What are Wood Boring Beetles?
Present on all continents but
Antarctica, wood-destroying Beetles (coleopteran order) are part of our
ecosystem and help decompose dead and dying trees into rich organic material.
Depending on their specie, wood-boring beetles can infest wood from healthy and
green to dried lumber, seasoned wood and even older antique furniture. Some
beetles live for years causing damage to appearance and structural integrity of
infested wood.
The most common species
in Marin County are the Lyctid (true powder post), the Bostrichic (false powder
post), the Anobiid (deathwatch or furniture) and the Cerambycid (old house
borer). A few other species like the Buprestid (flat head or metallic), the
oedermerid (wharf borer) and the scolytid (bark borer) are also found outside
and sometimes in exterior siding. Seldom seen by humans, the beetle’s most
visible sign of infestation are emergence holes on the surface of infested wood
members and powder beneath.
True Powder Post Beetles (Lyctid)
The Lyctus beetle is the
only “True Powder Post” beetle and produces a very fine talcum-like powder when
emerging through small round exit holes. Indigenous and most common in
California, it favors seasoned hardwood (oak, ash, mahogany, etc.) and can be
seen in hardwood floors as well as furniture. Sometimes Lyctus beetles emerge
from new furniture made with previously infested wood containing dormant eggs.
It can re-infest the same untreated wood to produce new generations and eggs
will hatch with warmer conditions ideal for survival and reproduction.
Re-infestation is unlikely in varnished and treated wood.
False Power Post Beetles
Often referring to several wood-destroying species such as
Anobiid, Bostrichid and Cerambycid, they are found worldwide in structural
wood members and furniture. Emergence holes are often seen on the surface of
wood members, door and window frames and antique furniture. Eggs survive for
years and hatch when the environmental conditions (temperature and humidity)
are conducive to their survival and reproduction.
Polycaon Stoutii
(Bostrichid)
Commonly known as the
“Black Polycaon”, it is one of the largest wood-boring California beetles.
Easily spotted by humans it rarely re-infests wood and favors hardwood over
softwood. Sometime infesting structural wood members of homes in fairly humid
areas, it emerges through large round holes to mate and reproduce.
Treatment and Prevention
For larger infestations,
fumigation of the entire structure is the only way to ascertain complete
eradication of wood-boring beetles. Since fumigation have no residual effect, it will not prevent re-infestation if
local conditions (humidity and temperature) are favorable to local species. All
beetles favor fairly moist wood (17% to 30% humidity) and the best is to
eliminate or limit humidity as feasible with proper drainage in and around the
structure and dryer basements and crawl spaces, and vapor membranes covering substructure soils.
In a dryer environment, or once the excessive moisture condition has been addressed in basements and crawlspaces, a surface
treatment with a borate based material such as TimBor or BoraCare (dosidium octaborate tetrahydrate) will deter further re-infestation of wood boring beetles. We also recommend periodic applications of wood preservatives or coatings (paint or vanishes) on exterior wood members to deck, stairs or balconies to deter
further re-infestation.
Call Marin Termite Control at (415) 456-9620
to speak to one of our state licensed inspectors and to schedule an inspection.
to speak to one of our state licensed inspectors and to schedule an inspection.
