# Patent

## Title
Spray apparatuses, uses of diatomaceous earth, and methods of controlling insect populations

## Abstract

There is disclosed a spray apparatus for holding contents comprising diatomaceous earth and a compressed propellant for propelling the diatomaceous earth. There is also disclosed use of diatomaceous earth to control a population of bedbugs, wherein the diatomaceous earth comprises remains of pennate diatoms. There is also disclosed a method of controlling a population of insects, the method comprising causing a compressed propellant to propel diatomaceous earth on a surface. Method of manufacturing a spray apparatus and methods of preparing diatomaceous earth for use in controlling a population of insects are also disclosed.

## Background
RELATED APPLICATIONS
This application is a continuation of and claims the benefit of PCT international patent application no. PCT/CA2012/001015, filed on Nov. 1, 2012. PCT international patent application no. PCT/CA2012/001015, filed on Nov. 1, 2012, claims the benefit of U.S. provisional patent application No. 61/563,220 filed on Nov. 23, 2011, and the benefit of PCT international patent application no. PCT/CA2012/000389 filed at the Canadian receiving office of the PCT on Apr. 26, 2012. PCT international patent application no. PCT/CA2012/000389 was filed as U.S. National Phase application Ser. No. 14/114,900 on Oct. 30, 2013. The entire contents of PCT international patent application no. PCT/CA2012/001015, filed on Nov. 1, 2012, U.S. provisional patent application No. 61/563,220 filed on Nov. 23, 2011, PCT international patent application no. PCT/CA2012/000389 filed at the Canadian receiving office of the PCT on Apr. 26, 2012, and U.S. application Ser. No. 14/114,900 filed on Oct. 30, 2013, are incorporated by reference herein.


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 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.
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.
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.
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:
FIG. 1 is a cross-sectional view of a spray apparatus according to one illustrative embodiment;
FIGS. 2 to 5 are secondary electron images of diatomaceous earth known as CELATOMTM MN-51;
FIG. 6 is a Rietveld refinement plot of the diatomaceous earth known as CELATOMTM MN-51;
FIG. 7 is a graph of particle size distribution of the diatomaceous earth known as CELATOMTM MN-51;
FIG. 8 is a secondary electron image of diatomaceous earth known as CELATOMTM MN-53;
FIG. 9 is a Rietveld refinement plot of the diatomaceous earth known as CELATOMTM MN-53;
FIG. 10 is a secondary electron image of diatomaceous earth known as AlpineTM Dust;
FIG. 11 is a Rietveld refinement plot of the diatomaceous earth known as AlpineTM Dust;
FIG. 12 is a secondary electron image of diatomaceous earth known as MotherEarthTM D;
FIG. 13 is a Rietveld refinement plot of the diatomaceous earth known as MotherEarthTM D;
FIG. 14 is a graph of particle size distribution of the diatomaceous earth known as MotherEarthTM D;
FIGS. 15 to 17 are secondary electron images of diatomaceous earth known as PRO-ACTIVETM;
FIG. 18 is a Rietveld refinement plot of the diatomaceous earth known as PRO-ACTIVETM;
FIG. 19 is a scanning electron microscope image of a smaller size fraction of the diatomaceous earth known as CELATOMTM MN-51; and
FIG. 20 is a scanning electron microscope image of a larger size fraction of the diatomaceous earth known as CELATOMTM MN-51.



DETAILED DESCRIPTION
A. Spray Apparatus
Referring to FIG. 1, a spray apparatus according to one illustrative embodiment is shown generally at 100. U.S. Pat. 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 U.S. Pat. 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 “202×509” (or 2 2/16 inches in diameter and 5 9/16 inches in height, or about 5.4 centimeters (“cm”) in diameter 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 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, U.S. Pat. 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.
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 138 mm A-D, and an actuator known to one skilled in the art as Act.025′′ NMBU Raised APSL 0.022 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.
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 “211×604” (or 2 11/16 inches in diameter and 6 4/16 inches in height, 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 “211×713” (or 2 11/16 inches in diameter and 7 13/16 inches in height, 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 “211×604” (or 2 11/16 inches in diameter and 6 4/16 inches in height, or about 6.8 cm in diameter and about 15.9 cm in height), 114 grams of propellant may be added, and for an aerosol container having a size known to one skilled in the art as “211×713” (or 2 11/16 inches in diameter and 7 13/16 inches in height, or about 6.8 cm in diameter and about 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.
1. 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, Nev., 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, Nev., 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.
FIGS. 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 FIGS. 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 CELATOM TM 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



Free Moisture




(Maximum % H2O)
Less than 5.0



(Typical % H2O)
3.0












Density
(lb/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










SiO2
73.6%



Al2O3
7.8%



Fe2O3
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°2θ 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 Soller 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). FIG. 6 is a Rietveld refinement plot of the diatomaceous earth known as CELATOMTM MN-51. FIG. 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 FIG. 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 CELATOM TM MN-51 by Rietveld


refinements.











Percent


Mineral
Ideal Formula
by Weight












Quartz
α-SiO2
2


Plagioclase
NaAlSi3O8—CaAl2Si2O8
18


Kaolinite
Al2Si2O5(OH)4
1


Montmorillonite
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2•nH2O
46


Amorphous Silica
SiO2•nH2O
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 FIG. 7 is a 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, Nev., United States of America. FIG. 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 CELATOM TM 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 % H2O)
Less than 5.0



(Typical % H2O)
3.0












Density
(lb/ft3)
(g/l)





Wet Bulk
31
500


Dry Bulk
11
175








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










SiO2
83.7%



Al2O3
5.6%



Fe2O3
2.3%



CaO
0.9%



MgO
0.3%



Other Oxides
1.9%



Loss on Ignition
5.0%









FIG. 9 is a Rietveld refinement plot of the diatomaceous earth known as CELATOMTM MN-53 obtained as described above for FIG. 6. FIG. 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 FIG. 9 are renormalized amorphous-free. The results of phase analysis of CELATOMTM MN-53 by Rietveld refinements are in Table 4 below.







TABLE 4







Results of phase analysis of CELATOM TM MN-53 by Rietveld


refinements.











Percent


Mineral
Ideal Formula
by Weight












Quartz
α-SiO2
2


Plagioclase
NaAlSi3O8—CaAl2Si2O8
24


Kaolinite
Al2Si2O5(OH)4
2


Montmorillonite
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2•nH2O
40


Amorphous Silica
SiO2•nH2O
31









3. AlpineTM Dust
FIG. 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, Mo., United States of America, and FIG. 11 is a Rietveld refinement plot of the diatomaceous earth known as AlpineTM Dust obtained as described above for FIG. 6. FIG. 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 FIG. 11 are renormalized amorphous-free. The results of phase analysis of AlpineTM Dust by Rietveld refinements are in Table 5 below.







TABLE 5







Results of phase analysis of Alpine TM Dust by Rietveld


refinements.











Percent


Mineral
Ideal Formula
by Weight












Quartz
α-SiO2
1


Plagioclase
NaAlSi3O8—CaAl2Si2O8
8


Montmorillonite
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2•nH2O
38


Amorphous Silica
SiO2•nH2O
53









4. MotherEarthTM D
FIG. 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, Mo., United States of America, and FIG. 13 is a Rietveld refinement plot of the diatomaceous earth known as MotherEarthTM D obtained as described above for FIG. 6. FIG. 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 FIG. 13 are renormalized amorphous-free. The results of phase analysis of MotherEarthTM D by Rietveld refinements are in Table 6 below.







TABLE 6







Results of phase analysis of MotherEarth TM D by Rietveld


refinements.











Percent


Mineral
Ideal Formula
by Weight












Quartz
α-SiO2
1


Plagioclase
NaAlSi3O8—CaAl2Si2O8
9


Montmorillonite
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2•nH2O
47


Amorphous Silica
SiO2•nH2O
43









Particle sizes of sample of the diatomaceous earth known as MotherEarthTM D were measured in a MastersizerTM 2000 in a water dispersant, and FIG. 14 is a graph of particle size distribution of the diatomaceous earth known as MotherEarthTM D.
5. PRO-ACTIVETM
FIGS. 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 FIG. 18 is a Rietveld refinement plot of the diatomaceous earth known as PRO-ACTIVETM obtained as described above for FIG. 6. FIG. 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 FIG. 18 are renormalized amorphous-free. The results of phase analysis of PRO-ACTIVETM by Rietveld refinements are in Table 7 below.







TABLE 7







Results of phase analysis of PRO-ACTIVE TM by Rietveld


refinements.











Percent


Mineral
Ideal Formula
by Weight












Quartz
α-SiO2
6


Plagioclase
NaAlSi3O8—CaAl2Si2O8
5


Alunite
K2Al6(SO4)4(OH)12
<1


Jarosite
K2Fe63+(SO4)4(OH)12
2


Anatase
TiO2
<1


K-feldspar
KAlSi3O8
1


Illite/Muscovite
K0.65Al2.0Al0.65Si3.35O10(OH)2
7


Kaolinite
Al2Si2O5(OH)4
1


Montmorillonite
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2•nH2O
50


Amorphous Silica
SiO2•nH2O
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 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 CELATOM TM MN-51.









Amount of CELATOM TM 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


0
3
0
4
0
5
















TABLE 9







Toxicity of adult bedbugs to CELATOM TM 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 CELATOMTM 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 CELATOMTM MN-51 was calculated as 0.7 mg. The data after 48 hours for CELATOMTM MN-53 were not good for calculation, and therefore LC50 for CELATOMTM 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 (“CIs”) for the LC50 and LC95 values, as shown in Table 10 below.







TABLE 10







LC50, LC95, and CI for CELATOM TM MN-51, Alpine TM


Dust, and MotherEarth TM D.













Time
LC50
CI of LC50
LC95
CI of LC95


Product
(hours)
(mg)
(mg)
(mg)
(mg)















CELATOM TM
24
0.24
 0.1-0.32
0.95
0.69-1.98


MN-51







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









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 FIG. 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


CELATOM TM MN-51.











Petri
Number





dish
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









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×about 45.7 cm×about 33.7 cm, or about 29 inches×about 18 inches×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×about 24 cm, or about 19.7 inches×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.
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.







TABLE 12







Number of bedbugs dead for 


CELATOM TM MN-51 (“51”),


MotherEarth TM D (“ME”), 


and control (“C”) Petri dishes.











Number Dead 
Number Dead 
Number Dead 


Petri
After 24 Hours
After 48 Hours
After 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


5
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 MotherEarthTM D diatomaceous earth was mixed with a red fluorescent dust from a luminous powder kit #1162A obtained from BioQuip Products Inc., Rancho Dominguez, Calif., 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.







TABLE 13







Number of bedbugs dead after 16 hours for CELATOM TM


MN-51, MotherEarth TM D, and control Petri dishes.










Petri Dish
CELATOM TM MN-51
MotherEarth TM 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.







TABLE 14







Weights of dust before shaking, after shaking, and amounts lost


from shaking.













Amount


Product Applied
Weight before
Weight after
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.







TABLE 15







Weights of filter paper before and after spraying aerosol, and


amounts of diatomaceous earth added from spraying.













Amount Added


Product Applied
Weight before
Weight after
from Spraying


in Aerosol Spray
Spraying (mg)
Spraying (mg)
(mg)













CELATOM TM 
164
175
11


MN-51
157.4
173
15.6



162
176
14


mean
161.1
174.7
13.5


CELATOM TM 
151.1
152.8
1.7


MN-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. FIG. 19 is a scanning electron microscope image of the smaller size fraction (particles less than about 11 micrometers in size) and FIG. 20 is a scanning electron microscope image of the larger size fraction (particles larger than about 11 micrometers in size). The scale bar in FIG. 19 represents 30 micrometers, whereas the scale bar in FIG. 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 CELATOM TM MN-51


and unseparated CELATOM TM MN-51.










Smaller Size Fraction of
Larger Size Fraction of



CELATOM TM MN-51
CELATOM TM MN-51












Number
Number
Number
Number


Amount
killed after
killed after
killed after
killed after


(mg)
24 hours
48 hours
24 hours
48 hours














1
8
20
0
0


2
10
21
1
1


4
14
22
2
2


8
15
24
3
3









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 CELATOM TM MN-51.












LC50 after 24
LC50 after 48



Sample
hours (mg)
hours (mg)






Smaller Size Fraction of
 3.038
 0.201



CELATOM TM MN-51
(0.983-13.803)
(0.000-0.688)



Larger Size Fraction of
50.221
50.221



CELATOM TM MN-51









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 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 CELATOMTM 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 CELATOMTM 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 CELATOMTM 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 other bedbugs (see Experiment #6), it is believed that overall CELATOMTM MN-51 may be more effective than MotherEarthTM 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. FIG. 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, FIG. 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 FIG. 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 FIGS. 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 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 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 CELATOMTM 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 Tabularia, 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 CELATOMTM 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 CELATOMTM 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 Tabularia; remains of Synedra; remains of Fragilariaceae; remains of 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, Nev., 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 CELATOMTM 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 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 FIG. 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 FIG. 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.
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 FIG. 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.
PCT international patent application no. PCT/CA2012/000389 filed at the Canadian receiving office of the PCT on Apr. 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 Apr. 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 FIG. 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 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.
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 FIG. 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.

## Claims

1. 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, wherein the diatomaceous earth comprises remains of pennate diatoms; and
an actuator for controllably releasing the propellant and the diatomaceous earth propelled by the propellant from the reservoir.

2. The apparatus of claim 1 wherein the pennate diatoms comprise Fragilariophyceae diatoms.

3. The apparatus of claim 2 wherein the Fragilariophyceae diatoms comprise Fragilariales diatoms.

4. The apparatus of claim 3 wherein the Fragilariales diatoms comprise Fragilariaceae diatoms.

5. The apparatus of claim 4 wherein the Fragilariaceae diatoms comprise diatoms selected from the group consisting of Synedra diatoms, Tabularia diatoms, and Fragilaria diatoms.

6. The apparatus of claim 1 wherein the diatomaceous earth comprises remains of diatoms having frustules having widths less than about 5 micrometers and lengths greater than about 20 micrometers.

7. The apparatus of claim 1 wherein the diatomaceous earth comprises remains of diatoms having frustules having widths less than about 3 micrometers and lengths greater than about 20 micrometers.

8. The apparatus of claim 1 wherein the diatomaceous earth comprises remains of diatoms having frustules having widths less than about 5 micrometers and lengths greater than about 30 micrometers.

9. The apparatus of claim 1 wherein the diatomaceous earth comprises remains of diatoms having frustules having widths less than about 3 micrometers and lengths greater than about 30 micrometers.

10. The apparatus of claim 1 wherein the diatomaceous earth comprises a smaller size fraction of particles less than about 11 micrometers in size.

11. The apparatus of claim 1 wherein the diatomaceous earth is flash dried.

12. The apparatus of claim 1 wherein the diatomaceous earth comprises diatomaceous earth from Clark Station, Nevada, United States of America.

13. The apparatus of claim 1 wherein the diatomaceous earth is at least about 3% by weight of the contents.

14. The apparatus of claim 1 wherein the diatomaceous earth is at least about 5% by weight of the contents.

15. The apparatus of claim 1 wherein the diatomaceous earth is at least about 7% by weight of the contents.

16. The apparatus of claim 5 wherein the diatomaceous earth is about 8% by weight of the contents.

17. A method of pest control, the method comprising exposing pests to diatomaceous earth comprising remains of pennate diatoms.

18. The method of claim 17 wherein the pennate diatoms comprise pennate diatoms selected from the group consisting ofFragilariophyceae diatoms, Fragilariales diatoms, Fragilariaceae diatoms, Synedra diatoms, Tabularia diatoms, and Fragilaria diatoms.

19. The method of claim 17 wherein the diatomaceous earth comprises remains of diatoms having frustules having widths less than about 5 micrometers and lengths greater than about 20 micrometers.

20. The method of claim 17 wherein the diatomaceous earth comprises a smaller size fraction of particles less than about 11 micrometers in size.

21. The method of claim 17 wherein exposing the pests to the diatomaceous earth comprises causing a compressed propellant to propel the diatomaceous earth on a surface.

22. A method of preparing diatomaceous earth for use as a pesticide, the method comprising size separating the diatomaceous earth into a smaller size fraction and into a larger size fraction.

23. The method of claim 22 wherein the smaller size fraction is a smaller size fraction of particles less than about 11 micrometers in size.

24. The method of claim 17 wherein the pests comprise insects.

25. The method of claim 24 wherein the insects comprise bedbugs.

26. The method of claim 17 wherein the pests comprise arachnids.

27. A furniture apparatus comprising a surface and comprising diatomaceous earth applied to the surface, wherein the diatomaceous earth comprises remains of pennate diatoms.

28. The apparatus of claim 27 wherein the pennate diatoms comprise pennate diatoms selected from the group consisting of Fragilariophyceae diatoms, Fragilariales diatoms, Fragilariaceae diatoms, Synedra diatoms, Tabularia diatoms, and Fragilaria diatoms.

29. The apparatus of claim 27 wherein the diatomaceous earth comprises a smaller size fraction of particles less than about 11 micrometers in size.

30. The apparatus of claim 27 wherein the apparatus is selected from the group consisting of a nightstand, a dresser, a bed, a mattress, and a headboard.