disease of maple trees in autumn. damage of rhytisma acerinum fungus in acer leaves. sick leaf with tar spots. the

autumn maple fungus disease rhytisma acerinum nature leaves pathogen leaf plant color green foliage tree black park fall forest spot september environment flora parasite fungal tar season natural fungicides acer hameenlinna diseases damage widespread infect saccharinum infected sapindaceae pseudoplatanus october infection phytopathology ascomycete botany illness biology ecology