Let's clear up a little misinformation here first (Sorry, Charley):
 
>The holes that the Carpenter Bee makes in wood is a chamber to raise
>their young.  They eat into the wood about one inch and then make a
>right angle turn and eat for up to 4 or 5 inches.  They capture insects,
>place them in the hole they have made, lay an egg on the insect and the
>when the Carpenter Bee larva hatches it lives on the insect.
 
Carpenter bees feed their larvae on pollen masses, like virtually every
other bee in the world. There are NO bees in existence which are predatory.
 
>While one hole might not cause much trouble, several holes can
>seriously weaken a timber.  Purdue University entomologists say that
>the best control is to use an insecticide, Sevin, in a powder form.
 
An alternative is to simply take a household pest spray and a cotton ball,
soak the ball, and stuff it into the hole. A lot simpler for the average
person than going out and buying a big thing of Sevin.
 
In fact, let me pass along something I recently posted on rec.gardens, for
those of you who may need to answer questions about carpenter bees in the
future:
 
Stopping carpenter bees is easier done in a
preventative sense than acting once they're established. Carpenter bees
clearly recognize a place as being a suitable spot to dig a nest by its
*texture*. If it feels like wood, and it's soft enough to chew through,
then they'll start digging away. The simple way to avoid carpenter bees,
then, is to coat the wood with SOMETHING that makes the actual surface of
the wood unreachable, such as a latex paint or a thick, glossy varnish. I
have yet to hear of a carpenter bee drilling through an unbroken coat of
either paint or varnish, which makes perfect sense. They have a brain no
bigger than a pinhead, after all, and it takes a very specific stimulus to
entice them to dig. Remove the stimulus, and you will not have a problem
with carpenter bees. Once they have begun nesting somewhere, you can
either stuff pesticide-soaked cotton balls into the holes, or simply wait
for the season to end, THEN plug the holes with "false wood" compound, and
THEN coat the wood as above.
 
I hope this helps.
 
Sincerely,
 
Doug Yanega    Depto. de Biologia Geral, Instituto de Ciencias Biologicas,
Univ. Fed. de Minas Gerais, Cx.P. 486, 30.161-970 Belo Horizonte, MG   BRAZIL
phone: 031-448-1223, fax: 031-44-5481  (from U.S., prefix 011-55)
                  http://www.icb.ufmg.br/~dyanega/
  "There are some enterprises in which a careful disorderliness
        is the true method" - Herman Melville, Moby Dick, Chap. 82