Patio Citrus with Sticky Residue: Scale Insects and Sooty Mold

Young citrus has black sticky residue with white powder on a few leaves. Owner asks for ID and treatment.

Diagnosis: Scale Insects + Sooty Mold

White powder: Protective covering of scale insects (cottony cushion scale or similar).
Sticky black: Honeydew excreted by scales + sooty mold growing on sugars.

Scales feed on sap, causing leaf drop and decline if unchecked.

Safer's Insecticidal Soap: Spray every 3–4 days; thorough coverage essential.
Q-tip + heavy mineral oil: Coat each scale mass individually (tedious but effective).
Systemic (if no fruit this year): Bayer Advanced Tree & Shrub Insecticide soil drench.

Ask for stronger chemistry if needed.

Plant Diseases: Ligustrum Leaf Issues: Diagnosing Tiny Leaves and Browning in Florida; Sticky Residue on Stephanotis: Honeydew and Sooty Mold; Gardenia Leaf Curl and Powder After Insecticide Spray; Bougainvillea Fungal Leaf Spot: Diagnosis and Recovery Plan; Yucca Natural Leaf Drop vs. Nutrient Deficiency; Schefflera Dropping Leaves? Check Watering and Root Health; Schefflera Losing Leaves in Low Light: Repotting, Salt Leaching, and Nutrient Clues; Identifying a Leafless Mystery Plant: Why Foliage Is Essential for Diagnosis; Citrus Nutrient Deficiency: pH Management Over Supplements; Lucky Bamboo Yellowing: Light, Water, and Root Health

Garden Articles

Plants