The following is information on current diseases being found in Delaware landscapes.
Late season leafspots are present on many landscape plants. Septoria leafspot is being seen on many dogwoods including C. sericea, amomum, and florida. Look for grayish angular spots on the leaves. Sometimes they can look like anthracnose but we generally don't see anthracnose here in the fall. Again no controls are needed. Leaf blotch on horsechestnut is another foliage disease that is causing some premature defoliation. Look for the large brown blotches with yellow borders that follow the major veins. Usually it does not affect the health of the tree either.
Leaf blotch on horsechestnut. Photo by Fabio Stergulc, Università di Udine, Bugwood.org
Information from Bob Mulrooney, Extension Plant Pathologist, UD.