Termites in underground ductwork, termites eating underground ductwork

Pictured are Subterranean termite
shelter tubes in the crawlspace of
a residential home. Picture on left
is the termite tubing building up a
support and picture on the right
is termite tubing dropping from
the girder supporting.

(Click to view larger image)

Pictures of a home with an in-floor heat register system that had termite damage to the
underground ducting (cardboard type material often referred to as Sonoduct) and the system
was replaced with metal ductwork. Owner initially called us because live subterranean termites
were flying out of her floor heat registers and our duct camera revealed Subterranean
termites eating the ductwork.
                                             (Click to view a larger image)

Subterranean termites (Reticulitermes hesperus)-

First things first. If you are seeing tiny light brown pellets sifting from a wall, overhead wooden member or
gathering in small piles around window or doors, you are not dealing with subterranean termites, but instead are
dealing with drywood termites, and if so, please refer to the drywood termite page of this site. Having said that,
subterranean termites are probably the most destructive termite in Southern California possibly due to the sheer
numbers that make up an average colony. Unlike Drywood termites, which can have upwards of a few thousand
members, the Subterranean termite colony can number more than a million members per colony.

Moisture sources for termites in your home- Subterranean termites require moisture to survive or thrive in an
environment and that is why infestations are normally found when remodeling a bathroom or kitchen area. In these
particular areas, the termite gains entrance into the structure from either the tub-trap cut-out in the slab, up the
copper water lines (due to the condensation), the drain lines or beneath the tub or shower pan. Other entry points
for subterranean termites are the seams from floating or supported concrete slab constructed structures, behind
exterior siding or stucco, up through settling cracks, plumbing protrusion lines, expansion cracks in garages. If the
structure is a crawlspace, then you will find the termites building either free-standing tubing from the ground to the
floor joists or tubing building up the foundation walls and/or pier post supports and into the joists or bottom sill
plates.

Ground contact a must for this termite- Subterranean termites must maintain contact with the soil for
replenishing purposes unless the structure that they are feeding upon has a plumbing leak or some other source
of moisture, above ground, for the termite. Interestingly enough, the very soil that they need to stay in contact with
also contains bacteria that, if not removed, will kill the termite and as a result, the subterranean termite workers
must constantly groom not only themselves but also the other members of the colony.

Termite mud-tubing- Unlike Drywood termites, the Subterranean termite will construct a mud-like shelter tubing
made up of both fecal material and a glue-like substance that binds the tubing together through which they can
accomplish all of their activities. There are no pellets with Subterranean termites and the mud-like tubing is divided
up into three types which are known as; exploratory tubing, drop tubing and working tubing. Exploratory tubing is
also known as migratory tubing and can often be found in the crawlspace beneath a home on the surface of the
ground.

Flying termites- Subterranean termite swarmer's (reproductives) are dark brown to black with grayish colored
wings and are much smaller than Drywood termites and they are approximately 1/4 inch in length. Note: one of the
differences between "flying termites" and "flying ants" is both the length and type of wings. Termite wings will be
much larger than the body whereas an ants wings are almost at equal length with the body. Plus, both ants and
termites have two pair of wings, however, the wings of the termite are of equal length and the ants wings, also in
pairs, are not of equal length. Swarmers are often seen on sunny days in the fall but sometimes are seen on
sunny days in the spring after a rain.

Treatment for Subterranean termites is entirely different than that of Drywood termites. Treatment for
subterranean termites can involve either establishing a repellent barrier around the structure, in the soil, or
installing a subterranean termite bait/monitor system in the ground around the structure. The barrier method is
known as a conventional treatment. We, at Perry's Termite Service, use a product called PREMISE 75. Unlike a
true repellent barrier, PREMISE 75 forms what is known as a non-repellent treated zone. Why is that important?
Because when a repellent pesticide is applied to the soil beneath the structure, the applicator has no way of
knowing if the pesticide is spreading to the intended areas and any imperfections in application (beneath the
structure) can allow for termite entry because the termites will simply go around the repellent pesticide and find an
area that was not treated. With a non-repellent treated zone, you can have the same application imperfections but
have entirely different results in that the termites pass right through the treated zone, of the non-repellent
PREMISE 75, and not even know that they have gone through it, thereby effecting the overall results of the
application. If the termites don't know that it (PREMISE 75) is there, they pass through it, become effected and
spread PREMISE to other colony members.

Most termite bait systems are designed to draw termites into the bait stations by placing a piece of wood
(usually pine) into the station and allowing the termites to feed upon the wood, thereby gaining their confidence.
After a period of time, the piece of wood is replaced with the actual bait and the hope is that the termites will
continue to feed upon the bait and eventually effect the results of both the termite colony and the termite pressure
at that particular structure. Localized treatments, with a pesticide solution, will also need to be applied to areas of
infestation in the structure, in conjunction with the bait system. Bait systems alone (in our opinion) will not solve the
termite problem. One of the reasons why we believe a bait system alone will not solve a termite problem is that
termite workers and soldiers are blind and cannot see the bait/monitor stations. Termites, through random
foraging, will encounter the bait/monitor stations and that is why you will normally see anywhere from 15-40
bait/monitor stations installed (for the average 1500 square foot home) around the perimeter of the home at
approximately 5-10 foot intervals. A case in point, is a home that we inspected several years back in Los Alamos
New Mexico. The homeowner had a different company install a bait system around the perimeter of his home to
control subterranean termites. When it came time to sell his home, the buyers agent, wanting a second impartial
inspection, hired our company to perform the termite inspection and upon inspection we discovered that the home
had evidence of both live termites and damaged sill plates in the basement of this home. Ironically, the live
termites and damage were found approximately 3 feet away from a wall mounted bait station that was installed in
addition to the ground stations. Obviously outraged that he still had live termites and damage after paying a few
thousand dollars for the termite bait system, both the homeowner and realtor asked us if the other company had
done anything wrong with the bait system installation and we told them no, that the company did nothing wrong
and that it was due to the very nature of the termite and their random foraging pattern. It is for this reason that we
recommend localized treatments, of a pesticide, be applied to areas of infestation in conjunction with the bait
system installation. Accompanying the baiting program should be a periodic visual inspection of the property which
is probably the most important factor in the success of the program. Periodic inspections should be performed at a
minimum of once a year or sooner.

For more information about treatments, see the "treatments" section of this site.