WOOD BORING BEETLE INSPECTION GUIDES
There are numerous species of wood-boring insects which occur in houses. Some of these cause considerable damage if not controlled quickly. Others are of minor importance and attack only unseasoned wood. Beetles, bees, and wasps all have larval, or grub, stages in their life cycles, and the mature flying insects produce entry or exit holes in the surface of the wood. Correct identification of the insect responsible for the damage is essential if the appropriate control method is to be selected.
To use the table, match the size and shape of the exit or entry holes in the wood to those shown in the table; note whether the damaged wood is a hardwood or softwood and whether damage is in a new or old wood product (evidence of inactive infestations of insects which attack only new wood will often be found in old wood; there is no need for control of these). Next, probe the wood to determine the appearance of the frass. It should then be possible to identify the insect type. It is clear from the table that there is often considerable variation within particular insect groups.
Table 1. Classification of families of beetles which attack wood. |
|
Living Wood |
Diseased and/or Dying Trees and also Logs |
Dry Seasoned Wood |
True Powderpost Beetle (Lyctidae) |
|
|
X |
Deathwatch Beetles (Anobiidae) |
|
|
X |
False Powderpost Beetle (Bostrichidae) |
X |
X |
X |
Round-Headed Borers (Cerambycidae) |
X |
X |
X |
Weevils (Several Families) (Curculionidae Included) |
X |
X |
X |
Flat-Headed Borers (Buprestidae) |
X |
X |
|
Ambrosia Beetles (Platypodidae & Scolytidae) |
X |
X |
|
Bark & Engraver Beetles (Scolytidae) |
X |
X |
|
Shape and Size (inches) of Exit/Entry Hole |
Wood Type |
Age of Wood Attacked |
Appearance of Frass in Tunnels |
Insect Type |
Reinfest |
Round 1/50 - 1/8 |
Softwood & hardwood |
New |
None Present |
Ambrosia beetles |
No |
Round 1/32 - 1/16 |
Hardwood |
New & old |
Fine, flour-like, loosely packed |
Lyctid beetles |
Yes |
Round 1/16 - 3/32 |
Bark/sapwood interface |
New |
Fine to coarse, bark colored, tightly packed |
Bark beetles |
No |
Round 1/16 - 1/8 |
Softwood & hardwood |
New & old |
Fine powder and pellets, loosely packed; pellets may be absent and frass tightly packed in some hardwoods |
Anobiid beetles |
Yes |
Round 3/32 - 9/32 |
Softwood & hardwood (bamboo) |
New |
Fine to coarse powder, tightly packed |
Bostrichid beetles |
Rarely |
Round 1/6 - 1/4 |
Softwood |
New |
Coarse, tightly packed |
Horntail or woodwasp |
No |
Round 1/2 |
Softwood |
New & old |
None Present |
Carpenter bee |
Yes |
Round-oval 1/8 - 3/8 |
Softwood & hardwood |
New |
Coarse to fibrous, mostly absent |
Round-headed borer |
No |
Oval 1/8 - 1/2 |
Softwood & hardwood |
New |
Sawdust-like, tightly packed |
Flat-headed borer |
No |
Oval 1/4 - 3/8 |
Softwood |
New & old |
Very fine powder & tiny pellets, tight |
Old house borer |
Yes |
Flat oval 1/2 or more or irregular surface groove 1/8 - 1/2 wide |
Softwood & hardwood |
New |
Absent or sawdust-like, coarse to fibrous; tightly packed |
Round- or flat-headed borer, wood machined after attack |
No |
|
