Strawberry: Common leaf spot
categories: Small Fruits Strawberry Strawberry Diseases
revision date: 2022-12-07 12:00
Photo by: R.S. Byther
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″ 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
Use Integrated Pest Management (IPM) for successful plant problem management.
Non-chemical Management
Select non-chemical management options as your first choice!
- Removing foliage after harvest reduces spore counts.
- After harvest, renovate by removing leaves of June-bearing plants 1⁄2″ above the crown, but do not mow other types.
Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.
- 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.
Approved Pesticides
Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.