Jan 24, 2012 – Beetles Above Us

QUESTION:

What would be the best product to use on powder post beetles that are in the living area on the ceiling? The ceiling is tongue and groove boards that look like they were sealed years ago.

ANSWER:

Well, this presents a problem, but start by making certain there is an active infestation. I don't want to be picky, but the True Powderpost Beetles in the genus Lyctus feed only on hardwoods, and a tongue and groove ceiling, it would seem, would more likely be pine of some kind. This doesn't mean you could not possibly have an ongoing beetle problem in the wood, but a more likely culprit might be Lead Cable Borer. Other WDO beetles could be ambrosia or deathwatch, but these beetles much prefer wood with a high moisture content, and unless there is a moisture problem in that ceiling it should not be either of those. If there are exit holes how big are they? Perhaps this could be some non-reinfesting beetle that would not need to be treated. 

Just out of curiosity, what is the evidence you are seeing that indicates an insect infestation there? Carpenter ants are one insect that just loves tongue and groove ceilings, as they have all those narrow channels already provided for their travel. If something is falling from the ceiling to tell you it is bugs, examine it closely using magnification. If it is beetles it would be very fine fecal material - powdery for Powderpost and gritty for deathwatch. Lead cable borers do not have fecal material falling from their exit holes, as all of their fecal matter is stringy and shoved into the feeding channels behind the larvae. Carpenter ants expel tiny pieces of wood chips and other junk they don't want in their galleries, so it would be fine sawdust with possibly some insect parts included. 

Now to get down to your actual question, but hopefully the first two paragraphs were useful, and mistaken identity of beetles in wood is pretty common. One problem is that the ceiling does likely have a finish on it, and this can limit what you can apply. One of the few products that actually can penetrate into the wood itself to kill beetle larvae living within is Bora-Care, formulated with solvents that move the active ingredient into the wood. But, it cannot be used over finishes on wood, but on bare wood only. All other surface treatments for beetles in wood are essentially that - surface treatments, and they do not penetrate the wood and the beetle larvae will continue to feed inside. What you may achieve would be to kill adult beetles as they exit if the residual is still on the wood, but this is iffy. 

There also are many products labeled for injection into the wood for WDO beetles, but I have some concerns that this might not work. The products, to my knowledge, do not travel in the wood beyond the point where they are injected, so beetles feeding nearby would not be affected. They would be killed if they managed to eat into the treated wood, but now we are talking about poor odds. However, this may be your only option if it turns out to be an ongoing infestation of beetles capable of reinfesting that wood. Of course, there also is complete structural fumigation as well as remove and replace the wood, but I would verify exactly what pest is present before going to those expensive options. 

If it turns out to be carpenter ants you have plenty of good choices, including many aerosols that can be injected into the galleries the ants are using for travel or making themselves. These can be injected by drilling very small holes in inconspicuous places until you feel the drill bit enter a hollow space, suggesting that ants could be using that for a nest or for travel. Even puffing a little residual dust into those galleries would be effective. 


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