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.
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