European shothole borer
3 host plants
Last updated
European shothole borer attacks weakened, dying, or recently dead Western red cedar and other conifers in Western Washington. You will see small, round exit holes in bark that resemble buckshot. This is primarily a pest of stressed, dying, or recently dead trees. Appearance is unsightly but trees under attack are usually already declining and cannot be saved.
The best defense is prevention through proper tree care; maintain vigor, avoid wounding, and ensure adequate watering and drainage. Once borers are established, no effective chemical control exists. Remove and destroy heavily infested wood, cutting into healthy sapwood to expose galleries and disrupt borers. Burn or chip infested material to destroy beetles before they emerge. Do not move infested firewood to new sites. Plant resistant species in locations where this beetle is problematic.
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Cultural Controls
- cultural control Severe infestations could indicate poor respiration of roots.
- A common cause of this is poor drainage or excess irrigation.
- The best management tool is to keep trees healthy with proper pruning, adequate but not excess water, and fertilizer.
- Healthy trees repel the beetles by plugging borer holes with sap and resins.
- Remove and destroy infested wood on the tree or piles of infested green wood nearby, especially cherry wood.
- Beetles also can attack young trees adjacent to piled...