We have a log cottage built in 1931 of black swamp cedar. An addition was added in 1969 but the outside of the logs have been painted for years. We are now finding powder post beetles in the newer logs. We had them treated 3 years ago with boron or borax by a pest control. We now have fresh signs of powder on the insides of some of the logs. The outside does not seem to be any worse although their are always signs of powder.
Should the inside logs be treated as well? There is nothing on the inside logs.
If you read through our POWDERPOST BEETLE CONTROL ARTICLE, you’ll learn about several treatment options that can help to deal with a powderpost beetle problem. One important point made in our article is that the typical “borax” application being done will only help to “prevent” future infestations and should not be used where an active problem exists. This is because (as our article explains) the beetle larvae are deep within the logs doing their damage and to kill them you’ll need something that will penetrate the wood. Borax cannot penetrate.
And though products like TIMBOR (very similar to Borax) are fine when you want to stop mold or wood destroying insects from targeting your structure, they should only be thought of as “preventive” and not “curative”. For curing problems, you must use something like BORACARE. The unique design of the Boracare enables it to both penetrate and kill whatever is living deep within the wood and this is critical if you wish to stop the damage that’s clearly happening.
You’ll also learn from our article that the holes you’re seeing are actually “exit” holes being created as adults hatch from their pupae casings and want to leave the deep and safe confines of the log. In other words, don’t get them confused with something that’s “entering” the log; quite the opposite is happening. On top this, once these adults emerge, they’ll attempt to mate and continue the process so in your case, any logs or other wood you wish to protect must be treated with Boracare ASAP. This treatment will both get the ones currently feeding on the logs as well as prevent future problems from ever starting.
So to answer your question; you most definitely need to have the inside logs treated. Furthermore, the material used must be something like Boracare. Lastly, before you next paint the outside of the cottage, I suggest you treat that side of the cottage as well to insure you get complete and thorough coverage with no weak points available.
Here are direct links to the information and products listed above:
Powderpost Beetle Control: http://www.powderpostbeetles.com/powderpost-beetle-control