Continuous wet weather leads to the right conditions for Entomosporium leaf spot to develop on your Indian Hawthorne bushes. Look for small, reddish-purple dots on new leaves that seem to die in the center of the spots. Yellow outlines will form on the outline of the spots. Later you will see the leaves turning red and falling off. This leaves your Indian Hawthorne with a lot less leaves and looking really unhealthy.
This fungus lives on the leaves that are infected and also on the surface of the ground. If you catch it early, remove the infected leaves. Like most fungi, removing select branches and allowing more airflow will let the plant dry quicker. This creates a less pleasant place for the fungus. Also remove the old leaves that have fallen to the ground.
Fungicides will help in controlling Entomosporium leaf spot. Use it about every two weeks when the weather keeps the area wet and the temperature is not hot enough to dry out the plant leaves quickly. Spring and Fall are prime time for this fungus to develop. If you continue to have problems with this disease year after year, consider replacing your plants with a different species.