Bagworm Prevention on Blue Spruce: Scout in Early June, Spray Only If Found

Don't Spray Calendar Dates

Bagworms have one generation, overwinter as eggs in bags. Hatch late May–early June. Larvae balloon on silk to new hosts.

Action Plan

1. Inspect first 2 weeks of June for tiny new bags (⅛").
2. If found, spray Bt immediately (works only on young larvae).
3. If none, don't spray—last year's treatment likely cleared them.

Waste not, want not. Scout, then treat.