? about Powder Post beetles

We moved into our new home last Janurary. It is 50 years old. At the time the house was pest free. This summer we started noticing tiny holes in the hardwood floors. It seems that we have Powder Post Beetles. The floors are sealed and treated. How could these bugs have nested? Can they nest again evern though the floors are treated?
I was thinking about spraying pesticide into the holes and then filling them. Will this work or will they bore out od new holes?
Thanks for any help.

If the floor was recently sealed the bugs may have laid eggs before the sale. They hatched and bored their way out. I think some borax based products will prevent further infestation (and is relatively non-toxic, to humans) but not what's already in the wood. The beetles like some wood better than others and some only infest at ceratin moisture content.

You might want to check the Wood Web on this one , Dr. Gene Wenghert (sp?) knows it all concern PPBs.