Bagworm
MODERATEThyridopteryx ephemeraeformis
Overview
A moth whose larvae construct distinctive spindle-shaped bags from silk and foliage fragments. They feed on over 100 species of trees and shrubs, with conifers being most vulnerable since they cannot regrow lost foliage as readily.
- Type
- Insect
- Severity
- MODERATE
- Source
- USFS
Symptoms
Spindle-shaped silk bags 1-2 inches long hanging from branches, defoliation starting at the top of the tree, brown needles on conifers, bags incorporating dead plant material as camouflage
Affected Species
Geographic Spread
Treatments
Hand-Picking Bags
Physical removal and destruction of bags from fall through early spring before eggs hatch. Effective on small to moderately infested trees and shrubs that are accessible.
Btk Spray on Young Larvae
Application of Bacillus thuringiensis var. kurstaki in late May through June when larvae have just hatched and are actively feeding outside their bags. Timing is critical.
Recommended Products & Tools
Helpful supplies for managing Bagworm. Always read and follow label directions, and confirm a diagnosis before treating.
Organic control that targets caterpillars when they're young.
Knocks down soft-bodied pests like aphids, mites, and scale crawlers.
Smothers overwintering eggs and crawlers; dormant or summer rates.
Soil-applied protection taken up by the tree for season-long control.
Sharp, clean cuts to remove affected wood — a tree-care essential.
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Frequently Asked Questions
What is Bagworm?
A moth whose larvae construct distinctive spindle-shaped bags from silk and foliage fragments. They feed on over 100 species of trees and shrubs, with conifers being most vulnerable since they cannot regrow lost foliage as readily.
What are the symptoms of Bagworm?
Spindle-shaped silk bags 1-2 inches long hanging from branches, defoliation starting at the top of the tree, brown needles on conifers, bags incorporating dead plant material as camouflage
Where is Bagworm currently found?
Bagworm is currently active in Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Missouri, Mississippi, North Carolina, Nebraska, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia. It has been reported in 28 total states across the United States.
What plants are affected by Bagworm?
Bagworm affects Eastern Red Cedar, Colorado Blue Spruce, Norway Spruce, American Holly, Common Boxwood. Susceptibility varies by species.
How do I treat Bagworm?
Treatment options for Bagworm include: Hand-Picking Bags, Btk Spray on Young Larvae. Treatment approaches may include chemical, biological, cultural, and mechanical methods depending on the severity and context.
Compare with Similar Ailments
Not sure if it's Bagworm? Compare it side-by-side with similar ailments.