Sticky 'Dirt' on Dwarf Lemon Leaves: Scale, Sooty Mold, and Protecting Your New Lime Tree

What "Stuck Dirt" Really Is

Sticky residue = honeydew from scale insects or mealybugs. The "dirt" adheres to this glue. Sooty mold (black fungus) grows on honeydew.

Scale: Adults = 1/8" circular/oval disks on leaves; juveniles = tiny cotton bits (mobile).
Mealybugs: Cottony white/grey clusters at leaf-stem junctions.

Ask brother to wait until infestation is controlled. Insects and fungal spores spread easily between nearby plants.

Plant Diseases: Lemon Tree Leaf Curl and Yellowing in Madrid: Environmental Stress; Sooty Mold on Citrus: Controlling the Underlying Insect Infestation Safely; Sapsucker Damage on Young Oak: Same Culprit, Different Tree; Dwarf Meyer Lemon Losing Leaves After Moving Indoors; Cottony Cushion Scale on Potted Lemon: Organic Control with Neem Oil; Mature Meyer Lemon Fruit Quality: Scale and Skin Disorder Management; Dwarf Citrus in Containers: Yellowing, Curling Leaves in Phoenix Heat; Dwarf Lemon Tree Leaf Curl: Leaf Miner Management in Canada; Scale and Sooty Mold on Potted Meyer Lemon: Treatment and Prevention; Scale Insects on Meyer Lemon: Sticky Leaves, Brown Bumps, and How to Save Your Tree

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