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