JPS6178340A - Control of nematodes - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for exterminating nematodes that mainly parasitize the roots of crops and cause poor growth of the crops.

[Prior Art] In recent agricultural methods that aim to increase yields by spraying large quantities of inorganic chemical fertilizers, damage caused by nematodes has become a major problem. In particular, agricultural production based on the cultivation method has a fixed cropping cycle in order to increase the efficiency of farmland use, making it susceptible to damage from nematodes. ll! ! Type 12 nematodes mainly parasitize the roots of crops, and when crops are infested with nematodes, the roots develop knob-like symptoms and the supply of nutrients to above-ground stems is blocked, resulting in poor growth. However, it often happens that the quality of the products is extremely low or the harvest is completely absent.

Conventionally, methods for protecting crops from parasitism by the above nematodes include:
Before planting crops, it is known to perform chemical fumigation of the soil using chloropicrin and disinfection of the soil by blowing high-temperature steam. It is also known that soil is removed or baked.

However, all of the conventional extermination methods described above are only methods that are carried out before planting crops to prevent nematode parasitism. If you do these things after planting crops, you will also damage the crops themselves, so if nematode parasitism occurs after planting crops, it can be said that you are completely helpless. In addition, both methods are inferior in workability and economic efficiency, and are a heavy burden on farmers. In addition, when chemicals are used, there is a risk that the chemicals remaining after treatment may cause growth problems. Furthermore, beneficial soil microorganisms also disappear, soil activity deteriorates, and the soil ecosystem is destroyed, and it takes a long period of time for the soil to recover to a suitable environment for plant growth, resulting in the loss of crops. It may also happen that good growth cannot be obtained.

[Problems to be solved by the invention] An object of the present invention is to ensure that nematodes can be exterminated even after crops have been planted, without causing harmful effects due to residual chemicals or destruction of the soil ecosystem. is the problem to be solved.

[Means for Solving the Problems] The means taken to solve the above problems in the present invention is to apply a DC base voltage intermittently to the soil, and at the same time, when applying the base voltage, The object of the present invention is to provide a method for exterminating nematodes by applying high voltage pulses in the same direction to the soil.

[Function] In the present invention, it is believed that the DC base voltage has the effect of generating a DC current in the body of the nematode, electrolyzing its water, leading to cell destruction, and weakening the nematode. It will be done. In addition, the high voltage pulse has the effect of exterminating nematodes by the shock current generated by the high voltage pulse.
It is thought that the base voltage and this high voltage pulse work together to weaken the nematode by applying the base voltage, and the weakened nematode is surely killed by the impact caused by the application of the high voltage pulse. It will be done.

On the other hand, in the present invention, since the exterminating means is an electric current, there is no need to worry about residuals like with chemicals, and the biological activity of microorganisms that are relatively resistant to electric current is maintained.
It has been confirmed that there is no risk of major damage to the soil ecosystem, and there is almost no negative impact on crops. This is thought to be because even though voltage is applied to the soil, it does not last for a very long time, and the resulting current is weak, as well as because microorganisms and plants have different biological characteristics.

[Example] As shown in FIG. 1, a pair of electrical terminals 2 are placed in soil l.
By burying the electric terminals 2a and 2b and applying a predetermined voltage from the voltage generator 3 to both electric terminals 2a and 2b, it is possible to apply a base voltage and a high voltage pulse to the soil 1 between the electric terminals 2a and 2b. can. In this case, as shown in the figure, if both the electrical terminals 2a, 2b are shaped like rods and the tip is shaped like a stone, there is an advantage that the electrical terminals 2a, 2b can be easily buried in the soil by simply pushing them from the ground surface. be.

When exterminating nematodes after planting the crop 4, connect both electrical terminals 2a with the roots 5 in between, as shown in the figure.

It is preferable to bury the nematodes 2b. Although nematodes are widely distributed in the soil 1, they especially gather in large numbers around the roots 5, so that they can be reliably exterminated. Furthermore, in the case of preventive extermination of nematodes before planting crops, the electrical terminals 2a and 2b may be buried near the planned planting location.

The base voltage applied to the soil l via the electrical terminals 2a, 2b is a DC voltage. This is to promote electrolysis within the body of the nematode.

The strength of the base voltage is preferably 100 to 800v.

In particular, 400 to 500V is suitable. If the base voltage is too low, sufficient nematode extermination effect will not be obtained, and if it is too high, there will be a risk of adverse effects on crops. This DC base voltage may be a steady voltage, but a half-wave or after-wave rectified voltage is preferable because it is easy to obtain a relatively high voltage.The base voltage is applied intermittently, and the voltage is 1 to 2.
It is preferable to repeatedly apply the base voltage for about 0 seconds, especially about 5 to 10 seconds, and then pause. If the application time of the base voltage is too short, it will be difficult to obtain the effect of exterminating nematodes.
On the other hand, if it is too long, it will likely have a negative impact on the crops. Also,
Although the pause time depends on the application time, it is generally about several seconds.

When applying the base voltage, a high voltage pulse whose positive and negative directions are aligned with the base voltage is sent from the voltage generator 3 to the electric terminal 2a,
2b to the soil 1. The reason for aligning the positive and negative directions with the base voltage is to apply a shock current to the nematodes without interfering with the electrolytic action caused by the base voltage. The strength of this high voltage pulse is 2000 to 7000V,
Particularly: 4,000 to 5,000 V is preferable; if the voltage is too low, sufficient synergistic effect with the base voltage will not be obtained; on the other hand, if the voltage is too high, the power consumption will only increase and the extermination effect will not be so great. For high voltage pulses that do not improve performance, a high voltage pulse is preferably obtained by boosting and rectifying an alternating current voltage because it is easy to obtain a high voltage pulse, and it is preferably applied at a rate of several to several tens of times per second.

It is preferable to apply two series of high voltage pulses so as to be superimposed on the base voltage. That is, when the base voltage is a steady voltage, if a high voltage pulse is applied at the same time as the base voltage is applied, the pulses will be naturally superimposed, but if the base voltage is a half-wave or aftereffect rectified voltage, ),
As shown in (b), it is preferable to generate a high voltage pulse V at the peak time vb of the base voltage and apply both in a superimposed manner to make it easier to obtain a synergistic effect by applying both voltages. It is. It is preferable that the operation of applying a high voltage pulse at the time of applying the base voltage is performed while alternately applying and stopping the application for a period of several minutes to several tens of minutes.

The power source for the voltage generator 3 may be a car battery or the like, but generally a low frequency AC power source such as a normal commercial AC power source may be selected as appropriate depending on the place of use. Furthermore, the distance between the two electrical terminals 2a, 2b is determined within a practically necessary range, but when a base voltage and a high voltage pulse are applied to both the electrical terminals 2a, 2b, a current of approximately several milliamperes may be generated. It is preferable to set it as a range.

The electric terminals 2a and 2b may be installed each time the need for extermination arises, but they may also be left in place until the end of harvest and extermination is performed at regular intervals; simply by turning on the switch. It is easy to operate as it can be exterminated. Also, even if it cannot be killed, it has the advantage of being able to drive away moles, earthworms, etc.

3 to 6 show other examples in which a base voltage and a high voltage pulse are applied to the soil l, respectively.

In FIG. 3, the electrical terminals 2a, 2b are plate-shaped. If such plate-shaped electric terminals 2a, 2b are used, current can be passed over a wide area at once, and there is an advantage that nematodes can be exterminated over a relatively wide area.

In the figure on page 144, a rod-shaped electric terminal 2a is buried close to the crop 4, and a cylindrical electric terminal 2b made of a net, a perforated plate, etc. is arranged so as to surround the roots 5. In this way, the current can be passed radially, making it easier to apply a potential in the direction of spread that is most likely to affect nematodes.

In FIG. 5, the electric terminals 2a and 2b are attached to a cart 6 and are shaped like discs. When the cart 6 is pulled by, for example, a tractor, the electric terminals 2a and 2b sink into the soil. It will rotate. In this way, nematodes can be exterminated simply by pulling the trolley 6 around with a tractor, so extermination treatment is easy even in large farmland. In this case, the voltage generator (numeral 3 in FIG. 1) and other necessary equipment may be placed on a small tractor such as a tractor, but they can also be placed on this trolley 6.

In FIG. 6, a rod-shaped electric terminal 2a is buried in the soil 1, while the other electric terminal 2b is in contact with the crop 4. In this way, the current can be reliably applied to the roots 5, so that the nematodes that have invaded the roots 5 and become parasitic can be more reliably exterminated.

Example 1 After rectifying the 100v, 50-cycle AC power supply,
The base voltage was increased to 300 V, and the voltage was applied intermittently for 5 minutes to the soil to which Nematoda nematodes, a type of nematode, had been added in advance in a cycle of applying for 10 seconds and resting for 5 seconds. When applying this base voltage, 250Q is superimposed on the base voltage.
Applying high voltage pulses of V at a rate of 50 times per second,
When the soil was observed under a microscope 12 hours later, it was confirmed that approximately 1 out of 10 Nematode nematodes were alive.

The same base voltage and high voltage pulses were applied to the above soil in the same cycle for 5 minutes, and after 12 hours, the soil was observed under a microscope, and no living nematodes were observed.

The electrical terminals were rod-shaped and arranged as described in FIG. 1, and were buried at a distance of 100 cm and a depth of 20 cm.

Example 2 Intermittent application was performed for 10 minutes in the same manner as in Example 1 except that the base voltage was 450 V and the high voltage pulse was 4000 V. As a result of microscopic observation of the soil after 12 hours, no living nematodes were confirmed.

Example 3 D1: After planting tomatoes in the soil, the same voltage as in Examples 1 and 2 was applied intermittently. As a result, no adverse effects were found on the tomatoes, and a good harvest was obtained.

Comparative example 1 100V, 50 cycle AC power supply as it is at 500V
A confining pressure was applied continuously for 5 minutes to the same soil as in Example 1 using the same electric terminal arrangement as in Example 1. Along with this AC output, a high voltage pulse of 4,000 V was applied at a rate of 50 times per second, and when the soil was observed under a microscope immediately after the application was completed, all of the added Nematodes were in a quiescent state. After another 12 hours, microscopic observation was performed again, and it was confirmed that most of the cat nematodes had started to become active again.

Comparative example 2 100V, 50 cycle AC power supply is 500V as it is
A high voltage pulse of 4,000 V was applied intermittently for 5 minutes in the same manner as in Example 1, with the base voltage being just increased to 4,000 V. During this application, the Nematodes appeared to be repellent and became motionless, but when observed under a microscope 12 hours after the application ended, it was confirmed that approximately 6 out of 10 Nematodes were alive. Ta.

[Effect of the invention 1] According to the present invention, there is no risk of adverse effects on crops, so nematodes can be exterminated before or after the crops are grown, and there is no risk of harmful effects caused by residual chemicals or destruction of the soil ecosystem. Nor. In addition, since insects can be exterminated simply by applying a voltage through an electric terminal, extermination work is easy and the economic burden is small. Therefore, it is extremely useful for preventing damage caused by nematodes, which have been increasing in size in recent years.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing an example of exterminating nematodes by the method of the present invention, and Figures 2 (a) and (b) are voltage waveform diagrams when high voltage pulses are superimposed on the base voltage, respectively. , and FIGS. 3 to 6 are explanatory views showing other examples of exterminating nematodes by the method of the present invention. l: soil, 2a, 2b: electrical terminals, 3: voltage generator, 4: crops, 5: roots, 6: trolley.

Claims (1)

[Claims] 1) A method for exterminating nematodes, which comprises intermittently applying a DC base voltage to the soil, and at the same time applying a high voltage pulse whose positive and negative directions are aligned with the base voltage when applying the base voltage to the soil.