Determine the insect problem, then use approved insecticides to control them. As the food supply is depleted, sooty mold growth will disappear. Wash plants with a weak soap solution if desired. Sometimes galling and disfigurement will be associated with the infections. In midsummer, infections on some plants will produce cup-like structures or tubular growths that will bear abundant orange spores.
Resistant cultivars are available in some cases.
Avoid overhead irrigation late in the day or night. Prune away shade-producing vegetation. Thin plants if needed to improve air movement and speed drying time. Rake and burn fallen leaves and plant debris. If necessary, spray regularly during known infection periods with a properly labeled material chosen from Table 8.