How to get rid of powder post beetles?

I have a round wood barn.  It's at least 50 years old and I added doors to the walk out basement part two summers ago.  Now I notice tiny exit holes and dribbles of very fine sawdust in many of the logs.  Some of the logs still have bark on them but they're mostly barkless.  I'm not sure if the doors changed the conditions under the barn but I'd like to keep the doors.

I've heard that borate solutions can be a way to kill the beetles.  I'm not sure if that's particularly toxic or not (I'm fine if it's toxic to these beetles).  

Are there other ways to get rid of the beetles effectively?  I like bugs everywhere but not if it damages the structural integrity of my barn.

Those beetles thrive whenever the wood is allowed to reach a certain moisture level. I wonder if the doors are keeping it too moist. The only thing I know about powder-post beetles is that you must not allow wood to get moist enough for them to be able to eat.

I see them regularly in crawl spaces where there's a dirt floor. Other houses of the same vintage, with a concrete floor and the furnace in the basement, seldom have this problem.

It's probably a good idea to consult a professional concerning what to do about it in the short run, but in the long run you need to deal with everything to do with drainage, ventilation and anything else you can do to bring down the moisture level.

Thanks Dale, I did suspect it could be due to moisture.  I think I fixed a couple drainage issues so it's rarely damp in there any more.  But it does have a dirt floor and it feels a bit humid.  I'm sure the doors are helping keep it moister in there that it was.

I'll think about ventilation.  Maybe there's a way to get some air flow through there....

Moisture can also be migrating up. To determine that, get some plastic and lay on the floor and then weigh it down with a few stones. After a few days, lift it up and see if there are lots of drips.

The missus was organizing down there today and just said that when she picked up old boards that were laying in the dirt, they were slightly or somewhat damp underneath.  The floor in general is powdery sand that you can kick up into a good dust storm.  But if you cover it with something I think the moisture can appear.  

I've been tempted to do a soil cement floor in there to avoid kicking up the dust.  Not sure that would do anything for the moisture transfer?

This is somewhere where a petroleum product makes sense. Get some of that nice thick plastic and lay it down after you rake up whatever quantity of sand you want to put on top of it. The doors may have kept the moisture in, but I suspect that it's the floor that provided the moisture.

Thanks Dale!  It's also sunk into a hillside so the walls may be providing some moisture too.  I'll take another look today.  Plus it's full full full of stuff which will make any of this work a pleasure...

I'm long overdue for an update.  I ended up paying someone to peel all the bark off the logs and then buying a product of some kind that you spray on to form a gritty crystalline surface on the logs and it also soaks in to keep the bugs from wanting to eat it.  A year later they are still making an appearance :(

We just carved some big windows in the doors and are working on other ways to increase the ventilation down there.  There's too much stuff in there to lay down plastic and I do suspect as much moisture is coming through the walls as is coming up through the floor.  We'll see if the ventilation does the trick...

Thanks for the update Mike.  Anyone else solve this issue?