Marssonina blotch

Marssonina blotch is a fungal disease of apple leaves and fruit that is caused by Diplocarpon coronariae.

Distribution
Marssonina blotch was historically an important apple disease in Japan and China. In the 1990s it became an important apple disease in India, and Korea. Marssonina blotch was detected in Europe by the early 2000s where it caused widespread disease, especially on organically managed apples. In the United States Marssonina blotch was first observed as a serious disease in 2017.