Notes on Blueberry Diseases
Stem cankers (Phomopsis and Fusicoccum)

Identification

Several stem cankers and diseases affect highbush blueberries. Fusicoccum forms distinct elliptical cankers on the lower half of the stem. Phomopsis cankers are less defined than fusicoccum, and appear as flattened and elongated areas on the stem. Both cankers can result in rapid wilting and dying of the two to three-year-old blueberry canes. Leaves turn reddish brown and remain attached to the cane.

Period of activity

Infection by canker-causing fungi can occur anytime during the growing season and especially in wet weather. Die-back symptoms are most obvious in midsummer when bushes are stressed by cropping or drought..

Management notes

Blueberry plants are more susceptible to phomopsis if they:

• are over-fertilized with nitrogen
  
• are grown in poorly drained soils
  
• suffer from winter injury
  
• are damaged or wounded by machine harvesters, for example
  

Prune out and burn diseased canes as soon as they appear.

Learn more...

• Notes on Blueberry Diseases and Insects
• OMAFRA Publication 360 Blueberry Calendar
• OMAFRA Publication 360 Fruit Production Recommendations
• OMAFRA Berry Crops Index page
• Michigan Blueberry Facts - Phomopsis canker and twig blight
  

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