Plum, Prune (Fresh): Shothole borer

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

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• 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.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

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

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