how to tell if beetle holes are new or old

If you find an infestation or the little holes how can you tell if its old or new? I have a cedar log home and do I need to strip all the varnish to apply the “cure” suggested to penetrate the wood and then re-varnish? Does it discolor the wood ? Thanks.

First, BORACARE goes on clear and once it soaks into the wood, essentially disappears. The wood will appear “wet” when you treat, just as if you washed it down with plain water, but once dry and the material is absorbed, it will go back to exactly as it once looked. Effectively there will be no trace or record the application was ever done.

Second, if you read our POWDERPOST BEETLE CONTROL ARTICLE, you’ll learn the holes you’re seeing are exit holes. Pupae that are fully developed will exit infested lumber and in this process, they create the holes you see. So they are only “active” for a brief moment. Once the adult drills through the wood surface and makes the hole, it will fly away and the hole is rarely ever used again. So to answer your question; no doubt the holes you see were at one point active but not anymore.

So what should you do? Here’s the easy answer. Monitor the area and see if any new holes appear. If they do, it will mean you have more pupae hatching and drilling out which means you have an active infestation. If you don’t find any new holes, it means the holes you see are old and there is little chance new ones will appear. But as you’ll learn in the article, it’s the young of this beetle that does the damage and since there is no way to tell if you have any young still in the wood currently chewing away, some people will opt to get it treated so they can be done with the issue once and for all. Ultimately the choice is yours and should be made based on the level of comfort you have for the situation. It’s kind of like insurance; it’s hard to have too much. In this case, going through the work of removing the varnish and treating would no doubt be a major task. But once done, the wood would be protected and you’d no longer have to wait and worry about whether or not there is more damage being absorbed.

Alternatively you could wait it out and see if anything new emerges and if it does, use that as a sign there is activity that needs to be addressed before the wood sustains more damage. In the end it’s your call and there is no “right or wrong” choice.

Here are direct links to the information and products listed above:


Powderpost Beetle Control Article:

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Comments on how to tell if beetle holes are new or old

September 20, 2011

Allen @ 9:44 am #

Thank you..that was very helpful.

September 23, 2011

Allen @ 9:11 pm #

How soon after the application of boracare can I apply stain and varnish? Thanks Allen