Pacific Northwest 1998 An Online Guide to Plant Disease Control

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OSU Extension Office
 
Blueberry -- Crown Gall
 
Cause: Agrobacterium tumefaciens, a bacterium that survives in soil and infects plants through wounds. The disease is a sporadic problem in propagation beds, young plantings, and a few established fields. Some cultivars seem more susceptible than others.
Symptoms: Galling occurs on branches, at the bases of canes, and on major roots. Young galls are cream to light brown; mature galls are dark brown to black and are rough and hard. An unusual symptom of crown gall is small galls erupting contiguously along the length of aerial branches. Galls may be in strips or may completely encircle the branch. Tissue underneath the galled area is green but necrotic between galls. This symptom does not extend to underground portions of the plant.

Note the galls that form along the canes in this out of focus picture.

 
Cultural control:

  1. Purchase clean stock, and inspect new plants before planting. Discard any diseased plants.
  2. Do not plant in previously infested fields, or rotate infested field to grasses or vegetables for 2 to 3 years before replanting blueberry.
  3. Preplant soil solarization has been effective for cherry nursery stock in western Oregon and may have some value for home or organic production. Place clear plastic on rototilled ground, which has been irrigated to near field capacity, from mid-July to mid-September. More effective on sandy loam soil.
  4. Remove and destroy diseased tissue.
  5. Prune bushes only during dry weather and frequently disinfect pruning equipment.
Chemical control: Gallex (ready to use) painted on very young galls to reduce further development. Galls may return the following year or, if treated late, may continue to develop. Tissue surrounding the gall may be injured, especially on younger plants. Prepare the surface by removing soil from around the galled area, and allow the area to dry before application. Not registered in Idaho. 12-hr reentry.
Biological control: Cuttings or plant roots may be dipped in a suspension of an antagonistic bacterium before planting. To be effective it must be applied a few hours after wounding.

  1. Galltrol-A. Not registered in Idaho. 12-hr reentry.
References:
Caruso, F.L. and D.C. Ramsdell. 1995. Compendium of Blueberry and Cranberry Diseases. St. Paul, MN: APS Press.
Content edited by: Jay W. Pscheidt on January 1, 2009
 
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