Sooty Mold is a thread-like, black-colored fungus that grows in honeydew secretions left by insect pests like Scale, Whitefly and Aphids. Once pests are controlled, sooty mold will dry out, flake-off and be less of a problem. You can wipe leaves with a wet cloth to clean houseplants.
Sooty Mold on the topsides of leaves interferes with photosynthesis by blocking sunlight. Along with the honeydew, it is sticky and drips from trees in summer heat making a mess of walkways, cars and pavement. Left untreated, it can lead to stunted growth and premature leaf drop. In order to control Sooty Mold, you have to control the insect pest secreting the honeydew.