The first thing to consider is whether the holes have just occurred or whether they were in the wood to begin with. There are a number of wood boring insects that attack trees while they are alive, and there are a number of other species that attack wood – that after the tree has been cut down.

Wood that goes for veneer may have a few holes (or other defects) and still be used. However, a couple of the pieces in your picture seen to have more holes than you would generally expect to be acceptable for veneer.

One way to determine if the holes are just in the veneer (and likely from borers in original the tree) is to use a toothpick to measure how deep the holes are (and if they extend through the veneer into the fiberboard or plywood behind the veneer).

From your question, it sounds like holes have appeared since the bar was installed in the house. If that’s the case, then it’s important to determine if there is still an active infestation or not, and then to determine what species may be there.

The veneer itself would not be the sole food source for insects creating those holes. Infestations going into the fiberboard would be a bit unusual, but that would depend on the exact materials used and construction of the bar (does the fiberboard extend all the way behind the veneer, etc.)

Recently formed holes (suggesting an active infestation) will have a powdery sawdust like material in the hole or on the floor beneath the hole. That material is the insect’s frass – composed of feces and small pieces of wood. Older hole may have the same powdery material but it will be covered with dust or debris.

If the sawdust material is present and feels like flour or talcum powder when rubbed between your fingers, it would be from a powderpost beetle.

If the material feels gritty, it would be from a deathwatch (aka, furniture) beetle in the family Anobiidae. These insects can feed on a wide range of materials – more than the powderpost beetles can feed on.

If the material seems to be packed in the hole and stick there, it would be from a false powderpost beetle. It is also extremely gritty.

You can also use a ball point pen to identify the culprit.

If only point of the pen fits in a hole, it’s likely from a powderpost beetle.

If cone of the pen tip goes in the hole, it’s likely from a deathwatch beetle.

If the entire tip can go in the hole, it’s likely from a false powderpost beetle.

Again, if you are seeing new holes, it’s important to identify what species may be present because each one is managed a bit differently. A pest control operator can help with identification and any needed treatment recommendations. Please write back if you have questions or would like additional information.