AU2007101164A4 - A system and method for the control of termites - Google Patents

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INNOVATION PATENT SPECIFICATION

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DATE FILED: Microbiological Decontamination Services Pty Ltd A SYSTEM AND METHOD FOR THE CONTROL OF TERMITES New Innovation Patent 6 December 2007 DRAFT INNOVATION PATENT APPLICAITON O A SYSTEM AND METHOD FOR THE CONTROL OF INSECTS 5 Field of the Invention The present invention relates to a system and method for the control of insects. In particular, the present invention relates to controlling subterranean insects such as termites. A particular application is the control of termites around or beneath a concrete slab. The present invention also relates to a method and system for controlling termites in the vicinity of a timber post or Stree.

Backqround of the Invention The present invention will be described with particular reference to the control of termites. However, it will be appreciated that the present invention may be used in the control of any suitable subterranean insect including fire ants and no limitation is intended thereby.

There a numerous methods for controlling termites egress into a building. These methods may be broadly identified as physical or chemical methods. The physical methods involve providing a physical barrier to the passage of termites. Examples of physical barriers include stainless steel mesh or granite. Particular attention needs to be made to the areas around where pipes penetrate a concrete slab. These areas can provide breaches through which termites may gain access to a building. To this end, a number of collars or similar barrier systems have been developed for application about pipe penetrations.

Chemical barriers rely upon application of a chemical into the soil around a building to create a chemical barrier. Early chemical barrier systems simply involved spraying a chemical into a trench dug around the building.

Organochlorine compounds were initially used as chemical barriers. These compounds are persistent in the environment and were active against termites for up to about 30 years. However these compounds are toxic and have been banned in most countries. The organochlorines have been replaced by other less toxic chemicals. However, the lifetime of these alternative chemicals is significantly less than the organochlorines which means that the chemical Sbarrier must be replaced every few years or so.

Conventional replenishment of chemical barriers involves redigging trenches and spraying or the use of injection rods. The difficulties in 5 reapplying an under slab concrete treatment will be appreciated.

Conventionally, holes are drilled in the slab through which a termiticide was injected.

A recognized difficulty with chemical barriers of the repellent type is 0 that if there is any breach in the system, such a breach will provide a passage 10 through which termites may pass. It is known that termites are able to actively Sseek out such a breach in a repellent chemical barrier. Expansion joints, cracks, and utility and plumbing lines are common termite entry points through a concrete slab. Termiticide breakdown, soil erosion, improper application, and careless construction practices (such as leaving wooden grade stakes in the slab or disturbing treated soil) are several ways that the chemical barrier can be broken.

Appreciation of this problem has led to the use of a class of termiticides commonly known as non-repellent termiticides as opposed to the earlier repellent and/or contact killing termiticides. These repellent compounds relied upon repelling a termite from the barrier and were thus subject to being breached. Non-repellent termiticides do not repel or immediately the termite but allows the termite to pass through the barrier. The non-repellents typically do not kill on contact but allow the termite to return to the nest carrying the toxin on their body. In this way they are able to infect other termites in the nest. However, the difficulties associated with reapplication of the nonrepellant termititicides remains.

In order to address the reapplication problem a number of systems and methods known in the art as termite reticulation systems have been proposed.

A common feature to all of these reticulation systems is a system of substantially rigid perforated pipes which may be placed beneath a concrete slab or in a trench about the perimeter of a building. Termiticide is introduced into the pipe and trickles through downward facing perforations in the pipes.

The present inventor has observed that in practice there are some difficulties associated with such replenishment systems. One difficulty is the potential for uneven application of the termiticide into the surrounding soil as a Sresult of the trickling of the termiticide into the soil. It will be appreciated that the liquid termiticide solution will follow the path of least resistance and may I selectively filter though micro fissures or the like in the soil, thereby providing an uneven chemical barrier. Although it is generally believed such an uneven or incomplete application ought not to be a major problem when using the new generation of non-repellent termiticides, the present inventor believes that there is an advantage to be gained by providing a more even application.

One approach to address the problem of uneven application is known in the industry as the Altis system. This system does not use pipe Sperforations but instead uses specially designed controlled flow-rate emitters fused into the pipe. Another important feature of the Altis system is that the pipes are laid over perforated sheeting so as to further provide an even distribution of termiticide.

Another approach to solve the problem associated with uneven delivery is to surround the pipe with a hydraulic conductor such as a geotextile material. The material absorbs the liquid for even transmittal to the surrounding environment. However, in practice the present inventor has observed that the termiticide tends to remain absorbed in the textile and does not diffuse effectively into the surrounding soil so as to provide an effective barrier. Still further the textile may act to draw the liquid from the pipe, thereby adversely affecting the flow rate.

It is therefore an object of the present invention to provide a system and method for controlling termites which may at least partially address the above difficulties or provide the public with a useful or commercial choice.

Summary of the Invention According to a first broad form of the invention there is provided a system for controlling insects in soil beneath or about a structure, the system comprising at least one substantially flexible pipe having perorations spaced along the length thereof and adapted to be placed in soil below a ground surface such that when placed, the perforations are facing in a substantially upwards direction and a source of liquid composition comprising an insecticide for pumping the liquid through the pipe at a pressure of at least about 80psi such that in use the liquid is forced at pressure though the Sperforations into the surrounding soil.

O The flexible pipe as used in the system of the invention may be made Sfrom any suitable material through which a fluid may flow under a pressure of at least about 80psi. Preferably the pressure is between about 100 and about 200 psi, most preferably in the order of 125psi. A suitable pipe is a coated PVC pipe.

Typically, the pipe is available in discrete lengths of up to about preferably about 10m. A length of pipe has a closed end and a filler end. The filler end is typically provided with a one way valve. Provision of discrete Slengths can reduce or substantially avoid a significant pressure drop along the length of the pipe. If the length of coverage is greater than 10m, multiple discrete lengths of pipe may be used.

The pipe is substantially flexible which means that it has the ability to bend up to about 900 or more. This enables a significant flexibility in the laying of the pipe and the use of corner connectors or the like may be avoided. This flexibility also allows the pipe to be coiled or wound around a slab penetration such as a utility or plumbing pipe.

The pipe is typically resilient such that it holds its shape when empty and under pressure during use but may resiliently respond to compressive forces that may be experienced by the passage of heavy machinery or vehicles should the pipe be laid under a construction site.

The pipe has spaced perforations. The spacing of the perforations is typically between about 100 and 300mm, preferably about 200mm. Typically the pipe has more than one perforation per spacing. In this case, the perforations are typically located so as to optimize the spray pattern of fluid being expelled therefrom. A preferred embodiment has perforations located so as to provide between about an 800 to about 1200, preferably about a90 spray pattern or in other words the perforations are spaced at an angle of between about 400 and about 600, typically about 450 on either side of the vertical axis of the pipe. Typically, the pipe has series of spaced opposed pairs of perforations.

For soil barrier applications around a structure, the pipe is typically laid

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between 50 to 300mm, typically about 100mm below the soil surface. In this case, the system typically includes an access device that allows the filler end of the or each pipe to be readily accessed. A suitable device is a junction or filler device in the form of a sleeve that is placed in the ground with the upper end substantially level with the ground surface. The sleeve is typically provided with a removable cap or closure. In use, the cap is removed to allow access to a filler end. In cases where multiple discrete lengths of pipe are 0 used a sleeve typically houses the filler ends of two or more pipes.

If required, the system may also include a length of feeder pipe to 0 extend the distance between the filler end of a pipe and a source of fluid. The feeder pipe is unperforated and is typically the same diameter as the perforated pipe. In the absence of perorations there is generally little or no pressure drop along the length of the feeder pipe.

The system of the invention is delivers a fluid. The fluid is generally a liquid composition comprising an insecticide. It will be appreciated that the composition may also include other agents known in the art such as surfactants, stabilizers, emulsifiers, dyes and the like.

The fluid may also be in the form of foam. The use of foaming agents with insecticide composition suitable for spray application is a relatively new development in termite control. A foaming agent is added to an insecticide solution which is applied under pressure. An advantage of foam is that it is able to penetrate into remote areas where conventional sprays can not go and are often missed. Foams may find use under concrete slabs, behind brick or other veneers, into framed walls and hollow block voids and shallow crawl spaces.

Foams are used to supplement the soil termiticide in completing the chemical barrier. Foamed termiticide is generally applied though an applicator nozzle. Generally it is necessary to drill holes to allow insertion of the applicator nozzle to a desired location. Foams are also available in pressurized containers. It will be understood that conventional reticulation systems which rely on a trickle feed are not able to deliver a foamed product.

The system of the present invention may be used in any suitable application where it is desired to be able to replenish an insecticide. The system may find applications as an under slab barrier, a perimeter barrier or for application of

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insecticide within wall cavities.

According to a further form of the invention, there is provided a method of controlling termites about a structure, the method comprising providing a length of a substantially flexible perforated pipe beneath or about the structure such that the perforations are faced in a substantially upwards direction and pumping a fluid though the pipe at a pressure of at least about 80 psi such that the fluid is forced through the perforations.

Termites are also known to attack structures such as timber stumps, 10 piers, posts and trees. The latter may be of particular commercial importance in a nursery environment. Conventional methods for protecting a pole or tree trunk from termite attack are by soil injection, a technique known in the art as rodding or trenching and backfilling. It is important to note that there is no current method known to the inventor for treating underneath an existing pole or tree. The flexible pipe of the present invention is able to be coiled or wrapped around a new or existing pole. The system may also be used to apply fungicides or, in the case of trees, fertilizer. Alternatively a second pipe system may be coiled around the post for delivery of the additional active agent.

It is preferable that the perforations are spaced at even intervals and the perforations are of constant size. To this end, the present inventor has developed an apparatus for perforating a pipe, the apparatus having; a drill head moveable between a hole drilling position and a feed mechanism for discreetly feeding the pipe past the drill head at predetermined intervals.

Preferably, the apparatus has a second drill head mounted at an angle to the first drill head such that opposed holes may be drilled in the pipe.

Brief Description of the Fiqures Figure 1 is a schematic view of the system of a preferred embodiment of the present invention located beneath a concrete slab of a structure; Figure 2 is a schematic view of another preferred system of the invention located about a post; Figure 3 is a cross sectional view of a preferred apparatus of the present invention; Figure 4 is a photograph of a preferred embodiment of the present Sinvention in use; Figure 5 is a photograph of a further preferred embodiment of the Spresent invention; Figure 6 is photograph of the embodiment of figure 5 after foam application; Figure 7 is a schematic diagram of a preferred system of the present invention as used to provide a chemical barrier to prevent termite ingress into 0 a dwelling; Figure 8 is a schematic cross section of a pipe laid in a trench and SFigure 9 is a perspective view of a junction box for use with the system as shown in Figure 7.

Detailed Description of the Figures Figure 1 shows part of a preferred system 11 the present invention. The system 11 includes a pipe 12 having pairs of 1.5mm diameter holes (not shown) and spaced at 200m intervals. The holes are spaced 450 on either side of the vertical axis of the pipe. The present inventor has found that such spacing provides an optimum spray pattern and distribution of fluid.

The pipe 12 is laid such that the holes face upwardly in an off centre manner in the soil 13 below a concrete slab 14 of a building. The pipe 12 is wrapped around a PVC plumbing pipe 15. Pipe 12 is held by a cable tie 16.

The pipe 12 is adapted for fluid connection to a fluid delivery system capable of delivering a pressure of up to about 300psi. A flow meter is operatively associated with the delivery system so that the amount of fluid delivered to the system may be accurately monitored and measured.

Figure 2 shows a schematic view of a further preferred system of the invention. In this case, the pipe 12 is wrapped around a wooden pole 17 in the ground. The pipe 12 is spiralled around the pole. A filler point 20 is located at ground level. In use, the filler point is attached to a delivery system as described above when it is desired to flow chemical through the pipe.

Figure 3 is a schematic view of a preferred apparatus 30 of the invention. The apparatus 30 has a drilling station 31 vertically 32 and horizontally 33 mounted drill units. The apparatus has a pneumatic press feeder 35 which draws the pipe 35 though the drill station. The feeder draws Sthe pipe through the drill station ain discrete 200mm intervals.

SExamples C 5 Example 1 A 10 metre long trench 150mm wide and 300mm deep was excavated and filled with a 70/30 blend of sand and loam. A pipe of the system of the invention was positioned at a depth of 100mm from the surface thus leaving 200mm to the bottom of the trench. This trial simulates a non-concrete t> 10 covered, perimeter vertical barrier treatment.

SExample 2 A 10m long trench 150mm wide and 300mm deep was excavated. The trench contained a 900 bend and a 300mm "step down" to account for varying building designs. Two 90mm diameter PVC pipes were inserted in the middle of the trench, spaced approximately 1 meter apart to act as penetrations such as a down pipe or toilet plumbing. The trench was back filled with a 70/30 blend of sand and loam. The pipe was positioned at a depth of 100mm from the surface thus leaving 200mm to the bottom of the trench and "looped" around each penetration as shown in figure 4.

The entire trench was then covered by 80mm of concrete via the use of 2 x 40mm thick slabs of concrete placed on top of each other. This trial simulates a perimeter vertical barrier treatment (including penetrations) that is covered by a concrete slab or path.

The delivery system consists of a 400 litre chemical tank pumped by a 4.5 HP Honda motor and brass Nova centrifical pump connected to the hose.

The system was pumped at a pressure of 125psi of Termidor at the label rate of 600ml. Termidor is a registered trade mark of Bayer. The active constituent of Termidor is 1 00g/L fipronil.

The system was treated at a rate of 1 00OL of mixture per cubic meter of soil.

The treatment pads were allowed to settle for 24 hours before soil sampling. The sampling tool consisted of a 29mm internal diameter steel tube with a stop marker at 100m from the end. The tube was pushed into the

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treated soil until the stopper touched the surface. Sampling was conducted every 500mm along the trench at the mid-point.

The soil sample was then placed into appropriately marked foil lined bag and immediately put into an ice filled cooler. After all the top 100mm of soil was sampled, the pipe was removed along with the top 200 mm of soil to allow sampling to b done at the bottom 100mm of trench. Therefore two samples were taken at the midpoint of the trench at the same distance alone the trench i.e.

Samples 1-21 from 0-100mm deep and 0 Samples 22-42 from 200-300mm deep.

The samples were then immediately placed into a freezer and kept overnight before delivery for analysis.

The results are shown in the Tablel below: Table 1 Example 1 Example 2 0-100mm 200-300mm 0-100mm 200-300mm Om 83.1 61.5 36.3 38.8 75.3 48.3 66.0 31.6 67.1 82.4 7.9 68.8 142.6 132.0 39.6 33.0 76.6 32.0 39.1 6.9 101.9 86.5 102.1 16.4 32.1 115.4 63.0 21.9 57.0 74.3 65.9 17.8 159.8 120.3 103.8 51.6 51.9 23.4 49.0 49.6 50.1 28.3 74.1 14.1 69.6 7205 76.6 25.6 24.3 73.4 11.8 51.0 119.1 121.9 57.9 83.9 28.1 11.4 115.4 26.5

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38.8 70.6 68.9 16.9 4800 70.5 74.9 40.3 8.5m 60.3 12.4 47.5 23.9 0.3 54.4 98.5 23.4 64.4 81.6 53.6 16.1 10.0 41.8 116.8 22.5 18.9 It can be seen form the results that both treatments provided a very even distribution of fipronil over the treated areas. The difference in some readings would be considered normal experimental variance. The end target for correct amount of fipronil in any treated zone should be between 20 and This trial shows that the system and method of the present invention provides a very satisfactory distribution of fipronil and provides the correct amount of fipronil in the treated zone as a vertical barrier.

Example 3 This trial was set up to simulate a gap between the soil and a simulated slab, in this case a piece of clear Perspex. Under normal reticulation systems do not address the problem of soil subsidence beneath a slab. By using a liquid the soil may be re-treated but the underside of the slab is not. This has the potential for allowing termite ingress into the building via travelling along the underside of the slab and bypassing any treatment.

The addition of a foaming agent to the system of the invention was tested to determine if such an under slab void could be filled and the correct volume of Termidor termiticide to the soil surrounding pipe penetrations to satisfy the requirements of Australian Standards 3660.2.

An area measuring 6.25m 2 was boxed using timber members. Various lengths and diameters of PVC pipe were laid in the test pad to simulate penetrations such as 50mm water pipes (small pipe) and 90mm toilet plumbing (large pipe).

A 10m length of pipe having opposed pairs of 1.5 perforations spaced 0at 200mm intervals was laid on the ground surface with the perforations facing downwardly, and looped about the penetrations. The pipe was then covered with a 100mm of a 70/30 blend of sand and loam. Figure 5 is a photograph of 5 the site prior to covering with the sand/loam mixture. The entire test pad was covered with a large sheet of Perspex to allow visual assessment of the treatment. The pipe has a closed end and a filler end fitted with a one way valve. Termidor concentrate was mixed at the label rate of 600mL of Termidor per 100 litres of water. The foaming agent was obtained from Becker Underwood under the tradename Pro-foam. This was used at the label recommended rate of 20ml of product per 1 litre of termiticide mixture.

The tank of a 4001itre chemical tank pumped by a 4.5 HP Honda motor and brass Nova centrifical pump having 100m of chemical hose was charged with water, termiticide and foaming agent as described above. The mixture was pumped through the pumps hose system until a creamy white liquid was observed to be flowing freely. By-pass agitation was applied and the system and the system was thoroughly circulated prior to treatment.

An alternative application system has a Y shaped connector having an air inlet, a fluid inlet and a foam outlet. Compressed air delivered by an air compressor run at at least 80psi is mixed fluid from a mixing tank. In this way foam is actually formed in the pipe rather than a mixing tank. As a result of the discrete length of pipe, no pressure drop is experienced along the length of the pipe. This ensures a substantially uniform application of foam.

Conventional reticulation systems are unable to operate under such pressures and in particular those systems having long lengths of pipe and/or supply multiple pipes through a manifold system. Significant pressure drops are experienced in such systems.

The aim of the trial was to protect the soil immediately surrounding the pipe penetrations; therefore a calculation was made on the basis that a vertical barrier be installed with dimensions of 100mm above the pipe, below the pipe and at least 80mm either side. This volumetric figure was multiplied by the lineal length of the pipes and was treated at the rate of 100L of mixture per cubic meter of soil as per requirements of the registered Termidor product label and the Australian Standard 3600 series.

Figure 6 shows the treatment pad after application of the foam.

SThe treatment pad was allowed to settle for 24 hours prior to sampling.

0 The Perspex was removed prior to sampling with a sampling tool consisting of a 29mm internal diameter steel tube with markers at 50mm intervals. The tube was pushed into the treated soil up to the depth required. One sample was taken at the top of one of the small PVC pipes. The pipes were then removed to allow sampling to be done at the bottom of the pipes, which is the treatment "shadow" that often allows termite ingress. These samples were Staken at various depths below the bottom of the pipe as described in Table 2 below.

All soil samples were laced into appropriately marked foil lined bags and immediately put into an ice filled cooler. The samples were them immediately delivered to the AgriSolutions Australia laboratory. This laboratory is a NATA registered facility accredited to OECD Principles of Good Laboratory practice. This accreditation is applicable to agricultural and veterinary chemical and residue analysis work.

Table 2 Sample Id Sample Description Fipronil content (mg/kg) 1 Soil on top of small pipe 53.7 2 Soil surface below small pipe (o-10mm) 56.2 3 Soil below small pipe (10-30mm) 34.1 4 Soil below small pipe (40-60mm)A 29.3 Soil below small pipe (40-60mm)B 26.2 6 Soil below small pipe (90-110mm) 18.5 7 Soil below large pipe (0-80mm)A 23.5 8 Soil below large pipe (0-80mm)B 13.9 It can be seen that the foaming treatment provided a very good distribution of fipronil, even below pipes that normally would be considered a weak spot or "shadow". As would be expected, the deeper under the pipe the less fiprinol was present.

Example 4 First and second 10 m trenches were dug at depths of 500m and 1 meter respectively. A 10m length of perforated pipe as described above was laid along the base of each trench. The trenches were re-filled with the removed soil. Termidor and a foaming agent were introduced into each pipe as described above for Example 3.

The aim of this trial was to simulate zone treatment of buildings with deep footings, retaining walls and step downs.

The treatment zone was allowed to settle for 24 hours before sampling commenced. Samples were taken from the top 100mm and bottom 100mm of each trench at intervals along the trench. A 500mm deep sample was taken from the 1 Meter deep trench. The results may be seen in Table 3.

Table 3 Sample Depth of Fipronil Residue Trench/mm (mg/kg) Top 100mm Test 1 500 12.1 Bottom 100 mm Test 1 500 8.8 Top 100mm Test 1 1 Metre 12.5 500mm down Test 1 1 Metre 25.1 1 Metre down Test 1 1 Metre 24.8 Top 100 Test 2 500mm 100.8 Bottom 100mm Test 2 500mm 20.2 Top 100mm Test 2 1 Metre 6.6 Bottom 100mm Test 2 1 Metre 500mm Down Test 2 1 Metre 1 Metre Down Test 2 1 Metre 203.4 Top 100mm Test 3 500mm Bottom 100mm Test 3 500mm 115.1 Top 100 Test 3 1 Metre 1.3 500mm Down Test 3 1 Metre 0.9 1 Metre Down Test 3 1 Metre 34.2

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Top 100mm Test 4 500mm 18.5 Bottom 100mm Test 4 500mm 22.8 Top 100mm Test 4 1 Metre 1.2 500mm down Test 4 1 Metre 2.6 1 Metre Down Test 4 1 Metre 0.4 It may be seen that at levels of 500mm and 1 Metre below the surface that fipronil is present in the upper 100mm of soil. It should also be noted that the test was conducted under conditions representing an actual construction site in that the soil was replaced in the trench (instead of sand/loam) and a bob cat was driven over the replaced soil. The results of this test are surprising considering that the conventional test depth is only 80mm. The present inventor is unaware of any other system capable of operating at these depths.

Figure 7 is a schematic view of a preferred system of the invention that has been installed to provide a chemical barrier in the soil around a dwelling 41. The system consists of lengths of 10m perforated PVC pipe 42. In order to install the system a trench is dug in the soil areas abutting the perimeter of the dwelling 41. The trench is dug to a depth 300mm to loosen the soil so it is not compacted. This provides improved chemical dispersion. The pipe 42 is laid in the top 100mm of the prepared trench 46. Figure 8 shows schematically a cross section of the trench 46. A length of pipe 42 10m long is placed in the trench 46 with the perforations 47 facing upwards. The pipe 42 has a closed end 43 and a filler end 44 fitted with a one way valve. The closed end 43 may be secured into the soil with a tent peg or the like. If there is a penetration such as a plumbing outlet or the like, the pipe may be wrapped around the penetration.

After the pipe 42 has been installed in the trench, a junction box 45 is installed. Figure 9 shows the junction box 45. The box 45 is in the form of a sleeve 47 having an open lower end 48 and an upper end 49 fitted with a removable cap 50. The lower end has opposed slots 50 through which the pipe 42 may pass. The junction box 45 is placed in the trench 46 such that the cap 50 is about level with the ground surface 51.

The above steps are repeated until pipe 42 has been laid about the full

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Operimeter of the dwelling 41. The system may be tested with water before refilling the trench.

In order to charge the pipe with termiticide, the cap 48 of the junction box 45 is removed to allow access to the filler end 44 of the pipe 42. A flexible supply hose is connected to the filler end by conventional hose joiners.

This may be compared earlier known low pressure reticulation systems which have a rigid feeder pipe connected to a perforated pipe. The rigid feeder pipe O is connected at one end underground to the perforated pipe and has a feeder 10 end projecting above ground. A disadvantage of this system is that the Sprojecting end of the feeder pipe is subject to tampering and/or damage.

Further the rigidity of the pipe necessitates at least a 90" bend in the pipe where it connects to the perforated pipe. Such a bend causes a significant reduction of pressure in the system. Other known systems use a manifold to connect multiple perorated pipes to a single feed pipe or line. These manifolds are limited to low pressure use as there is a significant pressure reduction by dividing flow from a single feeder pipe to a number of perforated pipes though a manifold or other connection. The system of the preset invention has a dedicated feeder perforated pipe connection such that there is minimal or no pressure drop upon charging the perforated pipe with fluid.

Once installed the perforations in the pipes may be cleared of soil or debris by the use of a flow of compressed air or cleaning fluid such as water through the system.

It will be appreciated that the system and method of the present invention is able to distribute an insecticide in an even and continuous manner both above and below the pipe The system is also able to deliver a foamed insecticide below a soil surface without the need for drilling and the use of applicator nozzles. The present inventor is unaware of any system that is able to deliver a foamed product through a perforated pipe.

The system is versatile and may be used for any number of suitable applications including around the perimeter of a structure, under slabs and in wall cavities. The latter application may also be useful for controlling other insect pests such as ants, cockroaches and the like. Still further, the system 16 is able to be flushed by blowing air or other cleaning fluid through the system.

SIn this way, any dust or debris which may otherwise clog the perforations may O be cleared therefrom.

SIt will be appreciated that various changes and modifications may be made to the invention as described and claimed herein without departing from the spirit and scope thereof.

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Claims (4)

1. A system for controlling insects in soil beneath or about a structure, the C system comprising at least one substantially flexible pipe having DO 5 perorations spaced along the length thereof and adapted to be placed in soil below a ground surface such that when placed, the perforations are facing in a substantially upwards direction and a source of liquid \D composition comprising an insecticide for pumping the liquid through the 0pipe at a pressure of at least about 80psi such that in use the liquid is r- 10 forced at pressure though the perforations into the surrounding soil.

2. The system of claim 1, wherein the liquid termiticide includes a foaming agent.

3. The system of claim 1 or claim 2 wherein the at least one substantially flexible pipe is provided in discrete lengths of between about 5 to about

4. The system of any one of claims 1 to 3, wherein the or each pipe has opposed pairs of perforations extending from about 400 to about 600 on either side of the vertical axis of the pipe when placed in the in soil. A method of controlling insects beneath or about a structure, the method comprising providing at least one length of a substantially flexible pipe having spaced pairs of opposed perforations and placing the or each length in soil below a ground surface such that the perforations are facing substantially upwards, providing a source of pressurized liquid comprising an insecticide, connecting the or each pipe to the source of pressurized liquid and pumping the pressurized liquid though the pipe at a pressure of at least about 80psi such that the liquid is forced at pressure though the perforations into the surrounding soil.