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Termites
HYG-2092-97
William F. Lyon
Common Name: Eastern Subterranean Termite
Typical signs of termite infestations include swarming of winged
adults in the spring (March, April, May, and June) and occasionally
autumn (September and October). A "swarm" is a group
of adult male and female reproductives that leave their nest to
establish a new colony. Swarming occurs when a colony reaches
a certain size. Emergence is stimulated when temperature and moisture
conditions are favorable, usually on warm days following rainfall.
Other signs of termite presence include "pencil-size"
mud tubes constructed over the surface of foundation walls, mud
protruding from cracks between boards and beams, and hollow sounds
from infested wood when it is tapped, or extreme softness when
probed with a knife. Termites feed slowly and there is no need
to panic. A few weeks or months may be needed to determine whether
the infestation is a do-it-yourself treatment or one that is complex,
requiring a commercial, licensed pest control firm. Consider getting
two to three estimates, and be cautious of price quotes that are
substantially lower or higher than the others.
Identification
Subterranean termites are social insects that live in nests or
colonies in the soil. Each colony consists of three forms or castes
of individuals, which are the reproductives, workers, and soldiers.
Reproductives can be winged (primary) or wingless (secondary).
The latter are found in mature colonies and serve as replacements
if something happens to the primary reproductives. Winged, primary
reproductives (alates) are coal black to pale yellow-brown, flattened
and about 1/4 to 3/8 inch long, with pale or smoke-gray to brown
wings. Secondary reproductives are white to cream-colored with
short wing buds. Workers are wingless, white to grayish-white
with a round, yellow-brown head and about 1/4 to 3/8 inch long.
Soldiers are also wingless and resemble workers except that they
have large, rectangular, yellowish and brown heads with large
mandibles (jaws).
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Swarmers have straight, bead-like antennae, a thick waist, and
a pair of long, equal-length wings, that break off easily. The
presence of winged termites, or their shedded wings, inside a
home should be a warning of a termite infestation. They can be
differentiated from adult winged ants that have elbowed antennae,
constricted waists, forewings are larger than the rear wings (unequal
size), and not easily detached.
Life Cycle and Habits
In a typical termite colony, the king and queen are the only active
reproductives; they perform no other function. They are fed by
the other termites, and some have lived up to 25 years.
A mature queen can lay thousands of eggs each year. During the
two-week incubation period, eggs are tended by the worker termites.
The nymph hatches directly from the egg. Attendants feed nymphs
regurgitated food for the first two weeks, enabling them through
molting to become workers, soldiers, reproductives, or supplementary
reproductives. As the reproductive nymph matures, its body lengthens
and sexual organs develop. The body turns black, eyes become functional,
and wings extend twice its body length.
The worker nymph has no eyes and is sterile. Its main function
is to provide the colony with food, usually obtained by eating
the understructure of buildings. The soldier nymph develops a
long, armored head and large jaws during its last molt. The sole
purpose of the soldier is to defend the colony against enemies
such as ants. All mature reproductives leave the colony at the
same time, usually in the spring and sometimes in the fall. Swarmers
are poor fliers and, when above ground, usually flutter a few
yards and fall. Swarmers, emerging outdoors from tree stumps,
railroad ties, etc., are usually not of concern and are in no
way an indication that the structure is infested. After dropping
to the ground, they shed their wings. Surviving males find compatible
mates and then burrow into the ground to become king and queen.
These termites live in nests underground and tunnel up for food,
which includes the wood understructure of homes.
A very small percentage of swarming termites survive to initiate
new colonies. Many are eaten by other insects, birds, etc. Likewise,
swarms emerging inside a structure usually never survive. However,
it is an indication of infestation. Entomologists at the University
of Tennessee feel colonies of ants or termites issue swarms four
to six years after being established. Others feel swarming can
occur in only two to three years.
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Workers need a high humidity to survive and will carry mud up
into the wood where feeding to maintain a 97 percent relative
humidity. Termites have the ability to move their colony up and
down in the soil to find the optimal temperature and moisture
conditions.
Workers build mud tubes from the soil to the wood in structures
on which they feed. Termites can feed on wood since they have
protozoans in their alimentary tract (gut) that digests cellulose,
the basic component of wood. Workers prefer to feed on fungus-infested
wood, but can feed equally well on undamaged wood. Workers secrete
food material from their mouths and anuses to feed the reproductives
and soldiers.
Control Measures
In most cases, once a termite infestation has been found, control
measures are best accomplished by a professional pest control
firm rather than a do-it-yourself treatment. (Homeowners seldom
have the experience, availability of pesticides and equipment
needed to perform the job effectively.) Deal only with a licensed,
certified pest control firm having an established place of business
and a good professional reputation. Ideally the firm will belong
to a city, state or national pest control association. Get at
least three competitive estimates before signing a contract for
control measures.
Prices for inspection, treatment estimates and conditions of warranties often vary considerably. (A guarantee is no better than the firm who presents it.) There is no need to be rushed into a termite control program. Delaying a few weeks or months makes little difference since termites feed slowly. It is more important to take your time to select a "reputable" pest control firm rather than to select a firm that can come over immediately or tomorrow.
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Prevention
Avoid moisture accumulation near the foundation. Divert water
away with properly functioning downspouts, gutters and splash
blocks. Ground near the foundation needs to be sloped or graded
in order for surface water to drain away from the building. Poor
draining may need tiles or drains installed. Termites and ants
are attracted to moisture.
Reduce humidity in crawl spaces with proper ventilation. Crawl
spaces should have ventilation openings in the foundation at the
rate of two square feet per 25 linear feet of foundation wall.
One vent needs to be within five feet of each exterior corner
of the building. Prevent shrubs, vines and other vegetation from
growing over and covering the vents. It is important to have maximum
cross-ventilation. Install polyethylene sheeting over 75 to 85
percent of the soil surface in crawl spaces to reduce excess moisture.
Before and during construction, never bury wood scraps or waste
lumber in the backfill, especially near the building. Be sure
to remove old form boards, grade stakes, etc. left in place after
the building was constructed. Remove old tree stumps and roots
around and beneath the building. Never stack or store firewood
lumber or other wood products against the foundation or within
the crawl space. Prevent trellises, vines, etc. from touching
the house. (Prevent any potential hidden paths of termite entry
into the structure which could bypass any termiticide soil barrier
already in place.)
Use termite metal shields on interior walls extending two inches
out and two inches down at a 45 degree angle from the wall. This
noncorrosive metal should have no cracks and be at least 12 inches
above the ground. The concrete foundation should be reinforced
to prevent cracking. Use concrete or steel supports, steps, etc.
when in contact with soil.
Borates (disodium octaborate tetrahydrate) and/or wolmanized
pressure-treated wood (chromated copper arsenate) protects against
termites and wood decay fungi. However, even railroad ties, telephone
poles and pressure treated wood, over time, can be subject to
termite attack. Mud tubes can be built over the surface or entry
gained through cut and cracked ends.
Most importantly, eliminate any wood contact with the soil. An
18 inch gap between the soil and wooden portions of the building
is ideal. However, at least try to maintain six to eight inches
between ground level and porch steps, lattice work, door or window
frames, etc. Pull or grade soil back away from the foundation.
Wood posts and stairs embedded in concrete can also be paths of
entry by termites.
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Wood mulch can attract termites, especially when damp and moist.
When mulch is used, avoid contact against the wood siding or frames
of doors and windows. Pea gravel or crushed stone are much less
attractive to termites, ants, pillbugs, millipedes, earwigs, crickets,
etc.
Insecticides
In nationwide field tests, the U.S. Department of Agriculture
Forest Service, Gulfport, Mississippi evaluates termiticide soil
treatments. In general, termiticides tested under concrete slabs
were 100 percent effective for five or more years when applied
at the highest rate, but often were less effective when applied
at lower rates (Source: Pest Management Magazine, pages 14, 15
& 16 - Feb. 1994, Vol. 13, No. 2). Termiticides tested included
bifenthrin (Biflex), cypermethrin (Demon TC), permethrin (Dragnet
FT), chlorpyrifos (Dursban TC), chlorpyrifos (Equity), cypermethrin
(Prevail), chlorpyrifos (Tenure), permethrin (Prelude) and fenvalerate
(Tribute). Termiticides under concrete slabs remained more effective
against subterranean termites for longer periods than when exposed
to weather conditions in ground board tests.
To achieve termite control for long periods of time, termiticides
must be applied as a continuous barrier in the soil at rates required
by their labels. The goal of a termite treatment is to place within
the soil and adjacent to the foundation, an uninterrupted chemical
barrier that will prevent termite travel from the nest in the
soil to the wood in the house. Anything less, in time, can permit
reinfestation by termites traveling through untreated gaps.
In reference to "spot treatments only" in areas of
the house where termites are seen, most pest control firms will
neither treat nor guarantee such a treatment. The reason is of
the high probability of termites eventually finding other untreated
points of entry into the structure. Localized spot treatments
are considered a gamble except in re-treatment situations. A guarantee
or annually, renewable contract is normally purchased for at least
the first three to five years after the initial treatment. Guarantees
often vary from firm to firm. Understand what is required by the
homeowner to keep the guarantee in force (a guarantee is no better
than the firm who presents it).
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Treating according to formulation label mixing directions using
Dursban Ortho-Klor 12.6 percent would cost the Do-It-Yourself
Treatment about 2-1/2 times more money for chemical costs than
the licensed pest control operator using Dursban TC 42.8 percent.
Treating foundation voids, under slabs, in hollow openings of
concrete blocks in foundation walls and drilling would require
still more chemical and higher costs. So, when evaluating very
low pest control operator (PCO) bid prices, always ask yourself,
"How can someone treat my home for less that the cost of
the chemical themselves?", "will the strength of the
application be less than according to label directions?",
and, "are corners being cut by using less solution than required
to best kill all the termites?"
In addition to the chemical costs there are several other expenses
reflected in the PCO bid. Among these are the purchase and maintenance
of the PCO's business establishment, equipment, training, labor
and liability insurance premiums.
Effective termite control usually requires specialized equipment
and often 200 or more gallons of prepared termiticide solution
per house, depending on size, basement, etc.
Some termiticide formulations have more odor than others. The
odor is generally due to solvents in the formulation rather than
the insecticide active ingredient. Odor can be reduced and eliminated
by ventilating with fans during and after treatment. If the odor
is of concern to the homeowner, odorless termiticides and termiticides
with special, low odor formulations are alternatives.
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Termite soil treatment is normally a job for the professional,
licensed, certified pest control operator. However, for wood treatment,
homeowners may apply borates (Bora-Care, Shell-Guard, Guardian)
or bendiocarb (Ficam D) one percent dust to voids or channels
in damaged structure members. For soil treatment, only chlorpyrifos
(Dursban) Ortho-Klor, available at garden centers, may be used
by homeowners. Sometimes, homeowners can "do-it-yourself"
when treating sandboxes, fence posts and other wood objects not
attached and away from the house.
Other products labeled for termite control include imidacloprid
(Premise 75), cyfluthrin (Tempo), permethrin (Flee), tralomethrin
(Saga), boric acid (Borid), borates (Bora-Care, Tim-Bor) and bendiocarb
+ pyrethrins (Ficam Plus). Also, deltamethrin (Delta Gard TC,
Suspend) is expected to be labeled for termites.
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Some alternate termite controls include:
1. Nematodes
Certain species of parasitic round worms (nematodes) will infest
and kill termites and other soil insects. They have been promoted
and marketed by a few companies since the early 1980s. Soil moisture
and soil type appear to limit the nematode's ability to move in
the soil and locate termites. Although effective in the laboratory,
under field conditions control is often quite variable.
2. Sand as a physical barrier
It has been suggested that a layer of sand with uniform size particles
could stop termite movement through the soil. This would have
to be a pre-construction practice for slab construction. Sand
would work as a physical barrier since termites would be unable
to manipulate the sand to create tunnels. Sand of correct particle
size, applied alongside building foundations in drier climates
such as California and Hawaii, look promising. More research is
needed under Midwest conditions.
3. Chemical baits
Wood or laminated texture cellulose favored by termites can be
impregnated with a toxicant and/or insect growth regulator (IGR).
Termite workers feed on the treated substance and carry it back
to the nest, reducing or eliminating the entire colony.
a) Dow Agro Science's Sentricon Colony Elimination System
utilizes an insect growth regulator (IGR) hexaflumuron bait 0.5
percent (non-insecticide) against subterranean termites. Commercially
available in May 1995 labeled for pest control operators only,
they monitor for termite activity on your property. The Sentricon
Station (a green cylindrical plastic tube with side ports for
termite access) is placed in the soil at 12 to 20 feet intervals
surrounding the house about 18 to 24 inches out from the structure.
The tube top has a flat, round cover that lies flush with the
soil surface when inserted to permit mowing grass over it. These
cylindrical tubes (ten-inches deep by two-inches wide) first baited
with wood (now a new, laminated texture cellulose), are placed
in the soil in prime termite foraging areas around your house
as a monitoring device to get "hits" (termites and feeding
damage). When 10 to 100 termite workers are found attacking the
wood in one or more stations, a baitube, containing Recruit*II
Termite Bait, is substituted. Captured termites feed on Recruit*II,
tunnel out and send their colony nestmates back to feed on the
bait.
After several weeks, the colony will start to decline and
eventually be eliminated. After a colony has been eliminated,
used Baitube devices will again be replaced with monitoring devices.
The pest control operator will continue to inspect on a monthly
basis for any signs of a new colony that might try to invade your
property.
Termites normally grow by molting (shedding their exoskeleton).
The bait, hexaflumuron is a "chitin synthesis inhibitor"
that prevents termites from growing by stopping the molting process.
As a result, the colony is eliminated over time.
The Sentricon System is more Integrated Pest Management
(IPM) oriented, and requires no drilling in floors and foundations,
less digging up of shrubs and other landscaping, and can be used
to treat houses with wells and cisterns. "Outdoor' in-ground
monitoring and baiting can be done without entering the house.
However, recently approved in April 1997 for Ohio is an "indoor"
above-ground baiting system, Recruit*AG wrap around soft packs
in mud tubes and hard packs on sills, (Ohio 24c Special Local
Need Registration). Bait can now be placed directly within mud
tubes indoors, such as crawl spaces, interior foundations, walls,
etc., year around, permitting faster direct access to bait and
quicker colony elimination.
Since colony elimination, "crashes," is not always
immediate (several weeks or months), the pest control operator
may do spot treatments with an approved, labeled pesticide for
quick localized control. Some PCOs guarantee if after two years
on the system and termites are still present, they will treat
with pesticides according to the customer's wishes.
The Sentricon System is ongoing and the customer pays for
continuous monitoring after elimination of the termites if required.
There is an initial installation fee and yearly fee per structure.
The system is a little more costly than pesticide treatments based
on extra labor and ongoing monitoring required. Ohio ranks second
in the nation (7-8,000 plus) behind Florida with paid customers
in the below ground Sentricon Termite Bait program.
Spring to early summer are good bait months. (Peak termite worker feeding months are March, April, May, June, September, November and December. If stations are "hit" by termite workers, then colonies often can be eliminated by autumn or the following spring, depending on the colony size, number of colonies, season, etc.
See our Sentricon section here at Grace
Services Inc.
For more specific details, call
Sentricon* Information
1-800-686-6200
WEB Address: Sentricon.com
b) FMC Corporation in October 1996 introduced a ready-to-use
Termite Bait Station using sulfluramid (FirstLine) 0.01%, a slow-acting
insecticide stomach poison in a cellulosic matrix labeled for
pest control operators only for termite colony reduction.
The bait suppresses or controls termites in infested areas. FirstLine
Termite Bait Stations must be placed in close proximity to active,
foraging termites. Insert stations in mulch or soil no more than
two feet apart. Focus on the areas of termite tubing. Termites
may require one to four months or more for control.
Bait stations can be inserted outdoors into soil, mulch, stumps,
slabs, etc., and indoors attached to infested wood or masonry.
PCOs inspect the stations every two to four weeks until the bait
is consumed and/or termite activity ceases. The frequency of inspection
depends on foraging pressure and climatic conditions.
For more specific details, call
FMC Corporation
1-800-321-3621
4. Biological
A fungus, Metarhizium anisopliae, Strain ESCI (Bio-Blast) is a
biological termiticide. It is odorless, vaporless, nonstaining
and infected termites can pass the agent (fungus) to other termites
through the horizontal transfer effect. Bio-Blast is labeled for
control of existing termite infestations in structures and their
immediate surroundings and for residual protection of treated
wood. Spray effectiveness is enhanced when applied to many foraging
termites. Treated termites return to the colony, spreading the
biological active ingredient to others. Treatments can be made
both indoors and outdoors.
For more details, contact
EcoScience Corporation
(732) 432-8200.
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NOTE: Disclaimer - This publication may contain pesticide recommendations that are subject to change at any time. These recommendations are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. Due to constantly changing labels and product registrations, some of the recommendations given in this writing may no longer be legal by the time you read them. If any information in these recommendations disagrees with the label, the recommendation must be disregarded. No endorsement is intended for products mentioned, nor is criticism meant for products not mentioned. The author and Ohio State University Extension assume no liability resulting from the use of these recommendations.
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