What Plants Do They Attack?

Bagworms are best known for damaging:

• Arborvitae

• Junipers

• Eastern Red Cedar

However, they aren't limited to evergreens. They can also feed on many deciduous trees and shrubs, including maple, oak, sycamore, willow, honeylocust, and several others.

Evergreens are often affected the most because they don't replace lost foliage as easily.

Why Timing Matters

Young bagworms don't stay small for long.

As they continue feeding, they grow larger and their protective bags become tougher. Once that happens, control becomes much more difficult.

Checking your plants now can prevent much larger problems later in the summer.

Signs to Look For

Watch for:

• Small spindle-shaped bags hanging from branches

• Browning or thinning foliage

• Chewed or missing needles and leaves

• Small bags that look like tiny pinecones or bits of dried foliage attached to twigs

Because the bags are made from the host plant itself, they often blend in surprisingly well.

How to Control Bagworms

Hand Removal

If you only find a few bags, simply remove them by hand and dispose of them.

This is often the easiest and most effective option for light infestations.

Treat While They're Young

If you have a larger infestation, early treatment is important.

Products containing Bacillus thuringiensis (Bt) are very effective against young caterpillars. As bagworms grow larger, additional insecticides labeled for bagworms may be needed, but treatments become less effective once the bags mature.

Always read and follow the pesticide label before applying any product.

We've Also Started Seeing Japanese Beetles

While bagworms are our biggest concern right now, we've also noticed the first Japanese beetles beginning to appear around the nursery.

We'll have more information on managing those as the season continues.

Need Help Identifying Bagworms?

Bring in a sample or stop by Carson's Nurseries.

Our team is happy to help identify what you're seeing and recommend the best treatment for your landscape before the damage gets worse.