Bagworms on Pine: Identification and Control

Pine tree has "spiked worms" attached to limbs, wrapping around them. Owner asks for ID and removal.

Diagnosis: Bagworms

Caterpillars build protective bags from silk and plant debris. They feed on foliage from inside the bag.

Reference: Bagworm Photos

Control Methods

Mechanical

Hand-pick bags in late fall (easily seen on evergreens). Cut attachment silk to prevent girdling.

Biological (Bt)

Apply Bacillus thuringiensis late June after egg hatch and ballooning. Effective on young larvae.

Chemical

Stomach insecticides: acephate, bifenthrin, carbaryl, chlorpyrifos, diazinon, malathion, etc. Thorough coverage needed—larvae protected in bags. Early application best.

Reference: PSU Bagworm Fact Sheet