Plaster Bagworms on Garage Walls: Harmless Spider Web Eaters

The small, case-bearing larvae on your garage walls are plaster bagworms (Phereoeca uterella), also called household case bearers. They build flat, spindle-shaped silk cases decorated with debris and drag them as they crawl.

Key Facts

• Related to clothes moths, but feed on spider webs, dead insects, and hair—not fabrics.
• Common in garages, sheds, under eaves—where spiders are abundant.
• Harmless. No damage to structure or belongings.

Control (If Desired)

• Vacuum or sweep them up.
• Reduce spiders (their food) by sweeping webs, sealing gaps, reducing outdoor lights that attract insects.
• No insecticide needed.

They're a curiosity, not a pest problem. A broom handles them.