WSU Extension

Hortsense

Strawberry
 
Disease
Common leaf spot 
Gray mold 
Red stele 
Viruses 
Insect
Aphids 
Brown marmorated stink bug 
Cutworms and armyworms 
Leafrollers 
Mites 
Root weevils 
Slugs 
Spittlebugs 
Spotted wing Drosophila (SWD) 



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Caption: Strawberry common leaf spot
Photo by: R.S. Byther
  
Strawberry : Common leaf spot
(revision date: 5/19/2015)


Biology
Common leaf spot is caused by a fungus that overwinters on old infected leaves. It produces abundant spores in lesions of infected leaves, and rain splashes them onto healthy tissue. Only young leaf tissue is susceptible to infecting, and long wet periods and warm temperatures encourage spread of the disease. Foliage symptoms start as dark purplish red spots, and eventually become grayish white. Developed spots are about a 1/10 inch in diameter, with a white center and reddish outline, and become scattered all over the leaf surface. Sometimes the whitish centers of spots fall out, leaving a hole in the leaf. Infections occur in moist weather and are most severe in spring and fall. "Olympus" and "Shuksan" cultivars are the most susceptible.
Management Options

Non-Chemical Management
  • Removing foliage after harvest reduces spore counts.
  • After harvest, renovate by removing leaves of June-bearing plants 0.5 inch above the crown, but do not mow other types.
Select non-chemical management options as your first choice!

Chemical Management

Leaf spot can still be a problem after renovation unless reinforced with chemical protection. Begin applying copper products when leaves emerge and continue weekly (every 10 to 14 days if using Bonide Copper Spray or Dust RTU) through the season.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Copper Fungicide Spray or Dust RTU [Organic]
    Active ingredient: basic copper sulfate  |  EPA reg no: 4-58
  • Bonide Liquid Copper Fungicide Conc/Organic Gardening
    Active ingredient: copper octanoate  |  EPA reg no: 67702-2-4
  • Soap-Shield Flowable Liquid Copper Fungicide [Organic]
    Active ingredient: copper octanoate  |  EPA reg no: 67702-2-56872
  • This list may not include all products registered for this use.
Images

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Caption: Strawberry common leaf spot
Photo by: R.S. Byther