> The carpenter bees that have from time to time inhabited my deck make new
> tunnels each year, evidenced by the large sawdust piles under their holes in
> the spring.  Since I was not poisoning the holes, that was not a cause of
> their tunneling.  Left unchecked, they can seriously affect the integrity of
> a structure.

If one wanted to raise carpenter bees, one could not do better than to put
a cedar shake roof on their house.  The spaces between the shakes are
the perfect size for them - they seem to view the spaces as pre-made
tunnels.  A friend of mine who owns a roofing company in PA, USA found
exactly this.  The owner had tried various approaches at "pest control",
and felt forced to replace the entire roof with non-wood (asphalt) shingles.

The roofing crew was happy to hear that carpenter bees have no stingers,
but were disappointed to hear that there would be no honey to harvest when
removing the roof, so I shipped them a case of honey to lift their spirits.  They
gave some to the homeowner, which likely has them confused for life about
carpenter bees.

        jim