Black sooty mold is often a clue to an insect problem rather than the primary problem itself. Honeydew from sap-feeding insects can support dark fungal growth on leaves and fruit.
Look for the source
Inspect for aphids, mealybugs, soft scales, whiteflies or psyllids and note heavy ant traffic. Simply washing the black coating without addressing the honeydew source may not solve the underlying issue.
Reference
UC IPM notes that honeydew-producing pests can lead to sooty mold. See its citrus leaf-damage guide.
← Fruit Tree Problem & Care Library
Need help with your fruit tree in South Orange County?
Earth People LandCare inspects struggling citrus, avocado, stone fruit and other backyard fruit trees in Laguna Beach, Dana Point, Laguna Niguel, San Clemente, San Juan Capistrano and Aliso Viejo. We review the tree, irrigation, root-zone conditions and visible pest symptoms, then recommend next steps.
On-site Plant Health Diagnostic: $150. Treatment, repairs and laboratory testing are quoted separately.
Explore fruit tree diagnosis & care →Send symptoms & photos →