Answer: Photinia is subject to black spot, especially if the leaves are wet overnight. Try to water the soil rather than the foliage (knowing that you can't control the rainfall) to avoid the spread of the disease. Daconil or Funginex are registered for use in Washington to protect newly unfurling foliage (apply according to label directions). Or, you can prune your plants in early spring, just as new growth begins. This will remove the old spotted leaves and, since the beauty of this shrub is in the bright red new growth, will encourage lots of healthy new growth.
Slugs and snails can be controlled with Sluggo.
Best wishes with your photinias!
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