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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Oak > Holes in trunk or branches

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Oak > Trunk/Branches > Holes in trunk or branches

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  • Image: Twolined chestnut borer 1
  • Image: Twolined chestnut borer 2
  • Image: Twolined chestnut borer 3

Twolined chestnut borer
Agrilus bilineatus

  • 1/8 inch D-shaped exit holes
  • Leaves in upper canopy look wilted, turn brown but remain attached to branch for several weeks
  • S-shaped galleries underneath bark
  • Bluish black bodies with two light stripes running down the wing covers
  • Larvae are approx. 1 inch long and white with 2 spines at abdomen tip
  • Damage visible mid to late summer
  • More information on twolined chestnut borer...
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  • Image: Roundheaded borers 1
  • Image: Roundheaded borers 2
  • Image: Roundheaded borers 3

Roundheaded borers/longhorned beetles
Enaphalodes rufulus, Goes pulcher, Enaphalodes
cortiphagus, Goes tigrinus, and others

  • ¼ to ½ inch elongate or circular exit holes in trunk or branches
  • Piles of sawdust on bark, ground or crevices; holes and surrounding areas in bark may be sap-stained
  • Adults are 1/4 to 3 inches long; cylindrical bodies with antenna as long or longer than its body
  • Larvae (called roundheaded borers) are wormlike and legless with a dark colored round head
  • More information on Roundheaded borers...
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  • Image: Carpenterworms 1
  • Image: Carpenterworms 2
  • Image: Carpenterworms 3

Prionoxystus robiniae

  • Exit holes in wood are round and large, about 1/2 inch
  • Galleries start in sapwood, eventually entering heartwood
  • Large amount of sawdust in piles present at trunk base
  • Stout bodied moths, black and light gray mottled forewings as large as 2 1/2 to 3 inches
  • Yellowish white caterpillars with brown heads; 2 to 3 inches long
  • More information on Carpenterworms...

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