Treating Sooty Mold on Magnolia Seedlings

Diagnosis

Black, wipe-off leaf coating = sooty mold growing on aphid honeydew. Ladybugs present = natural predators.

Treatment

• Control aphids with systemic insecticide (ask nursery for aphid/whitefly product).
• Spray both leaf surfaces.
• Note: Will also kill beneficial ladybugs.
• Mold washes off with rain after aphids are gone.

Key Takeaway

Sooty mold is a symptom; treat the aphid cause. Systemic insecticides are most effective for leaf-curling aphids.