JPH0971502A - Soil disinfecting and nematicidal agent and soil-disinfecting and nematicidal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a soil-disinfecting and nematicidal agent excellent in safety and persistency and capable of promoting growth of crops and provide a soil- disinfecting and nematicidal method. SOLUTION: This soil disinfecting and nematicidal agent contains, as a main component, a stabilized chlorine dioxide liquid stabilized so as to decrease decomposition rate by dispersing 50-150g/L chlorine dioxide into a pure water. A diluent obtained by diluting the soil-disinfecting and nematicidal agent to 50-200 times with water is sprayed in an amount of 2L/m<2> field onto a field and the field surface is covered with a plastic sheet for 5-10 day to prevent evaporation of the sprayed liquid.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a soil sterilizing / nematicidal agent containing a stabilized chlorine dioxide solution (Cl 0 ₂ ) as a main component and a soil sterilizing / nematicidal method.

[0002]

2. Description of the Related Art Chlorpicrin (a deleterious substance), methyl bromide (a deleterious substance), etc. are used as soil fumigants for sterilizing or exterminating soil pathogens and nematodes (nematodes), which are the main causes of continuous crop failure. Has been done.

The former, chloropicrin, has the strongest bactericidal activity, and when it is injected into soil, it is quickly gasified and diffused downward, exhibiting a bactericidal effect and non-selectively killing and killing many molds and bacteria. Although it is also effective as a nematode, it has strong gas toxicity and exhibits a strong irritating odor and tearing property.Therefore, avoid using it in the vicinity of residential areas, and be careful to handle it so that gas does not leak around people or livestock sheds. It costs. The latter methyl bromide is
It is effective against many soil pathogens and nematodes, has a higher vapor pressure than chlorpicrin, and is suitable for soil disinfection in the low temperature period, but since it is odorless, it often causes poisoning.

As described above, all of the conventional soil fumigants are harmful to humans and animals, require special attention in handling, and thus have low safety, and have a rapid effect on sterilization and nematicidal. There is a problem that it does not last long and that soil disease fungi and nematodes grow again in a short period of time, impairing the growth of crops.

[0005]

The problem to be solved is that the conventional soil fumigant described above is harmful to humans and animals.
The present invention provides a soil sterilizing / nematicidal agent excellent in safety and sustainability, which is low in safety and poor in sustainability of bactericidal / nematicidal effects, and which solves the above-mentioned problems. It is a thing.

[0006]

[Means for Solving the Problems] The invention of claim 1 comprises, as a main component, a stabilized chlorine dioxide solution in which 50 to 150 grams / liter of chlorine dioxide is dispersed in pure water and stabilized so that the decomposition rate becomes slow. It is a soil sterilizing and nematicide.

According to the invention of claim 2, the soil sterilizing / nematicidal agent of the invention of claim 1 is diluted 50 to 200 times with water, and 2 liters per square meter of the grassland is sprayed on the surface of the grassland. A soil sterilization and nematicidal method consisting of covering with a plastic sheet for 5 to 10 days to prevent evaporation of the sprayed liquid, which makes it possible to compare with conventional fumigants such as chloropicrin and methyl bromide. , The toxicity to humans and animals is extremely low, the handling safety is remarkably increased, and the quick-acting bactericidal and nematicidal effects are inferior to those of the conventional ones, but it is excellent in sustainability and can be used as a pathogen / nematode for a long period of time. It can keep the breeding density at a low level, suppress the development of growth disorders of crops, supplement oxygen to the root system of crops, and promote the growth thereof.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION To explain an embodiment of the present invention, the main component is a stabilized chlorine dioxide solution in which 50 to 150 grams / liter of chlorine dioxide is dispersed in pure water and stabilized so that the decomposition rate becomes slow. 50 to 20 soil sterilizers and nematicides with water
Disperse 2 liters of the diluted solution diluted 0 times per square meter of Hatakechi, cover the surface of Hatakechi with a plastic sheet for 5-10 days,
Soil sterilization and nematicidal are performed by preventing evaporation of spray liquid.

[0009] As a result, compared with the conventionally used fumigants such as chloropicrin and methyl dibromide, the toxicity to humans and animals is remarkably low, the handling safety is remarkably increased, and the bactericidal and nematicidal effects are immediately effective. Sex is inferior to the conventional one,
It has excellent sustainability, keeps the breeding density of pathogens and nematodes at a low level for a long period of time, can suppress the development of crop growth disorders, supplements the root system of the crop with oxygen, and promotes its development. You can do it.

Prior to the detailed description, the chlorine dioxide and the stabilized chlorine dioxide solution will be described first. Chlorine dioxide has a molecular weight of 67.46 and is a yellow to red-yellow gas at room temperature.
It has a pungent odor similar to that of chlorine and nitric acid, and has a gas specific gravity of about 3.0 grams / liter, a solid of yellow-red crystals with a melting point of -59 ° C, a liquid of reddish brown with a boiling point of 11 ° C, which decomposes with light to reach 100 ° C. Explodes and decomposes with. It dissolves well in water, and hot water contains chlorine (Cl ₂ ), oxygen (O _2
2 ), it decomposes to hypochlorous acid (H ClO) and shows a strong oxidizing action, as a bleaching agent for pulp, fiber, wheat flour, leather, oils and fats, beeswax, and as a sterilizing and deodorizing agent for tap water and pool water. in use.

This chlorine dioxide is properly handled and dispersed in pure water in a large amount (50 to 150 grams / liter) so that the decomposition rate is slowed down and stabilized so that it can be applied to various demands. A chlorinated chlorine dioxide solution that has been used as a germicide for water treatment plants and pools, a deodorant for hydrogen sulfide, methyl mercaptan, methyl sulfide, methyl disulfide, etc.
In addition to freshness-maintaining agents such as green vegetables, commercial and household deodorants,
It is also used as a fungicide, anti-corrosion agent, chlorine retention agent, algae growth inhibitor, and pollution control agent.

The general characteristics are as follows: (a) Chlorine dioxide gas, which has 2.6 times more oxidizing power than chlorine, is stably enclosed in pure water, which has a high degree of safety and a strong bactericidal action. Show. (A) When decomposed by heat, they become chlorine and oxygen, and when decomposed by light, they become hydrochloric acid and chloric acid, and their oxidizing power is weaker than that of chlorine, but their pH dependence is small. (C) When it is consumed, it is continuously replenished, and since free Cl 0 ₂ is always present in the aqueous solution, the bactericidal activity is slow-acting, but lasting, showing a remarkable bactericidal effect. (D) The stability of Cl 0 _{2 in} water is sodium hypochlorite (Na Cl 2
O) is more than 10 times.

(E) Regarding safety, chlorpicrin has a permissible concentration of 0.1 ppm, 0.7 milligrams / cubic meter, methyl bromide, a lethal dose of 10 to 20 milliliters / liter of air, and a stabilized chlorine dioxide solution (Cl ₂ O 5%). Oral toxicity in mice LD ₅₀ value is 2,650 milligrams per kilogram of body weight, toxicity to warm-blooded animals is extremely weak, TLM _{48 to} medaka is 39 ppm, and effective concentration is 10 ppm or less for sterilization. It is odorless, non-irritating, does not hurt the skin, and is highly safe to handle.

[0014]

Example 1 Regarding the sustainability of the bactericidal effect, diluted stabilized chlorine dioxide was diluted 1,000 times with water (Cl 0 ₂ concentration 50 ppm, pH 5.2).
Table 1 shows the results of the investigation of the bactericidal effect of the diluted solution. The experiment was performed in triplicate at the same time, and the value represents the average value.

[0015]

[Table 1]

As is clear from Table 1, the sustainability of the bactericidal activity against microorganisms floating in water is extremely excellent.

[0017]

[Example 2] Generally, the ratio of solid phase, liquid phase and gas phase of the soil in the main field is assumed to be 50:20:30 volume ratio.
To inject the stabilized chlorine dioxide solution (Cl O ₂ ) in the liquid phase (moisture) at 10 cm so as to keep the concentration at 50 ppm,
It is necessary to apply 2 liters of 100 times dilution liquid per 1 square meter (20 kg of soil liquid phase [moisture] of 10 cm depth). (It is 2,000 liters per 10 ares). Therefore, a 100-fold diluted solution 2 of stabilized chlorine dioxide solution (Cl ₂ O 5%) was applied to the entire surface of the 10-square-meter field.
The effect on soil microorganisms was investigated when 0 liter was sprayed with a power sprayer, the whole surface was covered with a polyethylene sheet so as not to get rainwater for the first 10 days, and after 10 days, this was removed. The survey was conducted three times before spraying and 10 and 20 days after spraying. Further, this experiment was performed three times at the same time, and the results are shown in Table 2 as an average value.

[0018]

[Table 2]

(Note) (1) The number of viable bacteria was determined by the dilution plate method using a medium, and the average number per 1 soil of the soil (2) The nematode density was determined by the Bellman method.

The expression of plant diseases is generally a disease in culture.
The density of protozoa is 1.0x10⁶ When accumulated above
It is said to occur in. Therefore, it is clear from Table 2
The stabilized chlorine dioxide solution (Cl 2 O₂ 5%) by soil
It is expected to predict the effectiveness of controlling the disease.

[0021]

[Example 3] Elizabeth melon in the field (1994
Table 3 shows the experimental results for the year, greenhouse cultivation, and area 10 are.

[0022]

[Table 3]

(Note) Group A (test group) Stabilized chlorine dioxide solution (Cl ₂ O 5%) 100 times diluted with 2,000 liters per 10 ares Group B (conventional group) Complete treatment with chlorpicrin (30 cm)
Drill a hole with a depth of about 15 cm for each x30 cm and inject 2 ml per hole)

As is clear from Table 3, in comparison with the B ward, the ward A has 55% of the weight of each of the excellent / excellent products with a weight of 800 grams or more, and the total yield increases by about 40%. Became. In the A ward, the number of bad fruits was 9 and extremely low. The quality standards are as follows.

[0025]

[Example 4] Tables 4 and 5 show the effects of pods (1994, greenhouse cultivation) on soil nematodes in the main field and cultivation test results.

[0026]

[Table 4]

(Note) Section A (test section) Stabilized chlorine dioxide solution (Cl ₂ O 5%) 100 times diluted with 2,000 liters per 10 ares Group B (conventional section) Complete treatment with chlorpicrin (30 cm)
Drill a hole with a depth of about 15 cm for each x30 cm and inject 2 ml per hole)

[0028]

[Table 5]

As is clear from Table 4 and Table 5,
The weight of each piece was excellent (about 9% plus), and the good ones were harvested. Regarding soil nematodes, the ward B has a strong surface insecticidal activity, but the number of surviving insects in the lower layers increases with time, and in February, nematode damage began to occur as usual, and the yield began to decline. There were almost no signs of nematode damage in the plot. Stabilized chlorine dioxide solution (Cl O ₂ ) is safer in handling and has a higher yield than chlorpicrin.
It is judged as a pesticide with high practical value. The quality standards are as follows.

The method of use will be described. First of all, when disinfecting the floor soil, carefully cut back the floor soil, loosen the lumps, stack them to a height of 30 cm (width is appropriate), flatten the surface, and stabilize the diluted dioxide 100 times per square meter. Spray 2 liters of chlorine liquid (Cl ₂ O 5%). A 30 cm high bed soil is piled on it and processed in the same manner. Then cover with a polyethylene sheet and press down with soil to prevent liquid or gas from escaping from the hem. After 7 to 10 days of spraying the liquid, remove the polyethylene sheet, cut it well, and use it after 7 to 10 days or more.

Next, in the disinfection method of the main field, the clay soil is cultivated / crushed, and the other soil is treated without cultivating. Spray 2 liters per square meter of the stabilized chlorine dioxide solution (Cl ₂ O 5%) diluted 50 to 200 times on the whole surface of the cultivated soil. Then, in order to prevent the evaporation of the liquid and raise the temperature, it is immediately covered with a polyethylene sheet. Covering period is 5 days after spraying in summer, 7-
10 days After removing the polyethylene sheet, plow and degas. In 5 to 7 days in summer and 15 days in other seasons, planting is carried out. It is recommended that the soil be suitable for disinfection so that it can be loosened by grasping it and opening it.

[0032]

EFFECTS OF THE INVENTION Since the present invention is constituted as described above, the toxicity to humans and animals is significantly lower than that of the conventional fumigants such as chloropicrin Cl ₃ C-NO ₂ and methyl bromide CH ₃ Br. , It is extremely safe to handle, and the bactericidal and nematicidal effects are inferior to the conventional ones, but it is excellent in sustainability and keeps the breeding density of pathogenic bacteria and nematodes at a low level for a long period of time. In addition, it is possible to suppress the development of growth disorders of crops and to supplement the root system of crops with oxygen to promote the growth thereof.

Claims (2)

[Claims] 1. A soil sterilizing and nematicidal agent comprising, as a main component, a stabilized chlorine dioxide solution in which 50 to 150 grams / liter of chlorine dioxide is dispersed in pure water and stabilized so that the decomposition rate becomes slow. 2. A soil sterilizing and nematicidal agent containing water as a main component of a stabilized chlorine dioxide liquid, wherein 50 to 150 grams / liter of chlorine dioxide is dispersed in pure water and stabilized so as to slow down the decomposition rate. 50
A soil sterilization and nematicidal method, which comprises spraying 2 liters of the diluted solution diluted to 200 times per 1 square meter of the field and covering the surface of the field with a plastic sheet for 5 to 10 days to prevent the spray solution from evaporating.