Black Coating on Crape Myrtle Is Sooty Mold, Not Fungus

Fungicides Won’t Work

The persistent black film on your crape myrtles—despite four fungicide sprays—is sooty mold growing on honeydew from aphids, scale, or whiteflies. It’s an insect problem, not a disease.

Target the Insects

• Inspect leaves and stems for the honeydew producers.
• Apply a systemic or contact insecticide labeled for that pest.
• Once insects are controlled, the sooty mold will gradually weather away.

See the Extension bulletin on sooty mold for details.