Pear: European canker (Nectria canker)

• Categories: Pear Pear Diseases Tree Fruits
• Last review date: 2025-08-23 06:36

Biology

Nectria or European canker is a fungal disease affecting the twigs and branches of pear and apple.

Young cankers occur at leaf nodes on twigs and are sunken, dark, and water-soaked in appearance. Twigs are often girdled and die back above the infected site.

Older cankers are either irregularly elongate and covered with dead bark, or are surrounded by roughened, irregular, cracked bark in concentric rings, indicating the infection’s yearly advance.

In spring or fall of the first season following infection, cankers produce white fungal fruiting bodies. Round, red fruiting bodies are produced on older cankers during subsequent winters and springs.

The fungus infects during rainy weather in the fall, attacking through leaf scars and wounds.

An eye rot may occur on the flower end of fruit, causing brown, depressed spots with lighter centers on the fruit surface.

Management Options

See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.

Non-chemical Management

Select non-chemical management options as your first choice!

• Prune out and destroy cankered tissues during dry weather in early summer.

Chemical Management

• Apply before fall rains and during early leaf fall.
• 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.

Approved Pesticides

If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.

• Bonide Copper Fungicide Spray or Dust RTU [Organic]
  Active ingredient: basic copper sulfate
  EPA registration number: 4-58
• Bonide Liquid Copper Fungicide Concentrate/Organic Gardening
  Active ingredient: copper octanoate
  EPA registration number: 67702-2-4
• Soap-Shield Flowable Liquid Copper Fungicide [Organic]
  Active ingredient: copper octanoate
  EPA registration number: 67702-2-56872
• This list may not include all products registered for this use.