Bagworm Infestation on Blue Spruce, Evergreens, and Cedars: Full Control Guide

Identification Confirmed

Small black caterpillars in silk bags covered with foliage debris = bagworms. They're on your spruce, evergreens, and cedars—classic hosts.

Life Cycle Key to Control

• Eggs overwinter in bags (300-1000/bag).
• Hatch late May–early June; larvae balloon on silk to new hosts.
• Bags enlarge through summer; pupate August; males emerge September.

Integrated Management

1. Hand-pick bags fall through winter. Cut silk bands.
2. Spray early June (young larvae) with Bt, Sevin, Orthene, Talstar, or Dursban. Thorough coverage essential.
3. Late-season sprays less effective but may reduce next year's population.

Why They're Devastating

Flightless females = localized population explosions. Complete defoliation kills conifers (no releafing). Deciduous hosts recover.