Boxwood Scale Infestation: Imidacloprid Soil Application

White Raised Spots on Boxwood Stems = Scale Insects

One boxwood among many has white scrapable spots on stems, progressing rapidly, leaves yellowing/dropping. Classic scale infestation (armored or soft).

Systemic Treatment

Apply imidacloprid (Bayer Advanced Garden Tree & Shrub Insect Control) as soil drench in late winter/early spring or before rain. Systemic uptake kills soft scales and certain species; not effective on armored scales (e.g., cottony cushion).

Alternative for Armored Scale

Horticultural oil sprays (dormant or growing season) smother armored scales. Identify scale type first.

Why Soil Application

• Large plants—spray drift risk.
• Systemic moves to all feeding sites.
• Season-long control.