JP7782804B2 - Device and method for exterminating mites - Google Patents

Description

The present invention relates to an extermination device and method for mites, and more specifically to an extermination device and method for mites, which are pests that cause disease in poultry farming and other livestock industries in poultry coop environments.

Chicken mites and fowl mites are known as pests that parasitize poultry and birds and cause diseases. Among these, chicken mites are known to multiply explosively in chicken coops and cause serious damage to the egg-laying poultry industry.
The mites that have multiplied explosively inside chicken coops target chickens resting at night to suck their blood, causing stress and weakness in the chickens, anemia, and even death from blood loss. As a result, direct damage such as a decrease in egg production and the occurrence of dirty eggs due to mite excrement and the crushing of blood-sucking mites is becoming more serious.
Furthermore, as an indirect damage, problems of bacterial and viral infections transmitted by mites have also been reported.
In addition, in recent years, the psychological burden on farm workers due to discomfort and allergies has increased, forcing some to quit their jobs, which has become a serious social issue in promoting the chicken industry.

A common measure to eradicate chicken mites is to spray insecticides, but because the developmental cycle of chicken mites is extremely short, with the period required for a generation to change within 10 days, individuals that are resistant to the chemicals are likely to appear.
For this reason, even if insecticides with new mechanisms of action are introduced, the insecticidal efficiency decreases year by year as susceptible populations are replaced by resistant populations with each generation, and it has become commonplace for multiple pesticides to be repeatedly sprayed.
Furthermore, because these chemicals are widely sprayed within chicken coops, the problem of chemical residues in shipped eggs and chicken meat is becoming apparent.

Japan's egg-laying poultry industry is a livestock industry with a highly concentrated and systematized production system and is highly competitive internationally. However, the economic damage caused by chicken mites has been increasing in recent years, and there is a need for effective methods of eliminating chicken mites that do not rely on insecticides.

Patent No. 6366119 Patent No. 5690986

"Manual for Countermeasures against Red Mite in Egg-Laying Chickens" Japan Poultry Association (2011)

As an effective means of eliminating chicken mites without using insecticides, pages 12-13 of Non-Patent Document 1 introduce a manual of general examples of chicken mite extermination practices in chicken coops.
According to this method, first, all chickens and equipment inside the chicken coop are removed from the coop, and then the inside of the coop is thoroughly cleaned using high-temperature, high-pressure water at 65°C or higher.
After that, spraying the chemicals and drying are repeated to create a complete red mites eradication environment.

However, this type of extermination method, which relies on thorough cleaning of the interior of chicken coops, is a large-scale cleaning job that takes up to a month per chicken coop, which means that it disrupts poultry farming operations and places a significant financial burden in terms of labor costs, making it difficult for small-scale poultry farmers to implement.

As a simpler extermination method other than the extermination method based on washing, for example, a method of exterminating chicken mites using an attraction and recovery technique as disclosed in Patent Document 1 and Patent Document 2 has been proposed.
These extermination methods using attraction and recovery techniques involve installing a red mites accumulation area equipped with an insulating layer of about 30 to 40°C or an electrostatically charged layer in any location within the poultry house, attracting the mites to that location and allowing them to form colonies, and then recovering and disposing of the red mites accumulation area at regular intervals to kill and eradicate the mites, thereby exterminating the mites.

However, this extermination method by attracting and recovering the mites requires frequent replacement and disposal of the mites' accumulation area.
The replacement of red mites' accumulation parts is generally carried out at short intervals of about one week in accordance with the red mites' life cycle, and the effort required for the replacement work and the cost of materials for the accumulation parts are issues.
Furthermore, since the nighttime blood-sucking activity of the mites in the accumulation area cannot be prevented between changes, the effect of reducing stress for chickens cannot be expected to be significant.

Therefore, the problem that this invention aims to solve is to provide a means for completely eradicating mites, such as chicken mites, in a poultry house environment that is effective and does not rely on insecticides, eliminating the need to replace or dispose of accumulation parts, and eliminating the labor involved in replacement work and the cost of accumulation part materials.

The means for solving the problems of the present invention are as follows:

First,
An extermination device for mites, characterized in that it comprises an electrode section in which linear discharge electrodes and linear ground electrodes made of a conductive material are arranged alternately and in parallel on the surface of a flat or curved insulating plate to form an electrode surface on the pulse generating side, and the main distance between adjacent discharge electrodes and ground electrodes is configured to be an arbitrary constant value of 0.3 mm or more and 2.5 mm or less, preferably 0.4 mm or more and 2.3 mm or less, and more preferably 0.5 mm or more and 2.0 mm or less, and a pulse generating means capable of applying a high voltage pulse with a maximum instantaneous voltage of 400 volts or more to the electrode section.
The mites to be exterminated are not limited to chicken mites and fowl mites that parasitize poultry and birds in the environment inside a chicken coop, but an extermination device having an electrode unit configured to set the size to a constant value of 0.5 mm or more and 2.0 mm or less is particularly effective against chicken mites, which are known to multiply explosively inside chicken coops.
The main distance between the electrodes means that the distance at the tip and branch portions of the irregularly shaped electrodes, where abnormal discharge is likely to occur, is excluded.

Secondly,
The high voltage pulse has a maximum instantaneous voltage of 1,000 volts or more, a pulse generation frequency of 10 hertz or more and 10,000 hertz or less, and a pulse width of 1 microsecond or more and 100,000 microseconds or less, as described in the first embodiment of the mite extermination device.

Third,
The mite extermination device described in the first or second aspect is characterized in that the electrode surface on the pulse generating side of the electrode unit is installed at an angle of 70 degrees or more and 180 degrees or less downward from the horizontal line, preferably in a horizontal position of 90 degrees, and more preferably in a downward position of 180 degrees.

Fourth,
Linear discharge electrodes and linear ground electrodes made of a conductive material are arranged alternately and in parallel on the surface of a flat or curved insulating plate to form an electrode surface on the pulse generating side, and the electrode section is configured so that the main distance between adjacent discharge electrodes and ground electrodes is an arbitrary constant value of 0.3 mm or more and 2.5 mm or less, preferably 0.4 mm or more and 2.3 mm or less, more preferably 0.5 mm or more and 2.0 mm or less, and is arranged on the movement path of mites,
This method for exterminating mites comprises applying a high voltage pulse having a maximum instantaneous voltage of 400 volts or more to the mites that have invaded the electrode portion, thereby killing and exterminating the mites.
Here, electrocution means killing mites such as chicken mites that have invaded the electrode section with a high-voltage pulse and flying them out of the electrode section; the electric shock from the high-voltage pulse kills the mites such as chicken mites, and at the same time, they split and scatter, flying out of the electrode section.

Fifth,
The method for exterminating mites described in the fourth aspect is characterized in that the high voltage pulse has a maximum instantaneous voltage of 1,000 volts or more, a pulse generation frequency of 10 Hz to 10,000 Hz, and a pulse width controlled within the range of 1 microsecond to 100,000 microseconds.

Sixth,
The method for exterminating mites described in the fourth or fifth aspect is characterized in that the electrode surface on the pulse generating side of the electrode unit is installed at an angle of 70 degrees or more and 180 degrees or less downward relative to the horizontal line, preferably in a horizontal position of 90 degrees, and more preferably in a downward position of 180 degrees.

The present invention can achieve the following effects:

In the poultry house environment, mites such as chicken mites that invade the electrode are killed by electrocution using high-voltage pulses, eliminating the need to replace or dispose of the accumulation unit, eliminating the hassle of replacement work and the cost of accumulation unit materials.

Mites such as chicken mites have an instinct to gather in small spaces, and chicken mites in particular are known to be easily attracted to spatially biased electric fields.
Following these behavioral characteristics, mites enter the electrode section, and when they come into contact with one of the electrodes, they become electrically charged.
When an electrically charged red mites approaches the other electrode, a high-voltage pulse current flows through the mites, electrocuting them and causing them to split and scatter, flying them out of the electrode area.

By arranging the discharge electrode and the ground electrode on an insulating plate with a constant inter-electrode distance of 0.5 mm to 2.0 mm, a pulsed electric field can be applied effectively over the entire surface of the electrode portion.
By placing this electrode part on the path of chicken mites and applying a pulse voltage, invading chicken mites can be reliably electrocuted and eliminated, thereby preventing chicken mites from invading behind the electrode part.

The distance between the electrodes is set to 0.5 mm or more in order to prevent short-circuit current from occurring due to the corpses of the chicken mites electrocuted by the pulse.
Typically, the body size of mites such as chicken mites is 1 mm or less, and after electrocution, their carcasses are blown out of the electrodes, but after sucking blood, some of the swollen mites may remain between the electrodes, which can cause a short circuit.
To avoid such short circuits, it is desirable that the distance between the electrodes is 0.5 mm or more.

The reason for setting the distance between the electrodes to 2.0 mm or less is to reduce the possibility that young chicken mites with small body lengths will pass through the vicinity of the center between the electrodes without receiving the pulsed electric shock.
If the distance between the electrodes is 2.0 mm or less, no blank area of the pulsed electric field occurs even in the center between the electrodes, and reliable electric shock extermination is possible.
From the above two viewpoints, it is desirable to set the inter-electrode distance within the range of 0.5 mm to 2.0 mm.

By controlling the maximum instantaneous voltage to 1,000 volts or more and the pulse generation frequency to within the range of 10 to 10,000 hertz, it is possible to generate high-voltage pulses with greater lethality, making it possible to miniaturize the electrode section of pest control devices and to demonstrate extermination effects against pests larger than chicken mites.

The reason why the maximum instantaneous voltage of the pulse is set to 1000 volts or more is to reliably kill chicken mites with a single pulse electric shock.
Normally, small insects such as mites can be killed by repeatedly applying low-voltage pulses of 1,000 volts or less, but in order to prevent invading chicken mites from escaping, it is preferable to reliably electrocute them with a single high-voltage pulse.
Furthermore, if the voltage is high, 1000 volts or more, it is expected that the electric shock effect will be effective in exterminating insects such as ants and centipedes, and at the same time, it will also be possible to prevent the infestation of mites that parasitize them.

The reason why the frequency of the high voltage pulse is set to 10 Hz or more is to keep the pulse pause time to 0.1 seconds or less so that red mites do not pass through the electrode portion during the pause time.
Since red mites can move at high speeds of about 1 cm per second, the longer the pause time, the greater the risk of them accidentally passing through.
To avoid this, it is desirable in the present invention to set the lower limit of the pulse generation frequency to 10 Hz or higher.

The reason why the frequency of the high voltage pulses is set to 10,000 Hz or less is to stabilize the shape of the continuous pulses.
At generating frequencies above 10,000 Hz, the interval between successive pulses becomes shorter, limiting the peak height and pulse width of the applied high voltage pulses.
Depending on the shape of the electrode portion, it may not be possible to apply an effective high electric field pulse, so it is desirable to set the upper limit of the generated frequency to 10,000 Hz.

The pulse width of the high voltage pulse is set to 1 microsecond or more and 100,000 microseconds or less because the insect killing rate decreases if the pulse width is outside this range.
In other words, if the pulse width is short, at the nanosecond level, less than 1 microsecond, a sufficient insecticidal effect against chicken mites cannot be obtained.
Furthermore, when the pulse width is long, if the off time is too short relative to the on time in relation to the frequency, discharge occurs, causing the electrodes to short-circuit, resulting in a decrease in the insect killing rate.

When a red mites invades between the electrodes, the high-voltage pulse causes the corpse to split and scatter outside the electrodes.
Here, if the electrode surface on the pulse generating side of the electrode unit is nearly horizontal or tilted upward from the horizontal line, these dead bodies tend to accumulate on the electrode surface, making regular cleaning necessary.
Therefore, by positioning the electrode surface on the pulse generating side of the electrode unit at a high inclination angle of 70 degrees or more downward from the horizontal line (see α1 in Figure 7), preferably in a completely horizontal position of 90 degrees (see α2 in Figure 7), and more preferably in a downward position of 180 degrees (see α3 in Figure 7), regular cleaning of the electrode surface becomes unnecessary.
Because the carcasses of red mites have an uneven shape, they are likely to get caught on the electrode part, but by setting the electrode surface that generates the pulses at an angle of 70 degrees or more downward from the horizontal, the carcasses will not remain on the electrode surface but will fall naturally downward.
If there are no restrictions on the installation facilities, it is most desirable to install the device facing downward at 180 degrees to the ground, in which case cleaning work will be almost unnecessary.

In this way, by installing the electrode surface on the pulse generating side at an angle of 70 degrees or more and 180 degrees or less downward from the horizontal line, preferably at a completely horizontal angle of 90 degrees, and more preferably at a downward angle of 180 degrees, it is possible to avoid the accumulation of not only dead chicken mites but also dust and feathers that fall from the air, making it possible to significantly reduce the risk of current short circuits due to foreign objects.
As a result, the frequency of regular electrode surface cleaning can be significantly reduced, enabling more efficient equipment management.

In addition, since the present invention uses high-voltage pulses to electrocute mites, and electricity is consumed only during electrocution, it is possible to exterminate mites in poultry houses, which require constant operation, with extremely low power consumption.

1 is an explanatory diagram of a device for exterminating mites of the present invention. FIG. 1 is an explanatory diagram of an example of installing the mite extermination device of the present invention in an egg-laying chicken farm. FIG. 10 is an explanatory diagram of the electrode portion in a horizontal position suitable for attachment around a square support pole. FIG. 10 is an explanatory diagram of the electrode portion in a horizontal position suitable for mounting around a round support pole. FIG. 10 is an explanatory diagram of a curved electrode portion suitable for attachment to the outer surface of a round support pole. FIG. 10 is an explanatory diagram of two rows of electrodes in a horizontal position suitable for attachment to the outer periphery of a square support. FIG. 10 is an explanatory diagram of the installation angle of the electrode surface relative to the square support post. 10 is a graph showing the relationship between pulse width and insect killing rate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the accompanying drawings, the same components are denoted by the same reference numerals, and duplicated explanations are omitted.
It should be noted that the description here is one embodiment of the present invention, and the present invention is not limited to this embodiment.

As shown in Figure 1, the mite extermination device of the present invention comprises an electrode unit 1 and a pulse generating means 5 capable of applying a high-voltage pulse with a maximum instantaneous voltage of 400 volts or more to the electrode unit 1.

The electrode part 1 is formed by arranging linear discharge electrodes 3 and linear ground electrodes 4 made of a conductive material in a comb-like pattern so that they are alternately and parallel to each other on the surface of a flat rectangular insulating plate 2, thereby forming an electrode surface on the pulse generating side.
That is, the electrode unit 1 is configured such that a comb-shaped discharge electrode 3 and a ground electrode 4 are arranged on the surface of a flat insulating plate 2 so that their comb-teeth portions are alternately nested and face each other.
Here, the discharge electrode 3 and the ground electrode 4 are arranged in parallel so that the main distance between the adjacent electrodes is a constant value.
In addition, at the tip or branch of an electrode having an irregular shape where abnormal discharge is likely to occur, the distance between the electrodes does not necessarily need to be constant, and the distance between the electrodes can be made wider to prevent discharge.

As the insulating plate 2, a wide range of materials such as paper phenol plates, paper epoxy plates, glass composite plates and glass epoxy plates, which are commonly used in printed circuit boards, can be used.
Furthermore, the insulating plate 2 does not necessarily have to be a rigid plate with high rigidity, and a bendable flexible plate such as polyimide or polyester can also be used.
An electrode unit 1 with an insulating plate 2 made from these flexible plates can be attached to the curved surface of a cylindrical support in a chicken coop (see Figures 4 and 5) or the corner of a square support (see Figure 6).

As the conductive material for the discharge electrode 3 and the ground electrode 4, a common copper wire or a punched copper plate can be used.
Iron-based materials can also be used, but because the inside of a chicken coop is a highly humid environment, stainless steel materials are preferable to prevent corrosion.
These electrodes are wired and fixed on the surface of the insulating plate 2 by mechanical pressure bonding or by using an organic adhesive.
In this wiring work, careful consideration must be given to ensuring that the distance between the electrodes after placement is as constant as possible in order to prevent abnormal discharge.

As the pulse generating means 5, a general pulse power supply device such as the circuit diagram shown in FIG. 1 can be used.
The pulse power supply device serving as pulse generating means 5 in this example periodically releases energy stored in a primary side capacitor 7 from a DC power supply 6 using a semiconductor switch 8, raises the voltage in a transformer 9, rectifies it using a diode 10, and then generates pulses using a secondary side capacitor 11.
The pulse power supply device is capable of generating pulses with a maximum instantaneous voltage of 1,000 volts or more, a pulse generation frequency of 10 to 10,000 hertz, and a pulse width of 1 to 100,000 microseconds.
The present invention does not limit the structure or circuit configuration of the pulse power supply device as the pulse generating means 5, and is widely applicable to other circuit configurations that use MOSFETs, bipolar transistors, IGBTs (insulated gate bipolar transistors), etc. as the switch mechanism, as long as the device configuration is capable of generating high voltage pulses with a maximum instantaneous voltage of 400 volts or more.

Next, with reference to FIG. 2, an example of installing the mites extermination device according to the present invention in an egg-laying chicken farm will be described.
In typical chicken coops, chickens are often raised in multiple-tiered chicken cages 13 from the perspective of management efficiency, and each tier of chicken cages 13 is usually equipped with water supply pipes 14, feeding troughs 15, egg collection cages 16, etc.
These structural members are supported by supports 17 installed on the floor 19, the walls, and the like.

In the poultry house shown in Figure 2, the electrode unit 1 of the mite extermination device of the present invention is placed at the bottom of the support 17 so that the electrode surface that generates the pulses is facing downward at an angle of 180 degrees (see α3 in Figure 7) downward from the horizontal line.
The electrode unit 1 is installed on all the supports 17 at a height lower than the support material of the lowest chicken cage 13.
This makes it possible to block the entry of mites from the floor surface 19.
In Figure 7, which explains the installation angle of the electrode surface on the pulse generation side of the electrode unit, α1 indicates an angle of 70 degrees downward from the horizontal line, α2 indicates 90 degrees in a completely horizontal state, which is a high inclination angle of 70 degrees or more, and α3 indicates 180 degrees in a downward state.
In FIG. 7, reference numerals 3 and 4 denote a discharge electrode and a ground electrode that form an electrode surface.

Since multiple chickens are raised in each poultry cage 13, the poultry droppings 20 that are produced are generally allowed to fall freely from the bottom grid of the poultry cage 13 onto the floor 19 or the like, and the accumulated poultry droppings are generally disposed of in bulk on a regular basis.
In order to prevent contamination of the electrode part 1 by the droppings, a dropping prevention plate 18 having an inverted concave shape with its peripheral part expanding downward outward is installed directly above the electrode part 1.

The pulse generating means 5 of the mite extermination device of the present invention installed in the poultry house shown in Figure 2 distributes and supplies pulse current to multiple electrode parts 1 via wiring 12, and is attached to the top of a single support 17.
Since the pulse generating means 5 is a precision electrical device, it is preferable to place it in a sealed casing and install it at a high place where droppings will not fall.
The DC power supply (see FIG. 1) supplied to the pulse generating means 5 may be battery-driven, or may be supplied by converting an external AC power supply into DC.

For structural members that are arranged horizontally, such as the water supply pipes 14, feeding troughs 15, and egg collection cages 16, a frame structure using support members that receive support not only from pillars 17 attached to the floor 19 but also from the walls and beams of the chicken house building (not shown) can be considered.
In such cases, measures to prevent chicken mites from entering the connecting members to the poultry house building are also necessary.
Therefore, it is desirable to install electrodes on all support members connected to the poultry house building to block the route of chicken mites entering the poultry cage.

FIG. 3 shows an example of the configuration of the electrode unit 1 attached to a square-shaped support 21 having a square cross section.
This electrode portion 1 has a rectangular opening at the center of a square insulating plate 2, through which a square support 21 can be passed.
By sealing the gap between the electrode part 1 and the square support 21, it is possible to prevent mites crawling up from the floor surface 19 (see FIG. 2) to the top of the square support 21 from bypassing the electrode part 1.

In the electrode unit 1, the distance from the electrode on the square support 21 side to the outermost electrode is the effective range of pulse electrocution.
If a high voltage pulse with a maximum instantaneous voltage of 1000 volts or more is applied, it is possible to electrocute chicken mites with just one pair of discharge electrode 3 and ground electrode 4, but when taking into consideration the reliability of extermination and the prevention of the invasion of large insects, it is preferable to use five or more pairs of electrodes, or to ensure an effective range of 10 mm or more.

FIG. 4 shows an example of the configuration of the electrode unit 1 attached to a round support 22 such as a pipe.
The discharge electrode 3 and the ground electrode 4 arranged in the electrode section 1 do not necessarily have to be straight, and for round supports 22 such as pipe supports or water supply pipes, the electrodes can be arranged concentrically. Even if the electrodes are curved, as long as the distance between the discharge electrode 3 and the ground electrode 4 is equal, there is no need to worry about abnormal discharge occurring, and the effect of pulse electrocution can be fully exerted.

In the electrode unit 1 shown in Figure 4, the electrode terminals at the top center can be separated, so if the circular insulating plate 2 is made flexible, the electrode unit 1 can be easily attached and detached from the round support 22.

In addition, by using a curved electrode such as the one shown in Figure 4, it is possible to widely apply it to a configuration in which the discharge electrode 3 and ground electrode 4 are arranged in a double spiral shape without branches, or a configuration in which electrodes arranged in a continuous concentric circle are connected to terminals on the back surface of the insulating plate 2.

FIG. 5 shows an example of the configuration of a curved electrode portion 1 attached to the outer surface of a round support 22 installed horizontally.
The electrode section 1 has discharge electrodes 3 and ground electrodes 4 arranged alternately in the horizontal direction.
If the insulating plate 2 of the electrode portion 1 is made of a flexible plate, the electrode portion 1 can be directly attached to the outer surface of the round support 22, which is a cylindrical member.
However, with this electrode structure, if the electrode surface on the pulse generating side is tilted downward at an angle of less than 70 degrees relative to the horizontal line, foreign matter is likely to accumulate on the upper surface of the electrode surface, so it is desirable to install a cover such as a dropping prevention plate 18 (see Figure 2) on top.

FIG. 6 shows an example of a configuration in which the electrode surfaces of two rows of electrode parts 1, one above the other, are arranged horizontally on the outer periphery of a square support 21.
The electrode section 1 has discharge electrodes 3 and ground electrodes 4 arranged alternately in the vertical direction.
If the electrode portion 1 uses a flexible insulating plate 2, the electrode portion 1 can be directly disposed on the outer periphery of the rectangular support 21 as well.
In order to make the electrode part 1 attachable and detachable, it is necessary to separate the insulating plate 2 at the terminal part or the like, but this separated part can become an entry point for red mites.
To avoid this, in this configuration example, two electrode parts 1 are arranged one above the other, with their cut-off parts positioned at diagonal corners of the square support 21 .
The probability that mites will pass through both the lower and upper separation sections is extremely low, so the risk of mites invading the upper section can be reduced.

Next, we will explain test examples of the present invention.

(Test Example 1)
A glass epoxy plate measuring 90 mm x 90 mm x 1.0 mm was used as the insulating plate, and an electrode section was fabricated on the insulating plate, with linear discharge electrodes and ground electrodes alternately arranged.
The discharge electrode and the ground electrode were both made of 18 μm copper wire, and the electrode parts were arranged so that the distance between the electrodes was 0.5 mm over the entire electrode surface.
The pulse generating means was fabricated according to the circuit diagram of FIG.

The electrode portion was set on the bottom surface of a 100 mm x 100 mm x 100 mm cubic container made of acrylic resin, and was connected to a pulse generating means installed outside the container with copper wiring.
After 300 red mites were placed in this cubic container, an acrylic lid was placed on top to seal the container, and a voltage of 3,400 volts was applied to the electrode portion for 40 seconds.

The insecticidal rate in this test example was 87%.
However, the 13% of the insects that could not be killed were individuals that had escaped to the walls or top lid of the cubic container, and it was visually confirmed that all mites that came into contact with the electrode were instantly electrocuted.

(Test Example 2)
As another test example, a red mites electrocution test was carried out under the same conditions as in Test Example 1, except that the inter-electrode distance was changed to 1.0 mm and the applied voltage was changed to 3,800 volts.
As a result, the insect killing rate after 40 seconds of voltage application was 90%.
In this test, too, 100% of the mites were electrocuted except for those that had escaped to the wall, confirming the reliable electrocution effect of high-voltage pulses on red mites.

Prototypes of electrode parts with an increased inter-electrode distance of 1.5 mm and 2.0 mm were also fabricated, and electrical characteristics were evaluated.
As a result, it was confirmed that the pulse discharge voltage increases as the electrode distance increases, further improving the killing ability.
When the electrode distance is 2.0 mm, a high voltage pulse of approximately 7,000 volts can be generated, which is expected to be effective in exterminating pests larger than chicken mites.

(Test Example 3)
The insecticidal rate was tested by changing the pulse width under the same conditions as in Test Example 1, except that the room temperature was 20.2°C and the applied voltage time was 30 seconds.
The test results are shown in FIG.
The test results confirmed that the insecticidal rate decreased when the pulse width was at the nanosecond level.
In addition, it was confirmed that when the pulse width is long, in relation to the frequency, if the off time is too short relative to the on time, a discharge occurs, causing the electrodes to short-circuit, resulting in a decrease in the insect killing rate.
In other words, it was confirmed that there are two cases in which the insect killing rate decreases: first, when the pulse width is too short, at the nanosecond level, and second, when the pulse width is too long compared to the repetition frequency.

(Comparative Example 1)
As a comparative example, an experiment on killing chicken mites by ultraviolet irradiation was conducted.
In the same three-dimensional container as in Test Example 1, mites were irradiated with 15 W ultraviolet UV-C for 3 to 60 minutes, and the insecticidal rate was measured.
As a result, the insecticidal rate was as low as 3% or less when exposed to ultraviolet light for up to 10 minutes, and almost no insecticidal effect was observed.
The kill rate finally reaches 70% after 30 minutes of irradiation, but considering the ecology of fast-moving mites, it is estimated that killing mites with ultraviolet light in a large chicken coop is practically difficult.

(Comparative Example 2)
As another comparative example, an insecticidal experiment by exposure to ozone was carried out.
An ozone generator was placed in the same cubic container as in Test Example 1, and the ozone concentration in the container was adjusted to 50 ppm.
Red mites were placed in the container and exposed to ozone for 3 to 60 minutes, and the insecticidal rate was measured.
The permissible concentration of ozone for humans is 0.1 ppm, and 50 ppm is a high concentration level that puts a human's life at risk within one hour. However, in this comparative example, the mite killing rate was only 6% even after 60 minutes of exposure, and almost no insecticidal effect was observed.

As explained above, the present invention is extremely useful as an extermination method for protecting chickens in the poultry farming industry from damage caused by pests such as chicken mites.

REFERENCE SIGNS LIST 1 Electrode part 2 Insulating plate 3 Discharge electrode 4 Ground electrode 5 Pulse generating means 6 Power supply 7 Primary side capacitor 8 Semiconductor switch 9 Transformer 10 Diode 11 Secondary side capacitor 12 Wiring 13 Poultry cage 14 Water supply pipe 15 Feeding trough 16 Egg collection cage 17 Support 18 Dropping prevention plate 19 Floor 20 Poultry droppings 21 Square support 22 Round support

Claims (4)

An apparatus for exterminating mites, including chicken mites, that live in chicken coops and parasitize poultry, comprising: an electrode section in which linear discharge electrodes and linear ground electrodes made of a conductive material are alternately arranged on the surface of an insulating plate to form an electrode surface that serves as a pulse generating side, and the main distance between adjacent discharge electrodes and ground electrodes is configured to be 0.5 mm or more and 2.0 mm or less; and pulse generating means capable of applying to the electrode section a high-voltage pulse having a maximum instantaneous voltage of 1,000 volts or more, a pulse generating frequency of 10 Hz or more and 10,000 Hz or less, and a pulse width of 1 microsecond or more and 100,000 microseconds or less . 2. The mite extermination device according to claim 1 , wherein the electrode surface of the electrode unit that generates the pulses is installed at an angle of 70 degrees or more and 180 degrees or less downward relative to the horizontal line. A method for exterminating mites, including chicken mites, that live in chicken coops and parasitize poultry, comprising: arranging linear discharge electrodes and linear ground electrodes made of a conductive material alternately on the surface of an insulating plate to form an electrode surface that generates a pulse; arranging an electrode section configured so that the main distance between adjacent discharge electrodes and ground electrodes is 0.5 mm or more and 2.0 mm or less, on the migration path of the mites; and electrocuting and exterminating mites that have invaded the electrode section by applying a high-voltage pulse having a maximum instantaneous voltage of 1,000 volts or more, a pulse generation frequency of 10 Hz to 10,000 Hz, and a pulse width of 1 microsecond to 100,000 microseconds . 4. The method for exterminating mites as described in claim 3 , wherein the electrode surface of the electrode unit that generates the pulses is installed at an angle of 70 degrees or more and 180 degrees or less downward relative to the horizontal line.