JP3945580B2 - Control of soil pests by low-voltage AC electricity - Google Patents

Description

上表のように、交流の１００Ｖ電圧付加は寒天の発熱により全個体が死亡したが、５０Ｖ以下では致死的影響を与えなかった。また、直流の通電は走化性を示す結果が得られた。直流による線虫の致死効果は電気化学反応によるものと判断された。
【００１６】
【実施例２】
電圧付加によるセンチュウ寄生度への影響
直径１８ｃｍの素焼鉢にサツマイモネコブセンチュウに汚染されたクロボク土壌（２４７±８０頭／２０ｇ土壌、３反復、ベルマン法）８５０ｍｌを詰め、１０ｃｍの距離をおいて平行になるように幅５ｃｍ長さ１０ｃｍの銅板を埋設した。電極間に３葉期のトマト苗（品種 タイニーティム）を５本定植して潅水した。１００Ｖ交流電源を変圧器（豊澄電源機器社製 Ｐ−４１０６及びＨＴ−１２０３）を用いて測定値７Ｖの連続、測定値１４Ｖの断続通電を行った。また、調光用サイリスタ（太洋電機産業社製 ＰＣ−３０）を調整して土壌に埋設した電極間電圧の測定値を１５Ｖに設定して通電した。交流１４Ｖの断続通電はタイマー（オムロン社製 Ｈ３ＣＲ）を変圧器の前に接続し、０．０５秒毎にオンオフして得た。１週間後に５００倍に希釈した液肥（ハイポネクスジャパン社製 微粉ハイポネクス）を散布した。４週間後にトマトを堀上げ、ネコブ寄生度、茎葉重、及びｐＨメータ（堀場製作所社製 Ｂ−２１１）を用いて土壌ｐＨを調査した。ネコブ寄生度は０（ネコブを認めない）から１，２，３，４（根系のほぼ７５％以上にネコブが認められる）の４段諧として、各段階は中間位を設けた。実験は無加温ハウス内で行った。実験期間中の平均温度は２７．６℃であった。結果の平均値を表２に示す。
【００１７】
【表２】

以上のように交流電気の連続、もしくは断続付加はネコブ寄生度を低下させた。
使用電力量を等しくした７Ｖ連続と１４Ｖ断続間でネコブ寄生度に大きな差は認められなかった。サイリスタを用いた断続付加のネコブ寄生度はやや低い傾向を示した。一方、通電した全ての区で線虫対照区に比べて茎葉重の低下が認められ、高温時の電圧付加は作物に対して生育を阻害する可能性が示唆された。
【００１８】
【実施例３】
電圧付加とセンチュウ寄生度及びトマト斑点病の抑制
直径１８ｃｍの素焼鉢にクロボク土壌８５０ｍｌを詰め、１０ｃｍの距離をおいて平行になるように幅５ｃｍ長さ１０ｃｍの銅板を埋設した。電極間に２葉期のトマト苗（品種 タイニーティム）を５本定植した。サツマイモネコブセンチュウのＩＩ期幼虫約１００００頭を含む懸濁液１０ｍｌを土壌表面に均一になるよう接種して潅水した。潅水直後の電極間の抵抗値は２５０Ωであった。可変変圧器と可変整流器を用いて、交流、直流をそれぞれ６Ｖに変換して通電した。交流はタイマーを用いて０．０５秒毎にオンオフして断続的に通電した。１週間後に５００倍に希釈した液肥（ハイポネクスジャパン社製 微粉ハイポネクス）を散布した。１週間経過前後からトマト斑点病の発症が全体に認められた。２週間後にトマト第１、第２本葉の斑点病発症葉数を調査した。発病葉数の調査後殺菌剤（マンゼブ水和剤）５００倍液を散布した。３週間後に土壌ｐＨを測定した。６週間後にトマトを堀上げてネコブ寄生度、茎葉重、卵嚢形成状況、電極の状態を調査した。ネコブ寄生度は０（ネコブを認めない）から１，２，３，４（根系のほぼ７５％以上にネコブが認められる）の４段階として、各段階は中間位を設けた。実験は無加温ハウス内で行った。実験期間中の平均温度は２３．３℃であった。結果の平均値を表３に示す。
【００１９】
【表３】

以上のように６Ｖの断続交流電圧、もしくは直流電圧の付加は、トマト斑点病（Ｓｔｅｍｐｈｙｌｉｕｍ ｌｙｃｏｐｅｒｓｉｃｉ）の発症、及びサツマイモネコブセンチュウのトマト根への侵入を抑制した。同時に交流を付加した区はトマト葉の濃緑化現象が認められた。一方、直流の付加は殆どの株が枯死し、茎葉重も低下して通電によるトマトの生育阻害は顕著であった。原因はｐＨの変化によるものと推測された。また、卵嚢の形成阻害は認められず次世代に影響を与えないと判断された。
【００２０】
【実施例４】
上限電圧の付加とセンチュウ寄生度
直径１８ｃｍの素焼鉢にサツマイモネコブセンチュウに汚染されたクロボク土壌（２１±６頭／２０ｇ土壌、３反復、ベルマン法）８５０ｍｌを詰め、１０ｃｍの距離をおいて平行になるように幅５ｃｍ長さ１０ｃｍの銅板を埋設した。電極間に４葉期のトマト苗（品種 タイニーティム）を５本定植して潅水した。１００Ｖ交流電源を変圧器（豊澄電源機器社製 ＨＴ−３００２）により３０Ｖに変換して断続通電した。また、調光用サイリスタを用い、電極間電圧の測定値を１５Ｖ、及び３０Ｖに設定して通電した。交流３０Ｖ断続通電はタイマーを変圧器の前に接続し、０．０５秒毎にオンオフした。１週間後に５００倍に希釈した液肥（ハイポネクスジャパン社製 微粉ハイポネクス）を散布した。定植直後の日中及び翌朝、通電による地温変化を測定した。７週間後にトマトを堀上げてネコブ寄生度、線虫密度、茎葉重を調査した。ネコブ寄生度は０（ネコブを認めない）から１，２，３，４（根系のほぼ７５％以上にネコブが認められる）の４段階として、各段階は中間位を設けた。実験は無加温ハウス内で行った。実験期間中の平均温度は２２．９℃であった。結果の平均値を表４に示す。
【００２１】
【表４】

以上のように１５Ｖ以上の電圧を付加した場合、いずれも地温上昇が認められ、サイリスタの測定電圧値３０Ｖの場合は、地温が４０℃を越えて１日後にトマトが萎凋枯死したため最終調査までいたらなかった。３０Ｖ断続通電、及びサイリスタの測定電圧値１５Ｖ通電は約３℃の地温上昇が認められたが、トマトの生育に影響を与えなかった。いずれも通電によりネコブ寄生度、及び第二世代線虫密度を低下させた。しかし、サイリスタの１５Ｖ通電区はネコブ寄生度の低下にも関わらずトマト茎葉重の減少が認められた。
【００２２】
【実施例５】
低周波交流付加とネコブ寄生度及びトマトの立ち枯れ率
直径１８ｃｍの素焼鉢にサツマイモネコブセンチュウに汚染されたクロボク土壌（６３±２１頭／２０ｇ土壌、３反復、ベルマン法）８５０ｍｌを詰め、１０ｃｍの距離をおいて平行になるように幅５ｃｍ長さ１０ｃｍの銅板を埋設した。電極間に３葉期のトマト苗（品種 タイニーティム）を５本定植し、サツマイモネコブセンチュウのＩＩ期幼虫約１５０００頭を接種して潅水した。１００Ｖ交流電源を可変変圧器と整流器（東洋計器社製 Ａ２０６４０ｊ）を用いて０．７Ｖの直流に変換した後、更に電磁リレー（オムロン社製 ＬＹ２）回路に組み込んで１時間、１日、１週間毎に陽極と陰極を交互に入れ替える低周波交流を調整して通電した。また、１週間交互０．０５秒断続通電は１週間ごとに陽極、陰極を入れ替えると同時にタイマーを変圧器の前に接続して０．０５秒毎にオンオフした。１週間交互１週間断続通電は１週間毎に通電を断続し、通電毎に陽極、陰極を入れ替えた。対照として０．７Ｖ直流の連続通電区を設けた。１週間後に５００倍に希釈した液肥（ハイポネクスジャパン社製 微粉ハイポネクス）を散布した。４週間後に本葉の数を調査した。立ち枯れ病による萎凋株は随時抜き取りネコブ寄生度を調査した。８週間後にトマトを堀上げてネコブ寄生度、茎葉重を調査した。また、試験紙（東洋濾紙社製 万能ｐＨ１−１１）でｐＨを測定した。ネコブ寄生度は０（ネコブを認めない）から１，２，３，４（根系のほぼ７５％以上にネコブが認められる）の４段階として、各段階の中間位を設けた。実験は加温ハウス内で行った。実験期間中の平均温度は１６．８℃であった。結果の平均値を表５に示す。
【００２３】
【表５】

上表中、ネロブ寄生度に枯死株を含み、茎葉重に枯死株を含まない。
以上のように低電圧の直流を長い周期を有する交流に変換することによって直流を連続通電した場合に発生する作物の生育阻害作用を防止することが可能になった。同時に、立ち枯れ病の発生やネコブ寄生度を低下させることが認められた。また、サツマイモネコブセンチュウ密度が高く、かつ栽培温度が低い本条件下においては、全ての個体でリン酸欠乏症状である茎葉の赤紫色化が認められた。
【００２４】
【発明の効果】
人体、作物に安全な３０Ｖ以下で種々の周期性を持った交流電気を土壌に連続的、もしくは断続的に通電することによって土壌病害虫の被害を抑制する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling soil pests in agriculture or horticulture.
[0002]
[Prior art]
Control of soil pests by continuous cropping is more difficult than pests on the ground. In many cases, a method of killing pests using a large amount of a strong pesticide is employed. In addition, a method of responding by using a large amount of compost and organic materials and utilizing the antagonism between organisms in the soil, and a method of introducing a resistant variety with low parasitic properties or strong resistance to pests are employed. Also, in large-scale agricultural areas, this is handled by rotating crops that cultivate a completely different type of crop.
[0003]
In addition, high frequency and high voltage are added to pine tree trunks for controlling pinewood nematodes.
[0004]
[Problems to be solved by the invention]
At present, pesticides such as chloropicrin, methyl bromide, 1,3-dichloropropene, and methyl isothiocyanate are mainly used to control soil pests in farmland. However, any of these drugs is easy to vaporize, has a strong irritation, and is used in large quantities, there is a risk of contaminating groundwater and air. In addition, methyl bromide is prohibited from being used in agricultural fields around the world since 2005 as a substance that destroys the ozone layer.
[0005]
In organic agriculture, instead of these pesticides, organic materials such as compost of several tons per 10 ares are dropped to increase and diversify microorganisms in the soil, thereby avoiding damage. On the other hand, however, the introduction of these large quantities of organic materials raises problems such as increasing the concentration of soil salts and eluting fertilizer components into groundwater. In addition, the introduction of resistant varieties cannot be a satisfactory countermeasure against pests because the superior traits for preference are lost or the microorganisms of strains that break resistance are generated. Rotation is difficult to use in intensive agriculture where the cultivation area is small and economic efficiency must be emphasized.
[0006]
In addition, it is difficult to secure safety as well as cost to introduce a method for applying high frequency and high voltage, which is being studied for controlling pinewood nematodes, to general farmland.
[0007]
[Means for Solving the Problems]
Examples of directly controlling biological activities using electricity include general methods such as promotion of crop growth by heating and lighting in agriculture and attraction of pests by light. In addition, the following is known. For example, Chemistry and Biology (2000, Vol. 38, NO. 8, 503-507) describes that cell functions can be controlled by electrical stimulation. In addition, nematology (Nematology, 2001, Vol. 3 (1), 31-34) describes that soil nematodes in contact with chemical substances generate a constant potential difference pulse.
[0008]
The addition of AC electricity of 50 V or less to sweet potato root nematodes on flat agar by the present inventor did not affect behavior or survival. Moreover, when a voltage of 100 V was applied, all individuals died within a few minutes due to severe convulsions, and it was assumed that the cause of this death was due to fever. On the other hand, when direct current was passed, the distribution of ions in the system changed, such as the elution of copper used for the electrodes, and deaths were observed.
[0009]
When electricity is used in open farmland soil, it is necessary to ensure the safety of humans and animals entering the soil and avoid the impact on crops. According to existing reports, it is said that the tolerance is somewhat high with DC electricity, but it is voltage 30V or less and current 0.05A or less that AC electricity has almost no influence on life. In addition, it was clarified that application of voltage to soil of 30 V or higher generates heat and cannot be used in crop cultivation under an environment where the soil temperature exceeds 30 ° C. due to high temperature damage. On the other hand, it was found that when direct current electricity was applied to the soil, the growth of crops was greatly hindered by making the concentration of substances such as hydrogen ion concentration in the soil non-uniform due to the electrochemical reaction. In addition to suppressing the occurrence of soil pests, the addition of voltage suggested that the leaves of the crop became dark green and increased fertilizer absorption.
[0010]
As a method of avoiding the above problems and simultaneously suppressing the occurrence of soil pests, it has been found that AC electricity of 30 V or less can be solved by energizing the soil continuously or intermittently. In addition, we found a method to convert the direct current electricity, which makes the material concentration in the soil inhomogeneous by electrochemical reaction, into low frequency alternating current electricity by a circuit that reverses the direction of the current at regular intervals.
[0011]
Although it is easiest to use a wired AC power source as the power source, a wind power generator or a solar cell can also be used. The voltage can be easily changed by using a transformer. For the intermittent voltage addition, a free intermittent time can be obtained by using a timer. In addition, it is possible to intermittently connect for a very short time by using a device for cutting current such as a thyristor. The application of voltage need not extend over the entire period of cultivation. In general, soil pests change depending on the growth stage, climate, and season of crops, and it is desirable to apply electricity in a timely manner to reduce costs.
[0012]
In order to convert direct current into alternating current having a free cycle, the electromagnetic relay can be opened and closed at a set time using a timer, and the anode and cathode of the direct current circuit incorporated in the relay can be alternately switched. The electrode material is preferably a copper or stainless steel plate that is not easily corroded, a net, or a spiral or hairy material such as cutting scraps, or an aluminum coating film that can be embedded easily and has a large surface area. .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described based on examples.
[0014]
[Example 1]
Behavior of nematode by applying voltage in petri dish 5 g of salt and 12 g of agar were heated and dissolved in 1 liter of tap water, and about 20 ml was poured into a 9 cm glass petri dish to prepare a flat plate. 200 microliters of suspended water containing about 20 stage II larvae of Meloidogyne incognita was dropped into the center of the petri dish. A copper electrode was embedded at a depth of 0.7 cm and a width of 1.5 cm so that both ends of the petri dish were parallel with a distance of 7 cm. Adjust the voltage to each level using a variable transformer (Sanyo Electric S-130-1), variable rectifier (Skynie BA-163), and tester (ETU-102A from Arrow Electronics Co., Ltd.). , AC electricity or DC electricity was applied. The behavior of the nematode was observed with a microscope for 5 minutes after energization. Some continued to observe the subsequent condition. The results are shown in Table 1.
[0015]
[Table 1]

As shown in the above table, the application of an alternating voltage of 100 V caused all individuals to die due to the fever of the agar, but had no lethal effect at 50 V or less. Moreover, the result which shows chemotaxis was obtained when direct current supply was carried out. The lethal effect of nematodes by direct current was judged to be due to electrochemical reactions.
[0016]
[Example 2]
Effect of voltage application on nematode parasitism 18 cm diameter clay pot filled with 850 ml of Kuroboku soil contaminated with sweet potato nematode (247 ± 80 heads / 20 g soil, 3 iterations, Bellman method), paralleled at a distance of 10 cm A copper plate having a width of 5 cm and a length of 10 cm was embedded. Five tomato seedlings (variety Tiny Tim) at the 3 leaf stage were planted between the electrodes and watered. Using a transformer (P-4106 and HT-1203, manufactured by Toyosumi Power Equipment Co., Ltd.), a 100V AC power source was subjected to continuous measurement of 7V and intermittent measurement of 14V. Moreover, the measured value of the voltage between the electrodes embedded in the soil by adjusting a dimming thyristor (PC-30 manufactured by Taiyo Denki Sangyo Co., Ltd.) was set to 15 V and energized. AC 14V intermittent energization was obtained by connecting a timer (H3CR manufactured by OMRON) in front of the transformer and turning it on and off every 0.05 seconds. One week later, liquid fertilizer diluted by a factor of 500 (fine powder hypoponex manufactured by Hyponex Japan) was sprayed. After 4 weeks, the tomatoes were dug up, and the soil pH was examined using a cat lobe parasitism, a foliage weight, and a pH meter (B-211, manufactured by Horiba, Ltd.). The degree of parasitism of the cat is 0 (no cat is recognized) to 1, 2, 3, 4 (the cat is found in almost 75% or more of the root system), and each stage has an intermediate position. The experiment was conducted in an unheated house. The average temperature during the experiment was 27.6 ° C. The average value of the results is shown in Table 2.
[0017]
[Table 2]

As described above, continuous or intermittent addition of AC electricity reduced the catob parasitic.
There was no significant difference in the degree of parasitism of the cat between 7V continuous and 14V intermittent with the same power consumption. Intermittent addition of Nekob parasitism using thyristors tended to be slightly lower. On the other hand, in all the energized plots, a decrease in the foliage weight was observed compared to the nematode control plot, suggesting that the application of voltage at high temperatures may inhibit the growth of crops.
[0018]
[Example 3]
Voltage application and inhibition of nematode parasitism and tomato spot disease A 850 ml of Kuroboku soil was packed in an unglazed pot having a diameter of 18 cm, and a copper plate having a width of 5 cm and a length of 10 cm was embedded so as to be parallel with a distance of 10 cm. Five two-leaf tomato seedlings (variety Tiny Tim) were planted between the electrodes. 10 ml of a suspension containing about 10,000 larvae of stage II larvae of sweet potato root-knot nematode was inoculated uniformly on the soil surface and watered. The resistance value between the electrodes immediately after irrigation was 250Ω. Using a variable transformer and variable rectifier, AC and DC were each converted to 6V and energized. The alternating current was turned on and off every 0.05 seconds using a timer and energized intermittently. One week later, liquid fertilizer diluted by a factor of 500 (fine powder hypoponex manufactured by Hyponex Japan) was sprayed. The onset of tomato spot disease was observed from around 1 week. Two weeks later, the number of leaf disease-causing leaves of the tomato first and second true leaves was examined. After the investigation of the number of diseased leaves, a 500-fold solution of bactericide (manzeb wettable powder) was sprayed. Soil pH was measured after 3 weeks. Six weeks later, the tomatoes were dug up to investigate the degree of cat parasitism, foliage weight, egg sac formation, and electrode condition. The degree of parasitism of the cat is 0 (no cat is recognized) to 1, 2, 3, 4 (a cat is found in almost 75% or more of the root system), and each stage has an intermediate position. The experiment was conducted in an unheated house. The average temperature during the experiment was 23.3 ° C. The average value of the results is shown in Table 3.
[0019]
[Table 3]

As described above, the intermittent AC voltage of 6 V or the application of a DC voltage suppressed the onset of tomato spot disease (Stemphyllium lycopersici) and the invasion of the root-knot nematode into the tomato root. At the same time, dark greening of tomato leaves was observed in the area where AC was added. On the other hand, the addition of direct current caused most strains to die, the stem and leaf weight also decreased, and the inhibition of tomato growth by electricity was significant. The cause was assumed to be due to a change in pH. In addition, inhibition of egg sac formation was not observed, and it was determined that it would not affect the next generation.
[0020]
[Example 4]
Adding upper limit voltage and nematode parasitic degree 18cm in diameter clay pot filled with 850ml of Kuroboku soil contaminated with sweet potato nematode (21 ± 6 heads / 20g soil, 3 repetitions, Bellman method) and paralleled at a distance of 10cm Thus, a copper plate having a width of 5 cm and a length of 10 cm was embedded. Five tomato seedlings (variety Tiny Tim) at the 4-leaf stage were planted between the electrodes and watered. A 100V AC power source was converted to 30V by a transformer (HT-3002 manufactured by Toyozumi Power Supply Co., Ltd.) and intermittently energized. In addition, using a dimming thyristor, the measured value of the interelectrode voltage was set to 15 V and 30 V, and the current was supplied. AC 30V intermittent energization connected a timer in front of the transformer and turned on and off every 0.05 seconds. One week later, liquid fertilizer diluted by a factor of 500 (fine powder hypoponex manufactured by Hyponex Japan) was sprayed. Changes in the ground temperature due to energization were measured during the day immediately after planting and in the next morning. Seven weeks later, the tomatoes were dug up to investigate the nematode parasitism, nematode density, and foliage weight. The degree of parasitism of the cat is 0 (no cat is recognized) to 1, 2, 3, 4 (a cat is found in almost 75% or more of the root system), and each stage has an intermediate position. The experiment was conducted in an unheated house. The average temperature during the experiment was 22.9 ° C. The average value of the results is shown in Table 4.
[0021]
[Table 4]

As described above, when a voltage of 15 V or higher was applied, an increase in the ground temperature was observed. When the measured voltage value of the thyristor was 30 V, the tomato died withering one day after the ground temperature exceeded 40 ° C. There wasn't. The 30V intermittent energization and the thyristor measured voltage value of 15V energization showed an increase in ground temperature of about 3 ° C., but did not affect the growth of tomatoes. In both cases, the catobacterial degree and the second generation nematode density were reduced by energization. However, in the thyristor 15V energized section, a decrease in tomato foliage weight was observed in spite of a decrease in the degree of parasitism of the cat.
[0022]
[Example 5]
Low frequency alternating current addition, Nekob parasitism and tomato wilt rate of 18cm diameter clay pot packed with 850ml of Kuroboku soil (63 ± 21 heads / 20g soil, 3 repetitions, Bellman method) contaminated with sweet potato root nematode, distance of 10cm A copper plate having a width of 5 cm and a length of 10 cm was embedded so as to be parallel to each other. Five three-leaf tomato seedlings (variety Tiny Tim) were planted between the electrodes, and about 15,000 larvae of stage II larvae were inoculated and watered. 100V AC power is converted to 0.7V DC using a variable transformer and rectifier (A20640j, manufactured by Toyo Keiki Co., Ltd.), and then incorporated into an electromagnetic relay (LY2 manufactured by OMRON Corporation) circuit for 1 hour, 1 day, 1 week Electricity was adjusted by adjusting the low-frequency alternating current in which the anode and the cathode were alternately switched every time. In addition, alternating 0.05-second intermittent energization for one week was switched on and off every 0.05 seconds by switching the anode and cathode every week and at the same time connecting a timer in front of the transformer. In the alternate energization for 1 week, the energization was interrupted every week, and the anode and the cathode were switched every time energization. As a control, a continuous energization zone of 0.7 V DC was provided. One week later, liquid fertilizer diluted by a factor of 500 (fine powder hypoponex manufactured by Hyponex Japan) was sprayed. Four weeks later, the number of true leaves was examined. Dwarf strains caused by withering disease were withdrawn from time to time, and the degree of parasitism in the cat was investigated. Eight weeks later, the tomatoes were dug up and the degree of cat parasitism and foliage were investigated. Further, the pH was measured with a test paper (universal pH 1-11 manufactured by Toyo Roshi Kaisha, Ltd.). The intermediate degree of each stage was set as four stages, from 0 (no recognized cat) to 1, 2, 3, 4 (approximately 75% or more of root system). The experiment was conducted in a warming house. The average temperature during the experiment was 16.8 ° C. The average value of the results is shown in Table 5.
[0023]
[Table 5]

In the above table, the nerobic parasite degree includes the dead strain and the foliage weight does not include the dead strain.
As described above, by converting low voltage direct current into alternating current having a long period, it has become possible to prevent the growth inhibition effect of crops that occurs when direct current is energized. At the same time, it was found that the occurrence of withering disease and the degree of parasitism of cat roots were reduced. Moreover, under the present conditions where the sweet potato nematode density was high and the cultivation temperature was low, reddish purple of the foliage, which is a phosphate deficiency symptom, was observed in all individuals.
[0024]
【The invention's effect】
The damage of soil pests is suppressed by continuously or intermittently supplying AC electricity with various periodicity at 30V or less that is safe for the human body and crops.

Claims (4)

  An amount of current that can suppress the nematode parasitic on the plant without affecting the plant by inserting an electrode into the soil, by converting AC electricity of 30V or less, or DC electricity of 30V or less to low frequency AC electricity at the electrode interval How to energize.   An amount of current that can suppress the nematode parasitic on the plant without affecting the plant by inserting an electrode into the soil, by converting AC electricity of 30V or less, or DC electricity of 30V or less to low frequency AC electricity at the electrode interval A method of energizing intermittently.   It is equipped with electrodes inserted into the soil, and converts the amount of current that can suppress infestation of nematodes to plants without affecting the plants, AC electricity of 30V or less, or DC electricity of 30V or less into low-frequency AC electricity at electrode intervals. A device that can be energized.   It is equipped with electrodes inserted into the soil, and converts the amount of current that can suppress infestation of nematodes to plants without affecting the plants, AC electricity of 30V or less, or DC electricity of 30V or less into low-frequency AC electricity at electrode intervals. A device that can be energized intermittently.