First report of Diplocarpon coronariae causing apple blotch disease of apple tree in Belgium

Summary

In October 2023, apple tree leaves presenting typical symptomscaused by the fungus Diplocarpon coronariae wereobserved in an unsprayed genetic resources evaluation orchard at theWalloon Agricultural Research Centre in Gembloux, Belgium. Appleblotch disease causes severe premature defoliation leading to reducefruit load and quality, and reduced tree vigour. This is the first report of D. coronariae in Belgium.The threat it could represent for organic apple orchards in Belgium,and particularly for untreated orchard meadows, is unknown but thepathogen is responsible for significant economic losses in several coun-tries