U.S. patent application number 11/440330 was filed with the patent office on 2006-11-16 for remote monitoring system for detecting termites.
Invention is credited to Nan Yao Su.
Application Number | 20060254123 11/440330 |
Document ID | / |
Family ID | 27370391 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060254123 |
Kind Code |
A1 |
Su; Nan Yao |
November 16, 2006 |
Remote monitoring system for detecting termites
Abstract
The subject invention pertains to materials and methods useful
for management of certain pests. The invention is particularly well
suited for the control of social insect pests and, particularly,
termites. The invention concerns unique toxicant-containing
matrices as well as apparatuses for monitoring pest activity and
presenting a toxicant. The invention is useful as part of an
Integrated Pest Management Program and can greatly reduce the
introduction of harmful chemicals into the environment.
Inventors: |
Su; Nan Yao; (Davie,
FL) |
Correspondence
Address: |
Stephen H. Docter;McDonnell Boehnen Hulbert & Berghoff
32nd Floor
300 S. Wacker Drive
Chicago
IL
60606
US
|
Family ID: |
27370391 |
Appl. No.: |
11/440330 |
Filed: |
May 24, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10161519 |
Jun 3, 2002 |
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11440330 |
May 24, 2006 |
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08467552 |
Jun 6, 1995 |
6397516 |
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10161519 |
Jun 3, 2002 |
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08323582 |
Oct 17, 1994 |
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08467552 |
Jun 6, 1995 |
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08062868 |
May 17, 1993 |
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08323582 |
Oct 17, 1994 |
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07975317 |
Nov 12, 1992 |
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08062868 |
May 17, 1993 |
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07891896 |
Jun 1, 1992 |
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07975317 |
Nov 12, 1992 |
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Current U.S.
Class: |
43/132.1 ;
43/131 |
Current CPC
Class: |
A01M 1/2011 20130101;
Y02A 40/166 20180101; Y02A 40/146 20180101; A01N 25/006 20130101;
A01M 2200/011 20130101; A01M 1/026 20130101 |
Class at
Publication: |
043/132.1 ;
043/131 |
International
Class: |
A01M 17/00 20060101
A01M017/00; A01M 1/20 20060101 A01M001/20 |
Claims
1. A delivery system for controlling termites wherein said delivery
system comprises a toxicant-free monitoring device, a
toxicant-containing matrix, and a durable non-termite-edible
delivery housing for simultaneously holding the toxicant-free
monitoring device and the toxicant-containing matrix, wherein the
delivery housing has a plurality of openings permitting termite
access to the toxicant-free monitoring device and the
toxicant-containing matrix, and the matrix of the
toxicant-containing matrix comprises a cellulose-containing
material.
2. The delivery system of claim 1 wherein the delivery housing is
made of plastic, aluminum, or stainless steel.
3. The delivery system of claim 1 wherein the toxicant-containing
matrix is present after termites are detected.
4. The delivery system of claim 1 wherein the toxicant-containing
matrix is enclosed in a casing permitting termite access to the
toxicant-containing matrix.
5. The delivery system of claim 4 wherein the casing is made of a
polymeric material having openings through which termites can
pass.
6. The delivery system of claim 1 wherein the monitoring device
comprises a cellulose-containing material.
7. The delivery system of claim 1 further comprising a cover for
the delivery housing.
8. The delivery system of claim 1 wherein the toxicant of the
toxicant-containing matrix is a slow-acting termiticide.
9. The delivery system of claim 8 wherein the slow-acting
termiticide is an acyl urea.
10. The delivery system of claim 9 wherein the acyl urea is
hexaflumuron.
11. A method for controlling termites wherein said method comprises
positioning a durable non-termite-edible delivery housing at a
location accessible to termites, placing a toxicant-free monitoring
device so that said toxicant-free monitoring device is held by said
delivery housing, and adding a toxicant-containing matrix within
said delivery housing, wherein the delivery housing has a plurality
of openings permitting termite access to the toxicant-free
monitoring device and toxicant-containing matrix.
12. The method of claim 1 wherein the delivery housing is made of
plastic, aluminum, or stainless steel.
13. The method of claim 11 wherein the toxicant-containing matrix
is added after termites are detected.
14. The method of claim 11 wherein the toxicant-containing matrix
is enclosed in a casing permitting termite access to the
toxicant-containing matrix.
15. The method of claim 14 wherein the casing is made of a
polymeric material having openings through which termites can
pass.
16. The method of claim 11 wherein the toxicant of the
toxicant-containing matrix is a slow-acting acyl urea.
17. The method of claim 11 wherein said delivery housing further
comprising a cover.
18. The method of claim 11 wherein the delivery housing is
positioned in a cavity in the ground.
19. The method of claim 11 wherein the monitoring device is placed
before said delivery housing is positioned.
20. The method of claim 11 wherein the monitoring device is placed
after said delivery housing is positioned.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/161,519, filed Jun. 3, 2002, which is a
continuation of U.S. patent application Ser. No. 08/467,552, filed
Jun. 6, 1995 and now U.S. Pat. No. 6,397,516, which is a
continuation of U.S. patent application Ser. No. 08/323,582, filed
Oct. 17, 1994, which is a continuation of U.S. patent application
Ser. No. 08/062,868, filed May 17, 1993, abandoned, which is a
continuation-in-part of U.S. patent application Ser. No.
07/975,317, filed Nov. 12, 1992, abandoned, which is a
continuation-in-part of U.S. patent application Ser. No.
07/891,896, filed Jun. 1, 1992, abandoned.
BACKGROUND OF THE INVENTION
[0002] Subterranean termites most often enter structures from the
surrounding soil to feed on wood, or other cellulosic material of
the structure and its contents. If unchecked, termites can cause
considerable damage. As a result, efforts to erect physical or
chemical barriers to prevent the entrance of termites into a
structure or to exterminate the termites after they have invaded a
structure have proven a considerable expense to the public (Su N.
Y., J. H. Scheffrahn [1990] Sociobiol. 17(1):77-94). The cost to
control termites in the United States exceeds one billion dollars
annually (Mauldin, J. K., S. C Jones, R. H. Beal [1987] The
International Research Group on Wood Preservation Document No.
IRG/WP/1323).
[0003] Subterranean termites construct an extensive foraging
gallery beneath the soil surface. A single colony may contain
several million termites with foraging territory extending up to
300 feet (Su, N. Y., R. H. Scheffrahn [1988] Sociobiol.
14(2):353-359). Since subterranean termites are a cryptic creature,
their presence is not normally known until after some damage,
foraging tubes, or live termites such as swarmers, are found. Some
subterranean termites are known to forage beneath an object on the
soil surface (Ettershank, G., J. A. Ettershank, W. G. Whitford
[1980] Environ. Entomol. 9:645-648).
[0004] Currently, there are two basic approaches for the control of
subterranean termites: preventive control and remedial control. In
some of the United States, it is mandatory that the soil underlying
the foundation of newly constructed buildings be pre-treated with a
pesticide (also referred to herein as termiticide) to prevent
termite infestation. Pesticide is typically sprayed over and into
the soil prior to construction. This pre-construction treatment
produces a horizontal barrier beneath the building. Because of the
lack of communication between pesticide applicator and construction
workers, the barrier often loses its continuity during the
construction. Moreover, the currently available soil termiticides
tend to lose their biological activity after five or more years to
the extent that the treated soil is no longer effective against
termite invasion. Established termite colonies in the soil may then
invade the structure if additional chemical is not applied beneath
and around the structure.
[0005] When a house or other building is infested by subterranean
termites, efforts are made to create a continuous barrier beneath
the building in the soil where the subterranean termites are
provided access to the building. A common method of creating this
barrier is to introduce termiticide around a building foundation by
injection into soil underlying concrete foundations, drenching the
soil surrounding the building perimeter, or a combination of both.
This type of post-construction treatment is labor-intensive and may
not adequately produce a continuous barrier (Frishman, A. M., B. L
Bret [1991] Pest Control 59(8):48, 52, 54, 56; Frishman, A. M., A.
St. Cyr [1988] Pest Control Technology 16(4):33, 34, 36).
[0006] Other remedial treatments include spot treatments such as
dusting or injecting termiticides within the walls of the building.
Robert Verkerk has described arsenic trioxide dust treatment using
termite lures (Verkerk, R. [1990] Building Out Termites, Pluto
Press Australia Limited, P.O. Box 199, Leichhardt, NSW 2040).
Verkerk describes the use of stakes or blocks of termite
susceptible timber to lure termites after the stakes or blocks have
been placed near a known termite problem. Once termite activity is
observed, arsenic trioxide is injected. Alternatively, a portion of
the termites may be dusted with arsenic trioxide.
[0007] Most spot treatments are done to stop existing termite
infestations at a particular area in a structure but generally
affect only a small portion of the subterranean termite population,
i.e., those termites which come into direct contact with the
pesticides. Because of the extensive foraging populations and
expansive territory of subterranean termite colonies, the vast
majority of the termite population is not affected by such spot
treatments.
[0008] U.S. Pat. No. 3,940,875 describes a method, however
impractical, for dispensing termite poison in the soil in an
attempt to extend the life of the barrier type treatment such that
the presence of termites is signalled by the release of an odor
when the termites feed on the poison. The '875 patent also
describes a termite-edible container which gives off an odor when
eaten by a termite. In addition to the '875 patent and the Verkerk
article referenced above, other publications describe the use of
termite-edible materials as components of schemes to control
termites. For example, Japanese patent application Nos. 61-198392
and 63-151033 describe wooden vessels specifically designed to
"attract" termites as part of a monitoring procedure. The 61-198382
application describes a vessel, preferably made from pine or cedar,
used in an attempt to attract termites. The 63-151033 application
also uses a wood attractant to entice termites. In the 63-151033
application, the termites are further exposed to a toxicant which
is then presumably carried back to the nest in hopes of killing the
queen via trophallaxis or food exchange. Neither Japanese
application provides any data establishing that the described
process actually has any impact on termite populations.
Furthermore, there is no indication that it is possible to
"attract" termites at art. These methods have further important
disadvantages. For example, the wooden inducing body will be
subjected to fungal decay before termite attack, especially in
moistened soil. Thus, frequent replacement of the inducing body is
needed during the monitoring period. Further, damage to the
inducing body can result in the penetration of the termiticide into
the ground. This is not environmentally acceptable.
[0009] One termite control method comprises placing a highly toxic
material, such as an arsenic-containing dust, at a site of
infestation in the hope that this will directly control an
effective number of termites at the site and also other termites
back in the colony. However, this method relies on pumping toxic
dust into a termite tunnel and depositing relatively large
quantities of dust.
[0010] Elaborate schemes of pipes to convey liquid termiticides
under and surrounding buildings have also been proposed for termite
control. It has been suggested that these liquid termiticides may
be dispensed into the soil surrounding and below the building
through these pipes to provide a continuous barrier to the
incursion of termites. This method requires a large quantity of
termiticides in order to saturate the soil surrounding the
building.
[0011] U.S. Pat. No. 5,027,546 describes a system intended for use
on above ground termites, Le, drywood termites, which controls
termites by freezing with liquid nitrogen. Although the liquid
nitrogen is essentially non-toxic in that no toxic residues
persist, it is hazardous to use and the method is a spot treatment
and will not affect the majority of termites. U.S. Pat. No.
4,043,073 describes a method which attempts to circumvent the
problem of repeated application of pesticide. The described method
functions by "encapsulating" the insecticide, thus making it more
persistent. The overt use of pesticides and their persistence in
the environment are not remedied by this system. Another proposed
system which fails to alleviate the problem of transferring
insecticide directly into the soil is U.S. Pat. No. 3,624,953. This
method employs a reservoir of insecticide wherein the vapors of the
insecticide are permitted to permeate the soil surrounding the
reservoir. Thus, exposure of the environment with toxic substances
is not avoided by using this method.
[0012] Toxicants which have less environmental effect and which
show activity against termites are known (Su, N. Y, M. Tamashiro,
M. Haverty [1987] J. Econ. Entomol. 80:1-4; Su, N. Y., R. H.
Scheffrahn [1988] Florida Entomologist 71(1):73-78; Su, N. Y., R.
H. Scheffrahn [1989]J. Econ. Entomol. 82(4):1125-1129; Su, N. Y, R.
H. Scheffrahn [1990] Sociobiol. 17(2):313-328; Su, N. Y. [1991]
Sociobiol. 19(1):211-220; Su, N. Y., R. H. Scheffrahn [1991] J.
Econ. Entomol. 84(1):170-175; Jones, S. [1984] J. Econ. Entomol.
77:1086-1091; Paton, R., L. R. Miller [1980] "Control of
Mastoternes darwiniensis Froggatt (Isoptera: Mastotermitidae) with
Mirex Baits," Australian Forest Research 10:249-258; McHenry, W.
E., U.S. Pat. No. 4,626,528; Henrick, C. A., U.S. Pat. No.
5,151,443). However, none of these toxicants have previously been
used in conjunction with a method which efficiently and
efficaciously delivers the toxicant to a target pest.
[0013] Australian Patent No. 1,597,293 (the '293 patent) and a
corresponding Great Britain Patent, No. 1,561,901, describe a
method which involves mixing insecticide with a food matrix
comprising cellulose and a binding agent. The method described in
the '293 patent relies on the termite ingesting the insecticide
along with the matrix, then returning to the colony to introduce
the insecticide to other termites through the natural process of
trophallaxis (food exchange between termites). However, the '293
patent describes usages only when termites are known to be present
and, furthermore, the described method fails to ensure that the
termites will initially find the matrix and relies on those
termites finding the matrix to transfer sufficient amounts of the
insecticide to the colony solely by trophallaxis. Like the Japanese
patent application No. 63-151033, the method of the '293 patent
requires that the matrix is more attractive to the termites than
surrounding materials. The method described in the '293 patent
relies on the moisture in the matrix (supposedly retained by the
binding agent, agar) to attract termites. The described method,
therefore, is primarily for termite species that are attracted to
moisture (or those under "water stress"). Moreover, the '293 method
fails to assure that the moisture will remain in the baits when
applied in the field awaiting termite arrival. This is an
unrealistic requirement for a practical application, because even a
moistened sawdust-agar matrix will desiccate within a few days when
placed in a dry soil.
[0014] It should be noted that attractants other than water for
termites have been investigated. For example, the extract from
brown-rot fungi chemically resembles the trail-following pheromones
of termites. Natural pheromones, however, are species- and even
colony-specific. A pheromone that is "attractive" to one species or
colony of termites may repel termites of other species or colonies.
It is of uncertain value, therefore, to incorporate pheromone
mimics (such as the brown-rot fungi extract) in a bait, especially
if a bait is to be used against a wide range of termite
species.
[0015] It should also be noted that trophallaxis is an uncertain
means of delivering the insecticide to the colony because it
assumes that digestive enzymes and other metabolic processes do not
affect the active ingredient. However, once the insecticide is
ingested by the termite, the insecticide may be rendered inactive
by the digestive process of the termites. Moreover, suppression of
a termite population requires that a substantial number of termites
in the colony are disabled before their damage potential is
diminished. Relying only on trophallaxis to transfer the toxicant
does not ensure that adequate numbers of termites will be
controlled.
[0016] Modifications to the method described in the '293 patent may
not increase the bait-intake of termites. For example, the '293
method requires that the matrix mixture be applied at a known
infestation site such as a termite mound or tree trunk. This
method, therefore, can be used only as a remedial treatment. The
'293 method cannot be used unless activity of termites is detected.
The '293 patent also proposes that a large quantity of toxicant
bait be placed at random locations as a preventative measure.
However, without providing a procedure for detecting termites, the
majority of this bait may desiccate or degrade due to fungal growth
and become unpalatable to termites. Moreover, an unnecessarily
large quantity of toxicant is applied in the environment.
[0017] It is therefore highly desirable to more effectively control
termites or other insects in a manner which assures that the
termites or other insects of interest are exposed to the toxicant,
which minimizes environmental harm by reducing the amount of
insecticide used, and which affects adequate numbers of termites in
a colony.
BRIEF SUMMARY OF THE INVENTION
[0018] The invention disclosed and claimed herein relates to a
method for controlling populations of pests. The invention is most
advantageously used for controlling the population of social
insects which communicate through chemical signals. Specifically
exemplified herein are methods and devices for the control of
insects of the order Isoptera, particularly, termites.
[0019] One preferred method of the subject invention is most easily
thought of as comprising two steps. These two steps can be repeated
to form a multistep process or the two steps can be conducted
concurrently. One step involves monitoring and/or capturing target
pests by a means which does not employ the use of any pesticide.
This step functions to detect the presence of pests. In addition,
this monitoring step can also function as a means to capture the
pest without causing the pest substantial harm or disturbance of
colony activity. In the embodiment of the invention wherein pests
are captured, the captured pest is still alive and, preferably,
capable of moving, eating, and producing chemical signals which can
attract fellow pests. This step of the process, wherein the pests
are detected or captured is hereinafter referred to as the
"monitoring" step.
[0020] The other step of the process involves controlling a
population of pests once they have been detected. The pests may
have been detected, for example, as a result of the monitoring
step. In the control step of the process, the pests are controlled
as a result of ingesting or otherwise contacting a toxicant. The
subject invention has been discovered to be highly effective in
controlling even extremely large termite colonies. Advantageously,
the control method utilizes only very small amounts of toxicant,
and this toxicant is applied in a strictly defined and controlled
manner to minimize exposure of the environment to toxicants. The
use of toxicant is confined in terms of the very limited quantity
and coverage of the toxicant, and in terms of the period during
which the toxicant is used. Once control is attained, the
monitoring step can continue. These steps can also be conducted
simultaneously.
[0021] Specific carriers of toxicants, such as bait or tracking
powder, are aspects of the subject invention. These carriers are
referred to herein as matrices. Also described are apparatuses for
presenting the toxicant-containing matrix to the target pest.
[0022] In a preferred embodiment of the invention, the control step
of the process can utilize pests which have been captured in the
monitoring step. Specifically, these captured pests can be used to
attract or recruit other pests to the toxicant-containing matrix,
herein referred to as "self-recruitment," and, in some instances,
to deliver toxicant to a nest or colony of the pests. The unique
use of captured pests to make the toxin matrix more attractive to
nestmates is referred to herein as "self-recruitment." As described
herein, a captured pest can be induced to chew or move through a
toxicant-containing matrix before travelling to the nest. In a
preferred embodiment of the subject invention, the toxicant is
relatively slow-acting so the pest can travel through the colony
territory before dying. Because the termite leaves the
toxicant-containing matrix before dying, this method prevents the
tainting of the carrier and vicinity of the matrix with dead or
dying termites. In the course of traveling within the nest, the
pest can leave a chemical trail directing or recruiting other of
the target pests to the toxicant-containing matrix. Also, the
captured pests can leave chemical signals in the
toxicant-containing matrix itself, communicating the desirability
of the food. Because these chemical markers are species- and even
colony-specific, these chemicals are highly advantageous for
self-recruitment of nestmates to the toxicant-containing matrix.
Also, the pest may deliver toxicant to the nest, for example, via
trophallaxis or cannibalism, where the toxicant can kill other
nestmates. The effect of this method is to make the
toxicant-containing matrix much more attractive to the termites.
This attractiveness can result from the highly specific trail
pheromones which direct other nestmates to the toxicant-containing
matrix and, more importantly, the deposit in the
toxicant-containing matrix of feeding-initiating pheromones which
can be highly specific for the particular termite colony which is
to be eliminated.
[0023] The invention also relates to materials used in carrying out
the novel methods. One critical element of the subject invention is
the toxicant-containing matrix which can comprise a toxicant and a
binder such as Methocel.RTM., agar, other cellulosic materials,
other materials which are non-repellant to the target pest, or a
combination of two or more of these components. Preferably, the
toxicant is slow-acting. If a cellulosic material is used, that
material may consist of wood particles. The matrix can further
comprise components which stabilize or regulate the matrix
environment. For example, a humectant such as a hygroscopic
component can be added to regulate the moisture content of the
matrix.
[0024] Certain novel apparatuses are also used according to the
subject invention. Specifically disclosed are apparatuses for
monitoring and controlling populations of insects, particularly
termites. For example, one such apparatus for monitoring the
presence of termites simply comprises a food source as a monitoring
device which can be strategically placed at sites surrounding a
structure, or at an agricultural location. These monitoring devices
are accessible to the pest management operator or property owner so
that they can be periodically monitored for evidence of the
presence of termites. Other apparatuses, such as electronic
devices, can be incorporated in the monitoring devices to alert the
homeowner or pest control operator to the presence of termites.
Where ground or soil surrounds a structure to be monitored for
termites, the monitoring device can be placed in the soil near the
structure or area to be monitored. Where no soil is around a
structure or when foraging galleries are detected above ground, the
monitoring device or toxicant-containing matrix can be placed above
ground. Advantageously, the monitoring device can be constructed so
that pests can be removed easily and without substantial harm
resulting to the pest, thereby allowing the pest to be used to
recruit other nestmates to the matrix.
[0025] Another apparatus useful according to the subject invention
comprises a housing which is specifically designed to enclose
either a monitoring device or toxicant-containing matrix. This
housing is useful for protecting the monitoring device and/or
toxicant-containing matrix from the environment. The monitoring
device or matrix can be enclosed within the housing in such a
manner so they can be removed with minimal disruption to the
foraging termites. This housing is preferably made from a durable,
non-biodegradable material.
[0026] The present invention provides an environmentally safe
termite control system requiring no complex machinery. The
invention provides apparatuses and methods for the monitoring of,
and delivery of a toxicant to, a target pest wherein the
apparatuses may be easily and safely serviced by property owners as
well as professional pest management workers.
[0027] Advantageously, the disclosed materials and procedures
minimize the risk of exposure to persons handling toxicants and
increase toxicant intake by termites. The methods of the subject
invention can drastically reduce pesticide use in the urban
environment. Moreover, this invention can be an important part of
an Integrated Pest Management (IPM) approach. The first phase of
the IPM can be designed to monitor termite activity. No pesticide
need be used until termite activity is detected. When activity is
detected, the second phase of the IPM can be employed wherein only
a small quantity of pesticide is used to control the entire colony
population. Once control is achieved, the monitoring step can be
repeated, as can the control step, if necessary, thus providing
indefinite protection to the structure or agricultural site.
[0028] As descried more fully herein, there are a variety of
methods and apparatuses which can be utilized to practice the
method of the subject invention. The precise methods and
apparatuses which would be optimal for a particular target pest and
environmental setting would be apparent to a person skilled in this
art using the teachings provided herein.
[0029] The descriptions and teachings which follow primarily focus
on the control of termites. Specific methods and apparatuses for
the control of termites are provided, but variations of these
methods and apparatuses and their applicability to pests other than
termites would be readily recognized and used by a person skilled
in this art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIGS. 1a-1d illustrate one embodiment of the invention
wherein a single station housing is used to house a monitoring
device and then a toxicant delivery tube. Specifically, FIG. 1a
shows placement of the monitoring device into a station
pre-positioned in the soil and placement of a cover over the
station; FIG. 1b shows termite foraging tunnels which lead to the
station and the monitoring device; FIG. 1c shows removal of the
monitoring device and replacement with a toxicant delivery tube
within the same station; and FIG. 1d shows that the termites
captured in the monitoring device are placed into the recruiters'
chamber of the toxicant delivery tube to recruit other termites to
the toxicant.
[0031] FIG. 2 shows a side and top view of a monitoring device and
a station housing.
[0032] FIG. 3 shows a bait tube with recruiters' chamber.
[0033] FIG. 4 shows a contiguous station housing containing
monitoring blocks placed in soil adjacent to a structure
foundation. A thin strip of metal foil is embedded in the
monitoring block. When the monitoring blocks are connected together
to surround the structure, a contiguous circuit is formed. Severe
infestation by termites in the monitoring block results in the
breaking of the circuit, which can be easily detected by an
electronic device.
[0034] FIGS. 5a-5c show one example of an termite
monitoring/capturing/toxicant-delivery station. FIGS. 5a and 5b
show a section cut out for placement against a wall having a
molding. FIG. 5c shows an exploded view of the box, toxicant
matrix, and lid as appropriately mounted against a wall.
[0035] FIG. 6 shows one example of a horizontal monitoring device
and station.
[0036] FIGS. 7a-7d show one example of the use of a horizontal
monitoring device and toxicant delivery system.
DETAILED DISCLOSURE OF THE INVENTION
[0037] The subject invention pertains to novel methods and
apparatuses for controlling populations of pests. The present
invention is based on the concept of providing a suitable toxicant
in a matrix which is non-repellant to the species of pest to be
controlled. In a preferred embodiment, the invention further
comprises a self-recruiting method of bringing additional pests to
the toxicant. As described in detail herein, the self-recruiting
aspect of the subject invention is a very unique and effective
means of making a toxicant-containing matrix much more attractive
to the pests from a specific colony which is to be eliminated.
Thus, a very important aspect of the invention is a means for
making a toxicant more attractive to pests, particularly pests from
a specific nest or colony.
[0038] The described method is most readily applicable to insects
which live in colonies and which communicate by chemical signals
such as, for example, pheromones. Pheromones are naturally produced
chemotactic compounds that termites and other insects are known to
use as communication signals. The described method can be used, for
example, to capture and control insects of the order Isoptera, and
is particularly useful for controlling populations of subterranean
termites. It would be readily apparent to persons of ordinary skill
in the art that the method and apparatuses are adaptable to a
variety of pest species. Examples of termite species which can be
controlled by use of the disclosed method include Coptotermes
formosanus, Reticulitermes flavipes, R. hesperus, R. virginicus, R.
tibialis, and Heterotermes aureus, as well as termite species of
the families (and pest genera) Mastotermitidae (Mastotermes
species), Hodotermididae (Anacanthotermes, Zootermopsis species),
Rhinotermitidae (Coptotermes, Heterotermes, Reticulitermes,
Psammotermes, Prorhinotermes, Schedorhinotemmes species),
Kalotermitidae (Glyptotermes, Neotermes, Cryptotermes,
Incisutermes, Kalotermes, Marginitermes species), Serritermitidae,
and Termitidae (Pencapritermes, Allodontermes, Microtermes,
Odontotermes, Nasutitermes, Termes, Amitermes, Globitermes,
Microcerotermes species), Termopsidae (Hodotermopsis, Zootermopsis
species), and other pest species of termites. For purposes of
brevity, the emphasis herein is directed to subterranean
termites.
[0039] A preferred embodiment of the invention features two
repeatable steps: (1) population monitoring/capturing (hereinafter
referred to as monitoring), and (2) delivery of a toxicant to a
pest through the use of a toxicant-containing matrix. The
monitoring step of the process comprises monitoring a particular
location to detect any termite activity. This step may further
comprise capturing termites. The toxicant delivery step involves
providing a slow-acting toxicant in a matrix which is eaten or
otherwise contacted by the termites. The slow-acting toxicant
allows termites to return to and move through their colony
territory before dying. Nestmates then follow the trail back to the
toxicant. As described more fully herein, the two principal steps
of the subject invention can be repeated as part of a pest
management program wherein the program involves the initial step of
monitoring for pest activity followed by control if pest activity
is observed. Once control is achieved, monitoring can be continued.
The steps may also be performed simultaneously. Also, an initial
monitoring step may not be necessary if termite activity has
already been detected. In a preferred embodiment, a single station
housing, as described herein, is used for both monitoring and
control. This station housing is a unique containment device which
is made of a durable, non-biodegradable material which permits
long-term monitoring and repeated cycles of monitoring and
control.
[0040] Each of the two above-referenced steps is described in more
detail below. Also discussed below in greater detail is the
self-recruitment aspect of the toxicant delivery step. Also
discussed in greater detail below are specific apparatuses useful
according to the subject invention.
[0041] A. Monitoring. The primary objective of the monitoring step
is to detect the presence of subterranean termites and not to
attract termites from other locations. If termites are present,
this step provides an opportunity to collect them. If termites are
collected, these termites can then be used for recruiting other
nestmates to a toxicant according to the toxicant delivery step of
the invention. Therefore, it is preferred that termites be
collected in a manner which does not adversely affect the termite's
viability. The terms "without affecting viability" and "remain
viable" mean that the captured termite is relatively unharmed and
that it is able to forage and, preferably, has sufficient mobility
to return to the nest.
[0042] Certain devices can be used to monitor for termite activity.
These devices are described in greater detail below. The monitoring
devices can be placed in, on, or above the ground. These devices
may be placed individually or interconnected to surround structures
to be monitored. The materials used for the monitoring device
should not repel or deter termites. Preferably, these materials
should have sufficient structural integrity to exist in variable
environments (high humidity, aridity) for a period sufficient for
termites to locate and access the monitoring devices. The
monitoring device should be able to withstand foraging activity by
a large number of termites so the device is not totally consumed
within a reasonable time interval between inspections.
[0043] In a preferred embodiment of the monitoring step, an article
can be both used to detect and capture the target termites. The
article is, thus, the "monitoring device," or "monitoring article."
The device employed in this monitoring step preferably allows the
capture of termites with a minimum amount of harm to the termites.
The device can be of any material which is susceptible to termite
infestation. Preferably, the material comprises cellulose.
[0044] One preferred embodiment of the monitoring step utilizes an
outer housing which is separate from but surrounds the monitoring
device. The outer housing is also referred to herein as the station
housing. In a preferred embodiment, the station housing can have a
plurality of entry points which allow termites access to the
monitoring device. These entry points must be large enough to allow
entry of the target pest and can be much larger. The station
housing can further comprise a reinforced tip at one end to
facilitate placement into the ground. The station housing may
further comprise, at the end opposite the reinforced tip, a cover.
The cover is described more fully below. The station housing for
horizontal placement in the soil or above ground placement is also
described below.
[0045] When a station housing is used, the same station housing can
be used for both the monitoring step and the toxicant delivery
step. For example, once termites are observed in the monitoring
step, the monitoring device (without toxicant) can be removed from
the station housing and replaced with a toxicant-containing matrix.
One advantage to the use of the station housing is that the termite
foraging tunnels will not be greatly disrupted by removal of the
monitoring device if the station housing remains in place. Thus,
when the monitoring device is replaced with a toxicant-containing
matrix, foraging can commence readily without extensive
restructuring of the foraging tunnels of the termites. Furthermore,
once control of the termite population has been achieved using the
toxicant-containing matrix, the toxicant-containing matrix can be
readily replaced with a monitoring device to resume monitoring of
the location. Throughout the process, the station housing can
remain in place. Thus, the station housing is preferably made from
a durable, non-biodegradable material and becomes a critical
component of the pest management program.
[0046] The monitoring device or, preferably, the station housing
containing the monitoring device, can be placed in the ground or
other appropriate location for a time sufficient to allow termite
infestation. The monitoring device can be placed in the ground
directly by being driven into the soil or placed into a
pre-existing hole or location of sufficient dimension to allow the
device to remain in position. Alternatively, the monitoring device
can be placed inside the station housing which is placed on or in
the ground. The monitoring device and/or station housing may lie
flat on the ground or be placed upright in a hole.
[0047] In one embodiment of the monitoring step, the monitoring
device is modified chemically and/or physically to increase the
possibility that the target pest will enter and move within the
device. A variety of chemical means, such as food, moisture, dry
rot fungus, and pheromones or their mimics (e.g., glycol
compounds), and physical characteristics, such as shape, size, and
texture, can be used to achieve this objective. One example of a
physical modification would be a cover placed over the station
housing, or over the monitoring device if the monitoring device is
used in the ground without the station housing.
[0048] Once infested by termites, the monitoring device can be
gently removed from the soil or from the station housing. As stated
above, it is advantageous to utilize a station housing to minimize
disruption to foraging tunnels. Upon removal of the monitoring
device, a toxicant-containing matrix can then be placed in the
station housing or other location previously occupied by the
monitoring device. In this way, toxicant is not used until the
presence of termites is determined by the monitoring step.
[0049] In a preferred embodiment described more fully below,
termites collected in the monitoring step are used to recruit more
termites to the toxicant. This is termed "self-recruitment."
Therefore, the monitoring device can be specifically designed to
facilitate capture of termites. Such a device, as described below,
may have interfacing sides. After removal from the ground or the
station housing, the interfacing sides of the monitoring device are
separated and termites extracted from them. The dimensions and
shape of the monitoring device are designed so that termites
foraging in the device can be extracted with minimum harm. "Minimum
harm" means that the termites which are captured remain viable and
are capable of foraging and producing pheromone and, preferably,
are able to return to the nest for recruiting nestmates. The
extracted termites are then used to recruit other termites from the
colony to, and through, a toxicant-containing matrix. Termites
foraging in the monitoring device can be transferred to a toxicant
delivery device by gently removing or tapping them from the
monitoring device into the toxicant delivery device. The
toxicant-delivery device is also referred to herein as a "bait
tube." The toxicant delivery device can comprise a chamber above
the toxicant-containing matrix into which the termites are placed.
This chamber is referred to herein as a recruiters' chamber. To
exit the bait tube and station housing, the termites must then
tunnel through the toxicant-containing matrix.
[0050] B. Toxicant delivery. The objective of the toxicant delivery
step is to induce as many pests as possible from a colony to
contact or eat a toxicant. The details of the toxicant delivery
step are herein described as pertaining to termites, particularly.
However, as stated above, the method can also apply to other
insects, especially those social insects which live in colonies or
nests and which communicate by chemical signals, i.e.,
pheromones.
[0051] The essential elements of a toxicant delivery system
comprise the presentation of an active ingredient (AI) and a
suitable carrier (matrix) in a manner that induces the target pest
to ingest or contact the AI. The toxicant-containing matrix should
be delivered in, on, or above the ground in a manner which
minimizes exposure of the environment, applicator, and other
non-target organisms to the toxicant. For example, a suitable
matrix can be a coatable, suspendable, impregnable natural or
artificial food source. The matrix does not need to attract pests,
but should not repel them. The presentation of the matrix (in a
station housing, etc.) may induce pests to contact the toxicant.
The suitable matrix further can be capable of being formed into a
desired shape for placing or packing into a station housing.
[0052] In a preferred embodiment for a non-rigid matrix, the
toxicant containing matrix is placed within a casing. This casing
is different from the station housing and, in fact, facilitates
easy placement of the toxicant-containing matrix into the station
housing. Although the toxicant-containing matrix and surrounding
casing are preferably placed into a station housing, the casing
can, alternatively, be made of sturdy material for placement
directly into the soil. The casing is necessary because, in a
preferred embodiment, the toxicant-containing matrix has a very
high moisture content and is somewhat amorphous and therefore needs
a casing to hold its shape. The casing also helps to prevent
desiccation, and it minimizes contact with the toxicant by the
handler and facilitates easy removal of the toxicant-containing
matrix when the toxicant delivery step is completed. Furthermore,
as described more fully below, the casing can be designed to
include or form a recruiters' chamber. The casing must permit entry
by the target pest; therefore, the casing must either comprise
appropriate openings or be of a material through which the pests
chew or otherwise create an opening. For example, thin polymeric
materials may be used to enclose the toxicant-containing matrix.
The toxicant-containing matrix can be enclosed within the casing
somewhat like a sausage within its casing. The use of a polymeric
material is particularly advantageous if that material is of a
nature such that it prevents or delays desiccation of the matrix.
Other materials which can be used to encase the toxicant-containing
matrix include, but are not limited to, cardboard and other
cellulose materials, even paper and wax. This method for packaging
the toxicant-containing matrix has the advantage of creating a
"dose-pack" which precisely provides the appropriate amount of
toxicant in a manner which minimizes contact with humans or the
environment.
[0053] Suitable matrices can be formable cellulose-containing
materials including, but not limited to, wood particles or wood
flour, recycled paper or cellulose ethers such as methylcellulose,
hydroxypropylmethylcellulose, and hydroxybutylmethylcellulose,
commercially available under the tradename of Methocel.RTM.
(trademark of the Dow Chemical Company). A preferred
cellulose-containing matrix is sawdust or wood flour which is not
repellent to target termite species. For use with termites and
other pest species which are attracted to, or reliant on, the
presence of sufficient moisture, the matrix can further comprise a
humectant for maintaining moisture content. An appropriate
humectant can have hygroscopic characteristics. The monitoring step
and toxicant delivery step could use the same matrix, except that
no toxicant is impregnated into the matrix used for the monitoring
step.
[0054] The preferred active ingredient should be slow-acting,
lethal at concentrations which do not repel target insects, and
capable of being combined with the matrix as described above. It is
intended that pests directly contacting or ingesting the toxicant
will not be killed immediately but will travel to and/or through
their colony to recruit other nestmates to the toxicant, thereby
resulting in the control of large numbers of colony members. The
term "delayed lethal effect" in the present specification means
that death does not occur immediately or within a short time such
as a few seconds or minutes after ingestion or contact of the
active ingredient by a termite. Rather, it is preferred that the
pest die hours or, more preferably, days or weeks after
encountering the toxicant. This delayed lethal effect permits the
termites to interact with the colony before death occurs, thus
allowing the location of the toxicant delivery system to be
communicated to nestmates within the colony. It is preferable that
the communication be effected by pheromones because these chemical
signals are a highly efficient means of communication, often being
specific to a particular species or colony. In addition,
communication by pheromones is enhanced according to the subject
invention by the deposit directly into the toxicant-containing
matrix of feeding-initiating pheromones. These pheromones are
deposited by the captured pests which are forced to forage through
the toxicant-containing matrix before exiting the toxicant-delivery
device and/or station housing to return to the colony. This unique
self-recruitment procedure results in a highly efficient process of
recruiting nestmates to the toxicant matrix, ensuring their
exposure to the slow-acting toxicant.
[0055] The active ingredient can comprise chemical insecticides,
insect growth regulators, or microbial pathogens or their toxin
preparation. Examples of toxicants include, but are not limited to,
borates (boric acid, disodium octaborate tetrahydrate), mirex,
sulfluramid and related fluoroalkyl sulfonamides, hydramethylnon,
avermectin, A-9248 (diiodomethyl para-tolyl sulfone),
fluorosulfonates, imidacloprid, azadirachtin, cyromazine, juvenile
hormones (JHs), juvenile hormone analogs (JHAs), or juvenile
hormone mimicries (JHMs) such as methoprene, hydroprene, triprene,
furnesinic acid ethyl and alkoxy derivatives, pyriproxyfen (Nylar),
fenoxycarb, and chitin synthesis inhibitors (CSIs) such as
hexaflumuron and other acyl ureas, diflubenzuron (Dimilin), and
azadirachtin. Biological control agents which can be used as the
"toxicant" include, but are not limited to, entomogenous fungi such
as Metarhizium anisopliae and Beauveria bassiania, entomogenous
nematodes such as Neoplectana carpocapsae, insect viruses,
pathogenic bacteria such as Bacillus thuringiensis, Aspergillus
flavus, and Serratia marcescens, or the toxin preparations derived
from B. thuringiensis or other biological control agents.
[0056] In addition, other insecticides can be used as
microencapsulated formulations. Microencapsulation can slow the
activity of otherwise fast-acting toxicants.
[0057] An example of the invention disclosed herein uses
hexaflumuron, which can be impregnated or incorporated into the
cellulose material during the formulation of the
toxicant-containing matrix.
[0058] As discussed above, a novel feature of one embodiment of the
subject invention comprises a "self-recruiting method" to use
collected termites to recruit other nestmates to the toxicant. It
is widely recognized that certain insects utilize chemical signals
such as pheromones, which can be deposited along a trail by an
insect which has located, for example, a food source. Subsequently,
other insects, usually from the same colony, detect the chemical
signal and are thus directed to that food source. Such
trail-following pheromones of some subterranean termites have been
identified; however, synthesis of such natural products or their
analogs is difficult, costly, and impractical. Moreover, the proper
concentration and composition of these pheromones can be species-
and colony-specific. Additionally, trail pheromones may be very
different from feeding-initiating pheromones. Insects are very
reluctant to eat their trail pheromones because consumption of
trail pheromones would remove the markers termites need to locate
food sources and nestmates. Thus, it is likely that the
incorporation of trail pheromones, or their analogs, into a
toxicant may well act to bring termites to a location but may
inhibit feeding at that location. Feeding behavior may be triggered
by different pheromones which would be expected to be specific for
particular pests and particular colonies. Therefore, reproducing
functional synthetic pheromones would be nearly impossible for the
desired purpose of widespread use in attracting termites and
initiating their feeding.
[0059] An advantageous feature of the "self-recruitment" embodiment
of the subject invention is to utilize a captured target pest to
produce the species- and colony-specific pheromone for recruiting
other pests to the toxicant and initiating feeding behavior. This
method makes the toxicant highly attractive compared to other known
methods and toxicants. The method is particularly well suited for
aggregating a great number of pests from a single colony to a
toxicant. In accordance with the self-recruitment embodiment,
termites collected in the monitoring phase are placed in the
toxicant-delivery device with toxicant-containing matrix and must
chew or move through the toxicant-containing matrix before
returning to their nest. In this manner, the termite ingests or
contacts the toxicant and leaves appropriate communication signals
throughout the toxicant-containing. matrix, which encourages other
nestmates to locate the toxicant-containing matrix and initiate
feeding activity.
[0060] In one embodiment of the self-recruiting system, termites in
the monitoring devices are gently tapped into an empty chamber (the
recruiters' chamber) situated at the top of the toxicant-containing
matrix (FIG. 3). This chamber may be, for example, about 3.0 cm in
diameter and about 2.0 cm deep. Smaller or much larger chambers
could also be used. The open end is then preferably closed or
capped. Small holes can be provided to allow air flow for termites
into the recruiters' chamber. These termites must then enter the
toxicant-containing matrix in order to exit the toxicant-delivery
device and station housing. Holes from the recruiters' chamber into
the matrix can be supplied to encourage this process. The termites
then tunnel through the toxicant-containing matrix before returning
to their galleries, thereby leaving species- or colony-specific
pheromones in the toxicant-containing matrix. The exiting process
may be encouraged by holes leading out of the matrix. This
arrangement forces termites to move through the toxicant-containing
matrix and thus leave favorable pheromones in the matrix and/or
station housing to recruit nestmates into the toxicant-containing
matrix. As discussed above, the self-recruiting procedure
advantageously uses nestmates to leave the species- and
colony-specific pheromones to recruit others from the same colony.
This is much preferable to the use of synthetic pheromones which
can fail because of their lack of specificity or because of their
initiation of trailing rather than feeding behavior. The deposit of
specific pheromones in the toxicant-containing matrix by the
captured termites thus aids in recruiting other nestmates to the
toxicant-containing matrix, whereupon they forage, are exposed to
toxicant, and deposit more pheromone, thus creating a cyclical,
self-recruiting termite control method.
[0061] C. Apparatuses. Employed at each step of the method of the
subject invention are novel apparatuses. As described above, one
method for the monitoring step employs a novel separable article
placed into the ground (or into a housing) for monitoring and
capturing termites indigenous to an area. The termites are captured
in such a way so that they remain viable and can be easily
transferred to the toxicant delivery device used in the toxicant
delivery step.
[0062] The monitoring device used in the monitoring/capture step
can be comprised of at least two-interfacing separable pieces which
can be bound together. The two-piece construction allows for easy
collection of termites within the device. For example, a wooden
stake can be comprised of two or more interfacing pieces which are
bound together. The binding which holds together the pieces can be
flexible metal bands, an adhesive tape, or the like. As shown in
FIG. 2, the interfacing pieces can be enclosed within a bracket
device comprised of horizontal bands which are interconnected by
longitudinal supports which form a bracket and which further has a
handle at one end to facilitate removal of the monitoring device
from the ground even when badly damaged by the termites.
[0063] Alternatively, for monitoring above-ground, an apparatus
which houses a food source such as sawdust, or a modified
monitoring device, can be placed on or attached to (or in side) a
tree or the wall of a structure. The above-ground monitoring device
is also easily accessible for periodic monitoring and capture of
pests for use in the toxicant delivery step.
[0064] The monitoring and toxicant delivery steps employ novel
housing apparatuses. The novel housing apparatuses, or station
housings, of the subject invention are designed to protect and
enclose the monitoring device and toxicant-containing matrix and,
preferably, to encourage termites to contact the
toxicant-containing matrix wherein the termites are exposed to
lethal doses of a slow-acting toxicant.
[0065] One embodiment of the subject invention can utilize a single
station housing which can house the monitoring device for use in
the monitoring step and then, after removing the monitoring device,
can also house the toxicant-containing matrix. Alternatively, the
station housing may be designed to simultaneously hold both the
monitoring device and the toxicant-delivery device. When the
monitoring step employs sawdust or other cellulose-containing
material as a component of the monitoring device, the sawdust can
be packaged in a casing for convenient placement into, and removal
from, the station housing. Preferably, the material used to package
the monitoring mixture can also be a cellulose-containing material
such as paper, cardboard, paperboard, or the like, so that it is
palatable to termites. Similarly, as described above, the toxicant
and its matrix can be packaged in a casing such as a
cellulose-containing package wherein the packaging serves as a
barrier to prevent the handler from exposure to the toxicant.
[0066] Thus, in a preferred embodiment, the station housing is
intended to remain in place indefinitely to house the monitoring
device for long-term monitoring and to house the
toxicant-containing matrix when necessary for control. Therefore,
for purposes of the subject invention, the station housing should
be durable enough to contain the monitoring device or
toxicant-containing matrix (or toxicant-delivery device) in
variable environments (i.e., wet vs. arid), and should be
constructed in a manner, or of a material that will allow target
pests to pass through the housing, i.e., with pre-formed entry
points, or of a material in which insects can form their own
openings. The station housing should be non-degradable and be
non-repellant to target insects. A preferred station housing is
capable of repeated or continued use, is environmentally
acceptable, and is an effective barrier between the toxicant and
the handler or the environment. It is also capable of being removed
and reused in another location. Materials from which the station
housing can be constructed include, but are not limited to,
polymers such as plastic, non-corrosive metal such as aluminum or
stainless steel, wax, and non-biodegradable cellulose-based
materials. Station housings which are not eaten by termites are
preferred. The station housing can be readily adapted for
above-ground use, for example, in trees or on structures.
[0067] A non-rigid toxicant-containing matrix will typically be
enclosed within another material (casing) so as to form a bait tube
(also referred to herein as a toxicant-delivery device) designed to
minimize direct contact of persons handling the bait tube with
toxicant-containing matrix and to allow termites collected from the
monitoring procedure to return back to the foraging galley for
recruiting other nestmates. The bait tube should be of a size and
shape that is large enough to contain an effective amount of
toxicant while still being easily handled by individuals. The bait
tube should further be of a size and shape that is accessible to
the target insects. The various shapes of the bait tube can
include, but are not limited to, cylinders, discs, rectangles, and
cones. The bait tube may be designed to be placed directly in the
soil or be of a shape that allows for compatible fit into the
station housing.
[0068] In a preferred embodiment, the station housing comprises a
cover which not only protects the monitoring device but also
performs several other important functions. Specifically, the cover
may be designed so as to modulate the microenvironment surrounding
the station housing. For example, the cover may advantageously be
designed to extend out beyond the boundaries of the main
compartment of the station housing such that the nearby ground will
be covered. This has the effect of shading the surrounding soil,
thus keeping the surrounding soil cool and moist in warm climates
or insulating for warmth in colder climates. These conditions have
been found to increase the chances that foraging termites will
contact the station housing and enclosed materials. An extended
cover also helps to facilitate visual location of the station
housing. The cover may be secured to the soil to stabilize the
entire housing as well as facilitating in the removal of the
internal apparatuses used with pulling the station housing out of
the soil.
[0069] To facilitate insertion and removal of the monitoring device
and toxicant-containing matrix, a closeable opening (also referred
to herein as the lid) may be provided in the cover. Advantageously,
the lid may be equipped with a tamper-resistant or child-resistant
mechanism. In a preferred embodiment, the lid will only be
removable with the aid of a tool specifically adapted for the
purpose of removing such lids. The tool then would be used to
facilitate inspection of the station housing. The station housing
may be of one piece construction or of multi-piece construction.
For example, the cover may be made as a separate piece which fits
onto or over the rest of the station housing. Alternatively, the
cover may be molded, or affixed to, the rest of the station
housing. Similarly, the lid may be affixed to or removable from the
cover and the rest of the station housing. One embodiment of the
station housing is shown in FIG. 2.
[0070] One embodiment of the cover is a circular or disc-shaped
device having a convex top and concave bottom side. Insulation
material such as expanded polystyrene foam may be incorporated in
the cover material to further maintain stable temperature and
humidity beneath the cover. The cover may be, for example, four
inches or more in diameter. The bottom side of the cover can be
radially ribbed or grooved. The top side can be smooth-surfaced. As
described above, at the center of the cover can be a closeable
opening (lid). The opening can be of sufficient dimension so that
the monitoring device or toxicant-containing matrix or bait tube
can be passed therethrough. The lid can also serve as an inspection
window. In addition, located approximately between the center and
outer edge of the cover can be small holes so that nails or similar
fasteners can secure the cover to the ground.
[0071] The station housing may also comprise an extractor, or
equivalent device, which facilitates the removal of the monitoring
device and toxicant-containing matrix (bait tube) from the station
housing. The extractor may comprise, for example, handles, strings,
cords, or other implement capable of directly pulling the
monitoring device and toxicant-containing matrix from the station
housing. Alternatively, the pulling device may be connected to a
shelf upon which the monitoring device or bait tube sits. The
pulling device then pulls the shelf and the monitoring device or
bait tube out of the station housing. This embodiment is
particularly advantageous because it enables the removal of either
the monitoring device or the toxicant-containing matrix. In this
way any contact with the toxicant-containing matrix can be
minimized. Furthermore, the activity of termites on either the
monitoring device or the toxicant-containing matrix may
substantially reduce or eliminate the structural integrity or
rigidity of these articles, thus making them difficult to remove
without the aid of an extractor which comprises a shelf component
to pull out the material. A further advantage of the shelf
component of the extractor is that it facilitates removal of any
dirt or debris which may accumulate in the station housing over a
period of time. This may be of particular importance in sandy soil.
The extractor may also function to hold together the pieces of the
monitoring device such that the device is in one piece when in the
station housing but is easily separated into two or more pieces
when removed from the housing.
[0072] In a preferred embodiment of the invention, termites
captured in the monitoring step are forced to move through the
toxicant-containing matrix before exiting to return to their
colony. In this embodiment, the station housing or the
toxicant-delivery device (bait tube), or both, are specifically
adapted to force termites through the toxicant-containing matrix.
For example, the casing for the toxicant-containing matrix may have
a rigid upper portion which extends a short distance beyond the end
of the toxicant-containing matrix. This rigid upper portion is
impenetrable to termites. The end of the casing is also
impenetrable to termites, and the rigid upper portion of the
casing, together with the end portion which is connected to the
rigid upper portion, form a recruiters' chamber with the final side
of the chamber being formed by the toxicant-containing matrix.
Thus, to exit the recruiters' chamber, the termite is forced to
move through the toxicant-containing matrix. Many different
versions of this recruiters' chamber could be envisioned, readily
constructed, and used by a person skilled in the art having access
to the teachings provided herein.
[0073] Following are examples which illustrate procedures,
including the best mode, for practicing the invention. These
examples should not be construed as limiting. All percentages are
by weight and all solvent mixture proportions are by volume unless
otherwise noted.
EXAMPLE 1
Integrated Pest Management System for the Control of Termites
[0074] One example of how methods of the subject invention can be
applied to the control of subterranean termites is as follows:
[0075] (a) Placement of the station housing and monitoring device.
A hole of appropriate dimension can be made in the soil for
positioning of the station housing. The station housing is placed
into the hole. The monitoring device is placed inside the station
housing. A cover can be placed over the station housing and the
cover secured to the surface of the ground. Alternatively, the
monitoring device can be placed inside the station housing which is
then inserted or hammered into the soil until the station housing
opening is near the soil surface. Also, the monitoring article or
station housing may be placed horizontally on the ground or beneath
the soil surface.
[0076] (b) Inspection of monitoring devices. The monitoring device
can be inspected periodically for evidence of termite infestation
by visually examining the device for signs of infestation.
Inspection of the monitoring device can be performed weekly,
bi-weekly, monthly, etc. as needed or desired. Inspection may be
done visually, or automatic monitoring devices may be used. For
example, termites are known to chew through soft metal. Therefore,
thin strips of metal may be incorporated into the monitoring device
and connected to an electronic device. When termites chew through
the thin metal, the circuit is broken, thus evidencing the presence
of termites. See FIG. 4. Also, the monitoring device may be
designed to detect the sound produced by termites as they feed on
the monitoring device.
[0077] (c) Detection of presence of termites. Upon the detection of
the presence of termites in the monitoring device, the monitoring
device is removed from the station housing (or soil) and replaced
with a toxicant-containing matrix, in a toxicant delivery device
(bait tube). Termites that are captured in the monitoring device
can be extracted and gently tapped into an upper chamber of the
toxicant delivery device. This upper chamber is the recruiters'
chamber. In order to exit, the termites must then move through the
toxicant-containing matrix to reach the exit points. No toxicant
needs to be used unless termites are detected from the monitoring
procedure (or are otherwise known to be present), thereby
eliminating the use of any unnecessary toxicant. When termites are
detected, the toxicant-containing matrix is utilized until no
termite activity is detected in the toxicant delivery device. At
that time, monitoring devices can be used again. In addition to the
practice of replacing monitoring devices with toxicant delivery
devices, another embodiment of the invention comprises a monitoring
device which remains in place and a toxicant delivery device which
can be added to, or fitted around, the monitoring device if the
need arises to deliver toxicant.
EXAMPLE 2
Preparation of Toxicant-Containing Matrix
[0078] The toxicant-containing matrix can comprise cellulose,
preferably in the form of a powder or small particles, and the
active ingredient of a toxicant. Cellulose in the form of powder
allows for a more homogeneous mixture of cellulose and toxicant and
facilitates packing and handling. A humectant component can be
added to the matrix to maintain moisture content. In one embodiment
of the invention, a Methocel.RTM. solution of about 1% to about 5%
can be used effectively. Methocel.RTM. is particularly advantageous
because it is a non-nutrient humectant that does not allow
microbial growth. An about 1-2% solution is preferred. Moisture
content can be varied according to the preferences of different
termite species. A preferred embodiment of the invention employs a
matrix comprising sawdust as the cellulose component, and water
sufficient to yield a moisture content of approximately 50% to
about 90% by weight. A moisture content of about 60-80% is
preferred. Water content can be varied but should be adequate to
thoroughly moisten the dry components of the matrix. The preferred
consistency of the final matrix is that of a semi-solid paste
whereby the sawdust or wood flour can be compacted together and
formed or shaped. Sawdust containing about 80% water was found to
stimulate feeding by the native subterranean termites
(Reticulitermes species) and the Formosan subterranean termite, C.
formosanus.
[0079] Further studies have shown that sawdust from hardwood
species such as, for example, oak, beech, birch, or maple is
preferred by some termites. This was a surprising result because it
previously was widely assumed that termites preferred soft wood
which is easier to eat. Practical considerations may, however,
militate in favor of using softer woods in some circumstances. As
used herein, reference to "sawdust" means fine wood particles which
may be so fine as to be known as wood flour, and which may be
produced from wood by any suitable process as well as by sawing
wood. Furthermore, the matrix can be made a preferred food by
suitable choice of the species of timber and also suitable choice
of the maximum particle size. The exact species of termite to be
eradicated will indicate the optimum wood flour and the optimum
particle size.
[0080] A procedure for the preparation of the toxicant-containing
matrix used for the toxicant delivery step is conducted as follows:
[0081] 1. Hardwood sawdust or wood flour is mixed with water in
proportions of approximately 80% water (w/w). Alternatively, the
water component can be a 1-2% Methocel.RTM. solution. [0082] 2.
Toxicant is thoroughly mixed into the sawdust/water matrix to
result in a homogeneous final concentration. When using
hexaflumuron, this concentration may be approximately 5000 ppm.
[0083] 3. The toxicant-containing matrix can be adjusted with
additional water or sawdust to achieve a semi-solid formable
consistency which can be packed into the station housing or,
preferably, into a casing to form a bait tube. [0084] 4. The
toxicant-containing matrix can be stored in a moisture-tight and
air-tight packaging to maintain the appropriate moisture
content.
EXAMPLE 3
Construction of Station Housing
[0085] In one embodiment of the invention, the station housing can
comprise a rigid tube which is pointed at one end and closeably
open at its opposite end. The tube is preferably made of a
non-biodegradable, durable material which is not attractive to, nor
eaten by, termites. The station housing should be made of a
material which resists decay or corrosion when exposed to moisture,
especially when buried underground for a period of time. The
texture of the station housing may be coarse. The station housing
will typically comprise entry points which enable termites to have
access to the monitoring device or toxicant-containing matrix
within. These entry points should not be so large or numerous as to
compromise the durability or structural integrity of the station
housing or allow dirt or debris to readily enter the inner chamber
of the station housing. However, the entry points should be
sufficient to provide ready access for termites to the materials
within. In one embodiment, numerous entry points on the side of the
station housing can lead to inner tubes that may be bent to attach
to the inner wall of the toxicant delivery tube. In this
embodiment, termites entering the station housing from the soil are
directed sideways and into the toxicant. The bent inner tubes
provide entry points for termites in the soil. Because they are
bent sideways, the toxicant-containing matrix cannot be directly
accessed from outside. In one embodiment, the entry points have a
diameter which is larger than the head of the termite but smaller
than the width of its head and two antennae. These holes can have,
for example, an inner diameter of about 0.25 cm.
[0086] A toxicant-delivery device (bait tube) can be added to the
station housing to a level lower than the closeably open end. This
level may be, for example, about 2.0 cm below the end. A plastic
insert forming a chamber can be placed into the bait tube. This
insert can form a recruiter chamber. The chamber can have holes in
the end which contact the bait tube so as to allow termites to exit
the chamber by entering the bait tube. The chamber may also have
very small holes to facilitate air flow. There may be, for example,
six holes having an inner diameter of about 0.25 cm. Vertical
tubings extending from the holes of the insert can be punctured
into the toxicant-containing matrix. This arrangement also helps to
tamper-proof the station housing because the toxicant-containing
matrix cannot be accessed from any external opening of the bait
station. The plastic insert can have a detachable cap at the end of
the chamber opposite the bait tube. The detachable cap is either
engaged with a snap-on attachment or can be threadedly engaged.
Preferably, the cap is made child-proof. The closed chamber thus
provides a location to place termites to be used for
self-recruitment.
EXAMPLE 4
Horizontal Station housings for Population Suppression of
Subterranean Termites
[0087] Placement of vertical type station housings is difficult in
some locations with rocky soil. Moreover, some termite species tend
to forage near the soil surface, making it unnecessary to place a
station as deep as that of the vertical type. Therefore, one
embodiment of the subject invention involves the use a horizontal
station housing that can be placed near soil surface.
[0088] Station housing. The station housing can be comprised of a
container with a cut-out bottom. As an example, this container may
be about 21.5.times.16.times.5.5 cm. Numerous holes can be drilled
through the four vertical walls of the container. These holes can
be, for example, about 3 mm in diameter inside and about 0.6 mm in
diameter outside. This hole arrangement prevents soil invasion into
the housing. Inner and outer walls can be sanded to provide a
surface suitable for termites to walk on. A monitoring device can
be made, for example, of three wooden pieces bound together with a
support strip attached to a handle. The monitoring device can be
placed inside the container and can be removed using an attached
handle with minimum disturbance to termites (FIG. 6).
[0089] Toxicant delivery. A container that fits within the station
housing can be used as a toxicant delivery device. This container
may be, for example, about 19.3.times.13.5.times.4.5 cm. Except for
a removable cover, numerous holes through all sides of the
container can be provided for termite entry. These holes may be,
for example about 0.24 cm in diameter. Holes can extend inside the
toxicant delivery device with inner tubes bent at about 90.degree.
to prevent tampering with the toxicant-containing matrix. The inner
and outer walls of the toxicant delivery device can be sanded. The
toxicant delivery device can be filled with the toxicant-containing
matrix up to, for example, about 1 cm from the top of the container
and covered with a lid.
[0090] Operating procedure. A station housing containing wooden
pieces as the monitoring device is placed beneath the ground and
covered with a thin layer of soil (FIGS. 9a, 9b). This thin layer.
of soil can be, for example, about 1 cm. Monitoring devices are
then checked periodically for termite activity. Monitoring devices
infested with termites are gently lifted and replaced by the
toxicant delivery device containing the toxicant-containing matrix
(FIG. 7). Termites extracted from the boards are gently tapped into
the upper 1 cm deep chamber of the toxicant delivery device (FIG.
9d), leaving the colony recognition semiochemicals in the
toxicant-containing matrix to "self-recruit" nestmates into the
toxicant delivery device.
EXAMPLE 5
[0091] The procedures, materials, and apparatuses of the subject
invention can be readily adapted for use for the control of
termites attacking croplands, forests, golf courses, and other
non-structural targets. The same general materials and methods may
be utilized with minor modifications, readily apparent to those
skilled in the art, to achieve optimal results.
EXAMPLE 6
Above-Ground Monitoring and Toxicant Delivery
[0092] In urban areas where the soil which surrounds a structure is
often paved with cement, or asphalt, or some like material, the
placement of the monitoring and/or toxicant delivery devices in or
on the ground may not be practical. Termite infestation, however,
is no less of a problem in these urban areas. Therefore, an
alternative application and design of the described invention
comprises a monitoring and/or toxicant delivery station which can
be used in an above-ground system. Such a system is also of value
anytime that an above-ground infestation is observed.
[0093] An above-ground design is illustrated in FIG. 5. This
above-ground system can comprise a station housing which is placed
or mounted in or on the wall of a structure. The station housing
can comprise a frame which is designed to simultaneously fit snugly
against the wall and a wooden door frame, a molding, or the like.
In one embodiment, the station housing can enclose a
toxicant-containing matrix, substantially as described above,
wherein the toxicant-containing matrix can be packaged in various
shapes and sizes, for example, a rectangular box shape, to
facilitate their use with the above-ground system housing. The
above-ground station housing can be substantially open at the side
which faces or is mounted against the wall. The side of the station
housing facing outward is closeably open, wherein a hinged lid or a
separate lid can be placed over the opening. The lid serves to
prevent exposure to toxicants by persons encountering the station
housing. The lid can further comprise a locking means to prevent
inadvertent exposure by children or others. The cover can also
serve to prevent moisture loss from the toxicant-containing matrix.
Moisture loss can also be prevented by the packaging of the
toxicant, wherein it is preferable to package the
toxicant-containing matrix in a casing which is edible by termites.
Such casings can be cardboard, paperboard, paper, and the like as
described above. A preferable material for packaging the
toxicant-containing matrix is wax-paper due to its
moisture-retaining characteristics.
[0094] After a station housing is attached to a wall fence, tree
stump, tree trunk, or other structural member, contact with the
termite galleries can be facilitated by drilling a hole through the
structural member into the gallery area. Initially, a cellulose
monitoring device may be placed in the housing. If termites are
detected, the monitoring device can be replaced with a
toxicant-containing matrix and collected termites used for
recruitment. In case of known termite activity, a toxicant-delivery
device may be placed in the station housing without the placement
of a monitoring device.
[0095] In one embodiment, cement or asphalt can effectively act as
a station housing. For example, a hole may be drilled into cement,
either inside or outside a structure, to gain access to the soil
below. The monitoring device may then be placed into the drilled
hole such that the device makes contact with soil. The device may
then be monitored and replaced with a toxicant-containing matrix,
preferably within a casing, if termite activity is observed. Of
course, a station housing may also be used in this instance by
inserting the station housing into the hole drilled in the cement.
When the cement hole is used as the station housing, a rubber
stopper or equivalent device can serve as the top, or
cover/lid.
[0096] Above-ground monitoring and toxicant delivery schemes can
also be widely adapted for use in trees.
EXAMPLE 7
[0097] Dyes may be incorporated into the matrix to assist the
applicator in identifying termite colonies and foraging range of
termites feeding on a monitoring article or toxicant bait.
Appropriate dyes include, but are not limited to, Nile Blue A and
Sudan Red 7B. A laboratory study showed that termites accepted bait
matrix containing 0.01-0.05% Nile Blue A, and were visibly stained
after feeding on the dyed material.
EXAMPLE 8
Field Testing Using Matrix Containing Hexaflumuron
[0098] 1. Procedures. Field colonies of the Formosan subterranean
termite, C formosanus, and the eastern subterranean termite, R.
flavipes, were selected for testing. Termite activity was measured
1-2 years before the introduction of a hexaflumuron treated matrix.
Monitoring stations contained pre-weighed wood blocks surrounded by
plastic containers buried beneath the soil surface. Wood weight
loss of a block was determined monthly or bimonthly to represent
activity of the subterranean termite colony being tested. A
multiple mark-recapture program was conducted to estimate the
foraging population size and foraging territory of each tested
colony. A mark-recapture program refers to a procedure wherein a
known number of termites are marked using a dye marker such as Nile
Blue A and then released back to the colony. A week later, termites
are recaptured from the same colony and the ratio of marked and
unmarked termites are recorded. Assuming the initially marked
termites are distributed homogeneously among colony population, the
total population is calculated using the number of initially marked
termites and the ratio of marked and unmarked termites (Begon, M.
[1979] Investigating animal abundance: capture-recapture for
biologist, University Park Press, Baltimore, Md.). Termite activity
was monitored throughout the toxicant delivery program. When
possible, another mark-recapture program was conducted to estimate
the post-toxicant delivery population of a colony.
[0099] 2. Toxicant-containing matrix. Pine or spruce sawdust was
impregnated with an acetone solution of hexaflumuron to yield
concentrations of 500-5,000 ppm (dry wt AI/dry wt sawdust) upon
evaporation of acetone. The toxicant-containing matrix was composed
of 20% treated sawdust and 80% of agar or Methocel.RTM. solution
(2%). A station housing was composed of a plastic tubing (2.9 cm
diam. I.D. by 16.5 cm high, one end closed, the other open) filled
with approximately 80 g of toxicant-containing matrix. This leaves
approximately 5 cm height of open space on the open end of the
tubing. Six layers of 9 holes (0.238 mm diameter) were pre-drilled
in the side of the tubing.
[0100] 3. Monitoring. Wooden stakes (3.4 cm by 3.4 cm by 30 cm)
were driven 2-25 cm into the ground. Once infested by termites, the
wooden stake was gently pulled out of the soil, leaving a hole of
ca. 3.4 cm by 3.4 cm and 20-25 cm deep. A station housing was
inserted into the hole. Termites were extracted from the infested
stakes and placed into the open space (5 cm high by 2.9 cm
diameter) on the open end of the toxicant bait station. The
extracted termites were forced to tunnel through the
toxicant-containing matrix to return to the colony, and to recruit
nestmates into the station housing. To compare the efficacy of
self-recruiting procedure in enhancing the toxicant intake, this
self-recruiting procedure was omitted in some station housings.
Station housings were checked monthly. The amount of matrix
consumed by termites from each station was subjected to the
analysis of variance using a completely randomized design
(P<0.05) to determine the significant difference in matrix
consumption between stations with the self-recruiting procedure and
those without
[0101] Results:
[0102] Experiment 1. The foraging population of this R. flavipes
colony was estimated at 476,000 in September. Infestations by this
colony were found in the door and door-frame of a nearby building.
Wood weight loss from the three monitoring devices was
approximately 2 g/station/day during the summer. The activity
declined during the winter to approximately 0.5 g/station/day.
Three bait tubes were introduced in February. By April, no termite
activity was found in any of the station housings. A total of 26 g
of toxicant-containing matrix was consumed by this termite colony.
The amount of active ingredient (AI) consumed was 3.87 mg. Because
of the absence of termite activity after April, it was concluded
that the entire colony of over 400,000 termites was eliminated by
the consumption of 3.87 mg hexaflumuron within two months.
[0103] Experiment 2. The foraging population of this R. flavipes
colony was estimated at 730,000 in September. This colony was
located in a non-residential area. Termite infestations were found
in trees and fallen logs of pine and oaks. From September through
the following spring, wood weight loss from the six monitoring
devices was approximately 2 g/station/day. Starting in April,
eleven station housings were used to deliver toxicant-containing
matrix. In June, termites maintained the activity level of 1.8
g/station/day. By July, however, the activity was reduced to 0
g/station/day. During the three months (April-June) baiting period,
a total of 122 g toxicant-containing matrix and 20 mg AI was
consumed. No termite activity was recorded in this location after
July. We conclude the 730,000 termites were eliminated by consuming
20 mg of hexaxflumuron.
[0104] Experiment 3. Structural infestation of this R. flavipes
colony persisted in a two-story building (approximately 1,500 m)
for at least 3 years. Residents reported annual spring swarming
from the structure for five consecutive years. Soil termiticide
treatments had been done by a pest control firm annually since the
erection of the building in 1986. Despite the soil termiticide
treatments, the foraging population of this R. flavipes was
estimated at 2,847,000 in May. Foraging territory was approximately
1,782 m.sup.2. Mean wood weight loss from the 13 station housings
with monitoring devices ranged 2-4 g/station/day. Following the
introduction of toxicant-delivery devices at 27 stations in August,
the activity was reduced to 0.1 g/station/day in September.
Termites, however, remained active in stations in October and
November. By December, no termite activity was detected from any of
the stations. During the four month toxicant-delivery period
(August-December), a total of 2,997 g toxicant-containing matrix
and 1,539 mg AI was consumed by this R. flavipes colony. Residents
of the building reported that this was the first time within the
last five years that they did not see the termites swarming. No
soil termiticide treatment was done the following year. In March of
the following year, termites were collected in one of the
monitoring devices. Because no dyed termites were found from this
collection, we speculated that a nearby colony might have migrated
into the territory of the baited colony. A mark-recapture program
conducted in March-April estimated 260,000 foraging termites in
this new colony. Assuming this is the remaining of the original
colony, the toxicant-delivery program conducted in August-December
had eliminated over 25 million termites.
[0105] Experiment 4. Foraging activity of this C. formosanus colony
has been monitored in an 11-story high rise. Numerous soil
termiticide treatments were done to prevent structural infestation
by this C. formosanus colony. Foraging population was estimated at
1,047,000 in September. The foraging territory extended to 1,614
m.sup.2. Mean wood weight loss was 2-4 g/station/day. Foraging
activity typically declined in winter but often peaked during
summer months (5-10 g/station/day). Five toxicant-delivery devices
were introduced in April. The foraging activity was reduced to less
than 2 g/station/day, and remained at the same low level until
October. By November, no termites were found in the stations, but
slight feeding activity was observed in a few stations until
February. During the toxicant-delivery program (April-February),
847 g of toxicant-containing matrix and 233 mg AI were consumed by
this C. formosanus colony. We concluded the colony of 1.0 million
termites was eliminated after consuming 233 mg of hexaflumuron over
a 10-month period.
[0106] Experiment 5. Despite repeated soil termiticide treatments
and a fumigation following the discovery of structural infestations
by this C. formosanus colony in a high rise, foraging activity
remained strong (mean wood weight loss: 6-10 g/station/day).
Activity of this colony did not decline even in winter months.
Foraging population was estimated at 2,431,000 in March. Over 90%
of the toxicant-containing matrix of stations introduced in May was
consumed within a month. Foraging activity in May-July was slightly
reduced (5 g/station/day). Subsequently, the mean wood weight loss
was further reduced to near zero in July-October. After November,
no termite activity has been recorded in any of the stations.
During the 6-month toxicant-delivery period (May-November), a total
of 89 station housings with toxicant-delivery devices were used. We
concluded that the colony of 2.4 million termites was eliminated by
the consumption of 742 mg hexaflumuron.
[0107] Experiment 6. Infestations by this C formosanus colony were
found in the utility room of a high rise. Foraging activity was
detected along the front yard of this building. The foraging
territory extended up to 185 m from one end to the other. This C.
formosanus colony consumed wood at a rate of approximately 5-10
g/station/day from 10 stations. The foraging population was
estimated at 1,225,000 in April. Following the introduction of
toxicant-delivery devices in July, foraging activities steadily
declined to near zero in October. After October, slight termite
activity (<1 g/station/day) remained in one station. Using
termites collected from this station, we conducted a mark-recapture
program in March and estimated 104,000 termites in the remaining
colony. A total of 42 stations were used during the 5-month
toxicant-delivery period (July-December), from which 1,182 g of
toxicant-containing matrix and 259 g AI were consumed. We concluded
the 259 mg of hexaflumuron reduced the population size of this
colony from 1.2 million termites in April to 104,000 the following
March.
EXAMPLE 9
Effects of the Self-Recruiting Procedure on Toxicant Bait
Consumption
[0108] Significantly more (P<0.05) toxicant-containing matrix
was consumed from station housings that received termites collected
from the monitoring devices (referred to as "self-recruited" bait
stations) than stations that were simply placed in the holes from
which infested devices were pulled ("not self-recruited" bait
stations). In one experiment, the mean weight of
toxicant-containing matrix consumed by C. formosanus from
self-recruited stations was 35.8 g/station while those of not
self-recruited stations was 6.5 g/station. With R. flavipes, the
mean weight of consumed toxicant-containing matrix was 39.2 and
17.2 gestation for self-recruited stations and not self-recruited
stations, respectively.
[0109] When more than 1% of the toxicant-containing matrix was
consumed from a station housing, the station was considered
attacked by termites. Using this criteria, 83% of self-recruited
stations were attached by C formosanus, while only 59.3% of not
self-recruited stations were attacked. With R. flavipes, the attack
rate for self-recruited stations was 94.7%, while 75% of the not
self-recruited stations were attacked.
[0110] It should be understood that the examples and embodiments
described herein are for illustrative purposes only and that
various modifications or changes in light thereof will be suggested
to persons skilled in the art and are to be included within the
spirit and purview of this application and the scope of the
appended claims.
* * * * *