Bronze Birch Borer in Wisconsin
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Bronze Birch Borer is currently active in Wisconsin. Watch your susceptible trees closely and act early.
About Bronze Birch Borer
A native North American wood-boring beetle that attacks birch trees, especially paper birch and European white birch in landscape settings. Larvae feed under the bark in a serpentine pattern, disrupting nutrient and water transport. Dieback starts at the top of the crown and progresses downward, the opposite pattern of many other pests.
Symptoms to watch for
Crown dieback starting at the top of the tree and progressing downward, D-shaped exit holes in bark (similar to emerald ash borer), raised serpentine ridges on bark surface from larval tunnels beneath, sparse yellowing foliage in upper crown, epicormic sprouting on trunk and lower branches
Trees at risk in Wisconsin
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Treatment options
Systemic Insecticide Treatment
Apply imidacloprid as a soil drench in spring or trunk inject emamectin benzoate for longer protection. Treatment is most effective when started before significant canopy loss.
Tree Vigor Maintenance
Keep birch trees well-watered (they are shallow-rooted and drought-sensitive), mulch to keep roots cool, and avoid soil compaction. Healthy trees are more resistant to borer attack.
Recommended Products & Tools
Helpful supplies for managing Bronze Birch Borer. Always read and follow label directions, and confirm a diagnosis before treating.
Knocks down soft-bodied pests like aphids, mites, and scale crawlers.
Smothers overwintering eggs and crawlers; dormant or summer rates.
Soil-applied protection taken up by the tree for season-long control.
Sharp, clean cuts to remove affected wood — a tree-care essential.
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Need help with Bronze Birch Borer in Wisconsin?
Connect with ISA Certified Arborists serving Wisconsin:
Frequently asked questions
Is Bronze Birch Borer in Wisconsin?
Bronze Birch Borer is currently active in Wisconsin. Watch your susceptible trees closely and act early.
What does Bronze Birch Borer look like?
Crown dieback starting at the top of the tree and progressing downward, D-shaped exit holes in bark (similar to emerald ash borer), raised serpentine ridges on bark surface from larval tunnels beneath, sparse yellowing foliage in upper crown, epicormic sprouting on trunk and lower branches
What trees does Bronze Birch Borer affect in Wisconsin?
It affects Paper Birch, River Birch. Susceptibility varies by species.
How do I treat Bronze Birch Borer?
Options include: Systemic Insecticide Treatment, Tree Vigor Maintenance. Confirm the diagnosis before treating, and consider a certified arborist for high-value trees.