WSU Extension

Hortsense

Common Insects & Mites : Shothole borer
(revision date: 4/30/2013)


Biology
Shothole borer is one of several bark beetle species that attack trees in stress due to disease, injury, etc. It is a small, black, stout, but somewhat elongate, beetle. The larvae of these beetles mine in the cambium layer under the bark of alder, cherry, apple, plum, and many ornamental trees. The result is almost always death of the tree. Evidence of infestation includes rapid tree decline and pencil-lead-sized emergence holes in the trunk and major limbs.
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. Destroy prunings to reduce chances of reinfestation.
  • Whitewash trunks of young trees or purchase white plastic tree trunk wraps to prevent sunburn.
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 an unhealthy condition. Direct trunk and limb sprays to infested and neighboring trees when adults are active (June-July, Sept-Oct) may be effective. Refer to the specific host plant for registered pesticides to manage shothole borers.

Images
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Caption: Shothole borer infestation holes
Photo by: A.L. Antonelli
Caption: Bark beetle larval galleries
Photo by: A.L. Antonelli
Caption: Shothole borer hole
Photo by: K. Grey
Caption: Bark beetle (very similar to shothole borer)
Photo by: A.L. Antonelli