Microwaving may not necessarily be the choice of champions. Case in point...
I was in college in the early 1980's when microwaves were becoming semi-affordable. Having our inquisitive minds fueled by copious quantities of alcohol one evening, one of my friends caught a roach running across the countertop in the kitchen. He grabbed it and tossed it into the microwave. Expecting the roach to go poof like a kernel of popcorn, we watched this stupid roach run around for over 30 minutes of nuking before we got bored. Next morning, the roach (still confined to the microwave) was still alive and well. Our experiment ended when he escaped from the microwave and was crushed under an empty beer bottle.
Microwave ovens are typically set to a frequency to cause water molecules to vibrate faster generating heat. Some bugs do not have enough moisture in their bodies to suffer much damage from microwaves.
You might consider 1. boiling 2. freezing 3. vacuum sealing or 4. storing the wood in an inert environment such as nitrogen or carbon dioxide
for the last two, I leave it to you to find out how long a bug can go without air.
Tom