Boring Beetles 101
Robert (Bob) Batman
Class Hexapoda or Insecta
Morphosis: Complete (egg, larva, pupa, adult)
Beetles are insects.
Beetles from certain families damage wood. This brief is
limited to the following five (5) Families of wood boring
beetles: 1) Family Buprestidae (the metallic
beetles, sometimes referred to as flathead beetles), 2) Family
Lyctidae (true powder post beetles), 3) Family
Anobiidae (deathwatch and furniture beetles), 4)
Family Cerambycidae (the long-horned beetles;
old house bores, new house bores, and etc.), and; 5) Family
Scolytidae (bark and ambrosia beetles).
Depending on the
species, either the adult or larva (in most cases), or both, feed
on and damage wood (your house, furniture, art work, and etc.), or
other cellulose items, like your favorite books.
The adults and
larvae don't usually hang around waiting for the pest control operator
to arrive. Therefore, identification as to which of the above critters
is doing the dastardly deed to your house, furniture, art work, and/or
books, is usually determined by close examination of the exit holes.
Sometimes, the frass is an identification aid for those who have been
so trained. The feeding pattern, markings within the holes (galleries),
could be another identification aid. With respect to ambrosia beetles,
fungus staining the wood within the galleries should be an identifying
sign as to the identity of the wood bore.
As you can see,
you may want to contract the services of a professional pest control
operator regarding this type pest: wood boring beetles. A small consulting
fee up front could save you big time latter on. Most pest control
companies charge an initial consultation fee to come to your residence
or workplace to inspect for wood bores, to discuss their findings
with you, and to make recommendations, based on their findings, regarding
control options including the cost for same. This is not a general
pest control service where the technician arrives, makes a quick pest
I.D., performs a control service, and leaves in 30 minutes. Generally,
the property owner will have to make certain preparations prior to
the control measures being performed. Wood bore controls can be expensive,
but it could be even more costly to ignore the problem.
(the metallic beetles/flathead wood borers): 1/4 to 5/8 inch
long oval holes; twice as long as wide. Frass is powdery and fibrous.
The adults of this family are usually of bright color and shiny, and
the larvae have an enlarged region behind the head which appears somewhat
flattened. The larvae feed on unseasoned softwood and hardwood, both.
This pest can be found in log homes, fences, furniture, and other
wooden items which are constructed of logs and/or branches that have
not been pressure/heat treated or properly seasoned (the common buzz
word, I believe, is 'Rustic'). Wreaths, furniture, and other
decorative items made from tree branches are common sources of infestation.
Newly fallen trees
and/or fresh cut logs/branches are what this pest calls home. The
adults (beetles) lay their eggs in the cracks and crevices of the
cut (where the tree/log/branch was cut). The larvae emerge from the
egg and bore into the fresh sap wood, and as the log begins to dry,
they bore deeper.
Some of these
beetles are attracted to smoke from a variety of burning materials.
OUCH! That beetle thing bites! If it is attracted to you and you treat
it badly, some of the Buprestidae species may bite you!
Life cycle: from
egg to adult, depending on the environment and other conditions, from
one year to over five years. Some species of this pest have been known
to emerge from wood twenty plus years after the wood had become part
of the finished product.
(true powder-post beetles): 1/32 to 1/16 inch round holes
in hardwood. Frass is fine with no grit. The adults are small, approximately
1/8 inch and sometimes a little longer, slender beetles which appear
flattened and vary in color from reddish brown to black . Adults are
strong flyers and are attracted to light. I've never seen a larvae
of this pest as long as 1/4 inch and they have always been creamy
to light tan, with a dark color head and 'C' shaped.
The larvae prefer
the older, seasoned sapwood and the only attack hardwood. Hello! hardwood
flooring, furniture, cabinets, picture frames, baseball bats, art
work which was hand-carved from hardwood, and other hardwood items.
Infestation evidence includes very small, round holes and activity
evidence would include the presence of smooth (not gritty) frass.
Life cycle: according
to most textbooks, from egg to adult in 2 and 1/2 months to one year,
depending on environmental and other conditions.
POINT OF INFORMATION:
In accordance with the official definition of the term, members of
the Lyctidae are the only 'true' powder-post beetles. However,
the term 'powder-post beetle' commonly refers any of the
members of three (3) closely related families: Lyctidae,
Anobiidae, and Bostrichidae. The common reference to all these beetles
as being 'powder-post beetles' comes from a similarity in
the nature of larvae activity and the resulting damage. See brief
comment regarding Bostrichidae below.
the false powder-post beetle, is somewhat larger than the other powder-post
beetles, cannot digest wood and has no other organism to perform the
function and, therefore, depends on the starch of the wood for nutrition.
Holes are slightly larger than other powder-post beetles; approximately
1/8 and up to 3/8 inch, if used for re-entry. A pest of only unseasoned
wood. Although mainly associated with hardwoods, certain species commonly
attack softwood. If you find no frass in the holes, check the galleries:
they should be tightly packed with it.
(deathwatch beetles and furniture beetles): 1/16 to 1/8 inch
holes and gritty frass. These small, reddish to blackish color adults
are less than 1/3 inch long. The larvae are wrinkled with tiny little
hairs and, depending on species, vary from 1/4 to 1/2 inch in overall
length. Although they seem to prefer the sapwood of seasoned softwoods,
they have also been found in seasoned hardwood.
Life cycle: Approximately
one year from egg to adult. Eggs are laid in the cracks and crevices
of seasoned (old)wood. After hatching, the larvae bore into
the wood and remain there, boring holes and feeding, for approximately
a year, sometimes more. The larvae burrow to near the surface to pupate.
After emerging from the pupa, the adult burrows to the surface of
the wood and emerges.
Some species of
this pest secrete an enzyme which permits them to digest wood without
the aid of microorganisms (protozoa).
( old house borers, new house borers, and other long-horned beetles,.):
1/4 to 5/8 inch oval-nearly round holes. The adults vary from 1/3
inch to over 1 inch and the larvae's body is round and tapers somewhat
towards the posterior.
Old house borer
(Hylotrupes bajulus [L]): is a pest of seasoned
softwoods (pine, fur, and spruce) and has been known to spend up to
ten years in the larval stage. Hey! What's my house framed with? The
larvae of this pest will not be found in rotten wood. Wharf and curculionidae
(snout beetles) like decaying, rotten wood, the old house bore does
The old house
borer can re-enter original or other seasoned softwoods.
Do I hear something chewing? The larvae of this pest reaches approximately
one (1) inch in length after four (4) years of feeding and, depending
on your hearing and/or perhaps some type of hearing enhancement device,
you may be able to hear the larvae feeding. The larvae of the old
house borer usually infest wood that is less than ten (10) year old.
Frass around surface exit holes implies recent activity.
New house borer
(Arhopalus productus [LeC]): is a pest of green
softwood lumber. It feeds on the sapwood and heartwood, both. Take
note: 1/4 inch oval exit holes can be found in hardwood flooring,
linoleum, wallboard materials, carpeting (you may not notice these),
and roofing materials. Although new house borers limit their feeding
to softwoods, these guys will chew exit holes through almost anything!
The life cycle
(egg to adult) requires at least two (2) years. Normally, the adults
emerge, leaving exit holes, within a couple of years following construction.
beetles are not normally considered pests that cause structural damage,
however, they do cause cosmetic/decor damage. These are short life
cycle (egg to adult within two years) pests which are limited to infesting
unseasoned wood (hardwood and softwood) and do not revisit the same
piece of wood following emergence through their 3/16 to 1/4 inch oval-round
exit holes. Frass in galleries and that falling outside of holes is
course and fibrous.
(bark and ambrosia beetles): small holes with light and dark
color frass (combination of color resulting from feeding on bark and
sapwood). This is a family consisting of numerous species
with the adult beetles ranging from red to brown to black in color.
Adult bark beetles
bore through the bark and lay their eggs under the bark of, usually,
but not always, injured or dying trees. The adults kick a fine powdery
frass out their entrance holes. After hatching, the larvae establish
an extensive tunnel network beneath the bark feeding on the soft sapwood.
This pest cannot feed on seasoned or structural wood and is usually
associated with wood which retains some bark (roughhewn) or wood which
has not been properly seasoned. I've found infestations in firewood
which was brought indoors, but not used immediately, as well as in
rustic lawn furniture which was brought inside for winter storage.
beetles do the damage by boring small pinholes into the sap and heartwood
of living, but injured or dying trees, and recently felled timber.
They do not feed on the wood, they simply bore into it. They seem
to like southern yellow pine.
larvae feed only on ambrosia fungi. The fungus spores are interjected
into the tunnels by the ambrosia beetles. When the fungus grows, it
stains the wood a blueish or dark brown color. Presence of this stain
is a good indication the pest is an ambrosia beetle as opposed to
one of the powder-post beetles. Ambrosia beetles may emerge from firewood,
other recently cut wood, or rustic furniture/decor items made from
unseasoned wood. Unlike powder-post beetles, this pest cannot reinfest
Professional service is recommended. If you think you have a wood
boring beetle problem, I'd recommend you call a knowledgeable pest
control operator, one you trust, and take his/her advise. The pest
and the situation, both, must be taken into consideration with respect
to selecting an appropriate control measure.
Wood boring beetles
can be very difficult to control! Proper identification is the first
step in controlling any pest, including wood boring beetles. When
it comes to wood-boring beetles, you may or may not have a serious
problem, and you won't know, until the pest is properly identified.
Remember, this is not a common household pest situation. Expect to
pay for professional's time require to inspect and recommendations
given at the initial service call as well as for any additional service(s)
to be performed latter.
Exterminators, Inc. a call, if you work or live in the greater Kansas
City Metro (KS & MO) area.
765-8844 or (913) 671-8844