Picture too blurry, you need a camera with a good macro mode. Examine them very closely with a magnifying glass over a well lit, dark colored non-shiny surface. Aphids have legs, fungus does not. If this can't be determined with it on the leaf, scrape off onto the dark colored surface for viewing.
Sometimes I find I can get a much closer look at things using a high quality computer scanner set at max native resolution with dark construction paper behind the object (do not put the lid down as it will mash what you are looking at).