From my own experience
A part of lumber that was affected by the bark beetle I sent for a firewoodt. They were cut out and then we fetched the larvae for experiments. We haven’t modern productsin our town,so I tried a disinfector № 276 “Antibug wood cosmetics" and a mixture of a kerosene, a turpentine 1:1.
So, "276" is a complete garbage, the larva didn’t die even after 10 minutes of “swimming” in this solution. The solution was dried up, and the larva pulled itself together and tried to escape.
A mixture of turpentine and kerosene is something, the larvae twitched about 5-15 seconds (depending on size) and dead.
Weekly I will look for more larvae on boards, and try a malathion. Choose the most efficient one!