I have been eradicating carpenter bees for almost 15 years.  They are
becoming more of a problem each year as their natural habitat of mostly
living in dead trees or limbs is being wiped out by the building of homes.
The stain down the side of a house under the fascia board is a combination of
pollen and waste.  Yes they are good pollinators, but like bumblebees are not
easily controlled for pollination of crops.  They ARE NOT good pollinators
for blueberries as they chew open the side of the bloom to get inside before
it blooms.  When it does bloom, most of your other pollinators use that side
entrance that the carpenter bee made thus eliminating the pollination
process.

The carpenter bee is almost always mistaken for a bumblebee or vice versa.
The main difference to watch for is the fascinating way the carpenter bee can
hover right in front of your face whereas a bumble bee is most likely to be
flying lower to the ground among the flowers.  The carpenter bee also has a
shiny black abdomen whereas the bumble bee is furry.  The female has a slick
stinger like the bumble bee therefore allowing her to put the stinger in and
out multiple times.   They build their nests in wood where the female drills
a perfectly round 1/2" hole where she will make a channel or gallery.
Galleries usually average 4 to 6 inches in length, but galleries used by a
number of bees may go up to 10 feet in length.  The female excavates the
gallery by means of her mandibles.  She can excavate 1 inch in six days.  She
furnishes her nest with "bee bread"  (a mixture of pollen and regurgitated
nectar); she lays an egg on top of it and closes the cell with chewed wood
pulp.  There may be six such sealed cells in a linear row in one gallery.
The larval period extends from 37 to 47 days.    These eggs hatch in late
spring/early summer.  They are territorial thus that family will return to
the nest where they will hibernate in that channel for the remaining part of
the summer and winter and will again emerge at the beginning of spring the
next year where each of those carpenter bees that hatched out will then begin
their own family.  The new family can start more holes in the same house or
use the neighbors house next door.    I have gotten as many as 12 carpenter
bees out of one hole.  Unless treated, they will continue to populate and if
inside fascia boards of your home, can cause enough damage to the point where
the boards have to be replaced.  Sometimes the woodpecker, who loves to eat
the larvae, will cause as much if not more damage than the carpenter bee
itself.  The female has a black face and can sting as well as bite.  The
male has a white face, no stinger, but can produce a painful bite.  (I had
one fall down my shirt and the bite produced blood)  They are not really
aggressive just intimidating when trying to defend their nest.

Carpenter bees prefer unpainted surfaces whether it be cedar, pine, redwood,
or salt treated wood.  However, I have seen them go through painted surfaces
on occasion.  The trick is to use several coats of a good paint and painting
the back side of fascia boards can discourage them.  Most people in this area
of VA prefer to have them eradicated.  I have a 3 step process which
eliminates the family that has taken up residence in decks, roofs, or fascia
boards.  The following spring when a new family begins emerging from trees or
a neighbors house, I ask the homeowner to keep watch because a new family
could possibly begin.  It is a matter of "nipping it in the bud" before it
becomes a full fledge infestation.  Plugging the holes only serves no purpose
as they will make a new hole to get out unless a chemical is forced into the
tunnel to eradicate the family.

I have 20 hives and have NEVER had a problem with a carpenter bee trying to
use the wood of a hive for his home.  I do have a cedar log about 2 feet long
where I have my "pets" that have been living there for the last few years.
They fly around my home but have never bothered the wood of my house.
However, they do love the cedar trees in my yard.

I hope this clears up some of the misinformation and misunderstanding of
carpenter bees.  They are a fascinating insect but still not as fascinating
as our wonderful honey bee!!!!!

Floyd Watkins
Knotts Island, NC/Va Beach, VA