Note: Descriptions are shown in the official language in which they were submitted.
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DIATOMACEOUS EARTH INTERMIXED WITH A COLOURING AGENT, AND
SPRAY APPARATUSES, USES, AND METHODS INVOLVING SAME
BACKGROUND
1. Field
The invention relates generally to insect population control, and more
particularly to
spray apparatuses, uses of diatomaceous earth, and methods of controlling
insect
populations.
2. Related Art
Many insects, such as the insects commonly known as "bedbugs" for example,
have
become pests in many parts of the world. A bedbug infestation of a building,
for
example, can be very costly, because often furniture must be destroyed and
replaced in order to remove bedbugs from the building. Further, in the case of
some
institutions such as hotels for example, closing large parts or all of the
hotel for
bedbug pest removal can result in significant loss of revenue.
Some known methods of controlling bedbug populations involve using synthetic
pesticides, but some pesticides may be harmful to humans and to other life.
Other
known methods of controlling bedbug populations include applying diatomaceous
earth, a naturally occurring siliceous sedimentary rock that includes
fossilized
remains of diatoms.
However, known methods of applying diatomaceous earth can be cumbersome. For
example, known methods of applying diatomaceous earth may undesirably require
handling the diatomaceous earth, for example to transfer the diatomaceous
earth
from a container not having an applicator to a separate applicator apparatus.
Also,
known applicator apparatuses may apply diatomaceous earth unevenly, which may
be wasteful or ineffective. In general, known methods of applying diatomaceous
CA 02847388 2014-03-21
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earth may be sufficiently complex so as to require professional involvement,
which
may undesirably add to cost and delay of bedbug treatment.
Also, numerous types of diatomaceous earth are available, and different types
of
diatomaceous earth vary widely and significantly from each other. It has been
estimated that there are approximately 100,000 extant diatom species, and some
diatomaceous earth may also include diverse combinations of one or more diatom
species and may also include extinct species in addition to the number of
extant
species. Diatom skeletons (which may also be referred to as "frustules") may
vary
widely and significantly in size and shape across a very large number of
diatom
species. Also, different insect species have different bodies that may be
affected
significantly differently by different types of diatomaceous earth. Therefore,
many
varieties of diatomaceous earth are available, and a variety of diatomaceous
earth
that is effective at controlling a population of one type of insect may not be
as
effective, or effective at all, at controlling a population of another type of
insect.
SUMMARY
According to one illustrative embodiment, there is provided a spray apparatus
comprising: a means for holding contents comprising diatomaceous earth and a
compressed propellant for propelling the diatomaceous earth from the means for
holding; and a means for controllably releasing the propellant and the
diatomaceous
earth propelled by the propellant from the means for holding.
According to another illustrative embodiment, there is provided a spray
apparatus
comprising: a body defining a reservoir holding contents comprising
diatomaceous
earth and a compressed propellant for propelling the diatomaceous earth from
the
reservoir; and an actuator for controllably releasing the propellant and the
diatomaceous earth propelled by the propellant from the reservoir.
According to another illustrative embodiment, there is provided use of
diatomaceous
earth to control a population of bedbugs, wherein the diatomaceous earth
comprises
remains of pennate diatoms.
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According to another illustrative embodiment, there is provided use of
diatomaceous
earth to control a population of Cimicidae, wherein the diatomaceous earth
comprises remains of pennate diatoms.
According to another illustrative embodiment, there is provided use of
diatomaceous
earth to control a population of Cimex, wherein the diatomaceous earth
comprises
remains of pennate diatoms.
According to another illustrative embodiment, there is provided use of
diatomaceous
earth to control a population of Cimex lectularius, wherein the diatomaceous
earth
comprises remains of pennate diatoms.
According to another illustrative embodiment, there is provided a method of
controlling a population of bedbugs, the method comprising exposing the
bedbugs to
diatomaceous earth comprising remains of pennate diatoms.
According to another illustrative embodiment, there is provided a method of
controlling a population of Cimicidae, the method comprising exposing the
Cimicidae
to diatomaceous earth comprising remains of pennate diatoms.
According to another illustrative embodiment, there is provided a method of
controlling a population of Cimex, the method comprising exposing the Cimex to
diatomaceous earth comprising remains of pennate diatoms.
According to another illustrative embodiment, there is provided a method of
controlling a population of Cimex lectularius, the method comprising exposing
the
Cimex lectularius to diatomaceous earth comprising remains of pennate diatoms.
According to another illustrative embodiment, there is provided a method of
controlling a population of insects, the method comprising causing a
compressed
propellant to propel diatomaceous earth on a surface.
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According to another illustrative embodiment, there is provided a method of
manufacturing a spray apparatus, the method comprising adding a smaller size
fraction of diatomaceous earth to the spray apparatus.
According to another illustrative embodiment, there is provided a method of
preparing diatomaceous earth for use in controlling a population of insects,
the
method comprising size separating the diatomaceous earth into a smaller size
fraction and into a larger size fraction.
According to another illustrative embodiment, there is provided a method of
preparing diatomaceous earth for use as a pesticide, the method comprising
intermixing a colouring agent with the diatomaceous earth.
According to another illustrative embodiment, there is provided a furniture
apparatus
comprising a surface and comprising diatomaceous earth applied to the surface,
wherein the diatomaceous earth comprises remains of pennate diatoms.
Other aspects and features of the present invention will become apparent to
those
ordinarily skilled in the art upon review of the following description of
illustrative
embodiments in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Figure 1 is a cross-sectional view of a spray apparatus according to
one
illustrative embodiment;
Figures 2 to 5 are secondary electron images of diatomaceous earth known as
CELATOMTm MN-51;
Figure 6 is a Rietveld refinement plot of the diatomaceous earth known
as
CELATOMTm MN-51;
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Figure 7 is a graph of particle size distribution of the diatomaceous
earth known
as CELATOMTm MN-51;
Figure 8 is a secondary electron image of diatomaceous earth known as
CELATOMTm MN-53;
Figure 9 is a Rietveld refinement plot of the diatomaceous earth known as
CELATOM-rm MN-53;
Figure 10 is a secondary electron image of diatomaceous earth known as
AlpineTM
Dust;
Figure 11 is a Rietveld refinement plot of the diatomaceous earth known
as
Alpine TM Dust;
Figure 12 is a secondary electron image of diatomaceous earth known as
MotherEarthTM D;
Figure 13 is a Rietveld refinement plot of the diatomaceous earth known
as
MotherEarth TM D;
Figure 14 is a graph of particle size distribution of the diatomaceous
earth known
as MotherEarthTm D;
Figures 15 to 17 are secondary electron images of diatomaceous earth known as
PRO-ACTIVE TM ;
Figure 18 is a Rietveld refinement plot of the diatomaceous earth known
as PRO-
ACTIVE TM ;
Figure 19 is a scanning electron microscope image of a smaller size
fraction of the
diatomaceous earth known as CELATOMTm MN-51; and
Figure 20 is a scanning electron microscope image of a larger size
fraction of the
diatomaceous earth known as CELATOMTm MN-51.
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DETAILED DESCRIPTION
A. Spray Apparatus
Referring to Figure 1, a spray apparatus according to one illustrative
embodiment is
shown generally at 100. United States Patent Nos. 6,394,321 and 6,581,807
describe aerosol containers that may be suitable for spraying powder, and in
some
embodiments the spray apparatus 100 may be similar to one of the aerosol
containers described and illustrated in United States Patent Nos. 6,394,321
and
6,581,807 or to other aerosol containers that may be suitable for spraying
powder.
The spray apparatus 100 in the embodiment shown includes a body 102 defining a
reservoir 104 therein. The body 102 may include a steel can, and the body 102
in
the embodiment shown is thus a rigid container. Alternative embodiments may
include or other material suitable, such as other rigid containers for
example, for
holding pressurized air. For example, the body 102 in one embodiment may be a
steel can having a size known to one skilled in the art as "202x509" (or 2-2
inches
16
in diameter and 5-9 inches in height, or about 5.4 centimetres ("cm") in
diameter
16
and about 14.1 cm in height) and having an inner epoxy coating, and which may
be
sized so that the reservoir 104 holds 170 grams of contents 106. The body 102
thus
holds the contents 106, although alternative embodiments may include different
structures to hold the contents 106. For example, in some embodiments, the
body
102 may include a tin-plated steel can with a protective liner.
In the embodiment shown, the contents 106 include diatomaceous earth 108 and a
propellant, which in some embodiments may be a mixture of isobutane and
propane
known to one skilled in the art as propellant A-46, and which in some
embodiments
may include about 75% isobutane and about 25% propane. In other embodiments,
the propellant may be a liquefied petroleum gas known to one skilled in the
art as
propellant blend A-70 available from Brenntag Canada Inc. of Toronto, Ontario,
Canada. In the embodiment shown, the propellant is in a gaseous phase 110, and
'
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also in a liquid phase 112 intermixed with the diatomaceous earth 108.
Further, the
contents 106 in the embodiment shown include an unmatured anhydrous alcohol
114 intermixed with the diatomaceous earth 108. The alcohol 114 may be
denatured
with fragrance, resin, a product known as BITREXTm, or another product for
example. The alcohol 114 may include an alcohol known to one skilled in the
art as
SD-40 or SDAG-6, for example. In some embodiments, such alcohol 114 may
evaporate generally rapidly one sprayed from the spray apparatus 100, thereby
leaving dried diatomaceous earth 108 on a surface (not shown) sprayed by the
spray apparatus 100.
In the embodiment shown, the alcohol 114 is about 54% by weight of the
contents
106, the propellant is about 38% by weight of the contents 106, and the
diatomaceous earth 108 is about 8% by weight of the contents 106. In other
embodiments, the diatomaceous earth 108 may be at least 3% by weight of the
contents 106, at least 5% by weight of the contents 106, or at least 7% by
weight of
the contents 106, for example, and in such embodiments the propellant may be
more than about 38% by weight of the contents 106 and/or the alcohol 114 may
be
more than about 54% by weight of the contents 106.
In still other embodiments, products other than diatomaceous earth, such as
other
products that may be effective to control bedbug populations or more generally
as
an insecticide or pesticide for example, may be intermixed with the
diatomaceous
earth 108. For example, United States Patent No. 8,101,408 describes various
legume extracts, such as one or more of PA1b-related peptides, terpenoid
saponins,
triterpenoid saponin, soyasaponin I, soyasaponin II, soyasaponin III,
soyasaponin VI,
dehydrosoyasaponin I, echinocystic acid 3-glucoside, glycyrrhizic acid,
hederacoside
C, beta-escin, alpha-hederin, and other acetic acid precipitated insecticidal
components. In various embodiments, such legume extracts may be intermixed
with
the diatomaceous earth 108, and in such embodiments the propellant may be less
than about 38% by weight of the contents 106 and/or the alcohol 114 may be
less
than about 54% by weight of the contents 106.
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One skilled in the art will appreciate that the contents 106 need not be
exactly in the
aforementioned proportions, that the spray apparatus 100 may function
similarly with
more or less of those components, and that "about" in this context means
refers to
variations of the aforementioned proportions that allow the spray apparatus
100 to
function with similar results.
The spray apparatus 100 also includes an aerosol valve assembly shown
generally
at 116 and including a tube 118, a valve housing 120 receiving the tube 118 at
the
bottom of the valve housing 120, a valve-closing coil spring 122, and a valve
body
124 having a hollow valve stem 126 defining lateral openings 128 extending
into the
interior of the valve stem 126. A gasket 130 surrounds the valve stem 126 and
seals
the openings 128 when the aerosol valve is closed. An actuator 132 is attached
to
the top of the valve stem 126 such that an outlet nozzle 134 of the actuator
132 is in
fluid communication with the interior of the valve stem 126.
Further, the reservoir 104 includes a ball bearing or marble 136 to facilitate
mixing the
contents 106 when the spray apparatus 100 is shaken. For example, in one
embodiment, the spray apparatus 100 may be shaken for about 8 to about 10
seconds, or vigorously for about 10 seconds, to achieve desirable mixing of
the
contents 106 before the contents 106 are sprayed from the spray apparatus 100.
One skilled in the art will appreciate numerous variations from the spray
apparatus
100. For example, alternative embodiments may include various alternative
cans,
valves, and actuators. For example, one embodiment may include a valve
suitable for
power and coated on a top side to prevent rusting, such as a valve known to
one
skilled in the art as Prec. powder valve S.2X.020 Ringed Barb 630 (OAL) (04-
0519-42)
G.Hex Buna B175 B.080x.030VT 412 Deep MC con. Epon Top Lam. Bot dimp. DT
138mm A-D, and an actuator known to one skilled in the art as Act. .025" NMBU
Raised APSL .022 White (21-9116-00-0343). Various embodiments may also include
a
cap (not shown) to protect the actuator from being actuated unintentionally,
such as
during shipping for example. Alternative embodiments may also include
different
contents, such as different propellants for example.
,
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Some embodiments of the spray apparatus 100 or alternative embodiments may be
prepared by a batch process. The description below is one example of a
manufacturing process for 1,000 kilograms of formulated product. First, 540
kilograms of anhydrous ethyl alcohol is held in a clean and dry stainless
steel tank,
and 80 kilograms of diatomaceous earth powder is then added slowly (to avoid
clumping) to the anhydrous ethyl alcohol under medium mixing using an air
mixer
until homogeneous to form a bulk concentrate of 620 kilograms. The mixing may
require about 15 minutes. Then, portions of the bulk concentrate are metered
through a filter into aerosol containers at a temperature between 68 F (about
20 C)
and 73 F (about 22.8 C). For an aerosol container having a size known to one
skilled in the art as "211x604" (or 21-1 inches in diameter and 6-4 inches in
height,
16 16
or about 6.8 cm in diameter and about 15.9 cm in height), 186 grams of bulk
concentrate may be added, and for an aerosol container having a size known to
one
skilled in the art as "211x713" (or 2-11 inches in diameter and 7-1-3 inches
in height,
16 16
or about 6.8 cm in diameter and about 19.8 cm in height), 248 grams of bulk
concentrate may be added.
Each aerosol container may then be fitted with an aerosol valve and subjected
to a
vacuum at 15 inches of mercury (about 50.8 kilopascals) to 20 inches of
mercury
(about 67.7 kilopascals). The propellant (A-70 in this example) may then be
metered
under pressure into each aerosol container at a temperature between 65 F
(about
18.3 C) and 70 F (about 21.1 C) and at a pressure of 600 pound-force per
square
inch gauge (about 4,238 kilopascals) to 650 pound-force per square inch gauge
(about 4,583 kilopascals), and each aerosol container may be then crimped
shut.
For an aerosol container having a size known to one skilled in the art as
"211x604"
(or 21-1 inches in diameter and 6-4 inches in height, or about 6.8 cm in
diameter
16 16
and about 15.9 cm in height), 114 grams of propellant may be added, and for an
,
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aerosol container having a size known to one skilled in the art as "211x713"
(or 21--1
16
inches in diameter and 7-13 inches in height, or about 6.8 cm in diameter and
about
16
19.8 cm in height), 152 grams of propellant may be added.
The aerosol containers may then be placed in a hot water bath of 130 F (about
54 C) to 140 F (about 60 C) for about 30 seconds to test the strength of the
aerosol
containers. An outer cap, a label, and lot number may then be placed on each
aerosol container, and the aerosol containers may be packaged in boxes for
distribution. The label may include precautionary information, such as
markings not
to use the aerosol container in the presence of an open flame or a spark, or
while
smoking, a warning that the aerosol container may explode if heated, a warning
not
to expose to temperatures above 50 C or 122 F, and a warning not puncture or
incinerate for example.
In operation, when the actuator 132 is pressed towards the body 102 against
the
force of the spring 122, the openings 128 pass below the gasket 130 to open
controllably the openings 128 and thus controllably allow the contents 106
pass
through the tube 118, through the openings 128, into the valve stem 126, into
the
actuator 132, and to be sprayed out the nozzle 134 under pressure from the
propellant. When the actuator 132 is released, the spring 122 urges the valve
stem
126 to the a position where the openings 128 are blocked by the gasket 130 to
close
the aerosol valve and prevent the contents 106 from entering into the valve
stem
under pressure from the propellant. Therefore, the nozzle 134 may controllably
release the propellant, and the diatomaceous earth 108 propelled by the
propellant,
from the reservoir 104.
B. Diatomaceous Earth Products
Numerous types of diatomaceous earth are available and vary, for example, on
the
sizes, shapes, and species of diatoms that contributed to the diatomaceous
earth.
,
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l. CELATOMTm MN-51
The diatomaceous earth 108 in some embodiments may include CELATOMTm MN-
51, which is available from EP Minerals, LLC of 9785 Gateway Drive, Suite
1000,
Reno, Nevada, United States of America. The diatomaceous earth known as
CELATOMTm MN-51 is believed to be a food-grade diatomaceous earth that
originates from a deposit formed from fresh-water diatoms at Clark Station,
Nevada,
United States of America, and that may be heat-treated or flash dried at about
900 F
(about 480 C) or at other temperatures, for example. In one embodiment, flash
drying diatomaceous earth involves heating the diatomaceous earth at about 900
F
(about 480 C) for about 15 seconds.
Figures 2 to 5 are secondary electron images (using a Philips XL-30 scanning
electron microscope after coating with evaporated gold) of the diatomaceous
earth
known as CELATOMTm MN-51. The scale bars in Figures 3 to 5 represent 30
micrometers in those Figures.
The diatomaceous earth known as CELATOMTm MN-51 is believed to have the
properties given in Table 1 below.
Table 1: Properties of CELATOMTm MN-51.
Structure Natural
Color Beige
G.E. Brightness 75
Sieve Analysis (Tyler) 6.5
% + 325 Mesh (>44 microns)
Median Particle Diameter (microns) 15.0
pH (10% slurry) 7.5
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Free Moisture
(Maximum % H20) Less than 5.0
(Typical % H20) 3.0
Density (1b/ft3) (g/l)
Wet Bulk 24 385
Dry Bulk 11 176
Specific Gravity 2.00
Refractive Index 1.46
Oil Absorption (ASTM F 726-81) % by weight 150
=
Water Absorption (ASTM F 726-81) % by weight 165
Chemical Analysis
Si02 73.6%
A1203 7.8%
Fe203 1.8%
CaO 5.6%
MgO 0.3%
Other Oxides 2.3%
Loss on Ignition 5.5%
A sample of the diatomaceous earth known as CELATOMTm MN-51 was reduced in
size to less than 10 micrometers for quantitative X-ray analysis by grinding
under
ethanol in a vibratory McCrone Micronising Mill for seven minutes. Step-scan X-
ray
powder-diffraction data were collected over a range 3-80 20 with CoKa
radiation on
a Bruker D8 Focus Bragg-Brentano diffractometer equipped with an Fe
monochromator foil, 0.6 mm (0.3 ) divergence slit, incident- and diffracted-
beam
'
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SoIler slits, and a LynxEye detector. The long fine-focus Co X-ray tube was
operated
at 35 kV and 40 mA, using a take-off angle of 6 .
The X-ray diffractograms were analyzed using the International Centre for
Diffraction
Database PDF-4 and Search-Match software by Siemens (Bruker). X-ray powder-
diffraction data of the sample were refined with Rietveld program Topas 4.2
(Bruker
AXS). Figure 6 is a Rietveld refinement plot of the diatomaceous earth known
as
CELATOMTm MN-51. Figure 6 shows observed intensity at each step and a
calculated pattern, and the line below the graph shows the difference between
the
observed and calculated intensities. The other lines in the graph show
individual
diffraction patterns of all phases, and the vertical bars represent positions
of all
Bragg reflections. The amounts given on Figure 6 are renormalized amorphous-
free.
The sample contained abundant montmorillonite, which exhibits stacking
disorder,
so the crystal structure is not predictable. An empirical model was used to
account
for this phase. In addition, the contribution of amorphous silica was modeled
with a
peak phase and its amount estimated. The results may be considered semi-
quantitative and are in Table 2 below.
Table 2: Results of phase analysis of CELATOMTm MN-51 by Rietveld
refinements.
Mineral Ideal Formula
Percent by Weight
Quartz a-Si02
2
Plagioclase NaAlSi308 ¨ CaAl2Si208
18
Kaolinite Al2S1208(OH)4
1
Montmorillonite (Na, Ca)0.3(Al, Mg)2S14010(OH)2. n H20
46
Amorphous Silica Si02.nH20
33
Particle sizes of sample of the diatomaceous earth known as CELATOMTm MN-51
were measured in a MastersizerTM 2000 in a water dispersant, and Figure 7 is a
,
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graph of particle size distribution of the diatomaceous earth known as
CELATOMTm
MN-51.
2. CELATOMTm MN-53
In an alternative embodiment, the diatomaceous earth may include diatomaceous
earth known as CELATOMTm MN-53, which is also available from EP Minerals, LLC
of 9785 Gateway Drive, Suite 1000, Reno, Nevada, United States of America.
Figure
8 is a secondary electron image (using a Philips XL-30 scanning electron
microscope after coating with evaporated gold) of the diatomaceous earth known
as
CELATOMTm MN-53. The diatomaceous earth known as CELATOMTm MN-53 is
believed to have the properties given in Table 3 below.
Table 3: Properties of CELATOMTm MN-53.
Structure Natural
Color Beige
G.E. Brightness 65
Sieve Analysis (Tyler) 5.0
% + 325 Mesh (>44 microns)
Median Particle Diameter (microns) 14.0
pH (10% slurry) 7.0
Free Moisture
(Maximum % H20) Less than 5.0
(Typical A) H20) 3.0
Density (Ib/ft3) (g/l)
Wet Bulk 31 500
Dry Bulk 11 175
'
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Specific Gravity 2.00
Refractive Index 1.46
Oil Absorption (ASTM F 726-81) % by weight 150
Water Absorption (ASTM F 726-81) % by weight 165
Chemical Analysis
Si02 83.7%
A1203 5.6%
_
Fe203 2.3%
Ca0 0.9%
MgO 0.3%
Other Oxides 1.9%
Loss on Ignition 5.0%
Figure 9 is a Rietveld refinement plot of the diatomaceous earth known as
CELATOMTm MN-53 obtained as described above for Figure 6. Figure 9 shows
observed intensity at each step and a calculated pattern, and the line below
the
graph shows the difference between the observed and calculated intensities.
The
other lines in the graph show individual diffraction patterns of all phases,
and the
vertical bars represent positions of all Bragg reflections. The amounts given
on
Figure 9 are renormalized amorphous-free. The results of phase analysis of
CELATOMTm MN-53 by Rietveld refinements are in Table 4 below.
,
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Table 4: Results of phase analysis of CELATOMTm MN-53 by Rietveld
refinements.
Mineral Ideal Formula
Percent by Weight
Quartz a-Si02
2
Plagioclase NaAlSi308¨ CaAl2Si208
24
Kaolinite Al2Si208(OH)4
2
Montmorillonite (Na,Ca)0.3(AI,Mg)2Si4010(OH)2.nH20
40
Amorphous Silica Si02.nH20 31
3. Alpine TM Dust
Figure 10 is a secondary electron image (using a Philips XL-30 scanning
electron
microscope after coating with evaporated gold) of diatomaceous earth known as
AlpineTm Dust ("Prescription Treatment Brand") obtained from Whitmire Micro-
Gen
Research Laboratories, Inc. of St. Louis, Missouri, United States of America,
and
Figure 11 is a Rietveld refinement plot of the diatomaceous earth known as
Alpine TM
Dust obtained as described above for Figure 6. Figure 11 shows observed
intensity
at each step and a calculated pattern, and the line below the graph shows the
difference between the observed and calculated intensities. The other lines in
the
graph show individual diffraction patterns of all phases, and the vertical
bars
represent positions of all Bragg reflections. The amounts given on Figure 11
are
renormalized amorphous-free. The results of phase analysis of AlpineTM Dust by
Rietveld refinements are in Table 5 below.
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Table 5: Results of phase analysis of Alpine TM Dust by Rietveld refinements.
Mineral Ideal Formula
Percent by Weight
Quartz a-Si02 1
Plagioclase NaAlSi308 ¨ CaAl2Si208 8
Montmorillonite (Na,Ca)0,3(AI,Mg)2Si4010(OH)2.nH20
38
Amorphous Silica Si02.nH20 53
4. MotherEarth TM D
Figure 12 is a secondary electron image (using a Philips XL-30 scanning
electron
microscope after coating with evaporated gold) of diatomaceous earth known as
MotherEarthTM D obtained from Whitmire Micro-Gen Research Laboratories, Inc.
of
St. Louis, Missouri, United States of America, and Figure 13 is a Rietveld
refinement
plot of the diatomaceous earth known as MotherEarthTM D obtained as described
above for Figure 6. Figure 13 shows observed intensity at each step and a
calculated pattern, and the line below the graph shows the difference between
the
observed and calculated intensities. The other lines in the graph show
individual
diffraction patterns of all phases, and the vertical bars represent positions
of all
Bragg reflections. The amounts given on Figure 13 are renormalized amorphous-
free. The results of phase analysis of MotherEarthTM D by Rietveld refinements
are
in Table 6 below.
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Table 6: Results of phase analysis of MotherEarthTM D by Rietveld
refinements.
Mineral Ideal Formula
Percent by Weight
Quartz a-Si02 1
Plagioclase NaAlSi308¨ CaAl2Si208 9
Montmorillonite (Na,Ca)0.3(AI,M9)2Si4010(OH)2.nH20
47
Amorphous Silica Si02.nH20
43
Particle sizes of sample of the diatomaceous earth known as MotherEarthTM D
were
measured in a MastersizerTM 2000 in a water dispersant, and Figure 14 is a
graph of
particle size distribution of the diatomaceous earth known as MotherEarthTM D.
5. PRO-AC TIVETm
Figures 15 to 17 are secondary electron images (using a Philips XL-30 scanning
electron microscope after coating with evaporated gold) of diatomaceous earth
known as PRO-ACTIVETm obtained from Pest Control Direct Ltd., Hailsham, East
Sussex, United Kingdom, and Figure 18 is a Rietveld refinement plot of the
diatomaceous earth known as PRO-ACTIVETm obtained as described above for
Figure 6. Figure 18 shows observed intensity at each step and a calculated
pattern,
and the line below the graph shows the difference between the observed and
calculated intensities. The other lines in the graph show individual
diffraction
patterns of all phases, and the vertical bars represent positions of all Bragg
reflections. The amounts given on Figure 18 are renormalized amorphous-free.
The
results of phase analysis of PRO-ACTIVETm by Rietveld refinements are in Table
7
below.
=
CA 02847388 2014-03-21
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Table 7: Results of phase analysis of PRO-ACTIVETm by Rietveld refinements.
Mineral Ideal Formula
Percent by Weight
Quartz a-Si02 6
Plagioclase NaAlSi308 ¨ CaAl2Si208 5
Alunite K2A18(SO4)4(OH)12 <1
Jarosite K2Fe83+(SO4)4(OH)12 2
Anatase TiO2 <1
K-feldspar KAISi308 1
Illite/Muscovite Ko.65Al2.0A10.65Si3.38010(OH)2 7
Kaolinite Al2Si205(OH)4 1
Montmorillonite (Nle,Ca)0.3(A17M9)2Si4010(OH)2.nH20 50
Amorphous Silica Si02.nH20 27
C. Experiments
Experiment #1
In one experiment ("Experiment #1"), small plastic Petri dishes available from
Gelman SciencesTM, each about 5.0 cm or about 2.0 inches in diameter, were
used
in bioassays. A small opening of about 1.5 cm (or about 0.6 inches) in
diameter was
cut in the lid and closed with a piece of gauze to allow air for bedbug
breathing. The
Petri dishes were lined with a filter paper about 4.25 cm (or about 1.7
inches) in
diameter. Diatomaceous earth was weighed and spread uniformly over the filter
paper with forceps. Ten adult field-collected common bedbugs (Cimex
lectularius)
were introduced in each of the Petri dishes, and the lids were placed over
them to
prevent their escape. Petri dishes were transferred in a plastic box lined
with paper
towels sprayed with water to maintain humidity in the box. Experiments were
conducted at room temperature, and mortality was noted 24, 48, 72, and 96
hours
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after the bedbugs were introduced into of the Petri dishes. Four
concentrations,
between about 0.5 milligrams ("mg") and about 2.0 mg, were used to calculate a
lowest lethal concentration sufficient to kill 50% of the bedbugs ("LC50") of
each
product. There was a single replication of 10 bedbugs each.
Tables 8 and 9 below show mortality data from Experiment #1, where "L" refers
to a
number of bedbugs still living after a corresponding time given in the tables,
and
where "D" refers to a number that died after the time given.
Table 8: Toxicity of adult bedbugs to CELATOMTm MN-51.
Amount of CELATOMTm MN-51
Time 2.0 mg 1.0 mg 0.8 mg 0.5 mg
(hours) L D L D L D L D
48 0 10 3 7 4 6 5 5
72 1 0 3 0 4 0 5
Table 9: Toxicity of adult bedbugs to CELATOMN MN-53.
Amount of CELATOM TM MN-53
Time 2.0 mg 1.0 mg 0.8 mg 0.5 mg
(hours) L D L D L D L D
48 6 4 9 1 7 3 8 2
72 6 4 9 1 7 3 8 2
96 0 10 4 6 6 4 7 3
All of the bedbugs died in CELATOM Tm MN-51 diatomaceous earth after 48 hours.
Therefore, LC50 for CELATOMTm MN-51 was calculated for 48 hours only, and LC50
after 48 hours for CELATOM Tm MN-51 was calculated as 0.7 mg. The data after
48
,
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hours for CELATOM Tm MN-53 were not good for calculation, and therefore LC50
for
CELATOM TM MN-53 was calculated after 96 hours as 0.8 mg (0.552-1.052).
Experiment #2
In another experiment ("Experiment #2"), mortality of CELATOMTm MN-51 was
compared with the diatomaceous earth products known as AlpineTM Dust,
MotherEarthTM D, and PRO-ACTIVETm. The various products were applied with
forceps and weighed on a small filter paper, which was then placed in a Petri
dish
(about 5.0 cm or about 2 inches diameter). Common bedbugs (Cimex lectularius)
were introduced in the various Petri dishes, and mortality was assessed in
each of
the Petri dishes after 24 hours and after 48 hours. Four to five
concentrations of
each product were used, the concentrations ranging from 0.25 mg to 6 mg, and
there were three replications of between 9 and 11 bedbugs (adults or last
instar
nymphs) in each replication. A probit analysis was used to calculate LC50 and
LC95
(lowest lethal concentrations sufficient to kill 95% of the bedbugs) values
and 95%
confidence intervals ("Cls") for the LC50 and LC95 values, as shown in Table
10
below.
Table 10: LC50, LC95, and Cl for CELATOMTm MN-51, AlpineTM Dust, and
MotherEarth TM D.
Product Time LC50 Cl of LC50 LC95 Cl of LC95
(hours) (mg) (mg) (mg) (mg)
CELATOMTm MN-51 24 0.24 0.1-0.32 0.95 0.69-1.98
Alpine TM Dust 24 6.36 3.83-29.27 52.57 15.88-3366
Alpine TM Dust 48 1.72 1.37-2.18 6.6 4.47-13.44
MotherEarth TM D 24 0.26 0.14-0.36 1.37 0.91-3.44
PRO-ACTIVE TM 24 3.2 2.28-5.34 28.8 12.8-
192.4
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Experiment #3
In another experiment ("Experiment #3"), six Petri dishes (each about 5.0 cm
or
about 2.0 inches in diameter) were sprayed with an aerosol including CELATOMTm
MN-51 using an apparatus similar to the spray apparatus 100 shown in Figure 1,
and a thin coating of the CELATOMTm MN-51 remained after drying; those six
Petri
dishes were used for an experimental group. An additional six Petri dishes
(each 5.0
cm or about 2.0 inches in diameter) did not receive the aerosol or the
diatomaceous
earth; those six Petri dishes were used for a control group. Five adult common
bedbugs (Cimex lectularius) were introduced with forceps into each of the 12
Petri
dishes, and lids were applied to prevent the bedbugs from escaping. Mortality
was
assessed 3, 15, 18, and 24 hours after the bedbugs were introduced into the
Petri
dishes, and there was no mortality in the control group. Mortality in the
experimental
group is shown in Table 11 below.
Table 11: Number of bedbugs dead from aerosol including CELATOMTm MN-
51.
Petri dish Number dead Number dead Number dead Number dead
number after 3 hours after 15 hours after 18 hours after 24 hours
1 0 5 5 5
2 0 2 3 5
3 0 5 5 5
4 0 4 5 5
5 0 5 5 5
6 0 3 3 5
Total 0 24 26 30
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Thus, in Experiment #3, all of the bedbugs exposed to the aerosol including
CELATOMTm MN-51 died within 24 hours, whereas none of the control group
bedbugs died within 24 hours.
Experiment #4
Another experiment ("Experiment #4") involved plastic RUBBERMAIDTm translucent
boxes (about 73.6 cm X about 45.7 cm X about 33.7 cm, or about 29 inches X
about
18 inches X about 13.3 inches), more particularly two such boxes as
experimental
boxes and two such boxes as control boxes. A section about 20 cm (or about 7.9
inches) wide in the center of each of the experimental boxes was sprayed with
the
aerosol including CELATOMTm MN-51 and allowed to dry. A piece of a field-
collected sheet (about 50 cm X about 24 cm, or about 19.7 inches X about 7.9
inches) was lined on one side of each of the boxes and used as a stimulant.
The
sheet was collected from a home infested with bedbugs, and had eggs and many
freshly fed bedbugs, but the bedbugs were collected from the sheet before
placing
pieces of the sheet into the boxes. Sides of the boxes opposite the pieces of
the
field-collected sheet were lined with a clean and new piece of cloth. Fifty
adult
common bedbugs (Cimex lectularius) were introduced into each box on the clean
cloth, and then the box was closed with a lid. The control boxes were similar
to the
experimental boxes but did not include the aerosol.
In all four of the boxes, the bedbugs moved from the sides of the boxes having
the
clean cloths to the sides of the boxes having the pieces of the field-
collected sheet.
There was no mortality in the control boxes after 48 hours, but after 24
hours, one of
the experimental boxes had mortality of 43 of the 50 bedbugs, and the other of
the
experimental boxes had mortality of 45 of the 50 bedbugs. All of the bedbugs
in the
experimental boxes died after 48 hours. The bedbugs were found dead lying on
their
backs and dusted with the product from the aerosol.
,
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Experiment #5
Another experiment ("Experiment #5") was the same as Experiment #4 except that
100 common bedbugs (Cimex lectularius) were introduced on the clean piece of
cloth as described for Experiment #4. Insects again moved from one side of the
box
to the other in all cases. There was no mortality in the control boxes,
whereas after
18 hours, 99 bedbugs died in one of the experimental boxes and 98 bedbugs died
in
the other one of the experimental boxes. All of the bedbugs in both
experimental
boxes died after 24 hours.
Experiment #6
In one experiment (Experiment #6), 1.5 mg of diatomaceous earth was placed on
a
piece of filter paper. One adult common bedbug (Cimex lectularius) (the
"treaded
bedbug") was dusted by introducing it on the filter paper using forceps. The
treated
bedbug was then introduced in a Petri dish (about 5.0 cm or about 2.0 inches
in
diameter) containing 4 untreated adult common bedbugs (Cimex lectularius).
Both
CELATOMTm MN-51 and MotherEarthTM D diatomaceous earths were tested using
this method. Control Petri dishes contained five bedbugs, none of which was
dusted
with diatomaceous earth. There were six replications with five bedbugs in
each. Petri
dishes were placed in a plastic box with a lid, and mortality was assessed
after 24
hours, 48 hours, and 96 hours. Table 12 below shows the number of bedbugs dead
in each of the six replications for CELATOMTm MN-51, MotherEarthTM D, and
control
Petri dishes after 24 hours, 48 hours, and 96 hours.
'
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Table 12: Number of bedbugs dead for CELATOMTm MN-51 ("51"),
MotherEarthTM D ("ME"), and control ("C") Petri dishes.
Number Dead After Number Dead After
Number Dead After
Petri 24 Hours 48 Hours 96 Hours
Dish 51 ME C 51 ME C 51 ME C
1 0 0 0 0 0 0 2 3
2
2 0 0 0 0 0 0 5 1
3
3 0 0 0 0 0 0 4 5
1
4 0 0 0 0 0 0 4 4
1
0 0 0 0 0 0 4 1 1
6 1 0 0 1 0 0 4 2
0
Total 1 0 0 1 0 0 23 16
8
Experiment #7
In another experiment (Experiment #7), 2.0 mg of either CELATOMTm MN-51 or
5
MotherEarthTM D diatomaceous earth was mixed with a red fluorescent dust from
a
luminous powder kit #1162A obtained from BioQuip Products Inc., Rancho
Dominguez, California, United States of America and placed on a piece of
filter
paper. One adult common bedbug (Cimex lectularius) was dusted by introducing
it
on the filter paper using forceps. The dusted bedbug was then introduced in a
Petri
dish (about 5.0 cm or about 2.0 inches in diameter) containing 4 untreated
adult
common bedbugs (Cimex lectularius). All Petri dishes were then placed in a
plastic
box with a lid. Control Petri dishes contained five adult common bedbugs
(Cimex
lectularius), none of which has been dusted with diatomaceous earth. There
were
three replications of each condition, and mortality was assessed after 16
hours. The
mortality data are shown in Table 13 below.
,
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Table 13: Number of bedbugs dead after 16 hours for CELATOMTm MN-51,
MotherEarthTM D, and control Petri dishes.
Petri Dish CELATOMTm MN-51 MotherEarthTM D Control
1 3 1 0
2 4 3 0
3 4 2 0
Total 11(61.1%) 6 (33.3%) 0
The fluorescent dye was visibly observed on the bedbugs that did not contact
the
diatomaceous earth directly, suggesting that such bedbugs came into contact
with
diatomaceous earth by contacting the bedbug that had contacted the
diatomaceous
earth directly.
Experiment #8
In another experiment ("Experiment #8"), diatomaceous earth dusts were weighed
on filter paper (FisherTM brand, about 5.5 cm or about 2.2 inches in
diameter). The
filter papers were shaken about 3 or 4 times to remove excess dust and were
weighed again to measure diatomaceous earth remaining on the paper. Table 14
below shows the weight of dust before shaking, the weight of dust remaining
after
shaking, and the amount lost from shaking as the difference between the weight
of
dust before shaking and the weight of dust after shaking.
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Table 14: Weights of dust before shaking, after shaking, and amounts lost
from shaking.
Product Applied Weight before Weight after Amount Lost from
as Dust Shaking (mg) Shaking (mg) Shaking (mg)
PRO-ACTIVE TM 5 1.8 3.2
5.3 2.7 2.6
6 3.1 2.9
mean 5.4 2.5 2.9
Alpine TM Dust 6.6 3.9 2.7
5.3 3.2 2.1
5.5 3.5 2
mean 5.8 3.5 2.3
MotherEarth TM D 6.5 3.4 3.1
6.5 4.3 2.2
6.8 3.7 3.1
mean 6.6 3.8 2.8
Similarly, filter paper was weighed, sprayed with aerosol, dried, and weighed
again
to measure the diatomaceous earth residue. There were three replications for
each
diatomaceous earth sample tested. Table 15 below shows weights of filter paper
before and after spraying aerosol with diatomaceous earth, and amounts of
diatomaceous earth added from spraying.
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Table 15: Weights of filter paper before and after spraying aerosol, and
amounts of diatomaceous earth added from spraying.
Product Applied Weight before Weight after Amount Added
in Aerosol Spray Spraying (mg)
Spraying (mg) from Spraying (mg)
CELATOM TM MN- 164 175
11
51 157.4 173
15.6
162 176 14
mean 161.1 174.7
13.5
CELATOMTm MN- 151.1 152.8
1.7
51 (in reduced 169.4 175.8
6.4
spraying volume)
162 170 8
mean 160.8 166.2
5.4
Experiment #9
In another experiment ("Experiment #9"), a sample of CELATOMTm MN-51 was size-
separated to separate into a smaller size fraction of particles less than
about 11
micrometers in size and into a larger size fraction of particles larger than
about 11
micrometers in size. The CELATOMTm MN-51 sample was size separated in a
centrifuge, and because some particles of CELATOMTm MN-51 are non-spherical,
11 micrometers is an approximate separation size and, for example, the smaller
size
fraction may include elongate particles that are longer than 11 micrometers.
In
general herein, "a smaller size fraction of particles less than about 11
micrometers in
size" may in some embodiments include a smaller size fraction from centrifugal
size
separation that may include elongate particles that are longer than 11
micrometers.
The size-separated powders were examined using a Philips XL-30 scanning
electron
microscope after coating with evaporated gold. Figure 19 is a scanning
electron
,
CA 02847388 2014-03-21
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microscope image of the smaller size fraction (particles less than about 11
micrometers in size) and Figure 20 is a scanning electron microscope image of
the
larger size fraction (particles larger than about 11 micrometers in size). The
scale
bar in Figure 19 represents 30 micrometers, whereas the scale bar in Figure 20
represents 120 micrometers. The original sample of CELATOMTm MN-51 was
reduced in weight by about 30% after the larger size fraction (particles
larger than
about 11 micrometers in size) was removed from it.
Efficacy against bedbugs of the smaller size fraction of CELATOMTm MN-51 and
of
the larger size fraction of CELATOMTm MN-51 was measured in three replications
of
eight adult common bedbugs (Cimex lectularius) each, for a total of 24 bedbugs
introduced. Samples were weighed and spread on filter papers in Petri dishes,
and
the bedbugs were then introduced. Mortality assessed after 24 hours and after
48
hours. Table 16 below shows the number of the initially introduced 24 bedbugs
that
were killed after 24 and after 48 hours when exposed to 1, 2, 4, and 8 mg of
the
smaller size fraction of CELATOMTm MN-51 and of the larger size fraction of
CELATOMTm MN-51.
Table 16: Recorded mortality for size-separated CELATOMTm MN-51 and
unseparated CELATOMTm MN-51.
Smaller Size Fraction of Larger Size Fraction of
CELATOMTm MN-51 CELATOM TM MN-51
Amount Number killed Number killed Number killed Number killed
(mg) after 24 hours after 48 hours after 24 hours after 48 hours
1 8 20 0 0
2 10 21 1 1
4 14 22 2 2
8 15 24 3 3
,
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From the data above, LC50 may be calculated as shown in Table 17 below. Table
17
also shows confidence intervals of LC50 in brackets where the confidence
intervals
were also calculated.
Table 17: LC50 for size-separated CELATOMTm MN-51.
LC50 after 24 LC50 after 48
Sample hours (mg) hours (mg)
Smaller Size Fraction of CELATOMTm MN-51 3.038 0.201
(0.983-13.803) (0.000-0.688)
Larger Size Fraction of CELATOMTm MN-51 50.221 50.221
D. Discussion of Experiments and of Uses of Diatomaceous Earth
In general, and without wishing to be bound by any theory, it is believed that
diatomaceous earth may damage exoskeletons of animals having exoskeletons,
which damage may lead to dehydration and death of the animals. Therefore, it
is
believed that diatomaceous earth, and various apparatuses such as the spray
apparatus 100 as described herein for example, may be effective in the control
of
populations of one or more of animals having exoskeletons, including
arthropods,
arachnids, insects, and bedbugs. Herein, "bedbugs" may refer to common bedbugs
(Cimex lectularius), or more generally to Cimex, or still more generally to
Cimicidae,
for example. Animal populations that may be controlled by diatomaceous earth
in
other embodiments may also include cockroaches, ants, fleas, and other pests.
Herein, "control" of an animal population may in various embodiments include
prevention of growth or survival of such a population before discovery of the
population, and also killing one or more members of such a population after
discovery of the population.
. Also without wishing to be bound by any theory, it is believed that
diatomaceous
earth may additionally or alternatively block or otherwise interfere with
spiracles on
'
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exoskeletons of bedbugs, thereby diminishing or eliminating passage of air
into the
trachea of the bedbugs and potentially asphyxiating the bedbugs.
Experiment #1 appears to indicate that LC50 for CELATOM Tm MN-51 after 48
hours
is less than or comparable to LC50 for CELATOMTm MN-53 after 96 hours. In
other
words, from Experiment #1, CELATOMTm MN-51 appears to kill at least as many
bedbugs in 48 hours as CELATOM Tm MN-53 kills in 96 hours. Also, Experiment #2
appears to indicate that LC50 and LC95 after 24 hours for CELATOMTm MN-51 are
significantly less than LC50 and LC95 after 24 hours for AlpineTM Dust and for
PRO-
ACTIVETm because the confidence intervals for those LC50 and LC95 values do
not
overlap. Moreover, from Experiment #2, CELATOMTm MN-51 appears to kill
significantly more bedbugs in 24 hours than AlpineTm Dust kills in 48 hours.
Therefore, Experiment #1 and Experiment #2 appear to indicate CELATOMTm MN-
51 is more effective at killing bedbugs, and thus in controlling bedbug
populations,
than CELATOMTm MN-53, AlpineTm Dust, and PRO-ACTIVETm.
Experiment #2 appears to indicate that to LC50 and LC95 after 24 hours for
CELATOM Tm MN-51 are less than LC50 and LC95 after 24 hours for MotherEarthTM
D, but the confidence intervals for those LC50 and LC95 values overlap.
Therefore,
according to Experiment #2, CELATOMTm MN-51 may be more effective than
MotherEarthTM D at killing bedbugs, and thus in controlling bedbug
populations, but
overlap in the confidence intervals raises some uncertainty. However,
Experiment #6
appears to indicate that when one bedbug contacted CELATOMTm MN-51, that one
bedbug was generally more effective at killing other bedbugs by transmitting
the
CELATOMTm MN-51 to the other bedbugs than was the case for MotherEarthTM D.
Because bedbugs appear to pick up diatomaceous earth even when briefly exposed
to the diatomaceous earth (such as by crossing an area treated with CELATOMTm
MN-51 as in Experiment #4 and in Experiment #5), because bedbugs appear to
pass diatomaceous earth to other bedbugs (see Experiment #6 and Experiment
#7),
and because CELATOMTm MN-51 appears to be more effective than MotherEarthTM
D in killing bedbugs by transmission of diatomaceous earth from one bedbug to
CA 02847388 2014-03-21
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other bedbugs (see Experiment #6), it is believed that overall CELATOMTm MN-51
may be more effective than MotherEarth Tm D in controlling bedbug populations.
In view of the foregoing, it is believed that CELATOMTm MN-51 may be more
effective in controlling bedbug populations than the other diatomaceous earth
products described above.
As indicated above, different insect species have different bodies that may be
affected significantly differently by different types of diatomaceous earth.
Without
wishing to be bound by any theory, it is believed that some characteristics of
CELATOMTm MN-51 may increase the effectiveness of CELATOMTm MN-51 when
compared to other varieties of diatomaceous earth. For example, some
characteristics of CELATOMTm MN-51 may increase the likelihood of diatomaceous
earth being transmitted from one bedbug to another, thereby apparently
increasing
effectiveness of CELATOMTm MN-51 in controlling bedbug populations when
compared to MotherEarthTM D as shown in Experiment #6.
In Experiment #9, a sample of CELATOMTm MN-51 was size separated into a
smaller size fraction and into a larger size fraction, and Experiment #9
appears to
indicate that the smaller size fraction was significantly more effective than
the larger
size fraction at killing bedbugs. Figure 17 illustrates fine grained, broken
diatom
frustules in the smaller size fraction. Larger grains are absent, but there
are
aggregates of broken diatom frustules of, roughly, tens of micrometers. In
contrast,
Figure 20 illustrates grains that range in size from tens of micrometers to
approximately 100 micrometers in length in the larger size fraction. Many
grains in
Figure 20 appear not to be diatomaceous material, but rather mineral grains.
Therefore, Experiment #9 appears to indicate that the diatom frustules of
CELATOMTm MN-51 are more effective at killing bedbugs than other components of
CELATOMTm MN-51.
As shown in Figures 2 to 5, some of the particles of CELATOMTm MN-51 appear to
be remains of diatoms having frustules having widths less than about 3
micrometers
CA 02847388 2014-03-21
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or less than about 5 micrometers and lengths greater than about 20 micrometers
or
greater than about 30 micrometers. It is believed that such diatoms may be
Fragilaria, Tabularia, or Synedra, or extinct species having similar size and
shape to
Fragilaria, Tabularia, or Synedra. More generally, it is believed that such
diatoms
may be Fragilariaceae, or more generally Fragilariales, or more generally
Fragilariophyceae, or more generally pennate diatoms, or extinct species
having
similar size and shape to Fragilariaceae, Fragilariales, Fragilariophyceae, or
pennate
diatoms. Herein, reference to "Fragilaria", "Tabularia", "Synedra",
"Fragilariaceae",
"Fragilariales", "Fragilariophyceae", or "pennate" diatoms in some embodiments
may
include, in addition to extant species known by such names, extinct species
having
similar size and shape to Fragilaria, Tabularia, Synedra, Fragilariaceae,
Fragilariales, Fragilariophyceae, or pennate diatoms respectively.
Because the diatom frustules of CELATOMTm MN-51 appear to be more effective at
killing bedbugs than other components of CELATOMTm MN-51 (see Experiment #9),
because CELATOMTm MN-51 appears to be more effective in controlling bedbug
populations than the other diatomaceous earth products described above (see
Experiment #1, Experiment #2, and Experiment #6), and because CELATOMTm MN-
51 appears to include one or more of remains of diatoms having frustules
having
widths less than about 3 micrometers or less than about 5 micrometers and
lengths
greater than about 20 micrometers or greater than about 30 micrometers,
remains of
Fragilaria, remains of Tabularia, remains of Synedra, remains of
Fragilariaceae,
remains of Fragilariales, remains of Fragilariophyceae, and remains of pennate
diatoms, it is believed, without wishing to be bound by any theory, that one
or more
of remains of diatoms having frustules having widths less than about 3
micrometers
or less than about 5 micrometers and lengths greater than about 20 micrometers
or
greater than about 30 micrometers, remains of Fragilaria, remains of
Tabularia,
remains of Synedra, remains of Fragilariaceae, remains of Fragilariales,
remains of
Fragilariophyceae, and remains of pennate diatoms may be more effective than
other diatom remains at controlling bedbug populations. Again without wishing
to be
bound by any theory, it is believed that such diatom remains may be sharper
than
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other diatom remains and thus more likely to pierce or otherwise damage
exoskeletons such as bedbug exoskeletons.
Also without wishing to be bound by any theory, it is believed that the size
and
shape of some particles in CELATOM Tm MN-51, such as one or more of remains of
diatoms having frustules having widths less than about 3 micrometers or less
than
about 5 micrometers and lengths greater than about 20 micrometers or greater
than
about 30 micrometers, remains of Fragilaria, remains of Tabular/a, remains of
Synedra, remains of Fragilariaceae, remains of Fragilariales, remains of
Fragilariophyceae, and remains of pennate diatoms, for example, may block or
otherwise interfere with spiracles on exoskeletons of bedbugs, thereby
diminishing
or eliminating passage of air into the trachea of the bedbugs and potentially
asphyxiating the bedbugs, more effectively than other types of diatomaceous
earth.
Again without wishing to be bound by any theory, it is believed that in some
embodiments, heat treatment or flash drying of CELATOM TM MN-51 may change the
characteristics of the diatomaceous earth to be more abrasive and thus more
damaging to animal exoskeletons, or more particularly to insect exoskeletons
or to
bedbug exoskeletons, and that such heat treatment or flash drying may also dry
out
the diatomaceous earth, thereby making the diatomaceous earth more absorbent
to
dehydrate and kill an animal or insect such as bedbug and potentially more
effective
in various embodiments including the various embodiments described herein.
Although CELATOM Tm MN-51 has been discussed above, some embodiments may
include alternative types of diatomaceous earth that may be supplied by other
suppliers but that may include some characteristics of CELATOMTm MN-51 and
that
thus may have effectiveness similar to the effectiveness of CELATOMTm MN-51.
In
general, such alternative types of diatomaceous earth in some embodiments may
also include one or more of: remains of diatoms having frustules having widths
less
than about 3 micrometers or less than about 5 micrometers and lengths greater
than
about 20 micrometers or greater than about 30 micrometers; remains of
Fragilaria;
remains of Tabular/a; remains of Synedra; remains of Fragilariaceae; remains
of
CA 02847388 2014-03-21
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Fragilariales; remains of Fragilariophyceae; and remains of pennate diatoms.
Additionally or alternatively, such alternative types of diatomaceous earth in
some
embodiments may be heat-treated or flash dried diatomaceous earth, such as
diatomaceous earth flash dried at about 480 C for about 15 seconds for
example, or
may more generally be modified diatomaceous earth. Such alternative types of
diatomaceous earth may also include other types of diatomaceous earth found in
deposits formed from fresh-water diatoms, such as the deposit at Clark
Station,
Nevada, United States of America for example. More generally, such alternative
types of diatomaceous earth may have one or more properties similar to one or
more of the properties of CELATOMTm MN-51 listed in Tables 1 and 2 above in
order to achieve effects that may be similar to the effects of CELATOM Tm MN-
51
described above.
Because Experiment #9 appears to indicate that the smaller size fraction was
significantly more effective than the larger size fraction at killing bedbugs,
alternative
embodiments may include a smaller size fraction of a size-separated
diatomaceous
earth instead of the diatomaceous earth itself. Again without wishing to be
bound by
any theory, it is believed that such smaller size fractions may include
greater
concentrations of relatively more effective diatom frustule remains.
Additionally or
alternatively, and again without wishing to be bound by any theory, it is
believed that
such smaller size fractions may more relatively effectively block or otherwise
interfere with spiracles on exoskeletons of bedbugs, thereby diminishing or
eliminating passage of air into the trachea of the bedbugs and potentially
asphyxiating the bedbugs.
Therefore, in various embodiments, the size-separated diatomaceous earth may
include CELATOMTm MN-51 for example, and may include diatomaceous earth size-
separated by centrifuge. Further, in some embodiments, the smaller size
fraction
may include or consist of particles less than a separation size, such as about
11
micrometers for example. In embodiments where the diatomaceous earth is size
separated by centrifuge, non-spherical particles may be size-separated such
that the
CA 02847388 2014-03-21
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smaller size fraction may include elongate particles that are longer than the
separation size. In general, size separating diatomaceous earth may prepare
diatomaceous earth for use in controlling a population of insects, such as for
use in
the spray apparatus 100 shown in Figure 1 for example.
Experiment #3, Experiment #4, and Experiment #5 appear to indicate that
diatomaceous earth delivered from an aerosol product, such as the spray
apparatus
100 shown in Figure 1 for example, is effective at killing bedbugs, and thus
in
controlling bedbug populations, even if the bedbugs only contact the
diatomaceous
earth briefly when crossing an area sprayed with diatomaceous earth (see
Experiment #4 and Experiment #5). In various embodiments, methods of using
such
an apparatus may include exposing bedbugs or other pests to diatomaceous
earth,
for example by spraying, propelling, or otherwise applying the diatomaceous
earth to
a surface. In some embodiments, when one bedbug contacts the diatomaceous
earth, that bedbug may spread the diatomaceous earth to other bedbugs (see
Experiment #6 and Experiment #7), and therefore causing one bedbug to contact
diatomaceous earth may cause death of several bedbugs. Therefore, in some
embodiments, spraying, propelling, or otherwise applying the diatomaceous
earth to
a surface where bedbugs are likely to be found may be effective even against
bedbugs that do not contact the surface where the diatomaceous earth was
applied.
Further, according to Experiment #8, quantities of dusts deposited on filter
papers
weighed less than diatomaceous earth residues deposited by spraying an aerosol
formulation on filter papers. Again, without wishing to be bound by any
theory, it is
believed that perhaps diatomaceous earth delivered from an aerosol product has
greater adhesiveness than a diatomaceous earth dust. The spray apparatus 100
and
alternative embodiments may therefore apply diatomaceous earth to some
surfaces
(such as vertical or generally vertical surfaces of furniture for example)
more durably
for longer-lasting control of bedbug populations than when compared to other
methods of applying diatomaceous earth to surfaces.
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Also without wishing to be bound by any theory, it is believed that perhaps
diatomaceous earth delivered from an aerosol product may be broken and reduced
in size when compared to diatomaceous earth applied as a dust for example,
perhaps from one or more of: crushing, such as from the ball bearing or marble
136
in response to shaking the body 102 in the embodiment shown in Figure 1; shear
stress in an aerosol can; turbulence in an aerosol can; and relatively high
velocities
from a propellant in an aerosol can.
Further, the spray apparatus 100 and alternative embodiments may be more
convenient or effective in the control of such insect populations when
compared to
other methods of applying diatomaceous earth to surfaces. For example, the
spray
apparatus 100 and alternative embodiments may advantageously apply
diatomaceous earth to a surface more evenly than when compared to other
methods
of applying diatomaceous earth to surfaces, because the propellant may cause a
generally even spray of diatomaceous earth. In some embodiments, a more even
application of diatomaceous earth may increase effectiveness of the
diatomaceous
earth by effectively covering a greater area of a surface, and may improve the
appearance of the surface by avoiding more noticeable areas of high
concentration
of diatomaceous earth. Further, the spray apparatus 100 and alternative
embodiments may enable a user to apply diatomaceous earth conveniently from a
single apparatus, without having to transfer the diatomaceous earth from a
container
to a separate applicator apparatus as may be required in other methods of
applying
diatomaceous earth to surfaces.
In view of the foregoing, it is believed that some embodiments of the spray
apparatus 100 and alternative embodiments may effectively control populations
of
insects such as bedbugs. Therefore, commercial use of embodiments of the spray
apparatus 100 and of alternative embodiments may involve distributing,
selling,
offering for sale, placing, or otherwise using such spray apparatuses in an
effort to
control populations of animals, such as animals having exoskeletons,
arthropods,
arachnids, insects, and bedbugs for example.
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PCT international patent application no. PCT/CA2012/000389 filed at the
Canadian
receiving office of the PCT on April 26, 2012 describes and illustrates
various
furniture apparatuses such as a nightstand, a dresser, a bed, a mattress, and
a
headboard that may include one or more substantially thermoplastic bodies
including
diatomaceous earth, legume extracts, or both incorporated therein, and such
furniture apparatuses according to some embodiments may assist in the control
of
bedbug and other insect populations. Therefore, commercial use of embodiments
of
the spray apparatus 100 and of alternative embodiments may also involve
distributing, selling, offering for sale, placing, or otherwise using such
spray
apparatuses together with such furniture apparatuses in an effort to control
populations of animals, such as animals having exoskeletons, arthropods,
arachnids, insects, and bedbugs for example.
As indicated in PCT international patent application no. PCT/CA2012/000389
filed at
the Canadian receiving office of the PCT on April 26, 2012, in some
embodiments of
furniture apparatuses, one or more internal surfaces may be darkly coloured,
such
as coloured black or another dark colour. Thus, for example when diatomaceous
earth is applied to such internal surfaces with an embodiment of the spray
apparatus
100 or an alternative embodiment, the lighter colour of the diatomaceous earth
may
make the diatomaceous earth more easily visible on such surfaces, and may
facilitate noticing an absence of such products on such surfaces. Therefore,
such
darkly coloured internal surfaces in some embodiments may assist with visibly
determining whether such internal surfaces have been sprayed or otherwise
treated
with diatomaceous earth or another more lightly coloured product, and such
visual
determinations may facilitate determining where and when such diatomaceous
earth
or other products should be applied to ensure a desired amount of such
diatomaceous earth or other products on various furniture apparatuses. More
generally, an embodiment of the spray apparatus 100 shown in Figure 1 or an
alternative embodiment may facilitate applying diatomaceous earth to surfaces
where bedbugs may be introduced into a room, such as a bed, dresser, or side
table
CA 02847388 2014-03-21
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where bedbugs may be introduced by occupants or from belongs of occupants of a
room, or other surfaces where bedbugs may be likely to travel.
As indicated in Tables 1 and 3 above, some naturally occurring diatomaceous
earth
is beige in colour. In some embodiments, for example when diatomaceous earth
is
applied to surfaces of drywall panels, beige diatomaceous earth may be
desirable
because the colour of the diatomaceous earth may be similar to a colour of the
surface to which the diatomaceous earth is applied, so that the diatomaceous
earth
may desirably be inconspicuous. However, in some other embodiments in which
inconspicuous diatomaceous earth may be desirable, and in which diatomaceous
earth is applied to surfaces that are not beige, the beige colour may impart
an
undesirable appearance to the surfaces to which the diatomaceous earth may be
applied.
For example, when applying diatomaceous earth, such as the diatomaceous earth
described herein for example, to green surfaces of plants, the beige colour
may
impart an undesirable appearance to the plants. Therefore, in some
embodiments,
diatomaceous earth, such as the diatomaceous earth described herein for
example,
may be intermixed with a green colouring agent to impart a green colour to the
diatomaceous earth so that the coloured diatomaceous earth is not as
noticeable, or
not noticeable at all, on the plants.
As another example, when applying diatomaceous earth, such as the diatomaceous
earth described herein for example, to surfaces of floors of a building, the
beige
colour may again impart an undesirable appearance to the floors. Therefore, in
some embodiments, diatomaceous earth, such as the diatomaceous earth described
herein for example, may be intermixed with a brown colouring agent to impart a
brown colour to the diatomaceous earth so that the coloured diatomaceous earth
is
not as noticeable, or not noticeable at all, on the floors.
As another example, when applying diatomaceous earth, such as the diatomaceous
earth described herein for example, to surfaces of a bed or to surfaces of a
mattress
CA 02847388 2014-03-21
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of a bed, the beige colour may again impart an undesirable appearance to the
bed
or mattress. Therefore, in some embodiments, diatomaceous earth, such as the
diatomaceous earth described herein for example, may be intermixed with a
white
colouring agent, such as a bleach for example, to impart a white colour to the
diatomaceous earth so that the coloured diatomaceous earth is not as
noticeable, or
not noticeable at all, on the bed or mattress.
In summary, a method of preparing diatomaceous earth, such as the diatomaceous
earth described herein for example, for use as a pesticide may involve
intermixing
the diatomaceous earth with a colouring agent. In various embodiments,
colouring
agents that may be intermixed with diatomaceous earth may include colouring
agents from Strait-LineTM Hi-Visibility Marking Chalk available from IRWIN
Tools. In
other embodiments, such colouring agents may include one or more natural dyes
from fruits or other sources.
Diatomaceous earth is a natural product, and in some embodiments, natural
products may be preferable over other pest control products, such as synthetic
pesticides for example, because natural products may be less harmful to
humans, to
other life, or more generally to the environment. In view of the foregoing,
the spray
apparatus 100 shown in Figure 1 and alternative embodiments may be
advantageous when compared to other methods of controlling bedbug and other
insect populations.
Although specific embodiments have been described and illustrated, such
embodiments should be considered illustrative only and not as limiting the
invention
as construed in accordance with the accompanying claims.
