Sooty mold

Sooty mold (also spelled sooty mould) is a collective term for different Ascomycete fungi, which includes many genera, commonly Cladosporium and Alternaria.^[1][2] It grows on plants and their fruit, but also environmental objects, like fences, garden furniture, stones, and even cars. The mold benefits from either a sugary exudate produced by the plant or fruit, or honeydew-secreting insects or sap suckers the plant may be infested by.

Sooty mold itself does little if any harm to the plant. Treatment is indicated when the mold is combined with insect infestation.