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University
of Rhode Island GreenShare Factsheets
Termites
Reticulitermes flavipes (Kollar)
Isoptera: Rhinotermitidae
Typical signs of termite infestations
include swarming of winged adults in the spring and occasionally
autumn. A "swarm" is
a group of adults 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.
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 6 to 9 mm (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 6 to 9 mm (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). 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 shedded wings inside a home are signs of a termite infestation.
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 wood 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 meters 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 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, they are an indication of infestation nearby.
Workers need 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 protozoa 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.
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 or certified pest control firm with 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. 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.
- 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.
- Reduce humidity in crawl spaces by providing proper
ventilation.
- Before and during construction, never bury wood scraps
or waste lumber in the backfill, especially near the building.
- 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.
- Concrete foundations 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) protect 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. A 46 cm (18 inch) gap between the soil and wooden portions
of the building is ideal. Try to maintain at least 15-20 cm
(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 for termites.
- Wood mulch can also 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: 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 an uninterrupted chemical
barrier within the soil and adjacent to the foundation. Anything
less can permit reinfestation by termites traveling through
untreated gaps. Most pest control firms will not guarantee "spot-control" treatments,
due to the high probability of termites eventually finding
other untreated points of entry into the structure. 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. Treating foundation
voids, under slabs, in hollow openings of concrete blocks in
foundation walls, and drilling would require still more chemical
and higher costs. When evaluating very low pest control operator
(PCO) bid prices, always ask yourself, "How can someone treat
my home for less than 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?" Effective termite
control usually requires specialized equipment and often 200
or more gallons of prepared termiticide solution per house,
depending on size, basement, etc. Termite soil treatment is
normally a job for the professional licensed, certified pest
control operator.
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. Termite bait stations are oriented
towards a more Integrated Pest Management (IPM) approach. For
more specific details, call Sentricon information (1-800-686-6200)
or FMC Corporation (Firstline) (1-800-321-3621).
Biological: A fungus, Metarhizium anisopliae,
Strain ESCI (Bio-Blast) acts as a biological termiticide. It
is odorless, vaporless, nonstaining and infected termites can
pass the agent (fungus) to other termites via horizontal transfer.
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.
Adapted from the
Ohio State University Extension, 1999
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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