Photinia is a common evergreen shrub with glossy green leaves and young red shoots.
Healthy Photinia
Photinia is sometimes planted as a specimen shrub, but is most popular as a fast-growing, dense, evergreen hedge. You may have noticed that many of these hedges in your neighbourhood are in very poor shape. Photinia is being plagued by leaf spot that is caused by the fungus Entomosporium maculatum, which can be devastating to the plant.
Photinia bright red shoots
Unfortunately for Vancouver gardens, leaf spot is most damaging during the rains of spring and fall. Let’s just say that’s a lot of rain!
Diagnosis: Does your Photinia have leaf spot?
Affected Photinia leaves will start showing symptoms of tiny, circular, bright red spots on both the top and bottom of the leaf. 
The many small spots can quickly spread into heavily diseased deep purplish or maroon border blotches with grey centers. If you look closely at the middle of each leaf spot you can often see a tiny black speck which is actually the source of the fungal spore.
If you start to notice affected leaves on your Photinia, even just a few spots, the leaf spot damage may not destroy the plant right away however the fungus will store spores on the plant for next spring’s or fall’s rains. 
Once your Photinia has a serious infestation, you will quickly notice very heavy leaf drop. If left untreated, this can lead to the plant’s death.
Disease: The fungus life cycle
The fungus has no problem hibernating on infected leaves and branches. During the rains of spring the spores are released and spread to new growth and healthy leaves in the splash of the rain. You often see infestation damage take place during the fall as well.
Treatment: How to treat the Photinia
Be cautious of where your irrigation system sprays as you do not want the foliage of the Photinia to be getting wet, nor do you want to overwater your Photinia. Try and provide more access to sun by clearing out some tree limbs if possible. Remove the diseased leaves by picking them off and rake up any fallen leaves. Do not fertilize the plants or prune or trim the plant to avoid promoting excessive new growth. On the other hand, severely damaged plants will require heavy pruning, with the goal of reducing the infected area of the plant and allowing more space and air movement. If the plant is severely damaged it may be necessary to remove it. If replacing it, remember to choose a completely different kind of plant, one that does not suffer from leaf spot. This includes roses, or Potentilla, Shrubby cinquefoil.
Treatment method and plan:
In Vancouver where we have a ban on many of the fungicides used to treat the leaf spot we can use a copper based treatment method. You will need to apply a copper fungicide 3 or 4 times during the spring. Start to spray your Photinia once the bright red new growth appears with additional treatments following every 2 weeks afterward for 1-2 months. It is important to make sure that all areas of the leaves and branch surfaces are sprayed. It is also quite effective to apply another 2 or 3 applications in mid-October to late-November.