JP6796605B2 - Electrostatic insecticidal method and electrostatic insecticide - Google Patents

Description

The present invention relates to an electrostatic insecticidal method and an electrostatic insecticidal apparatus, and more specifically, a storage pest that mainly nests in stored cereals, seeds, and grain products, especially the most destructive maize weevil (Sitophilus). It relates to an electrostatic insecticidal method and an electrostatic insecticide device suitable for selectively killing pests such as oryzae).

The most serious problem in the storage of harvested rice is the infestation of cereal pests, among which the maize weevil is the most destructive pest for cereals, seeds and grain products stored in elevators and bottles. Adult maize weevil survives for 4-5 months, and females lay 300-400 eggs during this period. The female uses her strong mandible to bite a hole in the grain, place an egg in it, and close the hole with the fluid in the gelatin chamber. The larvae often feed on the grain within the grain and grow, destroying the grain in the storage facility almost completely. Maize weevil is poorly dealt with as adults disperse by flight and parasitism may spread to nearby areas.

The best way to prevent the infestation of stored grain pests is to prevent invasion, and proper hygiene is essential before introducing new grains to minimize the risk of insect contamination of new grains. .. Therefore, new grains need to be screened before storage in bottles to eliminate fine substances and cracked grains, and the stored grains need to be inspected regularly.

However, despite these precautions, many storage facilities are often infested with stored pests, and final fumigation of the grains is unavoidable. However, fumigation agents are highly toxic, require specialized technical knowledge to use them properly, and have cost issues, so in reality fumigation disinfection It is difficult to implement.

JP-A-2007-195404

As mentioned above, the final fumigation disinfection of grains is unavoidable, but the current situation is that it is difficult to carry out due to technical problems and cost problems. The present invention has been made in view of the present situation, and in particular, a safe and economical electrostatic insecticidal method and an electrostatic insecticide device effective for selectively eradicating grain pests such as maize weevil that nest in rice grains. The challenge is to provide.

As a result of diligent research under the hypothesis that only insects will be electrocuted by the arc discharge generated instantaneously in the device due to the high conductivity of the insect body, the present inventors have developed the present invention. It has been completed.

That is, the invention according to claim 1 for solving the above-mentioned problems is a maximum voltage at which discharge does not occur in one of a pair of metal nets that are opposed to each other in parallel while maintaining a predetermined interval. By negatively charging with, an electric field is generated between the metal net and the other metal net, and grains that may contain grain pests are passed through the electric field, and the grain pests in the grains are passed through the skin. It is an electrostatic insecticidal method characterized by selectively electro-killing due to the conductivity of the grain and the insulating property of the grain.

In the invention according to claim 2 for solving the above problems, three metal nets, a central net and an outer net arranged on both sides thereof, are arranged in parallel with a predetermined interval between the nets. By negatively charging the central net with the maximum voltage at which discharge does not occur, an electric field is generated between the central net and each outer net, and grains that may contain grain pests are allowed to pass through the electric field. The electrostatic killing method is characterized by selectively electrolyzing the stored grain pests in the grain by the conductivity of the epidermis and the insulating property of the grain.

In the invention according to claim 3 for solving the above problems, a pair of metal nets are arranged in parallel while maintaining a predetermined interval, and a voltage generator is attached to one of the pair of metal nets. Is connected, the other metal net is connected to the ground wire, and the metal net to which the voltage generator is connected is negatively charged at the maximum voltage at which no discharge occurs, so that the other metal net is electrostatically induced. Rabitz is positively charged, than Te, a apparatus that an electric field is formed between the pair of metal nets, passing through the electric field, the in cereals which may contain stored grain pest It is an electrostatic insecticidal device characterized in that a stored grain pest can be selectively electrokilled by the conductivity of its epidermis and the insulating property of the grain .

In one embodiment, prior Symbol pair of metal nets is a mesh size of 20 mesh about stainless steel, and in one embodiment, the set of the pair of metal nets in one frame is 1 or more The set is made into a horizontally arranged sieve structure.

In the invention according to claim 6 for solving the above problems, three metal nets of a central net and an outer net arranged on both sides thereof are arranged in parallel, and a voltage generator is connected to the central net. the outer net are connected to respective ground line, the central net, by the discharge is negatively charged at the maximum voltage that does not occur, the by electrostatic induction each outer net positively charged, than Te, the A device in which an electric field is formed between the central net and the outer net , and the grain pests in a grain that may contain grain pests that pass through the electric field are defined as the conductivity of the epidermis. It is an electrostatic insecticidal device characterized in that it can be selectively electrokilled by the insulating property of the grain .

In one embodiment, prior Symbol three metal nets are made of stainless steel approximately mesh size 4 mesh. Further, in one embodiment, a sieve structure is formed in which one or a plurality of sets of the three metal nets are horizontally arranged in one frame.

The present invention is as described above, in which one or a central net of metal nets arranged in parallel with a predetermined interval is negatively charged at the maximum voltage at which no discharge occurs, thereby facing the metal. An electric field is generated between the net and the crop, and grains that may contain grain pests are passed through the electric field, and the grain pests in the grain are selected by the conductivity of the epidermis and the insulation of the grain. Efficient control of stored grain pests in stored crops because it has a simple structure of electric field killing and can be operated with low power consumption to effectively electric field pests that cause serious crop damage. It has an effect that it can be suitably used for, and also has an effect that the need for pesticide treatment can be eliminated.

It is a schematic diagram which shows the structure of one Embodiment of the electrostatic insecticide apparatus which concerns on this invention. It is a schematic diagram which shows the electric field formed between a pair of metal nets in the electrostatic insecticide apparatus which concerns on this invention. It is a schematic diagram which shows the electric killing principle of a pest in the electrostatic insecticide apparatus which concerns on this invention. It is a figure which shows the voltage which causes the discharge between the negatively charged metal net and the positively charged ground metal net arranged at different distances. It is a schematic diagram which shows the structure of the other embodiment of the electrostatic insecticide device which concerns on this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the first embodiment of the electrostatic pest method according to the present invention, one of a pair of metal nets that are opposed to each other in parallel while maintaining a predetermined interval is negative at the maximum voltage at which discharge does not occur. By charging the metal net, an electric field is generated between the metal net and the metal net, and the grain that may contain the grain pest is passed through the electric field, so that the grain pest in the grain is made conductive in its epidermis. It is characterized by selectively electrifying by utilizing sex.

Further, in the second embodiment of the electrostatic insecticidal method according to the present invention, three metal nets, a central net and an outer net arranged on both sides thereof, are parallel to each other while maintaining a predetermined interval between the nets. By arranging and negatively charging the central net with the maximum voltage at which no discharge occurs, an electric field is generated between the central net and each of the outer nets, and grains that may contain grain pests are placed in the electric field. It is characterized in that it is allowed to pass through and selectively electrolyzes the stored grain pests in the grain due to the conductivity of the epidermis and the insulating property of the grain.

FIG. 1 is a schematic view showing a schematic configuration of a first electrostatic insecticidal device for carrying out the first method, and as shown therein, the device is a pair of stainless steels maintained at predetermined intervals. Metal nets 1 and 2 made of steel or the like are arranged in parallel, a DC voltage generator 3 is connected to one metal net 1 of the pair of metal nets 1 and 2, and the other metal net 2 is a ground wire 4. Connected to and configured. The mesh size of the metal nets 1 and 2 is, for example, 20 meshes .

The metal net 1 to which the DC voltage generator 3 is connected is negatively charged at the maximum voltage at which discharge does not occur, and the other metal net 2 is positively charged by the accompanying electrostatic induction, and between both nets 1 and 2. An electric field is generated in (see FIG. 2). The distance between the electrodes between the metal net 1 and the metal net 2 is determined by the size of the metal nets 1 and 2 and the applied voltage (for example, as will be described later, a 90 × 25 cm object is 10 mm. In order to maintain the distance between the electrodes, a spacer 5 made of an insulating material such as polypropylene having a thickness corresponding to the distance is provided between the metal nets 1 and 2 to maintain the distance between the electrodes. Be sandwiched. Further, covers 6 and 7 made of an insulating material such as polypropylene are arranged on the outside of the metal nets 1 and 2 in order to prevent the grains from coming out through the mesh or from the side edges.

In the insect pest device having the above configuration, the metal net 1 is negatively charged at the maximum voltage at which discharge does not occur, and the metal net 2 is positively charged by electrostatic induction to generate an electric field between both nets 1 and 2. In other words, by putting the grain into the electric field between the two nets 1 and 2, it is possible to electrically kill the stored grain pests (insects). That is, since the skin of an insect has high conductivity, while the grain is an insulator, the insect selectively receives an instantaneous transient current due to an arc discharge from the metal net 1 in the electric field, and the electric field is generated. It is blown away from and killed by electricity.

FIG. 5 is a schematic view showing a schematic configuration of a second electrostatic insecticidal device for carrying out the second method, and as shown therein, the device is three pieces at a predetermined interval. Metal nets 1, 2 and 9 made of stainless steel or the like are arranged in parallel, a DC voltage generator 3 is connected to a central net 1 located in the center of the nets 1, 2 and 9, and the outer nets 2 and 9 outside the DC voltage generator 3 are grounded wires 4. It is connected to and configured. This second device is basically composed of three metal nets 1, 2 and 9 while the first device is composed of two metal nets 1 and 2. The composition remains the same.

That is, the central net 1 to which the DC voltage generator 3 is connected is negatively charged at the maximum voltage at which discharge does not occur, and the outer nets 2 and 9 on both sides are positively charged by the accompanying electrostatic induction, and the central net 1 is positively charged. between 1 and the outer net 2, and, that the electric field may arise from each between the central net 1 and the outer net 9. The distance between the electrodes between the nets 1, 2 and 9 is determined by the size of each net 1, 2 and 9 and the applied voltage as in the case of the first device, and each The mesh size of the nets 1, 2, and 9 is about 4 meshes, which is large enough for rice grains to pass through.

In the second device shown in FIG. 5, the nets 1, 2, and 9 are horizontally arranged to form a sieve structure housed in the frame 10. In this case, a set consisting of three nets 1, 2, and 9 can be formed into a multi-layer structure in which one set or a plurality of sets are laminated. Also in the case of the first device, a set composed of a pair of nets 1 and 2 can be formed into a multi-layer structure in which one set or a plurality of sets are laminated. The nets 1 and 2 in the first apparatus are represented by a square shape, but in the case of this sieve structure, it is preferable to make the nets 1 and 2 circular as shown in FIG.

The pesticide device having the above configuration is in an electric field in a state where an electric field is generated between the nets 1 and 2 (and between the nets 1 and 9) by negatively charging the metal net 1 with the maximum voltage at which discharge does not occur. By throwing grains into the grain, it is possible to electrically kill pests (insects) in the grains. That is, since the skin of an insect has high conductivity, while the grain is an insulator, the insect selectively receives an instantaneous transient current due to an arc discharge from the metal net 1 in the electric field, and the electric field is generated. It is blown away from and killed by electricity.

In order to confirm the effectiveness of this method and this device, the present inventors conducted the following insecticidal effect confirmation test on this device alone or in combination with insects and cereals, and then conducted the following insecticidal effect confirmation test. , We tried to optimize the configuration of this device by finding the most appropriate distance between electrodes and applied voltage.

Insects used In this test, maize weevil (S. oryzae) was used as a stored grain pest. Maize weevil larvae were obtained from the preserved culture strains of the applicant's laboratory and bred in a growth chamber at 25 ± 2 ° C and 60 ± 5% relative humidity (RH) until emergence. Adult maize weevil were collected using an insect aspirator and bred under the same conditions on a group of rice grains in a plastic container (diameter 20 cm, height 10 cm). The average body size of adult maize weevil (average length from head to wing tip in 20 adults) was 2.56 ± 0.28 mm.

Test equipment and experimental contents In the first experiment, two metal nets 1 and 2 made of stainless steel with a size of 10 x 25 cm and 20 mesh were prepared, and these were arranged in parallel at a distance of 5 to 10 mm, and at each distance. On the other hand, the metal net 1 was negatively charged at 1 to 10 kV and under different RH conditions (30%, 65%, and 90%) (this test apparatus corresponds to the first apparatus. is there.). The continuous current was measured by the attached galvanometer 8 to obtain the minimum voltage at which a discharge was generated from the metal net 1.

In the second experiment, the metal net 1 was negatively charged at the maximum voltage at which no discharge was generated at the distances between the nets, and an adult maize weevil was blown between the metal nets 1 and 2 using an insect inhaler. An insect-mediated discharge (arc discharge) was recorded as a transient current by a galvanometer 8, and after the insect passed through the electric field, their mortality rate and limb amputation status were examined. In this experiment, 20 adults were used for each combination of pole distance and test voltage.

Adult maize weevil was then mixed with the rice grain group (10, 50, and 100 insects per 100 g of rice grain group) and the mixture was introduced between the metal nets 1 and 2 to amputate the dead insects and limbs. The ratio with insects was calculated. These test devices were performed in a room maintained at 20 ° C. and 40% RH. The experiment was performed 3 times and the data were shown as mean and standard deviation (SD). Significant differences between treatments were determined using the Tukey method.

In the third experiment, for scale-up, larger stainless steel nets (90 x 25 cm) were used and charged at a distance of 10 mm with the same voltage generator 3 at 9.1 kV for practical use of the present invention. I checked the sex. The pest-parasitic rice grain group in the bag was introduced into the device after counting the number of insects, and the effectiveness of pest eradication by this method was accurately evaluated.

Results and Examination In the first experiment, the voltage at which a discharge (electron emission) was generated from the metal net 1 was determined at the distance between each electrode and under different RH conditions. FIG. 4 is a graph showing the relationship between the distance between the electrodes and the applied voltage. Each of the three down arrows in the graph points from left to right to the lowest voltage that produces a discharge under conditions of relative humidity (RH) 90, 65, and 40%. From these data, the boundary between the voltage that causes discharge and the voltage that does not generate discharge can be read for each electrode distance. If the RH changes, the optimum conditions for the distance between the electrodes and the working voltage can be reset according to these data.

In the following experiments, the distance between the nets 1 and 2 was fixed, and a conductor was introduced by applying the maximum voltage that did not cause discharge. The conductor introduced electricity (free electrons) between the nets 1 and 2 according to its capacitance. It was transmitted to the space of. Our hypothesis is that this conductor material can act as a temporary acceptor of electrons from the metal net 1 and as a donor of electrons to the other metal net 2 by reducing the distance between the electrodes. It was that. For the purpose of confirming this hypothesis, insects were good biological conductors (see Figure 3). Many studies to date have reported that the epidermis, the outer protective layer that covers the bodies of many invertebrates, is efficiently charged by its high conductivity, and that of the maize weevil. Adults also have this epidermal structure.

In the second experiment, a test was conducted to determine the validity of the above hypothesis. Table 1 shows several combinations of electrode-to-electrode distance and voltage (ie, the highest non-discharge voltage at a given distance), the survival rate (mortality) of adult maize weevil introduced into an electric field, and instantaneous transients. It is a record of the magnitude of the electric current.

≪Table 1≫

Once the insects were introduced in this experiment, the electrons instantly moved from the metal net 1 side to the ground on the metal net 2 side via the insects. This electron transfer was simultaneously recorded by two galvanometers 8 as transient currents of the same magnitude. This current pushed the insects towards the lower exit. All introduced insects were electrolyzed at any combination of electrode-to-electrode distance and voltage tested (Table 1). The magnitude of the transient current and the impact on the insect increased with the applied voltage. The increased impact on insects was evident in the increased number of insects with amputated limbs.

From these results, the effectiveness of the present invention can be sufficiently confirmed, and the results show that the methods and devices according to the present invention can be applied to the direct eradication of grain pests. I can say.

In subsequent experiments, only the rice grains were introduced into the electric field of the test equipment, and it was confirmed that no current was generated at any of the previously applied distances between the electrodes and the combination of voltage. In this experiment, the volume or surface resistivity of the rice grains was not measured, but the results show that the rice grains are highly insulating and therefore only insects mixed in the rice grain group due to the high conductivity of their epidermis. It suggests that it will be selectively impacted by electrons.

Next, a confirmation test for eradication of insects was conducted using a mixture of rice grains and adult maize weevil. Table 2 shows the insect mortality rate and limb amputation rate in this study.

≪Table 2≫

For this mixture, the insects were selectively subjected to electron impact at any combination of electrode distance and voltage, and in fact, the galvanometer 8 recorded as many transient currents as the number of introduced insects. did. As a result, all insects were killed, regardless of their density within the rice grain population (Table 2). It is understood that in the electric killing of insects passing through an electric field, all intervals and charging processes are equally effective, and amputation of the limbs becomes more and more intense as the voltage increases. These results are exactly the same as the results of the second experiment, indicating that selective electron transfer targeting insects is not hindered by the presence of rice grains in the sample.

Based on the results of the above experiments, the method according to the present invention is applied to the eradication of maize weevil nesting in commercial bagged rice (20 kg) that has failed the formal inspection due to contamination by grain pests. I was able to. In this method, the larger stainless steel nets 1 and 2 with the maximum inter-electrode distance (10 mm) and the maximum voltage (9.1 kV) were used to increase the rice grain group processing capacity. As a result, all the rice grains in each bag were treated within a short time (10 to 11 minutes), and all the insects could be eliminated without any trace. From these results, the most effective and practical application example of the present invention is to incorporate the present device into the line between the rice milling process and the packaging process for preparing bagged rice of harmless insects. Can be done.

Theoretically, the methods according to the invention are applicable to all pests with a conductive cuticle layer, at least Lasioderma serricorne, Tribolium castaneum, and Callosobruchus chin. It was confirmed that it can be effectively applied to the control of stored grain pests such as.

The test results of the test device corresponding to the first device have been described above, but it is considered that the same results can be obtained in the case of the second device. The method and apparatus according to the present invention have been developed mainly for the treatment of grains that may be contaminated with stored grain pests, and for the treatment, the grains are dropped from above and the present device is used. The method of passing through is the most suitable. Therefore, it is recommended that this device have a sieve structure.

As described above, the method and apparatus according to the present invention negatively charge one of a pair of metal nets that are opposed to each other in parallel at a predetermined interval at the maximum voltage at which discharge does not occur. By causing the electric field to be generated between the electric field and the other metal net, a grain that may contain a grain pest is passed through the electric field, and the grain pest is allowed to be insulated from the dielectric property of its epidermis and the grain. It has a simple structure of selectively electric-killing depending on the sex, and it can be operated with low power consumption to effectively electric-kill stored grain pests that cause serious crop damage, so efficiency in stored crops. It can be suitably used for the control of crop pests, and the need for pesticide treatment can be eliminated, and its industrial utility is extremely high.

1, 2, 9 Metal net 3 Voltage generator 4 Ground wire 5 Spacer 6, 7 Cover 8 Galvanometer 10 Frame

Claims (8)

By negatively charging one of the pair of metal nets that are opposed to each other in parallel at a predetermined interval with the maximum voltage at which no discharge occurs, an electric field is created between the metal net and the other metal net. By passing grains that may be generated and containing grain pests through the electric field, the grain pests in the grains are selectively electro-discharged by the conductivity of the epidermis and the insulation of the grains. A characteristic electrostatic insecticidal method. Three metal nets, a central net and an outer net arranged on both sides of the central net, are arranged in parallel with a predetermined interval between the nets, and the central net is made negative at the maximum voltage at which no discharge occurs. By charging, an electric field is generated between the outer nets and grains that may contain grain pests are passed through the electric field, and the grain pests in the grains are made to have conductivity of the epidermis. An electrostatic insecticidal method characterized by selectively electrifying by the insulating property of the grain. A pair of metal nets are arranged in parallel while maintaining a predetermined interval, a voltage generator is connected to one metal net of the pair of metal nets, and the other metal net is connected to a ground wire. The metal net to which the voltage generator is connected is negatively charged at the maximum voltage at which no discharge occurs, so that the other metal net is positively charged by electrostatic induction, and thus the pair of metal nets. A device in which an electric field is formed between them, and the grain pests in a grain that may contain grain pests that pass through the electric field are divided into the conductivity of the epidermis and the insulation of the grains. An electrostatic insecticidal device characterized in that it can be selectively electrokilled by means of. The electrostatic insecticide according to claim 3, wherein the pair of metal nets are made of stainless steel having a mesh size of about 20 meshes. One is a sieve structure set of the pair of metal nets are arranged in one or a plurality of sets horizontally in the frame, the electrostatic insecticidal device according to claim 3 or 4. Three metal nets, a central net and an outer net arranged on both sides thereof, are arranged in parallel, a voltage generator is connected to the central net, the outer nets are each connected to a ground wire, and the central net is formed. by discharge is negatively charged at the maximum voltage that does not occur, is the charge each of the outer net positively by electrostatic induction, than Te, and the electric field is formed between said central net said outer net The device is capable of selectively electrifying the stored grain pests in a grain that may contain the stored grain pests that pass through the electric field due to the conductivity of the epidermis and the insulating property of the grains. An electrostatic insecticidal device characterized by. The electrostatic insecticide according to claim 6, wherein the three metal nets are made of stainless steel having a mesh size of about 4 meshes. Set of three metal nets in one frame are sieve structure disposed on one or more sets horizontal electrostatic insecticidal apparatus according to claim 6 or 7.