Hemlock woolly adelgid

Hemlock woolly adelgids coat hemlock twigs with distinctive white, fluffy, cotton-like wax structures from late fall through spring in Western Washington. Despite the visual impact, these insects rarely cause serious damage to western hemlock because the host species is tolerant and natural predator populations effectively suppress outbreaks. You notice the white woolly covering on hemlock branches. Dieback is typically not a concern.

Monitor western hemlock trees for adelgid presence; no control is needed in Western Washington. Native predators including Laricobius nigrinus and Leucopis species maintain populations at low levels. Avoid insecticides that disrupt beneficial insects. Maintain hemlock tree health through appropriate cultural practices and adequate moisture.