Arborvitae Leafminer vs. Bagworm: Corrected Diagnosis and Treatment

Initial Misidentification Corrected

A Maryland gardener found eggs/caterpillars on arborvitae, initially diagnosed as bagworm, but later identified as arborvitae leafminer.

Leafminer Life Cycle and Control

• Eggs laid on branch tips – Larvae tunnel into foliage, causing browning
• Sevin controls external larvae – Only before leaf entry
• Systemic needed for internal larvae – Acephate (Orthene) penetrates foliage
• Treat all arborvitae – Eggs likely on all plants

Early detection and systemic treatment prevent extensive damage.