Diseased Red Tipped Photonia
Hi - Your plant has symptoms of Entomosporium, a common fungal leaf spot disease of Photinia. This disease rarely kills the plant, but it is not attractive. In some cases, the disease can be so problematic that homeowners decide to remove the shrub. We do not recommend planting this shrub due to this disease.
The fungus overwinters in infected leaf debris (or on the infected leaves). Practice good sanitation. Rake and dispose of infected foliage, avoid overhead irrigation, also avoid mid-summer pruning that may stimulate flushes of susceptible foliage.
A fungicide will not control or clear up the existing symptoms. If you do want to use a fungicide, it would have to be applied to newly emerging leaves in the spring and periodically during the growing season in order to be effective. See our website for photos and more information. https://extension.umd.edu/hgic/topics/leaf-spot-red-tip-photinia
This publication goes into further detail about the disease and management options, https://www.pubs.ext.vt.edu/450/450-609/450-609.html