Photinia Leaf Spot or scab

Photinia Leaf Spot or scab ( Entomosporium maculatum )
Entomosporium maculatum affects woody members of the Rosaceae Family but for gardeners, it is most notable with the Photinias. Other hosts include pear trees, hawthorn, Pyracantha, Sorbus and quince.
Photinia is quite a robust plant, the main problem with larger photinia is that they are very popular with gardeners to produce instant screens using larger plants which can be expensive. The high value of larger photinia plants is causing the nurseries to grow them by feeding with access levels of nitrates to produce height as quickly as possible. This produces very soft growth which is susceptible to disease and pests, especially Photinia Leaf Spot or scab.
Before using fungicides to try to cause the problem often feed with a high potash feed with harden the foliage and often solve the problem. If that does not work the next stage is to check the soil pH. Photinia will not grow well in chalky soil, needing neutral to acid conditions. 
For more advice on growing Photinia ask your gardening expert on the GardenAdvice MyGardenTeam service