Black Powder on Crepe Myrtles? It's Sooty Mold from Aphids—Here's the Fix

Diagnosis

Central LA, clay soil. Black powdery substance, wilty leaves, webs with tiny insects. = Sooty mold growing on aphid honeydew. Webs likely spider mites or other.

Solution

• Target aphids, not fungus. Fungicide does nothing for insects.
• Use systemic insecticide for aphids (soil or foliar).
• Check local nursery for systemic aphid product.

Why It Works

Kill aphids → honeydew stops → sooty mold starves and weathers away.