Woolly Adelgid Infestation on Eastern Hemlock Hedge: Professional Treatment Required

Identification

A 60-year-old, 8-ft Eastern hemlock hedge in CT covered in white cottony masses (90% of needles) is infested with hemlock woolly adelgid (Adelges tsugae). Untreated, death in 3–5 years.

Effective Treatment Protocol

Hire a licensed pesticide applicator (e.g., Bartlett Tree Experts, The Care of Trees) with ISA arborist on staff. Apply 2% horticultural oil (SunSpray, Rockland) thoroughly, both sides of foliage. Two sprays 3–4 weeks apart now, plus one in fall to kill overwintering eggs. Follow with deep root feeding to stimulate recovery.

Biological Control

Predator beetles (Laricobius nigrinus) are used in forest settings but are costly ($5/beetle) and not typically for residential hedges. Oil sprays are the standard.