| Media
Contacts:
Michael G.
Waldvogel, 919/515-8881
Paul K. Mueller,
News Services, 919/515-3470
July
10, 2003
Unlike
Their Busy Cousins, These Bees are Boring
FOR
IMMEDIATE RELEASE
| If
you’ve noticed bumblebees buzzing around
your wooden eaves or deck railings, they may not
be misguided but harmless flower-seekers. Instead,
they’re probably carpenter bees, which use
their strong jaws to drill circular tunnels into
exposed wooden surfaces. Unlike termites, they’re
not interested in your porch or shed as food,
but as a protected refuge for their offspring.
Like their bumbling cousins, they feed on nectar
and pollen.
Even
if you don’t notice their industrious tunneling,
you might spot the telltale scattering of sawdust
under a work-site, usually the underside of a
wooden surface.
|
A
carpenter bee excavates a nest in a treated
deck rail, showing the shiny black tail that
distinguishes it from the look-alike bumblebee.
(Photo courtesy of NC State Cooperative Extension
Service)
|
Distinguished
from bumblebees by their glossy black tails, carpenter
bees excavate round, half-inch-diameter entrance holes
for these nests, then drill horizontally into the wood,
along the grain, for six or seven inches. The female
deposits her eggs in this tunnel, along with a pollen
ball for their nourishment when they hatch, then seals
the section, repeating this process until she’s
filled several cells. In five to seven weeks, the offspring
are ready to burrow out and start their wood-workers’
lives.
According
to Michael D. Waldvogel, extension specialist in the
Department
of Entomology at North Carolina State University,
the bees typically don’t cause serious structural
damage to wood. “But in the case of thin wood,
such as siding,” says Waldvogel, “their
damage can be severe. And woodpeckers may damage infested
wood in search of bee larvae in the tunnels. Holes on
exposed surfaces may lead to damage by wood-decaying
fungi or attack by other insects such as carpenter ants.”
Carpenter bees are far more interested in foraging and
other bee-tasks than pestering you, Waldvogel said.
Males don’t have stingers, but will let you know
if you’re intruding on their territory. Females,
which do have stingers, use them only if highly agitated.
The bees
usually re-use tunnels, rather than bore new ones, especially
when colder weather prompts them to find winter quarters.
They emerge in the spring, and that’s when new
“construction” usually begins. The young
bees develop within the tunnels, and emerge as adults
in late summer.
Sometimes
several bees will use the same entrance hole, but each
“family” will have its own gallery branching
off the main tunnel. If the same hole is used for several
years, says Waldvogel, tunnels may extend several feet
into the wood.
Preventing
damage from these bees is difficult, according to the
entomologist, because insecticide sprays don’t
linger long on wood, and carpenter bees don’t
ingest the wood anyway. “Applying a pesticide
to all possible sites is usually both impractical and
unsafe,” Waldvogel says, “and trying to
spray hovering bees is not a sensible or particularly
safe use of pesticides, either.”
You can
try treating the tunnels with an insecticidal dust,
he says, and then – after two or three days –
caulking the holes. This will usually kill both adults
and offspring. “Just plugging untreated tunnels
might trap bees inside,” he says, “but more
resourceful bees will simply chew another exit hole.”
-30-
|
Raleigh,
NC 27695
