Umm, I am not certain, but are you sure it isn't insects? There are a species of aphids called woolly aphids that appear to be fungus, but really aren't. Look closely at this "stuff" and use a magnifying glass if need be. Or just give it a spray with soapy water if nothing else.
If you notice,, when you post a topic,, several from past years show at the bottom. These are usually similar to whatever topic you need help with. Read the first one below from 2015. Similar problem >
