WSU Extension

Hortsense

Plum, Prune (Fresh)
 
Disease
Armillaria root rot 
Bacterial canker 
Black knot 
Brown rot 
Crown gall 
Cytospora canker 
Plum pockets 
Russeting 
Shothole (Coryneum blight) 
Silver leaf 
Virus diseases 
Insect
Aphids 
Apple-and-thorn skeletonizer 
Brown marmorated stink bug 
Earwigs 
Fruittree leafroller 
Leafhoppers 
Pacific flatheaded borer 
Peach twig borer 
Peachtree borer 
Pear slug 
Scale insects 
Shothole borer 
Spider mites 
Spotted wing Drosophila (SWD) 



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Caption: Crown gall
Photo by: R.S. Byther
  
Plum, Prune (Fresh) : Crown gall
(revision date: 5/20/2014)


Biology
Crown gall is caused by a soilborne bacterium. The bacteria infect through wounds on the crown and roots. Young galls are fleshy, white, enlarged masses on the roots or stems. Older galls are hardened and turn dark brown and woody or corky in appearance. They range in size from less than an inch to several inches across. The bacteria can be spread from infected to clean soil by water movement. Damage varies with location and size of galls. Small galls are essentially harmless. Large galls on the crown may weaken or girdle trees. The growths can also be an aesthetic concern.
Management Options

Non-Chemical Management
  • Plant disease-free materials.
  • Remove and destroy declining trees with large crown galls. Also remove roots and surrounding soil when possible.
  • Prune out galls when practical. Sterilize pruning tools between cuts to avoid spreading bacteria to healthy tissue.
  • Avoid injuries to the bark, crown, and roots while planting.
  • Do not replant susceptible species in infected soil.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images

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Caption: Crown gall
Photo by: R.S. Byther