I got an email from the Yates Gardening Club today that reminded me about the sooty mould I used to have on my lemon tree.
It looked like this:
If you ever see this kind of black ash on your citrus leaves or lots of ants, make sure you tackle the problem. It's caused by scale insects which are sap suckers and will likely kill your tree. You need to use a pyrethrim-based spray to smother and suffocate the insects.
you both correct , Mold is the end result of an initial problem , The insects break the membrane on a leaf giving Mold a food source , Mold cannot self sustain its life without a spore a food source and moisture , as no one can stop mold as it is needed in our enviroment to break down organic matter , your both correct , wage a war on the insects quickly .