Fungi are spread anywhere and can live on their own or as parasites of other eukaryote organisms. Some species can tolerate adverse conditions, such as, for instance, extreme temperatures: some live even at 5-6 degrees below zero, others at temperatures above 50 degrees. Mildews are microscopic fungi that look like a white, grey, green or black dusty coating. They are usually visible on such foods as bread, jam and fruits in the form of a blue or green coating.