WO2009030072A1

WO2009030072A1 - Methods of preventing termite from eroding wood pole

Info

Publication number: WO2009030072A1
Application number: PCT/CN2007/002669
Authority: WO
Inventors: Kin Chuen John Ho
Original assignee: Kin Chuen John Ho
Priority date: 2007-09-07
Filing date: 2007-09-07
Publication date: 2009-03-12

Abstract

A method of preventing termite from eroding wood pole(5), including paving PE film around the pole, installing a sand drain and a vertical drainage pipe(4) in the soil combined with termiticides, collecting the information of the pole, measuring the concentration change of termiticides in soil, analyzing the plural observed data of the pole and termiticides, calculating the strength-decline of the pole and determining the minimum effective dose of termiticides, to make a handling procedure in application of termiticides. The method can prevent effectively termite from eroding wood pole over a long period.

Description

Method for preventing termites from invading wooden poles

The present invention relates to a method for controlling termites, and more particularly to a method for preventing termites from invading wooden poles to effectively extend the usable life of wooden poles. Background technique

Pressure Treated Wood Pole is one of the most common and cheapest materials used to support electric wires, power supply equipment, crossbeams, and communication facilities. It has many advantages, such as high support strength and quality. Easy to handle, long service life and more. Because wooden poles are exposed to natural phenomena such as sunlight and rain, this natural erosion is difficult to avoid, and such aging process is relatively slow. Many wooden poles used in World War II have been used today. Still in use. However, the wooden poles in use are plagued by another serious problem - the erosion of termites. Once termites begin to invade wooden poles, it is difficult to stop, and the rate of attack by termites on wood materials is staggering. Experience has taught us that many wooden poles used in the wild are affected by termites to varying degrees, so they have to be processed and replaced with wooden poles within 15-25 years after starting to use wooden poles, which leads to overall cost. Raise. In order to deal with termite infestation, more than four methods have been used, including treatment of the ground floor to treat the wood material itself. For example, the specification of US Pat. No. 5,022,134 discloses a replacement of poles or supports that are damaged by termites. The method and system of the body, the invention achieves the purpose of preventing termites by the treatment of the foundation, that is, forming a sleeve with stainless steel or other metal materials in the underground space, and then pouring cement concrete or other incompressible materials therein. , etc., after the fastening, the wooden material is implanted to achieve the purpose of preventing termites. nice A method for treating a foundation is also disclosed in the specification of the Japanese Patent No. 4,625,474, which is a plastic pipe having a crack in the underground of a wooden material, on which cement and a wooden floor are laid, and a termite-killing agent is periodically filled in the plastic pipe. , thereby preventing termites from eroding the wooden floor through the gap of the cement. Both of these methods are limited to prevent the erosion of termites, can not be effective for a long time, and do not establish an effective management system for the effective management of wood materials, and the two methods are costly and difficult to operate. Other methods for treating the wood material itself, such as the specification of Chinese Patent No. CN86102280, disclose a method for modifying Pinus massoniana and other woods for the purpose of controlling termites. The method is to modify the wood by chemical and physical treatment of the wood, that is, to use steam to dry the wood, then to release the turpentine, and then to use the rosin modifier (rosin, industrial alcohol, pentachlorophenol, polyvinyl butyral) The mixture) is immersed in the wood at normal temperature and pressure for 3 to 5 minutes to complete the treatment. This method has a certain effect on the control of termites, but the chemical dose will decrease with time, and the risk of termite infestation will be higher and higher. The method disclosed in the patent specification of the Chinese Patent Application No. CN200580002595.3 is that the termite-containing termiticide is applied to the surface of the wood material, and the wood material is buried in the ground. This method is only to prevent the infestation of termites in a short period of time. The defect is that the concentration of termiticide on the wood material will gradually decrease over time, and eventually disappears, so that it does not prevent for a long time. Moreover, direct contact of chemical components with the soil is also an infringement of the environment itself. All of the above methods can only prevent the termites from invading the wood material, and there is no scientific management system to continuously deal with the damage of termites, so it is insufficient in extending the service life of the wood materials. Therefore, how to effectively control the infestation of termites for a long time, and establish a scientific management method to continuously deal with the damage of termites, and reduce the damage to the soil and the environment, has become a difficult problem to be broken. Summary of the invention

In order to solve the above problems, an object of the present invention is to provide a method which can effectively prevent termites from invading wooden poles for a long period of time, thereby prolonging the service life of the wood poles, and is economical and environmentally friendly.

The method of the present invention adopts the following technical solution: A method for preventing termites from invading wooden poles, the method comprising the following steps:

(1) forming a space downward on the floor where the wooden pole is to be erected and laying the permeation-preventing material on the inner wall of the space;

(2) placing the wooden shield pole in the space and filling the space with sieved earth mixed with a termiticide;

(3) Collecting the original information about the erected wooden pole itself and the space it erects, including the basic information of the wooden pole, the shaft condition and strength data of the wooden shield pole, the termite concentration in the soil, and a period of time. After the time, the same erected wooden pole itself and the same information in the space it is erected;

(4) Based on the above-described sampling data analysis, the decay rate of the wooden pole and the minimum termite agent content are determined and an operation procedure for the normal spraying of the termiticide is established.

A further improvement of the invention resides in that the barrier material in step (1) is a polymeric film.

A further improvement of the present invention is that the polymer film is a high density polyethylene film (HDPE).

A further improvement of the present invention is that the thickness of the impervious material in the step (1) is 3-5 mm.

According to a further improvement of the present invention, the step (2) further comprises the following steps: (1) laying a layer of 100-200 mm thick sieved soil on the anti-permeate substance at the bottom of the formed space, and compacting the soil at the same time ; (3) Repeat steps (1) and (2) described above until the soil fills the entire formed space.

A further improvement of the present invention resides in the provision of a drainage sand well and a vertical drainage riser adjacent to the wooden poles in the space formed prior to the filling of the wooden poles.

A further improvement of the invention resides in that the drainage sand well and the vertical drainage riser are constructed as follows:

(1) Insert two scorpions of two sizes at both ends in the formed space, in which the smooth and non-porous small scorpion slides into the large scorpion formed by the stainless steel mesh, and a prefabricated vertical drainage vertical is placed inside the small scorpion. Tube

(2) After filling and fixing the large scorpion, slowly inject high-permeability sand into the gap between the scorpion and the prefabricated vertical drainage standpipe, and slowly pull out the scorpion from the big scorpion until the sand is completely filled. Full of scorpions and small scorpions are completely drawn from the big scorpion.

A further improvement of the invention resides in that the vertical drain riser is higher than the fill layer.

A further improvement of the present invention is that, in the step (3), useful information for collecting wooden poles includes: basic information of wood poles (wood type, manufacturer name, year of production, chemical treatment method, pole size, The wire structure, the number of conductors, the span and angle of the conductors on the pole, the position of the wooden pole after the placement of the wooden poles, etc.); the strength of the shaft of the wooden pole and the body of the recording pole from the ground to 1500 mm The state within the height: the thickness of the pole wall and the cavity of the pole; and collecting the original soil sample near the wooden pole and testing the concentration of the termiticide in the soil, and repeating the above sampling after a period of time, and continuously Sample multiple times.

A further improvement of the invention is that the soil sample is taken from a distance of 150 mm from the ground. Where.

A further improvement of the present invention is that the data collection and sampling time interval is 1-5 years.

A further improvement of the present invention is that the decay rate of the wood pole and the decrease in the termite concentration in the soil are determined by a curve drawn from the test results obtained from the original sampling and subsequent multiple resampling.

A further improvement of the present invention is that, after the wooden pole is placed, when the decay rate of the wooden pole is 90%, the concentration of the termiticide in the soil at this time is determined to be the lowest effective concentration value.

A further improvement of the present invention is that the operation procedure for spraying the termiticide is carried out when the concentration of the termiticide in the soil reaches a minimum.

A further improvement of the present invention is that the operation procedure of spraying the termiticide comprises the following steps:

(1) Select a spray point in a certain area around the wooden pole;

(2') forming a space into the hollow tube and inserting it in the soil of the selected point;

(3) An injection of an effective amount of the termiticide is injected from the upper end of the tube.

A further improvement of the invention is that the dose injected is equal to the average loss in the soil.

A further improvement of the invention is that the depth of the inserted soil is at least 300 mm.

A further improvement of the invention is that the repeating area is a rectangular area of 200 mm x 200 mm.

Compared with the prior art, the beneficial effects that the invention can achieve are:

(1) Using high-density polyethylene as a protective layer, because high-density polyethylene has the advantages of long service life, acid resistance, chemical solvent resistance, etc., it can effectively prevent the loss of termiticide and, at the same time, does not affect the surrounding soil. Causing damage; (2) Using drainage sand wells and vertical drainage risers to shorten the time for soil fastening;

(3) Drainage sand wells and vertical drainage risers can continuously discharge water and moisture from the soil at the bottom of wooden poles, which inhibits the survival and reproduction of termites. In addition, the chance of mold damage to wooden poles can be greatly reduced;

(4) Repeated spraying of termite-killing agent at intervals, effectively maintaining the concentration of termite-killing agent in the soil, reducing the risk of termite erosion and prolonging the life of wooden poles;

(5) Reduce the economic cost of frequent replacement of wooden poles. DRAWINGS

The invention will now be described in further detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of the formation of a space down the floor and the laying of an anti-seepage material in the method of the present invention.

Figure 2 is a schematic illustration of the size of the drainage sand well in the method of the present invention.

Figure 3 is a schematic illustration of the placement of a pole and a drain sand well in the method of the present invention.

Figure 4 is a schematic illustration of the fabrication of a vertical drain riser in the method of the present invention.

Figure 5 is a graph showing the tightening of soil over time in the method of the present invention.

Figure 6 is a graph showing the decay curve of the wood pole and the concentration of the termiticide in the method of the present invention.

Figure 7 is a graph showing the relationship between the spraying of termiticide and the decay rate of wood poles in the method of the present invention.

Figure 8 is a schematic illustration of the spray of termiticide in the process of the present invention.

Figure 9 is a graph showing the life cycle distribution of wood poles in the method of the present invention. detailed description Figure 1 shows the space formed on the floor of the wooden pole to be erected in the present invention. The present invention is to dig down a small pit on the ground. Of course, a pit can be formed by chiseling or the like. . The size of the pit is slightly larger than the diameter of the wooden pole, and the bottom area of the pit is smaller than the top area, which is convenient for operation and may be equal to or larger than the top. The pit 1 excavated in the present embodiment is a pit having a bottom of 650 mm X 650 mm and a top portion of 650 mm x 850 mm and a depth of 1500 mm. Then, a layer of impervious material is laid on the inner wall of the formed pit, preferably a high-density polyethylene film having a thickness of about 3-5 mm, which can serve as a fortress due to the excellent performance of high-density polyethylene. The loss rate of termite killings is small. A wooden pole 5 is placed in the pit in which the high-density polyethylene layer is laid. The diameter of the pole 5 is generally selected to be between 250 and 400 mm, and the present invention is preferably 300 mm. While the wooden pole 5 is placed, a drainage sand well and a vertical drainage riser are prepared, wherein, referring to Figures 2, 3 and 4, the drainage sand well and the vertical drainage vertical pipe are constructed as follows:

In the space formed, two scorpions 2 and 3, which are open at both ends, are placed, wherein the scorpion 2 slides into the large scorpion 3 made of stainless steel mesh, and a prefabricated vertical drainage standpipe is arranged inside the scorpion 2 4; In the present embodiment, the size of the tweezers are made of stainless steel material, and the surface of the small tweezers must be smooth and non-porous, wherein the size of the tweezers 2 is 80 mm x 200 mm x l 500 mm, and the size of the tweezers 3 is 83 mm x 203 mm x l 500 mm, which is convenient for operation. It is to provide two handles 21 on both sides of the small dice 2. After filling and fixing the large scorpion, slowly inject high-permeability sand into the gap between the small scorpion and the prefabricated vertical drainage standpipe, while holding the handle 2 1 slowly pull the scorpion from the big scorpion until the sand Completely fill the big scorpion and the small scorpion is completely extracted from the big scorpion.

The filling process includes the following steps:

(1) laying a layer of 100-200 mm thick sieved soil on the anti-permeate substance at the bottom of the formed space, and compacting the soil at the same time; (2) uniformly spraying the formulated termiticide on the compacted soil;

(3) Repeat steps (1) and (2) described above until the soil fills the entire formed space.

The concentration of the termiticide to be sprayed for the first time should be higher than 10%-30% of the recommended concentration on the product label to maintain a high effective concentration value for a long period of time. Termiticide can be selected from the trade names: Prevail FT, Dursban TC, Cyren TC, Termidor 80 WG, Cypermethrin G-Pro, Permethrin TC, Biflex TC, Torpedo, Tribute, Dragnet FT. The dilution of each product is not the same, for example, the dilution of the Prevail FT emulsion is 49-98 times. The placement of a wooden pole requires about 30L of termiticide to be diluted by 50 times. The required Prevail FT is about 0.6L. The concentration of the first spray used in the present invention should be higher than the recommended 10%. The termiticide emulsion used should be 0.66L. Dilute 50 times, that is, dilute to 30L with 29.34L of water and spray onto the soil layer. The dose to be sprayed can be determined as needed, but each concentration should be maintained at a minimum effective concentration.

In practice, some soils are difficult to get wet. Therefore, it is inevitable to loosen the soil and sift the soil. In the filling step (1), the thickness of the soil layer to be laid each time can be arbitrarily adjusted according to the operation requirements, and is generally selected to be between 100 and 200 mm, and the present invention is preferably 100 mm. The vertical drainage riser needs to be higher than the ground by a certain distance. The invention selects 200mm higher. The vertical drainage vertical pipe and the drainage sand well can shorten the fixed period of the soil. See Figure 5, curve 6 shows the fastening without drainage sand well. Time, curve 7 shows the tightening time of the drainage sand well. It is obvious that the drainage sand well can be tightened in the T _s soil, and it takes longer without the sand well. The specific time varies depending on the surrounding soil. There are drainage sand wells and vertical drainage risers. The general fixed period is between several months and 1-2 years. If you do not need a drain sand well and a vertical drain standpipe, it will take 10-20 years. At the same time, the drainage sand well and the vertical drainage vertical pipe can continuously remove water and moisture from the soil at the bottom of the pole to strengthen the soil and inhibit the survival of termites. Conditions of reproduction. In addition, the chance of mold damage to wooden poles can be greatly reduced.

In order to test the beneficial effects of the present invention, we conducted random multiple tests on the parameters of a plurality of wooden poles used before the method of the present invention, mainly pole strength test and soil test to determine the decay rate and soil killing. The minimum effective concentration value of the termite agent. The invention is a random sampling analysis of electric poles planted in the suburbs of Hong Kong. The specific steps are as follows:

a. Useful information for collecting wooden poles, including the type of wooden pole, manufacturer name, year of production, chemical treatment method, pole size, wire structure set on the pole, number of conductors, conductor span and angle, utilization The global positioning device measures the location after the placement of the wooden pole and the like;

b. Using a pole scanner, an ultrasonic detector, a micro-drilling device, etc., to detect the thickness of the pole wall and the cavity of the pole by the state of the pole body from the ground to a height of 1500 mm;

c testing the strength of the pole, the present invention uses the Mechanical Pole Testing (MPT) to measure the strength of the electric stem;

d. Collect raw soil samples near the wooden poles and measure the concentration of termite in the soil. The soil is taken from a soil layer 150 mm below the ground.

Record the above measurement results, repeat the above steps at intervals, and sample several times in succession. The length of time depends on the local natural conditions, generally 1 - 5 years, and the present invention uses 3 years. If termites are often found in the area, or in a humid environment like a stream, the time interval is shorter.

According to the measured data, the curve of the decay curve of the pole over time and the concentration of the termiticide is shown as shown in Fig. 6. The curve 8 shows the concentration of the termiticide in the HDPE high density polyethylene film soil. Line 9 shows the decay curve of HDPE high density polyethylene film and no termite agent wood pole; curve 10 shows no HDPE high density polyethylene film but added termite agent after wood The decay curve of the rod; curve 1 1 shows the decay curve of the wood pole after the addition of the termite agent to the HDPE high density polyethylene film. According to this curve, on the time axis of the abscissa, the concentration gradually decreases with time, and curves 9, 10, and 11 represent the decay rate of the pole, and when the decay rate is attenuated from 100% to 0, the curve The longest time of 1 1 and the shortest time of curve 9 fully demonstrate the effect of the HDPE high-density polyethylene barrier material barrier against the loss of termiticide.

The test data used in the present invention is as follows:

Test period: 2002.4-2007.3

Pole source: Douglas Fir (pressurized wooden pole) in the United States Buried depth: 450mm

Electric 4 dry treatment: Chromated Copper Arsenate (CCA)

Environment: Highly sensitive areas of termites, where the soil is extremely humid and all samples are in the same area

How to place the pole:

A, add HDPE high-density polyethylene film insulation layer, add termite-treated soil, add drainage sand well;

B. The HDPE high-density polyethylene film separator is not used, and the drainage sand well is not prepared, but the termite-killing agent is added to the soil;

C, the above three are not used.

In March 2007, the inspectors tested the above three types of poles A, B and C. The results were as follows: No signs of termite erosion were found in A, and a small amount of termites were found in the cockroaches. The degree of termite erosion in C was quite serious. . At the same time, the concentration of termiticide in the soil detected in cockroaches was only reduced by 30%, while the concentration of termiticide in soil in B decreased by more than 70%.

Over time, the termiticide in the soil will gradually decompose, evaporate and lose, resulting in a decrease in the concentration of termiticide in the soil, although the high density polyethylene barrier It can reduce the rate of decrease of the termiticide concentration, but its chemical composition will slowly lose. Therefore, special methods are needed to maintain the minimum concentration of termiticide in the soil. The present invention establishes normal spraying to kill termites. The procedure of the agent meets the above requirements.

To do this, you need to determine a Minimum Terminicide Concentration Level (MTCL). MTCL is an arbitrary value, which is determined by the implementer. Below the minimum value, the chance of decay of the pole strength will increase, and once the pole begins to rot, in addition to using the external auxiliary support method to strengthen the wooden pole body, the pole It can't be repaired by itself, until the pole is rotten and can't be used, then it can be removed and replaced. However, setting a high MTCL means that the frequency of re-spraying of termiticide is high, resulting in increased costs. Preferably, in the present invention, after the first installation is completed, when the decay rate of the electric pole is detected to be 90%, the concentration of the termiticide at this time is determined to be the lowest concentration MTCL.

According to the value of multiple repeated sampling detection, the graph shown in Fig. 7 is obtained, wherein the abscissa indicates the time axis, the ordinate indicates the decay rate of the wooden pole, and the curve 12 indicates the termite concentration curve; Curve 13 shows MTCL; curve 14 shows the decay curve of the pole after adding HDPE high-density polyethylene film and termiticide; curve 15 shows the decay of wooden pole after the first spraying of termite-killing agent Curve; curve 16 shows the decay curve of the wooden pole after the second spraying of the termiticide. As can be seen from the figure, when the time is 10, the decay rate of the pole is 90%, and the spraying procedure of the termiticide is applied. The dose of the spray is equal to the average loss of the termiticide. In practice, it is about 5-10 years.

According to Figure 7, a normal spray termiticide schedule can be developed. When t!, the first spraying procedure is carried out; between ^, in the case of no change in environmental conditions, the decay rate of the pole will decrease on average, when the concentration of the termiticide falls to MTCL, ie at t ₂ = 2xti, the second spraying procedure is carried out; and so on, the third spraying time is t ₃ = 3xt, so we get the time t^nxt of the nth spraying. By spot check, when it is detected that the pole concentration in a certain area is lower than the set minimum value, it is necessary to re-spray the termiticide. Referring to Figure 8, the method of spraying is as follows:

(1) Insert a drill bit, drill hole or large nail into the soil near the wooden pole 5 to a depth of about 300-600 mm, and then remove the drill bit, drill hole or large nail;

(2) Insert a hollow tube 1 8 to remove the bottom of the hole formed by the drill bit, drill hole or large nail. The diameter of the tube 18 is 8mm. The tube body is evenly covered with small holes to facilitate the termite killing agent. Holes are injected into the soil;

(3) Connect the injection bottle 17 filled with the pre-formulated termiticide solution at the other end of the tube 18. The injection bottle mouth is provided with a switch system 19, when connected, the switch system 19 is opened, and then all the solutions in the bottle are opened. Injecting soil;

(4) Remove the bottle 17 and the tube 18;

(5) Repeat the above steps in a rectangular area of approximately 200 mm x 200 mm around the wooden pole 5.

Of course, other spraying methods can be used as long as the termiticide can be sprayed into the soil and the minimum effective concentration is maintained. The above spraying method is only a preferred embodiment of the present embodiment.

After adopting the above method, the life of the wooden pole is effectively extended. In order to determine the impact of the above method on the life cycle of wooden poles, we use probabilistic methods to predict and analyze the life cycle of wooden shield poles. The methods include nonlinear regression approximation, optimal curve fitting method, and central limit. Theorem and normal distribution method and so on.

Figure 9 shows the life cycle distribution curve of the pole, where the abscissa indicates the age of the wood pole, the ordinate indicates the number of poles, and the curve 22 is the original wood without the method of the present invention. The life cycle distribution curve of the pole, the curve 20 is a life cycle distribution curve of the wooden pole after the method of the invention is used. The curve is obtained by mathematical calculation based on the result of the above random multiple sampling test, and the more the sampled result is, the more refined the calculated value is. Indeed. Comparing the curve 20 and the curve 22 of FIG. 9 can clearly see that the life cycle of the wooden shield pole is effectively extended after using the method of the invention, and the termite is not used within 20 years after the wooden pole is used. The electric pole is replaced by erosion, thereby greatly reducing the economic cost loss such as manpower and material resources caused by large-scale replacement of wooden poles.

In the present invention, the term "termiticide" means an active compound or ingredient which kills or repels termites, or a composition which is dispersed in an aqueous medium. The effective dosage and composition of the termiticide can be arbitrarily selected, which does not greatly affect the effects of the present invention.

It will be appreciated by those skilled in the art that the present invention may be practiced otherwise. Accordingly, the present invention includes all modifications that come within the spirit and scope of the invention as claimed.

Claims

Claim

What is claimed is: 1. A method of preventing termites from invading a wooden pole, the method comprising the steps of:

(2) placing the wooden pole in the space and filling the space with sifted earth mixed with a termiticide;

(3) Collecting information about the erected wooden pole itself and the space in which it is erected, including basic information about the wooden pole, the shaft and strength data of the wooden pole, the termite concentration in the soil, and over time. After that, the same erected wooden pole itself and the same information in the space it is erected;

The method according to claim 1, wherein the permeation resistant material in the step (1) is a polymer film.

3. The method of claim 2 wherein: said polymeric film is a high density polyethylene film.

The method according to claim 1 or 2 or 3, wherein the thickness of the impervious material in the step (1) is 3-5 mm.

The method according to claim 1, wherein the step (2) further comprises the following steps:

(1) laying a layer of 100-200 mm thick sieved soil on the impervious material at the bottom of the formed space while compacting the soil;

(3) repeating the steps (1) and (2) described until the soil fills the entire formed space Between.

The method according to claim 1, characterized in that: while the wooden pole is placed, a drainage sand well and a vertical drainage riser are arranged adjacent to the wooden pole in the formed space before filling the soil. .

7. The method of claim 6 wherein: said drainage sand well and vertical drainage riser are constructed in the following manner:

(1) Inserting two scorpions of two sizes at both ends in the formed space, wherein a small vertical scorpion slides into the large scorpion, and a prefabricated vertical drainage vertical pipe is arranged inside the small scorpion;

8. The method of claim 7 wherein: said vertical drain riser is higher than said fill layer.

The method according to claim 1, wherein in the step (3), the useful information for collecting the wooden pole comprises: the basic information of the wooden shield pole, that is, the type of the wood, the name of the manufacturer, and the year of production. , chemical treatment methods, pole size, wire structure set on the pole, number of conductors, conductor span and angle, use of global positioning device to measure the position after placement of the wooden pole; test the strength and record of the shaft of the wooden pole The state of the pole body from the ground to a height of 1500 mm: the thickness of the pole wall and the cavity of the pole; and the collection of the original soil sample near the wooden pole to test the concentration of the termiticide in the soil, and after a period of time The above sampling was repeated and samples were taken several times in succession.

10. The method of claim 9 wherein: said soil sample is taken from 150 mm below the giant ground.

The method according to claim 9, wherein: said time interval It is 1-5 years.

12. The method according to claim 1, wherein: the decay rate of the wooden pole and the concentration of the termiticide in the mud are reduced by a test result obtained from the original sampling and subsequent repeated sampling of the plurality of times. determine.

The method according to claim 1, wherein: after the wooden pole is placed, when the decay rate of the wooden pole is 90%, the concentration of the termiticide in the soil is determined to be the lowest. Effective concentration value.

The method according to claim 1 or 13, wherein when the concentration of the termite-killing agent in the soil reaches a minimum value, an operation procedure of spraying the termiticide is carried out.

15. The method of claim 14 wherein: said operating procedure for spraying the termiticide comprises the steps of:

(1) selecting a spraying point in an area around the wooden pole;

(2) forming a space into the hollow tube and inserting it in the soil of the selected point;

(3) An injection of an effective amount of termiticide is injected from the upper end of the tube.

16. A method according to claim 14 or claim 15 wherein: the dose injected is equal to the average lost dose in the soil. '

17. The method of claim 15 wherein: said inserted soil has a depth of at least 300 mm.

The method according to claim 15, wherein: the repeated area is a rectangular area of 200 mm x 200 mm.