Now Is the Time to Check for Bagworms in Your Landscape (Early Spring Guide)
As the weather warms and plants begin actively growing, it’s a great time to inspect your trees and shrubs—especially evergreens. Early spring is one of the best times to spot bagworms before they hatch and become a bigger problem later in the season.
Bagworms can cause serious damage to landscape plants if left untreated, but catching them early makes control much easier.
Quick Take: Why Check for Bagworms Now?
- Last year’s bags can still be attached to branches and may contain hundreds of overwintering eggs.
- Removing bags now can prevent a major infestation later.
- If you need to spray, treatments work best when caterpillars are small (late spring into early summer).
What Are Bagworms?
Bagworms are caterpillars that live inside small protective cases (“bags”) made from silk and bits of plant material. These bags look like tiny hanging cones attached to branches.
The insect most commonly affecting landscapes in our region is the evergreen bagworm (Thyridopteryx ephemeraeformis). While they’re often associated with evergreens, bagworms can feed on a wide range of plants.
Common bagworm host plants (evergreens)
- Arborvitae
- Juniper
- Cedar
- Spruce
- Pine
- Leyland cypress
Bagworms can also feed on some deciduous plants
- Maple
- Oak
- Sycamore
- Rose
- Flowering plum
Bagworm Life Cycle (and Why Timing Matters)
Understanding the bagworm life cycle explains why early detection is so important.
Overwintering stage
Bagworms spend the winter as eggs inside bags that remain attached to branches from the previous year. Each bag can contain hundreds of eggs.
Spring hatch
In late spring, tiny caterpillars hatch and begin feeding on nearby foliage. As they grow, they create and carry the distinctive bag.
Summer feeding
Throughout summer, bagworms continue feeding and enlarging their bags. This is when the most visible damage occurs.
Late summer and fall
By late summer, caterpillars mature. Male moths emerge and fertilize females, which remain inside their bags. Females lay eggs inside the bag and die—leaving the next generation protected for winter.
How Bagworms Damage Plants
Bagworms chew foliage. On evergreens, this can be especially damaging because evergreens don’t replace lost needles quickly.
Signs of bagworm damage
- Brown or thinning areas on evergreens
- Defoliated branch tips
- Overall plant decline
Heavy infestations can severely damage—or even kill—arborvitae and other evergreens if left untreated.
Deciduous trees can often recover from some feeding, but damage can still weaken plants and reduce curb appeal.
What to Look For Right Now (Early Spring)
Early detection is the easiest way to prevent bigger problems later.
Look for:
- Small bag-like structures hanging from branches
- Bags made of dried needles, leaves, or twigs
- Bags that resemble tiny pinecones or stuck-on debris
Last year’s bags can blend in, especially on arborvitae and juniper. These are the bags most likely to contain overwintering eggs.
How to Get Rid of Bagworms
The best bagworm control method depends on the time of year and how many you find.
1) Hand removal (best right now)
Early spring is a great time to remove bagworms by hand.
Steps:
- Pick the bags off branches
- Place them in a sealed bag or drop them into soapy water
- Dispose of them in the trash
Removing bags before eggs hatch can prevent hundreds of caterpillars from emerging.
2) Insecticide treatment (after hatch)
Once eggs hatch and caterpillars begin feeding, insecticide control is most effective while caterpillars are small and actively feeding.
Eight® Insect Control is highly effective against bagworms when applied at the right time.
- Spray thoroughly on affected plants
- Follow label directions for coverage and safety
- Treat in late spring and early summer for best results
Early Attention Makes a Big Difference
Bagworms are much easier to manage when caught early. Taking a few minutes to inspect your landscape now—and treating at the right time—can protect your evergreens and prevent serious damage later in the season.
Need Help Identifying Bagworms?
If you’re unsure whether you’re seeing bagworms or have questions about treatment, bring a sample or photo to Guilford Garden Center. We’re happy to help you identify the problem and recommend the best next step to keep your landscape healthy.
