Black Sooty Mold

Black Sooty Mold and Sooty Mold are common names used to describe several species of fungi that produce a dark, powdery film on leaves and fruit. While unsightly, they do not actually infect the plant. These molds are often members of Alternaria or Cladosporium and grow on honeydew secreted by soft-bodied plant pests (Aphids, Leafhoppers, Mealybugs, Psyllids, Scale, Whiteflies). If allowed to spread unchecked, sooty mold may restrict leaves exposure to sunlight, thereby reducing the plants ability to photosynthesize.

Since it is soft-bodied pests that provide a food source for the sooty mold, control stems from controlling the pests, not the fungus. Soapy water mixes often knock back pest populations and should be repeated at least weekly while symptoms persist. If that is not adequate, Neem Oil or Horticultural Oil like JMS Stylet Oil can be applied to foliage to smother pests and fungal spores.