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Holly and Camellia White Underside Coating: Cottony Cushion Scale

Shady coastal NE Florida yard: holly and camellia have white powdery/webby substance on leaf undersides, leaves drop when covered. Likely cottony cushion scale (Icerya purchasi).

Treatment

Horticultural oil or insecticidal soap (thorough underside coverage).
Systemic: Imidacloprid soil drench (Bayer Tree & Shrub) in spring.
Biological control: Vedalia beetle (Rodolia cardinalis) — may establish naturally.

Note

Some responses promote "Atomic Grow." Extension recommends proven IPM. Test any product on small area first.

Plant Diseases: Diagnosing Single Holly Bush Leaf Curl; Holly Sooty Mold and Leaf Drop: Insect-Driven Dual Symptom; Boxwood Blight: Identifying and Managing Volutella Stem Blight; Camellia Dieback: Root Rot or Algal Leaf Spot?; Holly Leaf Miner: Systemic Insecticides for Internal Feeders; Managing Black Spot Fungus on Holly Bushes; Cylindrocladium Leaf Spot on Holly: Identification and Fungicide Program; Winterizing Holly Bushes in Midcoast Maine; Holly Bushes Failing Repeatedly: Drainage Problems and Soil Amendment; Why Holly Bushes Turn Yellow from the Center Out

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