maple leaves with yellow spots of disease on white. tar spot of maple (rhytisma acerinum) is a fungal disease.

maple acer tar spot disease rhytisma acerinum autumn background black botany bright brown closeup damage environment fall flora foliage forest fungal fungus green illness impact infection isolated large leaf leaves mycology natural nature outdoor parasite pathogen pattern plant rounded season spring stain summer surface texture tree white wild yellow spots early stage white disease