I have black sticky substance on the oranges on my orange tree. Are the oranges still safe to eat? What's the best way to get it off the oranges if it is safe?
Means you've got bugs on it or a larger plant above it that are pooping out sugary secretions. The blackness is a fungus growing on this "honeydew" called sooty mold.
Your tree has either aphids, mealy bug, or most likely scale. Sooty mold is non toxic, and the fruit is very safe to consume. Control the insect, and you will automatically control the sooty mold. - Millet
