Black Sooty Mold on Holly: Control the Sucking Insects First

Cause

Black coating on holly leaves is sooty mold growing on honeydew from scale, aphids, or whiteflies. The mold itself doesn’t infect the plant.

Target the insects: Apply Bayer Advanced Tree & Shrub Insect Control (imidacloprid) as a soil drench. Roots translocate it to foliage; insects die when they feed.
Mold will weather away once honeydew stops.
Berries: Hollies need male and female plants for fruit; ensure you have both.

Systemic soil treatment provides season-long control.

Plant Diseases: Variegated Holly Leaf Discoloration: Treating Fungal Leaf Spot; Variegated Holly Losing Lower Leaves: Scale and Chlorotic Shoots; Holly Scale Infestation: Oil or Systemic Insecticide; Identifying and Treating Powdery Mildew on Holly Trees; Identifying and Managing Powdery Mildew on Holly Bushes; Scale or Powdery Mildew on Lilac: Neem Oil vs. Atomic Grow; Holly Yellow Leaves: Check for Scale Insects; Replanting After Holly Removal: Dealing with Scale and Sooty Mold Residue; Powdery Mildew on Holly: Fungicide Options and Application Timing; Holly Scale Infestation: Identification and Treatment Plan

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