Leaf Spot(Entomosporium mespili)
Leaf spot is a fungus that attacks primarily plants in the rose family. The leaves start to get small redish spots with a yellow halo around them that gradually get darker and larger. Then spore forming bodies will appear covered by a glossy membrane. Leaf spot disease activity is drastically effected by weather conditions. In Southern California, heavey rains in late spring will cause a high incidents of leaf spot disease on a variety of common landscape plants. Suseptable hosts include: Evergreen Pears, Indian Hawthorn, Toyon, Tababuia, pyracantha, and photinia. When trees are heavily infected the fungus can cause severe leaf drop or even totally defoliate a tree.
Preventative measures include no overhead watering, giving plants adaquate spacing, and removing infected leaves.