WSU Extension

Hortsense

Camellia : Flower and petal blight
(revision date: 2/25/2015)


Biology
Flower and petal blight is a fungal disease of camellia flowers. Leaves, stems, and roots are not attacked. Symptoms begin with development of brown spots on the petals. These spots quickly enlarge until the entire flower is brown and dry or leathery and drops from the plant. Dark brown veins in lighter brown petals are a characteristic symptom. Olive-brown or black fungus bodies, up to an inch in diameter, can develop in the bases of infected flowers. These fungal structures persist in the soil, causing reinfection. This disease may be confused with injury caused by weather, which is usually only found on the outer margin of flowers. Disease development is favored by cool, wet conditions. All species and varieties of camellia appear equally susceptible to this blight.
Management Options

Non-Chemical Management
  • Plant only disease-free materials. To reduce chances of planting infected materials, it is best to plant bare-root plants with no color showing in the buds.
  • Remove and destroy diseased flowers to reduce chances of reinfection.
  • Remove and destroy (do not compost) all plant debris from beneath camellias.
  • Remove 3-4 inches of soil beneath diseased shrubs and replace with clean soil to help reduce reinfection.
Select non-chemical management options as your first choice!

Chemical Management

Apply to foliage to protect blooms as flower buds begin to swell.

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 Lawn & Landscape
    Active ingredient: thiophanate methyl  |  EPA reg no: 53883-183-4
  • This list may not include all products registered for this use.
Images
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Caption: Camellia flower blight: healthy vs. diseased blooms
Photo by: OSU slide library