Ascochyta coronaria Ellis & Davis, (1903) Marssonina coronaria (Ellis & Davis) Davis, (1914) Diplocarpon mali Y. Harada & Sawamura, (1974) Diplocarpon coronariae[1] is a plant pathogen that causes Marssonina blotch on apple.

[2] Marssonina blotch is a fungal disease of apple leaves and fruit[3] that is caused by Diplocarpon coronaria.

[4] Marssonina blotch was historically an important apple disease in Japan[3] and China.

[7] Marssonina blotch was detected in Europe by the early 2000s[8] where it caused widespread disease, especially on organically managed apples.

[9] In the United States Marssonina blotch was first observed as a serious disease in 2017.