I have been given some rough cut lumber from 2 to 3 thich. This lumber had been piled in an old barn for about 20 years. There is lots of evidence of what I think are powder post beetles.
My intent is to lathe turn various articles fron it.
Request treatment recommendations. The wood could possibly be turned and then treated if warpage would not be a problem
Many of the articles would be used to hold various foods, nuts, and candy,
I think the small holes that remain after turning will give the piece "character".
I agree; the exit holes created as adult beetles leave the wood does give the finished look some character. That being said, we don't want any of these pieces providing the structure with live beetles so some treatments will be needed to insure this doesn't happen.
Regarding warping; when done properly this should not be a problem. I've treated lumber as thin as 1" thick pine that was very dry and there was no sign anything was ever applied once dried and cured out. I'm sure the same result would be achieved in your scenario. And this should be true whether you treat before or after turning the wood.
Additionally, the treatment soaks "into" the wood and does not lie on it's surface. If the treated lumber is left unfinished it would be safe to use for any purpose once allowed to cure (which generally only takes a few days; 1-2 weeks max). And if the wood is to be sealed there would be no chance of unwanted exposures.
As for the treatment option; no doubt the BORACARE would be the best option. As is the wood would probably be in it's easiest shape to treat. And since Boracare is virtually odorless, the wood can be treated inside since most of the country is a bit cold right now. You don't cite how much wood you actually have but if needed we can help you calculate how much will be needed.
Here are direct links to the information and products listed above:
Powder Post Beetle Article: http://www.powderpostbeetles.com/powderpost-beetle-control