WSU Extension

Hortsense

Plum, Prune (Fresh)
 
Disease
Armillaria root rot 
Bacterial canker 
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: Shothole borer holes on apple
Photo by: R.S. Byther
  
Plum, Prune (Fresh) : Shothole borer
(revision date: 5/20/2014)


Biology
Shothole borers are small (1/10" or less), brown to black, stubby-nosed beetles. Adults feed at the base of leaves or twigs. Later, they bore into the bark and lay eggs along a narrow gallery paralleling the grain of the wood. The white, legless grubs (bark beetles) feed by boring between the bark and sapwood, making narrow tunnels filled with sawdust-like frass (excrement). Feeding larvae can weaken or girdle trees. Larval galleries are typically at right angles to the first gallery, with the grubs pupating at the end of the galleries. The emerging adults leave tiny round "shotholes" in the bark, giving the beetle its name. Shothole borers are especially attracted to injured, stressed, or dying trees, but can also attack healthy trees. Fruit, ornamental, and forest trees and shrubs can be attacked.
Management Options

Non-Chemical Management
  • Provide proper culture. Healthy trees are less likely to be attacked and more likely to survive infestations.
  • Prune out infested wood. Remove or destroy prunings to reduce chances of reinfestation.
Select non-chemical management options as your first choice!

Chemical Management

Burn prunings and keep trees in vigorous growing condition. Borer attack usually indicates trees are in unhealthy condition.

Images

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Caption: Shothole borer holes on apple
Photo by: R.S. Byther
Caption: Shothole borer infestation holes
Photo by: A.L. Antonelli
Caption: Shothole borer galleries
Photo by: E.H. Beers
Caption: Bark beetle (very similar to shothole borer)
Photo by: A.L. Antonelli