06-02-2011, 10:40 AM
Sounds like sooty mold. Neem oil or another oil will kill it and it is then easy to clean off. If left is will interfere with photosynthesis.
I have plenty, it is caused by fire ants farming mealybug and their honeydew then attracts the sooty mold. A nasty cycle that can kill plants.
Need to eliminate the ants as well as the sooty mold and whatever bug the ants are farming.