Sooty Mold: Causes and Control

Multiple fungi cause this disease on any plant. Appears as powdery dark brown/black coating on leaves—hence "sooty mold." Fungi feed on plant secretions and honeydew from aphids, mealybugs, scale. Mild alone, but weakens plants combined with heavy insect damage.

Control

Reduce honeydew-excreting insects. Rinse small ornamentals by hand; hose down larger areas (trees, groundcovers). No chemical control exists.