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Description

Adelgids (Adelges cooleyii, A. lariciatus, A strobilobius, Pineus pinifoliae, P. similis) are soft-bodied insects closely related to aphids.

Cooley Spruce Gall Adelgid
Cooley Spruce Gall Adelgid

 Old galls (top) and newly forming galls (bottom) are
evidence of an infestation of Cooley spruce gall adelgids

Plants Affected

Symptoms

The first generation feeds on the succulent new needles at the branch terminals.   The insect injects a hormone during feeding which closely mimics plant hormones responsible for cell division.

The tree responds by forming a gall at these feeding sites. The young adelgids enter this gall and are sheltered inside it through their growth cycle.

Controls

Cultural or Non-chemical Controls:

  • Hand pick the newly formed green galls off the twigs in June and destroy them.

Chemical Controls:

  • A chemical application may be warranted in late May if the entire tree is heavily infested.

For more information on chemicals available for control of these pests, call Agriculture Canada's Pesticides Directorate in Ottawa (toll-free) at 1-800-267-6315. Chemical pesticides may be toxic to humans, animals, birds, fish, and beneficial insects. Follow all label instructions and precautions listed by the manufacturer.

Last updated: 12/11/2014 12:29:18 PM