The cool wet weather has provided a good environment for anthracnose to grow.
24+ Fungal Leaf Spot Magnolia. Common fungi responsible for leaf spot diseases in midwestern shade and ornamental trees. Remove affected leaves from the tree and the ground around the tree and dispose of them to stop the fungus from spreading.
You Need To Be Aware Of The Diseases That Affect Magnolia Trees Gardenerdy from pixfeeds.com
None of these examples are diseases. As the university of connecticut (uconn) extension observes, in the presence of the fungal spores, all it takes is a film of water on. This is especially true when the potting mix is consistently wet and the plant's foliage remains wet for long periods, especially at night.
Individual leaves with spots can be picked off and destroyed.
Lesioned leaf with fungal fruiting bodies. Fungal leaf spots and the hosts they infect. Individual leaves with spots can be picked off and destroyed. Fungal bodies may appear as black dots in the spots, either in rings or in a central cluster.
