Answer: Sooty mold is a charcoal black fungus that appears as a black coating on the surface of leaves, fruits, twigs and branches of many deciduous and evergreen shrubs and trees. Honeydew is a sweet, clear, sticky substance secreted by insects such as aphids, mealybugs, scale, and whiteflies. The honeydew drops from the insects to the leaves and twigs. Wind-blown sooty mold spores that stick to the honeydew then have a suitable medium for growth. When spores germinate, they send out black fungal strands (mycelial threads) that cover the plant tissue and cause the discoloration. The sooty mold looks unattractive, but it won't hurt your plants. The major concern is to control the population of insects that is causing the honeydew, which develops into sooty mold. Have the pests identified so you know what you are trying to contol and then use the appropriate insecticide. Once the insects are gone, the sooty mold will weather away on its own.
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