WSU Extension

Hortsense

Caption: Photinia leaf spots and twig cankers
Photo by: R.S. Byther
  
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Photinia : Leaf spot (Diplocarpon)
(revision date: 4/23/2014)


Biology
Fungal leaf spot of photinia is characterized by the presence of red to purple spots on the leaves. The spots are small at first, but soon enlarge and develop brown to grayish necrotic centers. Small dark fruiting bodies of the fungus can sometimes be seen in the center of the spots. Severely infected leaves may drop, sometimes resulting in considerable defoliation. The disease can be spread by splashing water and overwinters on diseased plant tissues. New growth is particularly susceptible. In western Washington, photinia may develop a physiological leaf spot that resembles fungal leaf spot.
Management Options

Non-Chemical Management
  • Plant in full sun.
  • Space plantings and prune to improve air circulation.
  • Clean up and destroy fallen leaves.
  • Avoid overhead watering, or limit it to times when foliage can dry quickly.
  • Avoid summer pruning, which promotes a flush of susceptible new growth.
Select non-chemical management options as your first choice!

Chemical Management


Use in early spring as young shoots develop. Homeowners should not make foliar applications to trees over 10 ft tall. Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Fung-onil Multi-Purpose Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 60063-9-4
  • Bonide Infuse Systemic Disease Control
    Active ingredient: propiconazole  |  EPA reg no: 100-773-4
  • ferti-lome Liquid Systemic Fungicide II R-T-Spray
    Active ingredient: propiconazole  |  EPA reg no: 53883-184-7401
  • GardenTech Daconil Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 67572-82-71004
  • Monterey Liqui-Cop Copper Fungicidal Garden Spray
    Active ingredient: copper-ammonia complex  |  EPA reg no: 54705-7
  • Ortho Max Garden Disease Control Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 239-2522
  • Spectracide IMMUNOX Multi-Purpose Fungicide Spray Conc
    Active ingredient: myclobutanil  |  EPA reg no: 9688-123-8845
  • This list may not include all products registered for this use.
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Caption: Photinia leaf spots and twig cankers
Photo by: R.S. Byther