Patent Application
20110265369
Drying wood is known in the field of wood preparation and preservation. There is a broad spectrum of processes that are utilized to dry wood. One such process occurs naturally to wood maintained at atmospheric conditions, such as with the aging of cut logs on a wood pile. This drying reduces the water content of the wood, while the wood remains susceptible to decay and cellular degeneration due to fungal pathogens, for example. Other drying techniques utilize heated chambers, such as kilns, maintained at elevated temperatures, such as those between about 40 degrees C. (105 degrees F.) and about 90 degrees C. (195 degrees F.), to more quickly dry wood. Wood dried in this manner is conventionally utilized as lumber, such as for construction projects and the like. Other conventional drying processes utilize high-temperature steam to dry wood at temperatures of between about 90 degrees C. (195 degrees F.) and about 150 degrees C. (302 degrees F.). This temperature level provides shorter drying times and more dimensionally-stable lumber, as compared with the previously discussed processes. Such conventional lumber is typically marketed for sale having a water content of between about 15 percent and about 18 percent. Once such lumber is in use in an ambient environment for some time, such as in a frame house, the wood has a water content of between about 10 percent and about 15 percent.
Another conventional wood drying process utilizes even more elevated temperatures, such as between about 150 degrees C. (302 degrees F.) and about 215 degrees C. (420 degrees F.) to alter the color of the wood itself. The upper limit on the heating can be higher than the 215 degrees C. (420 degrees F.) noted above, as long as the temperature remains below the charring temperature of the treated wood. Such processing is conventionally utilized to create the appearance of stained wood, without the use of chemical stains. Because such wood is superheated to elevated temperatures, much of the water content is removed from the wood, bringing water levels in the heat-treated wood to between about two percent and about ten percent. Although this process is known in the art of wood preparation and preservation, the wood product created by the process has not been used conventionally as a medium for monitoring or controlling termites.
Moreover, conventional techniques and knowledge regarding termite monitoring and controlling teach that this wood would not be of use for monitoring and controlling termites. First, wood having a higher water content, such as between about 10 percent and about 20 percent is conventionally thought to be more attractive to termites. Second, heat-treating wood in this manner produces a heat-treated wood product that is less hygroscopic than untreated wood or wood dried at lower temperatures. As such, conventional wisdom regarding termite feeding would indicate that such wood would not be attractive to termites because even with additional water available (such as with a below ground installation), the heat-treated wood will resist the absorption of water. Without absorbing water, the conventional wisdom goes, the termites will not be interested in feeding.
In contrast with this conventional thinking regarding termite food selection and contrary to past understanding and teaching regarding termite wood preferences, the present invention utilizes such heat-treated wood with relatively lower levels of water and less hygroscopy than conventionally treated wood with unexpected success as a food source and attractant for termites. Additional benefits include enhanced resistance to microbiological attack and an increased amount of extractable compounds attractive to foraging termites. A termite monitoring and control method utilizing this heat-treated wood thus provides unexpected benefits over more conventional wood-based termite stations.
Many termite monitoring and control devices, and methods, are known and such devices may be formed in a wide variety of configurations. Many of such devices employ an attractant food source made from a medium or substrate that is attractive to termites to encourage the termites to continue feeding from the attractant once the termites come upon the food source. The termites may then be eliminated by providing a toxicant containing bait placed at the feeding point in the termite monitoring and control device. Examples of such devices and methods include those described in U.S. Pat. No. 7,086,196 titled Pest Control Device and Method, issued Aug. 8, 2006, and in co-pending U.S. patent application Ser. No. 11/770,379, titled Method of Monitoring and Controlling Termites with Heat-Treated Wood, filed Jun. 28, 2007. In such control devices, the food source may comprise cellulosic material, such as paper, cardboard, compressed tablets, agar matrix with or without sugar, or any other suitable feeding material.
In one embodiment, a method of at least one of monitoring and controlling termite populations in an area accessible to the termites according to one embodiment generally comprises locating in the area a heat treated wood extract, the extract being extracted from wood that has been heat-treated to a temperature of greater than about 150 degrees C.
In another embodiment, a method of at least one of monitoring and controlling termite populations in an area accessible to the termites generally comprises locating a termite station housing generally at an area accessible to termites, the termite station housing having at least one opening therein providing communication between an interior and the exterior of the termite station housing. An aggregation base is positioned within the interior of the housing. A heat treated wood extract is deposited at least one of in the interior of the housing and in the environment exterior of the housing, with the heat treated wood extract having been extracted from wood that has been heat-treated to a temperature of greater than about 150 degrees C.
In another embodiment, an attractant for use in monitoring and controlling termite populations generally comprises a heat treated wood extract, the extract being extracted from a hot water extraction of wood that has been heat-treated to a temperature of greater than about 150 degrees C.
In another embodiment, a method of monitoring and controlling a termite population generally comprises locating a termite station housing generally at an area accessible to termites. The termite station housing has at least one opening therein providing communication between an interior and the exterior of the termite station housing. A particulate heat treated wood is deposited in the station housing, with the heat treated wood having been heat treated to a temperature of greater than about 150 degrees C.
With reference now to the drawings, and in particular to
The base panel 25 suitably has an outer surface 35 (
With particular reference to
These base panel openings 39 are used to mount the base panel 25 (and hence the container 23) on the mounting surface M using suitable fasteners such as screw fasteners 43 (
Providing a plurality of such openings 39 in the base panel 25 allows the base panel (and hence the termite station 21) to be arranged at a desired location on the mounting surface M, such as with one or more of the openings located over an opening (not shown) formed by termites in the mounting surface, while providing sufficient additional openings through which fasteners 43 may extend through the base panel into the mounting surface at a more stable (e.g., less damaged) or stronger segment of the mounting surface. Thus, in such an embodiment the number of openings 39 exceeds the number of fasteners used to fasten the base panel on the mounting surface M by at least one. The openings 39 also allow the termite station 21 to be secured to the mounting surface M by passing the fasteners 43 through a single structural member of the container 23, i.e., the base panel 25, as opposed to multiple components thereof. For example, the lid 31 of the container 23 is free of openings that may otherwise be used as in the case with conventional designs because it is unnecessary for mounting fasteners to extend through the lid. This arrangement makes it easier to visually place the termite station 21, and in particular the base panel 25, in the desired location on the mounting surface M and also allows opening and closing of the lid 31 while the termite station remains mounted on the mounting surface, and in particular without having to loosen or remove the mounting fasteners.
The openings 39 in the base panel 25 also provide multiple entry points for the ingress and egress of termites to and from the interior space 33 of the container 31 through the base panel 25. To this end, the base panel is openings 39 are generally chamfered, or tapered outward (e.g., expanding in planar dimension) from the base panel outer surface 35 to the inner surface 37 thereof as illustrated in
Peripheral (i.e., side entry) openings 47 are formed in the end panels 27 and side panels 29 (i.e., broadly, the side) of the illustrated container 23 in spaced relationship with each other about the periphery of the container. More suitably, these peripheral openings 47 extend from the respective end panels 27 and side panels 29 to the base panel 25 (i.e., to the corners where the end panels and side panels meet the base panel), to allow termites to enter the interior space 33 of the container 23 from the sides thereof, such as along a termite tunnel formed along the mounting surface M (
As best seen in
In the illustrated embodiment (as best illustrated in
It is contemplated, however, that the access closures 50 may be formed separate from and removeably connected to the container at the peripheral openings 47, such as thermal welding, adhesive or other suitable connecting technique without departing from the scope of this invention. It is also understood that in some embodiments the access closures 50 may be refastenably connected to the container 23 (such as, for example, by adhesive, hook and loop fasteners or other suitable mechanical fasteners) so that the termite station 21 can be reconfigured and reused in treating a different termite tunnel or other infestation within the scope of this invention.
In another suitable embodiment, illustrated in
One or more raised spacing elements (e.g., nubs 49 as illustrated in
Referring back to
In other embodiments, it is contemplated that the lid 31 may instead be formed separate from the rest of the container 23 and be entirely placeable on and removable from the rest of the container. It is also understood that any suitable releasable securement arrangement other than a latch and catch arrangement may be used to releasably secure the lid 31 it its closed position and remain within the scope of this invention. While in the illustrated embodiments herein the side (i.e., the end and side panels 27, 29) of the container 23 is secured to (and more suitably formed integrally with) the base panel 25, it is contemplated that the side may instead be secured to the lid 31 and hinged to the base panel 25 for positioning along with the lid between the closed and open positions thereof to provide access to the interior space 33 of the container.
A cartridge 51 is suitably sized and configured for disposition at least in part within the container 23 and more suitably entirely within the interior space 33 of the container in the closed position of the container lid 31. With particular reference to
The aggregation member 61 in one embodiment comprises an attractant, and more suitably what is referred to herein as a non-physical attractant. A “non-physical” attractant is intended to refer herein to an attractant that does not require physical contact by a termite to induce foraging. For example, in one particularly suitable embodiment the non-physical attractant comprises a wood that has been heat treated at an elevated temperature, such as at least about 150 degrees C. (302 degrees F.) and more suitably between about 150 degrees C. and 215 degrees C. (420 degrees F.).
Wood is an organic material found as the primary content of the stems of woody plants (e.g., trees and shrubs). Dry wood is composed of fibers of cellulose (from about 40 percent to about 50 percent by dry weight) and hemicelluloses (from about 20 percent to about 30 percent by dry weight) held together by lignin (from about 25 percent to about 30 percent by dry weight). Wood also contains extractives, which are compounds that can be extracted using various solvents and are often less than 500 grams/mole in molecular weight. In general, these extractives constitute from about two percent to about eight percent (dry weight) of the wood components.
Cellulose is the most abundant component in wood and plays a major role in giving wood its mechanical strength. A molecule of cellulose consists of β-D-glucose units bonded with β(1→4) lingages to form a long linear chain and has a molecular weight that ranges from several thousand to many million grams/mole. The molecular chains in cellulose form elementary fibrils or micelles. The micelles align with the cellulose fibrils oriented in the same direction and are tightly packed together. Cellulose elementary fibrils are then layered together in parallel with hemicelluloses and pectins in between to form microfibrils. When the microfibrils are aggregated in larger bundles and lignin impregnated within the structure, fibrils are generated, which in turn form wood fibers.
Hemicelluloses comprise from about 20 percent to about 30 percent by dry weight. Smaller than cellulose molecules, the average molecular weight of hemicelluloses range from about 10,000 grams/mole to about 30,000 grams/mole. The composition of hemicelluloses varies between hardwoods (i.e., oak, mahogany) and softwoods (i.e., pine, cedar). The hemicelluloses of hardwoods are predominantly of glucuronoxylan (from about fifteen percent to about 30 percent) and to a minor extent glucomannan (from about two percent to about five percent). The hemicelluloses of softwoods consists predominantly of galactoglucomannan (about twenty percent) and smaller amounts of arabinoglucuroxylan (from about five percent to about ten percent).
Pectins and starch are also found in wood, but typically in minor amounts, less than about one percent each. Pectins resemble hemicelluloses in structure and are found in the middle lamella, primary cell wall and tori of bordered pits and also to a small extent in the fibril structure. Starch can be found in parenchyma cells serving as storage of nutrition for the living tree, and it consists of amylase and amylopectin.
Lignin is an amorphous polymer with a wide variation in configuration. Lignin is often considered to be the glue of the wood structure. The backbone of the lignin structure is based on three types of phenyl propane units: guaiacyl, syringyl, and p-hydroxyphenyl. Softwoods consist mainly of guaiacyl units and also to some extent of p-hydroxyphenyl units. In contrast, hardwood lignins consist of syringly and guaiacyl units.
When wood is dried, these chemical compounds that make up the structure of wood undergo various changes. In particular, according to one embodiment herein, the aggregation member 61 comprises wood dried at an elevated temperature of between about 150 degrees C. (302 degrees F.) and about 215 degrees C. (420 degrees F.), whereat these chemical changes are different from those produced by drying at lower temperature ranges, such as below about 150 degrees C. (302 degrees F.). In another exemplary embodiment herein, the aggregation member 61 comprises wood that is dried at an elevated temperature of between about 185 degrees C. (365 degrees F.) and about 215 degrees C. (420 degrees F.). In particular, it is believed that the heat-treated wood undergoes changes affecting the available space for air and moisture in the wood. In particular, the porosity and permeability of the wood is changed. The porosity defines the ratio of the volume fraction of void space within a solid. The permeability defines the rate of diffusion of a fluid through a porous body.
It is believed that after such treatment the porosity may increase as liquids and other compounds not strongly bound to the structure of the wood are removed with the heating of the wood, such as by evaporation. Taken alone, this change would indicate that such heat-treated wood would be more hygroscopic than untreated wood, as there is more available space within the wood. But this conclusion ignores the changes also made to the permeability of the treated wood. Permeability exists where cells and/or voids can interconnect to one another. For example, with a hardwood, intervessel pitting can create openings in membranes, allowing for improved permeability. It is believed that after such heat treatment, however, those membranes may become occluded or encrusted. Such occlusions decrease overall permeability. Moreover, the pits may also become aspirated, whereby the wood assumes a closed-cell structure that again decreases overall permeability. It is also believed that such heat treatment can cause substantial disconnection of adjacent microfibrils within the heat-treated wood. Whereas with living or non-heat treated wood, these adjacent microfibrils provide structures for transport of liquid through the wood via normal translaminar vascular flow of phloem and xylem tissue. With their detachment, a disconnection is created within the wood that impedes the flow of liquids, thereby decreasing hygroscopy (i.e., increasing hydrophobicity). It is also believed that the increased wood shrinkage that occurs at the heat treatment temperature can lead to increased detachment of adjacent xylem tissue cells and adjacent phloem tissue cells (i.e., vascular cells), thereby inhibiting liquid passage through normal pathways of tissue cells. As would be understood by one skilled in the art, these changes depend upon the starting porosity, permeability, and density of the wood, but it is believed that such changes are generally applicable to many wood species. Moreover, such heat treatment processes may cause other changes to the structure and nature of the wood not mentioned here without departing from the scope of the embodiments of the present invention.
In addition to changes in hygroscopy and hydrophobicity, wood heat-treated in this manner also includes changes associated with other chemical compounds normally bound to the cellulose materials in the wood. While not being bound to a particular theory, it is believed that as part of the heat-treatment process, the bonds normally binding these chemical compounds (e.g., volatile, semi-volatile, and naturally-extractable compounds (e.g., aromatic compounds), such as compounds derived from tannins, terpenes, and oils, among others) to the cellulose of the wood are broken, thereby allowing movement of the compounds more readily from the wood and into the area surrounding the wood (e.g., soil), as compared with conventional wood decay. As such, these chemical compounds may be extracted, or released, and more readily spread from the wood, thereby attracting termites to the wood.
Heat-treatment of wood in this manner generally proceeds as follows. First, the wood is dried to remove a substantial portion of the liquid from the wood. In one embodiment, the drying process occurs in a range from about 110 degrees C. (230 degrees F.) to about 175 degrees C. (345 degrees F.). The dried wood is then heated to and maintained at an elevated temperature, such as between about 150 degrees C. (302 degrees F.) and about 215 degrees C. (420 degrees F.), and more suitably between about 185 degrees C. (365 degrees F.) and about 215 degrees C. (420 degrees F.). It is contemplated that in other embodiments the elevated temperature at which the wood is heat-treated may exceed 215 degrees C. (420 degrees F.) as long as the temperature remains below the ignition temperature of the wood specimen to inhibit charring or burning of the treated wood. The treated wood is suitably maintained at this temperature for a time sufficient to undergo the changes described above. In one exemplary embodiment, the wood is maintained at the elevated temperature for between about two hours and about three hours. The dried wood material is then cooled by a suitable cooling method such as air cooling, liquid cooling or other know method.
In one exemplary embodiment, the dried heat-treated wood may then be partially rehydrated to increase the liquid content of the cellulose material to levels of between about one percent and about eighteen percent. In still another exemplary embodiment, the heat-treated wood may be partially rehydrated to levels of between about one percent and about ten percent. In yet another exemplary embodiment, the dried wood material may be partially rehydrated to levels of between about two percent and about ten percent. It is understood, however, that the heat-treated wood need not be partially rehydrated, such that the liquid content in the dried wood is less than about one percent, without departing from the scope of this invention.
In this experiment, samples of aspen wood heat-treated according to one suitable embodiment and conventionally-treated aspen wood were evaluated to determine Reticulitermues flavipes termite feeding preference between these wood samples.
The heat-treated wood was processed as follows. The wood was cut to a common board dimension, such as a standard 2×4 plank (i.e., cross section of about 38 millimeters (1.5 inches) by about 89 millimeters (3.5 inches)). The wood was then placed within a kiln or high temperature/pressure vessel. The temperature within the vessel was increased rapidly to about 100 degrees C. (212 degrees F.) and held until the wood uniformly reached approximately zero percent moisture content. The temperature was then steadily increased to and maintained at about 185 degrees C. (365 degrees F.) for a period of about 120 to 180 minutes. After drying, the temperature of the wood was decreased to between about 80 degrees C. (176 degrees F.) and about 90 degrees C. (194 degrees F.). A steam spray was used during the cooling period to reduce the temperature of the wood and to increase the moisture content of the wood to between two percent and about ten percent. The entire heating and cooling down process took approximately 36 hours to complete.
The conventionally-treated aspen wood was kiln dried at a temperature of about 85 degrees C. (185 degrees F.) and about 90 degrees C. (195 degrees F.) for about five to six days. After drying, the conventionally- treated aspen wood was allowed to cool to ambient.
The experiment was conducted utilizing both a choice and a no-choice laboratory bioassay. The purpose of the study was to determine the preference, based upon association and/or consumption, between the two wood samples described above. With the choice laboratory bioassay, 300 termites by weight with 20 grams (0.7 ounce) of sand at 12% moisture were added to a petri dish with an average weight across all replications of an approximately 4 gram (0.141 ounce) portion of the two types of wood located in respective opposite halves of the petri dish. The termites were placed between the portions of wood and were allowed to move to and consume the wood they preferred. After 31 days, the termites on or near each of the pieces of wood were counted. In addition, the termites were removed from the wood and the wood weighed to determine the amount consumed. This choice test was repeated seventeen times with seventeen sets of 300 termites and new wood samples.
For the no-choice bioassay, 300 termites by weight with 20 grams (0.7 ounce) of sand at 12% moisture were added to a petri dish with an average weight across all replications of an approximately 4 gram (0.141 ounce) portion of one of the wood samples. The termites were placed across from the portion of wood and were allowed to move freely within the test chamber and consume the wood. After 31 days, the termites were removed from the wood and the wood weighed to determine the amount consumed. This choice test was repeated five times with five sets of 300 termites and new wood samples for each of the two different types (heat-treated and conventionally treated) of wood samples.
With respect to consumption in the choice bioassay, the wood heat-treated at elevated temperatures realized a mean consumption rate of 19.0 milligrams per gram of termites per day (19.0 milliounces per ounce of termites per day) with a standard deviation of 2.9 over the seventeen choice tests. In contrast, the conventionally-treated wood realized a consumption rate of 15.1 milligrams per gram of termites per day (15.1 milliounces per ounce of termites per day) with a standard deviation of 5.0 over the seventeen choice tests. In the no-choice bioassay, the wood heat-treated at elevated temperatures realized a consumption rate of 42.4 milligrams per gram of termites per day (42.4 milliounces per ounce of termites per day) with a standard deviation of 1.6 over the five no-choice tests. In contrast, the conventionally-treated wood realized a consumption rate of 37.5 milligrams per gram of termites per day (37.5 milliounces per ounce of termites per day) with a standard deviation of 5.6 over the five no-choice tests. Thus, for both the choice and no-choice bioassays, the wood that was heat-treated at elevated temperatures realized greater consumption rates than the conventionally-treated wood.
Moreover, when considering association, rather than consumption, the mean number of termites over the seventeen choice bioassay tests located in the half of the petri dish including the wood that was heat-treated at elevated temperatures was 183, with a standard deviation of 34. In contrast, the mean number of termites located in the other half of the petri dish including the conventionally-treated wood was 72, with a standard deviation of 40. Of the 300 termites included in each experiment, a mean of 47 died during the experiment. This result occurred even though the wood that was heat-treated at elevated temperatures was significantly drier, having less internal moisture content, than the conventionally-treated wood. This indicates, rather unexpectedly, that the reduced moisture content of the wood heat-treated at elevated temperatures did not deter the termites from feeding on the wood and even more unexpectedly it attracted more of the termites due to the physical and/or chemical characteristics of the wood. Termites in this study demonstrated significantly greater attraction to or preference for the wood heat-treated at elevated temperatures as compared to the conventionally treated wood.
In view of the above Experiment, the increased non-physical attraction and association preference of the wood heat-treated at elevated temperatures may significantly enhance the efficacy of a termite monitoring and/or baiting station that includes such a wood. As a more particular example, the illustrated aggregation member 61 comprises a solid wood block 67 that has been heat-treated at elevated temperatures as discussed above. It is understood, though, that the heat-treated wood from which the aggregation member 61 is made may alternatively be in a mulch form, a powder form or other suitable form. The aggregation member 61 is also suitably free from toxicant. For example, the above-described heat-treated wood has no added or natural toxicants.
In other embodiments, it is contemplated that the aggregation member 61 may instead comprise a non-toxic physical attractant, i.e., an attractant that once contacted by a termite promotes further foraging by termites. Suitable examples of such physical attractants include, without limitation, paper, cardboard, wood (e.g., other than wood that has been heat-treated in as described above) and other cellulose materials. Additionally an agar matrix alone or combined with sugars (i.e., xylose, mannose, galactose) and/or purified cellulose materials may be used as the aggregation member 61 to attract termites due to its moisture content and/or feeding attractant.
The bait matrix 63 suitably comprises a non-toxic attractant and may or may not carry a toxicant for eliminating or suppressing termite infestations. As one example, the illustrated bait matrix 61 comprises a purified cellulose powder compressed into one or more tablets 69. Without toxicant added to the bait matrix 61, the bait matrix may be suitably used to monitor for the presence of termites in the area of the termite station 21. Toxicant, if added to the bait matrix 61, is suitably one or more of a delayed-action type toxicant, or an insect growth regulator, pathogen or metabolic inhibitor. One such toxic bait matrix 61 is disclosed in co-assigned U.S. Pat. No. 6,416,752 entitled “Termite Bait Composition and Method”, the entire disclosure of which is incorporated herein by reference. It is understood that other suitable known monitoring and/or toxic bait matrix materials and/or compositions may used without departing from the scope of this invention. In the illustrated embodiment, four such toxic bait matrix tablets 69 are used in the cartridge 51. However, it is contemplated that any number of bait matrices, including a single bait matrix, may be used without departing from the scope of this invention.
The illustrated cartridge holder 65 comprises a cup portion 71 configured generally as a pair of cylindrical cups 73 (e.g., each having a closed end 75, an open end 77 and a side wall 79 extending therebetween) with overlapped segments so that the cup portion defines a generally 8-shaped bait matrix pocket 81. The pocket 81 is suitably sized and configured for at least receiving, and more suitably for receiving and retaining, the bait matrix 63 therein and more suitably for receiving and retaining one or more of the illustrated circular tablets 69 therein. For example, the figure 8-shaped pocket 81 of
A plurality of projections, such as in the form of ribs 83 in the illustrated embodiment, are disposed lengthwise along the inner surface of each cup side wall 79 to extend laterally inward of the pocket 81 formed by the generally cylindrical cups 73. For example, the ribs 83 illustrated in
Still referring to
Suitable spacing structure is provided to space at least a portion of the aggregation member 61 from the base panel 25 in what is referred to herein as an operating configuration (
The spacing structure may alternatively be formed into the aggregation member 61, such as grooves, slots or other voids formed in the outer surface of the wood block 67, so that less than the entire outer surface of the wood block (e.g., where the grooves, etc. are located) lies against the base panel 25 in the operating configuration of the termite station 21. In other contemplated embodiments, suitable spacing structure may be formed integrally with the inner surface 37 of the base panel 25, or it may be formed separate from and attached thereto, at one or more locations contacted by the aggregation member 61 in the operating configuration of the termite station 21. While less preferred, it is also understood that other suitable spacing structure may be formed and remain separate from both the cartridge 51 and the container 23 and disposed therebetween in the container to space at least a portion of the aggregation member 61 from the base panel.
As best seen in
As best seen in
With reference again to
To use the termite station 21 for monitoring and/or treating against termite infestation, the lid 31 is opened and the cartridge 51 is removed from the container 23. The cartridge cover 101 (if present) is removed from the cartridge 51 to ex pose the aggregation member 61 and bait matrix tablets 69. The cartridge 51 is re-inserted, open end first, into the container 23 so that the aggregation member 61 now faces the base panel 25 and is otherwise spaced from the base panel by the standoff elements 99 (broadly, spacing structure) and the bait matrix tablets 69 are spaced from the base panel by spacing elements 49 as illustrated in
In operation, with the termite station 21 configured in its operating configuration, as termites approach the base panel 25 from outside the container 23, either from behind the base panel or from the sides of the container, they quickly enter through the openings 39 formed in the base panel or through the peripheral openings 47 formed in the end and/or side panels 27, 29 where the corresponding access panels removed. The placement and arrangement of the aggregation member 61 relative to the bait matrix 63 (i.e., nearer to the base panel 25, end panels 27 and side panels 29 than the bait matrix) results in the termites first encountering the aggregation member after entering the interior space 33 of the container. Where the aggregation member 61 is a non-physical attractant, such as the previously described heat-treated wood block 67, the termites may even be lured or drawn by the aggregation member into the termite station 21. The termites, induced by the aggregation member 61 to forage further within the container 23, ultimately discover and are induced to consume the bait matrix 63.
Where the bait matrix 63 is free from toxicant and is used instead for monitoring, the termites leave visual evidence of attacking the bait matrix, such as exploratory tunnels built by termites as they consume the bait material so that signs of termite infestation are left on the surface of the material, or mud tubing constructed across the surface of the material or into the cup portion of the cartridge holder. By adding toxicant to the bait matrix 63, foraging termites ingest the toxicant-containing bait and return portions of the bait to the nest through the pre-existing network of passageways, thereby effectively treating against the infestation.
It is expected that over time the need to replace to the cartridge 51 will arise, such as following long periods of non-infestation and exposure to environmental conditions, or following prolonged periods of infestation in which a substantial amount of the bait matrix 63 (e.g., the tablets 69 of the illustrated embodiment) is consumed. The cartridge 51 may be replaced by opening the lid 31, removing the old cartridge (e.g., as a single unit) and inserting a new one that includes a new aggregation member 61 and new tablets 69. Alternatively, if a new aggregation member 61 is not needed, just the bait matrix 63 (e.g., the tablets 69) may be replaced in the old cartridge 51 and the old cartridge reinserted back into the container 23. Because the aggregation member 61, bait matrix 63 and holder 65 are held in assembly as a single unit, the entire cartridge 51 is readily replaced without having to reach into the termite station 21, i.e., only the cup portion 71 of the holder 65 need be grasped and pulled outward to remove the cartridge from the container 23.
While in the illustrated embodiments of
With particular reference to
A cap 528 is removably received on the top surface 516 to close the housing 512. The cap 528 is removably secured to the top surface 516 of the housing 512. In one embodiment, the cap 528 has a pair of tabs 530 that extend into slots 532 in the top surface 516 of the housing 512. The cap 528 is then rotated either counter clockwise or clockwise to engage the cap 528. The tabs include a chamfer 534 along a leading edge 536 of the tab 530. As the cap 528 rotates into position, the chamfer 534 helps guide the tab 530 into position within the slot 532. Other suitable means for securing the cap 528 to the top surface 516 may be used.
Preferably, the housing 512 is formed from a durable, corrosion resistant material, as for example, an acrylic or high strength plastic. Although shown as having a generally cylindrical shape, the housing 512 may be any other suitable shape, such as rectangular. Preferably, the station 510 has a maximum height of less than about 18 inches (457 mm) and maximum diameter or width of less than about 12 inches (305 mm), and more preferably the station has a maximum height of less than about 9 inches (229 mm) and maximum width of less than about 4 inches (102 mm).
The station 510 includes at least one opening 537 passing through the side wall 514 to permit the ingress and egress of termites into and out of the interior volume 520 of station. Preferably, the side wall 514 has several vertical elongated openings 537 therein extending substantially the entire length of the side wall. As used herewith, vertical is used in reference to the preferred orientation of the station 510 with the top surface 516 facing in an upward direction. It is contemplated however, that other shapes and orientations for the openings may be used. For example, the openings may be horizontal elongated openings, or may be circular openings randomly placed or formed in a repeating pattern. Additionally, there may be openings 537 in the bottom surface 518 leading to the interior volume 520. In an alternate version, the openings 537 are formed only in a lower portion 538 of the side wall 514 of the housing 512 such that an upper portion 539 of the side wall 514 near the top surface 516 of the housing 512 is imperforate.
In use, the station 510 is at least partially received within a cavity accessible to termites, while still being accessible above ground by a user. The cavity may be a subterranean cavity, or may be a cavity within a wall or other framework of a building or other above ground structure. The cavity may be formed in the soil, or the cavity may be formed in a paving material, such as concrete or asphalt, with soil beneath the paving material. Preferably, the station 510 is substantially entirely received within the cavity such that only the top surface 516 and cap 528 are accessible from above ground. However, in some situations, the station 510 may be nearly entirely on top of the ground, such that the cavity is very shallow.
In one embodiment, as shown in
Alternately, the aggregation base 522 is received directly within the cavity. For example, when the aggregation base 522 is to be used in a more durable environment where there is little possibility that sidewalls of the cavity will collapse around the aggregation base 522, such as, for example, in paving material, the aggregation base 522 can be placed directly into the cavity. The monitoring container 524 or the bait container 525 then may be positioned in the cavity adjacent to, and preferably directly above, the aggregation base 522. In such an embodiment, there is no need for a station to receive the aggregation base 522 and the containers 524, 525. A suitable cap, designs of which are known in the art, would then be placed over the cavity to secure the aggregation base 522 and containers 524 or 525 within the cavity. However, in the above embodiments, the aggregation base 522 is located in the cavity or station 510 in a substantially stationary manner so that there is minimal disturbance to the aggregation site and the termites while the containers 524 or 525 are being inspected, removed and/or replaced.
Alternately, the aggregation base 522 may be made of plastic or other suitable material and filled with cellulosic material, such as paper, cardboard, compressed tablets, or other suitable feeding material and may have holes providing access to the feeding material. In such a version, the aggregation base 522 may be similar in construction to the container 524. Additionally, the aggregation base may be made from a foam material. In some of these embodiments, the aggregation base may not have a void space free of material, but the base is still preferably configured so that termites feeding on the aggregation base or material within the aggregation base will form an aggregation site within the base.
Referring now to
Referring to both
Preferably, the combined length of one container 524 or 525 and the aggregation base 522 is less than the length of the housing 512 so that the container 524 or 525 can be received within the housing 512 in a manner which will not interfere with placement of the cap 528 to cover the top surface 516 of the housing 512. Preferably, for reasons which will be more fully discussed below, the lid 552 and/or the cup 550 are transparent (or at least partially transparent).
As shown in
The monitoring container 524 is configured to be replaceably received adjacent the aggregation base 522 (see, e.g.,
The lid 552 of the containers 524, 525 also may have at least one opening 570 (see
The lid 552 is removably secured to the cup 550 using any suitable means. Referring to
In operation, a cavity of appropriate dimensions can be made in the soil or other structure for positioning of the station 510. Typically, the aggregation base 522 and monitoring container 524 are placed inside the station housing 512, and the station 510 is then inserted or pressed into the cavity until the top surface 516 of the station housing 512 is near the soil surface. However, in some instances, such as when there is a known presence of or conditions conducive for termites, it may be desirable to directly begin using the bait container 525 with the aggregation base 522 and not use a monitoring container 524. Alternatively, the aggregation base 522 is placed directly into the cavity. The container, either 524 or 525, is then placed into the cavity adjacent the aggregation base 522. The description below will describe the aggregation base 522 as being placed within the station 510, but it is contemplated that the aggregation base may be placed adjacent to the monitoring container 524 or bait container 525 without the use of a station 510 as described above. Termites locate the station 510 and the aggregation base 522 as the result of their foraging in search of food sources.
As termites approach the outside of the station 510, they quickly enter through the openings 537 and move inside to find the aggregation base 522, which is a potential food source. The openings 537 in the station encourage the termites to quickly pass through the side wall 14 to the aggregation base 522. If the termites enter through the openings 537 and contact the container 524 or 525 above the aggregation base 522, the imperforate sidewalls of the container direct the termites down along the elongate openings 537 to the aggregation base 522. The channels 544 encourage the termites to enter the aggregation base 522 and begin to use the internal void 542 created by the base as an aggregation site. The void 542 creates a stopping area in the center for aggregation. Once inside, they will move toward the top of the aggregation base 522 and into the monitoring container 524. Because only the monitoring container 524 is removed to monitor for termite activity, the aggregation base 522 remains undisturbed, thereby maintaining the void 542 of the aggregation base 522 and the aggregation site therein intact.
The station 510 can be inspected periodically for evidence of termite infestation by visually examining the monitoring container 524 for signs of infestation. Inspection of the station 510 can be performed weekly, bi-weekly, monthly, etc. as needed or desired. An inspection is performed by removing the cap 528 and visually inspecting the chamber 553 of the monitoring container 524 or the aggregation base 522 for termite attack. Because of the nature of termite attack against a cellulosic material, such as the monitoring medium 555 or the aggregation base 522, visible signs or evidence of such attack will invariably be left on the monitors. This evidence can include, for example, exploratory tunnels built by termites as they consume the material in such a way that telltale signs of termite infestation are left on the surface of the material and/or mud tubing constructed over and across the interior surface of the station housing 512 or monitoring container 524. Such signs of infestation would be obvious to anyone skilled in the art of termite damage detection. If termite attack is discovered, the station 510 is baited by replacing the monitoring container 524 with a bait container 525. Alternately, the monitoring medium 555 can be removed and replaced with the bait 557. If no termite attack is discovered, the monitoring container 524 is returned to the station 510. The cap 528 is replaced and the station 510 is inspected again after the appropriate interval.
Termites consuming the aggregation base 522 will discover and transition to feeding upon the nearby monitoring medium 555 in the monitoring container 524. This can be for one or more reasons. If the monitoring medium 555 is of a consistency more preferred by termites than the aggregation base 522, then termites may cease to consume the aggregation base 522 and transition to consuming the monitoring medium 555 before the entire aggregation base 522 is consumed. If termites continue to consume the aggregation base 522, the termites will still transition in the normal process of termite foraging to consuming the monitoring medium 555 when the aggregation base 522 is entirely consumed. Because the monitoring medium 555 is nearby and is of a nature preferably consumed by termites, they invariably begin consuming the monitoring medium.
Once termites have been discovered attacking the monitoring medium 555 or aggregation base 522, the station 510 is baited with the toxicant containing bait 557. Preferably, the monitoring container 524 is removed and replaced with the bait 557 in container 525. The toxicant-containing bait may be in the form of purified cellulose toxicant delivery tablets. One suitable termite bait composition is described in co-assigned U.S. Pat. No. 6,416,752 entitled “Termite Bait Composition and Method”, the disclosure of which is incorporated herein in its entirety by reference.
The toxicant in the bait 57 is preferably of the delayed-action type, or an insect growth regulator, pathogen or metabolic inhibitor. Preferably, it comprises a nontoxic bait composition to which the pesticide toxicant is added. Any suitable termite pesticide composition may be used in connection with the present invention. In one embodiment, the bait is in the form of tablets. For example, in one suitable embodiment, the bait 557 comprises at least one compressed tablet having a mass of between about 10 grams (0.35 ounce) and about 45 grams (1.6 ounces), more preferably between about 25 grams (0.88 ounce) and about 40 grams (1.4 ounces), and even more preferably about 35 grams (1.2 ounces).
The removal, inspection and/or replacement of the containers 524, 525 within the housing 512 does not substantially disturb the pre-existing network of access galleries or passageways previously established between the termite colony or nest and the aggregation site in the aggregation base 522 since the base is not displaced during removal and substitution of the container 524, 525. Thus, the disturbance of the aggregation site in the aggregation base 522 is minimized, reducing the likelihood that the termites will abandon the feeding site. Also, communication and access between the pesticide containing container 525 and the termite colony is quickly established upon substitution of the monitoring container 524 with the bait container 525. Foraging termites ingest the pesticide-containing bait 557 and also return portions of the toxic bait to the nest through the pre-existing network of passageways.
The station 510 is inspected at regular intervals (e.g., every 15 to 120 days) to assess the extent of termite consumption of the bait 557. When the bait 557 in the container 525 has been substantially consumed, more bait can be added by removing the lid 552 and inserting more bait in the container 525 or simply by replacing the container with a fresh container. Thus, during normal inspection and/or replacement of containers 524, 525, the aggregation base 522 is not removed and disturbance to the aggregation site is minimized. It may be necessary to periodically replace the aggregation base 522 (e.g., once a year to freshen up the aggregation base 522). This however, is not usually done while termites are actively feeding from the site.
In accordance with another embodiment of a method for treating insects, and more suitably for treating subterranean insects and even more suitably for treating subterranean termites, the heat-treated wood described previously herein may be deployed in the station housing instead of, or in addition to, the aggregation base 522. For example, in one embodiment the aggregation base may be formed of the heat-treated wood but otherwise constructed in the same manner as the aggregation base illustrated in
In each of the above embodiments, the heat-treated wood is suitably exposed to the moist environment (e.g., moist air, soil, and/or ground water) surrounding the station housing, such as by being directly exposed to the environment surround the station housing, or by being placed in a container that is suitably liquid permeable to permit exposure of the heat-treated wood to moisture in the environment surrounding the container. In such an arrangement, upon exposure to sufficient moisture, a liquid extract containing one or more compositions of the heat-treated wood leaches from the heat-treated wood out of the station housing and into the surrounding soil. The liquid extract thus broadly defines a liquid attractant and generally forms an attractant zone surrounding the station housing to further attract termites to the station housing.
In another embodiment of a method for monitoring and/or controlling insects, and more suitably for monitoring and/or controlling insects and even more suitably for monitoring and/or controlling termites, a heat treated wood extract is suitably generated from the heat-treated wood and then deposited in an area to be monitored and controlled (e.g., into a cavity where no station housing is used) for use in attracting and monitoring termite activity, or deposited into the soil or other environment exterior of the station housing, and/or deposited into the station housing for subsequent release into and absorption by the soil surrounding the station housing. As used herein, the term “heat treated wood extract” is intended to broadly refer to a liquid extract such as an aqueous extract or non-aqueous extract of the heat treated wood, or a solid extract (such as in a solid, particulate or other dried form) of a liquid extract of the heat treated wood.
As one example of a particularly suitable embodiment, the dried heat treated wood described above is subjected to a water extraction to generate an aqueous heat treated wood extract. More suitably, in accordance with one process for generating the aqueous extract, the dried, heat treated wood, in particular form, is combined with a volume of water and the mixture is heated, and more suitably brought to a boil for a time period of at least about 10 minutes, more suitably in the range of about 10 minutes to about 120 minutes, and even more suitably in the range of about 30 minutes to about 120 minutes. The mixture is then filtered to remove particulates, leaving an aqueous heat-treated wood extract containing extractives from the heat treated wood. It is contemplated that a liquid extract may be generated other than in water to provide a non-aqueous heat treated wood extract without departing from the scope of this invention. The liquid heat treated wood extract generated via extraction may be used as an attractant by itself or in conjunction with an insect monitor and/or control system such as the above-ground system of
In this experiment, an aqueous heat treated wood extract of aspen wood heat-treated according to one suitable embodiment, and filtered water, were evaluated to determine Reticulitermues flavipes termite feeding preference between these samples.
The heat-treated wood was processed as follows to generate the aqueous extract. The wood was cut to a common board dimension, such as a standard 2×4 plank (i.e., cross section of about 38 millimeters (1.5 inches) by about 89 millimeters (3.5 inches)). The wood was then placed within a kiln or high temperature/pressure vessel. The temperature within the vessel was increased rapidly to about 100 degrees C. (212 degrees F.) and held until the wood uniformly reached approximately zero percent moisture content. The temperature was then steadily increased to and maintained at about 185 degrees C. (365 degrees F.) for a period of about 120 to 180 minutes. After drying, the temperature of the wood was decreased to between about 80 degrees C. (176 degrees F.) and about 90 degrees C. (194 degrees F.). A steam spray was used during the cooling period to reduce the temperature of the wood and to increase the moisture content of the wood to between two percent and about ten percent. The entire heating and cooling down process took approximately 36 hours to complete.
The heat treated wood was ground by mechanical process until the particulate size of the material was in the range of 1 to 250 microns. A measure amount equal to approximately one-third the volume of a standard U.S. gallon liquid was then placed in filtered water and boiled for a period of 20 minutes. After boiling, the water/heat-treated wood mixture was allowed to cool and then filtered to remove particulates from the mixture, leaving the aqueous heat treated wood extract.
Whatman brand filter papers, Cat. No. 1001-150 (150 mm diameter) were soaked in the aqueous heat treated wood extract and allowed to air dry. Additional filter papers were soaked in filtered water (e.g., without heat treated wood extractives) and allowed to air dry. The dried filter papers were then placed about 12 inches apart on top of termite infested soil inside an aquarium for a period of two weeks, during which time the aquarium was visually inspected and termite activity observed. After two weeks, visual observation revealed that the filter paper treated with the aqueous heat treated wood extract was extensively fed upon and penetrated, while the filter paper treated with filtered water had substantially less feeding activity and in some instances no feeding activity.
In one suitable embodiment of a method for monitoring and/or controlling insect populations, and more suitably termite populations, the aqueous heat treated wood extract (broadly, the liquid heat treated wood extract and more broadly the heat treated wood extract) is delivered to the station housing of a termite monitor and control system such as the system of
In another embodiment, the liquid heat treated wood extract may be carried on or in a suitable carrier, such as by being soaked into or coated on a substrate such as cardboard, paper, wood or other suitable substrate, or contained within a suitable container (broadly, a carrier) that allows the solution to leak out therefrom. In such an embodiment the carrier may be placed in the station housing of an above ground system (
In other embodiments, a liquid heat treated wood extract may be subjected to de-solventization, such as without limitation boiling down the extract, by freeze-drying, by vapor induced evaporation, another suitable de-solventization process or any combination thereof to generate a heat treated wood extract in solid form (i.e., a solid mass or a particulate such as a powder or crystalline form). The heat treated wood extract may then be placed into the station housing in the same manner as the liquid heat treated wood extract and/or the particulate heat treated wood described previously.
As various changes could be made in the above methods and products without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not limiting.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US09/48195 | 6/23/2009 | WO | 00 | 3/8/2011 |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 61076195 | Jun 2008 | US |
| Child | 13000990 | US |
