JP2002275009A - Soil fumigating method and soil fumigant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soil fumigating method and to obtain a soil fumigant enabling a juvenile plant to be raised by seeding after soil soil fumigation treatment. SOLUTION: This soil fumigant is obtained by making granules having allyl isothiocyanate or methyl isothiocyanate borne on a carrier a granular aggregate buy using a water-soluble binder. The soil fumigating method involves the steps of mixing the above fumigant into soil, covering the resultant soil with a mulching film, and injecting the soil with water. Since the active ingredient of the fumigant begins to degrade by water, on making a soil fumigation treatment along with injecting the soil with water, seeds can be sown or a juvenile plant can be raised just after the fumigating treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a soil fumigating method and a soil fumigant using allyl isothiocyanate or methyl isothiocyanate, and more particularly, to a method for decomposing active ingredients in soil and controlling pathogens. The present invention relates to a soil fumigating method using allyl isothiocyanate or methyl isothiocyanate having an excellent balance and a soil fumigant containing the allyl isothiocyanate or methyl isothiocyanate.

[0002]

2. Description of the Related Art As methods for killing infectious pathogenic microorganisms and pests in soil and facilitating breeding, there have been conventionally used methods such as burning soil, steam disinfection, electric heat disinfection, and flame radiation disinfection.
There is a method using a drug such as chloropicrin or formalin. In particular, fumigation with chemicals is known as a simple method because it vaporizes bactericidal and insect-repellent vapors at room temperature and thereby kills soil pathogens, and can be germproof in a wide range. For example, methyl bromide, one of the fumigants,
It is a compound that is widely used because it has the advantages of being broadly effective in controlling soil diseases, having a simple treatment, and having a short treatment time.

However, methyl bromide has been reduced in production and its use has been restricted due to the problem of global warming. For this reason, the development of alternatives is urgent.

[0004] As such an alternative, there is a chloropicrin-containing preparation for fumigation, which is used in large quantities as a warehouse fumigant for rice grains and the like because chloropicrin itself is safe against fire. For example, JP-A-7-247202 discloses powdered chloropicrin obtained by mixing an organic polymer compound with chloropicrin, then spray-drying and instantaneously coating with an organic polymer compound. I have. This is because chloropicrin is a liquid at normal temperature, and if used as it is, it has high antibacterial properties and nematicidal properties, so it exhibits volatilization, irritation, and tearing properties, and adversely affects the human body. The pulverized product is suppressed in volatilization in a dry state, absorbs moisture from the soil after being sprayed on the soil, rapidly destroys the coating, and exhibits a pathogen controlling effect.
Chloropicrin and its degradation products are harmful to plants at an effective concentration for controlling pathogens, and when used in soil fumigation, must be sowed in soil unless the components are volatilized over time, or larvae It is also known that plants cannot be vegetated.

As other soil fumigants, the use of dazomet, carbum, DD and the like has been studied, but they have not been satisfactory yet. This is because, for example, dazomet agents are limited in the types of diseases and pathogens to be treated, and may require the use of other agents in combination. Because there is.

[0006] On the other hand, allyl isothiocyanate is a natural antibacterial compound containing a fragrance component of wasabi as an active ingredient, has a broad antibacterial spectrum from fungi to bacteria, and has a very small amount of fragrance component. Japanese Unexamined Patent Application Publication No. 2000-86414 discloses a novel antibacterial and antibacterial effect. For this reason, for example, JP-A-10-2
JP 87516 discloses a solid insecticide in which an insecticide component containing allyl isothiocyanate as an active ingredient is contained and held in a solid carrier. The allyl isothiocyanate is a volatile liquid at room temperature, and utilizes the solid insecticide that the volatile gas exerts an insecticidal effect on clothing pests. For this reason, for example, when used in a substantially closed storage case, even when the storage case is continuously closed for a long period of six months or more, the stored clothes may be damaged by clothing pests. Can be sufficiently prevented. However, due to the lower vapor pressure compared to methyl bromide,
Even if it is sprayed on soil, it is effective only on the soil surface, and is not used for soil treatment.

[0007]

As described above, the drawbacks of the conventional soil fumigant are as follows: (1) As in the case of allyl isothiocyanate, the active ingredient is unlikely to diffuse into the soil due to its low vapor pressure, and it is not sufficient. That it cannot be treated; (2) it may be irritating to the processor during handling because it is liquid at room temperature, such as chloropicrin and allyl isothiocyanate; Decomposition products are harmful to plants, but removal of harmful substances is not easy. (4) Long-term degassing is required for sufficient removal of harmful substances, resulting in long time required for fumigation treatment. (5) The target disease is limited.

However, conventionally, although there is a method of controlling volatilization by powdering or the like to secure safety during work, soil fumigation originally has a bactericidal and biocidal effect. To grow plants after soil fumigation,
It requires a removal step such as volatilization of the fumigant, and there is no soil fumigating method or soil fumigant that can be sown immediately after fumigation or grow larvae.

[0009]

The present inventor has conducted detailed studies on the identification of compounds having a soil fumigant effect.
When soil treatment was performed using a soil fumigant containing a specific amount of allyl isothiocyanate or methyl isothiocyanate, excellent operability was obtained, and a certain antibacterial effect was obtained even in an environment where the outside temperature was different, and Began to decompose due to the presence of moisture, and because of the excellent balance between this decomposition rate and the pathogen control effect, they found that they did not inhibit the growth of plants even if seeded within a short time after soil treatment. Completed. That is, the present invention provides the following (1) to (1)
5) is intended to be provided.

(1) A soil fumigant containing 0.5 to 30% by mass of allyl isothiocyanate or methyl isothiocyanate is mixed in the soil, the soil is covered with a multi-film, and then water is injected into the soil. Is the soil fumigation method.

(2) After covering with the multi-film,
The soil fumigation method according to the above (1), wherein the soil is heated before and / or after the water injection.

(3) The soil fumigation method according to the above (2), wherein the method for heating the soil comprises adding lime nitrogen and organic matter to the soil.

(4) The soil fumigation method according to the above (2), wherein the method for heating the soil is heating by solar heat.

(5) The soil fumigation method according to the above (2), wherein the method of heating the soil comprises adding lime nitrogen and organic matter to the soil and heating by solar heat.

(6) The soil fumigation method according to the above (2), wherein the method for heating the soil comprises introducing steam or a heated gas into a pipe previously buried in the soil.

(7) The method according to any one of the above (1) to (6), wherein the soil fumigant is a granular material having allyl isothiocyanate or methyl isothiocyanate supported on a carrier.

(8) The soil fumigating method according to the above (7), wherein the soil fumigant is formed by assembling the granules with a water-soluble binder.

(9) The soil fumigating method according to the above (8), wherein the soil fumigant is obtained by coating the aggregate with polyvinyl alcohol and water-soluble cellulose.

(10) A soil fumigant which is a granular material having allyl isothiocyanate or methyl isothiocyanate supported on a carrier.

(11) A soil fumigant in which a granular material having allyl isothiocyanate or methyl isothiocyanate supported on a carrier is formed into an aggregate of granular materials with a water-soluble binder.

(12) The above (10) or (1), wherein the soil fumigant is obtained by further coating the granular material or the aggregate with polyvinyl alcohol or water-soluble cellulose.
The soil fumigant according to 1).

(13) The soil fumigant according to the above (11) or (12), wherein the aggregate further contains a disintegrant in addition to the granular material.

(14) The soil fumigant according to the above (13), wherein the disintegrant is water-soluble hydroxypropylcellulose.

(15) The content of the allyl isothiocyanate or methyl isothiocyanate is 0.5 to 3
The soil fumigant according to any one of the above (10) to (14), which is 0% by mass.

[0025]

DISCLOSURE OF THE INVENTION The first object of the present invention is a soil fumigant in which allyl isothiocyanate or methyl isothiocyanate is supported on a carrier and the granules are aggregated with a water-soluble binder. .

The soil fumigant is required to have excellent soil bactericidal and insect repellent effects against a wide range of pathogens, but the soil after fumigation is used to sow or grow larvae. Therefore, it is necessary not to leave such toxicity that inhibits their growth. The allyl isothiocyanate and methyl isothiocyanate used in the present invention start to be decomposed by moisture or heat, and the decomposed product has no harmful effect on plants, and has sufficient antibacterial and insecticidal effects against soil pathogens during the decomposition process. It turned out to be obtained. Particularly, in the case of a preparation in which granules supporting allyl isothiocyanate or methyl isothiocyanate are aggregated with a water-soluble binder or the surface of which is coated, the binder or the coating agent is dissolved by the addition of soil moisture, and the allyl isothiocyanate is dissolved. And methyl isothiocyanate are released into the soil, which has an immediate effect, and at the same time, the active ingredient immediately starts to decompose due to the moisture in the soil, so that the residual amount of the drug in the soil is small. Moreover, since the active ingredient is supported on a carrier, the active ingredient can be handled as a granular substance or a solid substance that is an aggregate thereof, and can be easily administered to soil. Hereinafter, the present invention will be described in detail.

The carrier for supporting allyl isothiocyanate or methyl isothiocyanate is not particularly limited as long as it is not harmful to plants in soil.
For this reason, silicate compounds, activated carbon, zeolites, diatomaceous earth, ceramics, other porous materials, sawdust, granular pulp, and other biodegradable substances can be exemplified.

Examples of the silicate compound include magnesium metasilicate aluminate, calcium metasilicate aluminate, sodium metasilicate aluminate, potassium metasilicate aluminate, and silicic anhydride.

Activated carbon is porous carbon used for gas purification, deodorizing agents, decolorizing agents, etc., and has many fine pores of several centimeters per ten million. For this reason, the property of adsorbing substances is extremely strong. Wood, sawdust, coconut shells, lignin and other plant-based materials, bovine bone, chicken dung, blood charcoal and other animal-based materials, as well as lignite, lignite, large coal, and coal Some of them are carbonized and then activated and purified. Any of them can be used.

Zeolite is a type of silicate containing aluminum (aluminosilicate), also called zeolite, and is characterized by a structure occupied by fine pores. In the present invention, natural products may be used, and synthetic zeolites may be used. The fine pores are used because molecules corresponding to the diameter of the pores are absorbed and desorbed. Specifically, ZCP-50 and ZCE-50 (trade names, manufactured by Catalyst Chemicals) and TSZ-300, TSZ-500, and TSZ-6 (trade names, manufactured by Toyo Soda Kogyo Co., Ltd.)
00, TSZ-700, trade name LZ-, manufactured by Union Showa
Y52, LZ-Y62, SK-500 and the like.

Diatomaceous earth is a siliceous sediment consisting of the remains of a diatom, a single-cell algae, and is a carrier that can be preferably used because it has biodegradability after being used in soil treatment. Also, ceramics are usually
This is a general term for materials obtained by thermal processing of non-heavy metal inorganic materials, and is preferably used because it has excellent heat resistance and corrosion resistance. It is to be noted that the present invention is not limited to these, and natural sand or porous lava obtained by further finely pulverizing porous lava may be used as a carrier.

As another biodegradable substance, there is a biodegradable resin formed into a granular form. Specifically, polyglycolic acid, polylactic acid, poly-β-propiolactone,
Poly-γ-butyrolactone, poly-δ-valerolactone, polylactones such as poly-ε-caprolactone, poly-3-hydroxybutyrate, polyhydroxyalkanoates such as poly-3-hydroxybililate, chitin, chitosan, Polysaccharides such as poly-p-dioxanone, trimellilen carbonate polymer, polymalic acid, acid anhydride polymer, polyalkylcyanoacrylate, amylose, starch, dextran, and copolymers thereof are exemplified. In addition, polyglycolic acid / polyalkylene block copolymer (JP-A-59-100130), urethane polymer (JP-A-63-278924), β-malolactone polymer (JP-A-56-26929) And polyether glycol-based polymers (Japanese Patent Laid-Open No. 1-195862).
No.), polypeptides (Publication No. 63-502039)
No.), polyimino carbonate (Macromolec)
ules, vol. 22, no. 5, p. 2029), polydepsipeptide (Japanese Patent Publication No. 1-211574), polyethylene glycol succinate (JP-A-50-47492),
A wide variety of polymers such as a lignin-like polymer (Japanese Patent Publication No. 54-8502) are known.

Although the particle size of these carriers is not particularly limited,
Generally, the average particle size is 0.1 to 20 mm, particularly preferably 0.3 to 8 mm. If the diameter is smaller than 0.1 mm, the workability may be inferior due to a large amount of dust. On the other hand,
If it exceeds 20 mm, the immediate effect may be inferior when this is subsequently made into an aggregate. The granular material in the present specification may have an average particle diameter in the above range, and the name may not be called powder, granule or fine granule.

In order to carry allyl isothiocyanate or methyl isothiocyanate on the above-mentioned carrier, these agents are dissolved in a solvent at a concentration of 10 to 80% by mass, more preferably 30 to 50% by mass, and loaded by impregnation or the like. Thereafter, the solvent may be removed by vacuum drying.

The solvent to be used is preferably one which can dissolve allyl isothiocyanate or methyl isothiocyanate and can be easily volatilized under vacuum. Alcohol such as methylene chloride, methanol, ethanol, butanol, ether, acetone , Xylene, a mixed solution of methyl alcohol and methylene chloride and the like can be preferably used. As a result, a granular material having allyl isothiocyanate or methyl isothiocyanate supported on a carrier is obtained.

The soil fumigant of the present invention is the above-mentioned granular material or an aggregate of the granular material with a water-soluble binder. When the soil fumigant is applied to the soil,
The water-soluble binder or coating agent is dissolved by water in the soil or by water added to the soil,
Since the carrier used generally has a strong water adsorption capacity, it absorbs water, and the allyl isothiocyanate or methyl isothiocyanate in the water moves from the carrier into the soil and is released into the soil, whereby the allyl isothiocyanate or methyl is released. Isothiocyanates control or control bacteria and pests in the soil. In particular, from the viewpoint of improving the handleability of allyl isothiocyanate and methyl isothiocyanate which are liquid at ordinary temperature, it is preferable that the water-soluble binder used has an organic gas barrier property.

Specifically, examples of the water-soluble binder to be used include plant-based and animal-based natural water-soluble polymers, semi-synthetic water-soluble polymers, and synthetic water-soluble polymers. For example, polyvinyl alcohol, ethylene vinyl alcohol such as polyvinyl methyl ether, polyethylene glycol, cellulose derivatives such as cellulose and methyl cellulose and hydroxypropyl cellulose, soluble starch and its derivatives, carboxymethyl starch, starch-based natural products such as dextrin, mannan , Chitosan, guar gum, xanthan gum, gum arabic, glucose,
Examples include, but are not limited to, sugars such as sucrose, amino acids such as glycine, gelatin, and serine or derivatives thereof, and natural substances such as polylactic acid, sodium alginate, and casein. In the present invention, one or more of the above-mentioned water-soluble banders may be used.

In the present invention, among the above-mentioned water-soluble binders, it is preferable to use water-soluble cellulose such as polyvinyl alcohol and hydroxypropyl cellulose having low permeability to organic solvents. Since they are excellent in water solubility, they can easily release the contents by the moisture in the soil at a soil temperature of 10 to 70 ° C., and can obtain a rapid soil pathogen controlling effect by allyl isothiocyanate or methyl isothiocyanate. Further, the decomposition of these active ingredients is started by this moisture, and the residual amount of the compound can be reduced after the bactericidal and insect repellent. Conventionally, when chloropicrin or the like is used for soil fumigation, the active ingredient or its decomposed product is harmful to plants, so it takes a long time to remove the ingredient, so that seeding after fumigation treatment can be performed quickly. Could not be done. However, in the present invention, since the treatment is carried out at a high temperature and in the presence of water, the active ingredient is actively decomposed, thereby reducing the amount of the remaining active ingredient in the soil. You can now vegetate.

In the present invention, the aggregate preferably contains a disintegrant. This is because the addition of the disintegrant facilitates the dispersion of the aggregate and promotes the release of the active ingredient.

In the present invention, it is particularly preferable to use water-soluble hydroxypropylcellulose as a disintegrant. This is because, in the compound, the hydrogen bond is dissociated in the presence of water, and the three-dimensional structure changes, so that the aggregate can be easily dispersed in the original granular material by the moisture in the soil. In particular, in the present invention, from the viewpoint of improving the handleability of the active ingredient, a relatively large carrier is used or an aggregate of fine carriers is used, and the active ingredient is effectively used in the soil from the soil fumigant. To dissipate, in the case of the aggregate, add a disintegrant such as water-soluble hydroxypropyl cellulose,
After adding and mixing the fumigant into the soil, the addition of water immediately destroys the soil fumigant and speeds up the diffusion of the active ingredient gas.

In the present invention, additives such as fillers and surfactants can be used as long as the function of controlling the dissolution of the active ingredient is not impaired. The powder used as a filler in the present invention is a poorly water-soluble or water-insoluble powder. These fillers are uniformly dispersed in the aggregate,
Those having poor dispersibility require a dispersibility improving treatment such as facilitating dispersion with a surfactant or the like. Preferred materials for these fillers include talc, calcium carbonate, clay, diatomaceous earth, silica and salts thereof. When these are used, the coating strength of the aggregate tends to decrease as the amount of use increases, regardless of which powder is used.

The surfactant which can be used in the present invention may be any of cationic, anionic, amphoteric and nonionic surfactants. Balance is important. If the hydrophilicity is too strong, the particles are not uniformly dispersed in the aggregate and aggregate to cause a film defect. Those with strong lipophilicity have no effect on the coating, but tend to have a slightly inferior dissolution promoting effect. H of these surfactants
LB is less than 15, preferably in the range of 11 to 13.

Further, the soil fumigant of the present invention may be one obtained by coating the above-mentioned granular material or its aggregate with polyvinyl alcohol or water-soluble cellulose. As described above, when the outer periphery of the granular material or the aggregate thereof is coated, handling during soil treatment becomes easy, and the decomposition rate of allyl isothiocyanate or methyl isothiocyanate is controlled by adjusting the thickness of the coating layer. be able to.
In particular, in summer work environments, high temperatures can lead to high concentrations of ambient air allyl isothiocyanate or methyl isothiocyanate during the mixing of soil fumigants into soil. As a result of examining a method that can be used easily regardless of the season and that does not increase the concentration of allyl isothiocyanate or methyl isothiocyanate during the work of mixing in the soil or coating with a multi-film, the surface of the aggregate was polyvinyl When coated with a water-soluble polymer such as alcohol, the coating layer on the surface of the soil fumigant dissolves without increasing the concentration of the active ingredient and after the addition of water or by heat treatment, and the gas concentration in the soil is reduced. And it was found that the desired treatment could be performed.

As a method for further coating the granular material or the aggregate thereof of the present invention, a known method can be applied. For example, a water-soluble binder is dissolved in an organic solvent or water in the same manner as in the jet coating method or the jet coating method, and then the solution is added to an assembly moving by a rotating pan, a rotating drum, etc., and simultaneously dried by blowing hot air. Alternatively, a method of forming and growing a film may be used. The average particle size of the soil fumigant, which is the thus obtained granular material of the present invention and its aggregate, is 0.1%.
-20 mm, more preferably 0.1-10 mm, particularly preferably 0.3-8 mm. If it is less than 0.1 mm, mixing with the soil becomes difficult, while if it is more than 20 mm, the decomposition rate may decrease.

The content of allyl isothiocyanate or methyl isothiocyanate in the thus obtained soil fumigant is 0.5 to 3 based on the total mass of the soil fumigant.
0% by mass, particularly preferably 10 to 10% by mass.
20% by mass. When the amount is less than 0.5% by mass, the soil fumigation effect is not sufficiently exerted. On the other hand, when the amount exceeds 30% by mass, the loss during production or during the soil fumigation treatment increases. The soil fumigant of the present invention may contain only allyl isothiocyanate or methyl isothiocyanate, or may be a combination of these.

Although the amount of the soil fumigant used in the present invention varies depending on the kind of the target bacteria or pests, etc.
It is preferable to use 1 to 50 kg for 0a.

A second aspect of the present invention is to mix a soil fumigant containing 0.5 to 30% by mass of allyl isothiocyanate or methyl isothiocyanate into soil, cover the soil with a multi-film, and Is a soil fumigation method.

Since allyl isothiocyanate or methyl isothiocyanate itself is liquid at normal temperature and has a low vapor pressure of 10 mmHg and 40 mmHg, sufficient treatment of the entire soil can be performed even if it is administered to the soil. Can not. However, if this is 0.5-30
When used as a soil fumigant containing mass%, it can be easily mixed into the soil without increasing the concentration during the operation, and therefore, it is possible to control bacteria and insects not only on the soil surface but also in the soil over a wide area. It is. At this time, as the soil fumigant to be used, for example, the soil fumigant of the present invention is preferable. According to this fumigant, a soil fumigant containing allyl isothiocyanate or methyl isothiocyanate is put into the soil with an existing agricultural machine such as a cultivator, mixed, and heated, so that the soil can be buried in a short time of 1 to 20 days. It turned out that it could be processed to the desired depth.

A feature of the method of the present invention is that the soil surface is covered with a multi-film. As a result, a phenomenon in which the active ingredient diffuses into the outside air before the processing is completed can be prevented, and sufficient processing can be performed. In addition, it also functions as a heat insulator when the soil is heated for the purpose of promoting sufficient diffusion and decomposition of the active ingredient in the soil.

Further, the method of the present invention is characterized in that the soil fumigant is mixed into soil and then water is injected. Allyl isothiocyanate and methyl isothiocyanate start to decompose by water administration, but during soil fumigation,
This is because most of the active ingredients were not decomposed, and the decomposition of the active ingredients was terminated after the soil was germ- and insect-proof. Therefore, it was found that sowing and vegetation of larvae can be quickly performed after soil treatment. Such properties of allyl isothiocyanate and methyl isothiocyanate have not been known at all. The water injection in the present invention means that the soil contains a sufficient amount of water for promoting the release and decomposition of allyl isothiocyanate and methyl isothiocyanate from the above-mentioned purpose.
It is preferably about 80% by mass. Therefore, if the soil before the addition of the soil fumigant holds the above range of moisture, the decomposition of the fumigant is started without water injection. However, the active ingredient is decomposed before obtaining a sufficient fumigation effect. Therefore, in order to sufficiently secure the soil fumigation effect, it is preferable to mix the soil fumigant into the soil, cover with a multi-film, and then pour water.

Specifically, when the soil fumigant is mixed with soil and brought into contact with water, it is slower than the pathogen control rate, but at a sufficient rate, 3 to 10 days after the addition of water, to allyl isothiocyanate or methyl isothiocyanate. Thiocyanates can be degraded to an extent that they are not harmful to plants.
Conventionally, regarding the soil fumigation treatment, an effective amount of fumigation gas was administered into the soil, and attention was paid only to the antibacterial and insect repellent properties. Therefore, there was no concept of injecting water into the soil for the purpose of soil fumigation. However, in the present invention, allyl isothiocyanate or methyl isothiocyanate is used as an active ingredient for soil fumigation, and as a result of focusing on the decomposability of the compound by water, the relationship between the pathogen control effect and the decomposition rate by water shows that It was found that it was in harmony with breeding after fumigation. Therefore, by simply adding the step of “water injection”, an extremely practical soil fumigation method was completed.

In the present invention, it is preferable to heat the soil before and / or after the water injection after covering with the multi-film. Since the boiling point of allyl isothiocyanate and methyl isothiocyanate is higher than that of methyl bromide or the like, fumigation is promoted by heating.
Such a method of heating the soil may be heating by solar heat, but such a heating effect may not be obtained depending on the season. For this reason, for example, steam or a heating gas is introduced into a pipe buried in the soil in advance, or lime nitrogen and an organic substance are added to the soil, and a heating method using a heat generation effect by contact with fermentation heat or moisture is used. There may be. In particular, it is economical to use solar heat in summer, and a method of mixing lime nitrogen and organic matter is preferable in that a soil improvement effect by composting lime nitrogen and organic matter can be expected.

The heating may be any as long as it assists in fumigation of the active ingredients allyl isothiocyanate and methyl isothiocyanate. Therefore, the soil temperature should be raised to 20 to 70 ° C., particularly preferably 40 to 60 ° C. I just want to be able.

More specifically, the surface of the field in summer is covered with a multi-film, and the soil temperature is sufficiently raised by solar heat treatment or the like, and the water-soluble binder is dissolved with the moisture in the soil, and the allyl is charged and mixed into the soil. By activating a soil fumigant containing isothiocyanate or methyl isothiocyanate to control pathogens, and then removing the multi-film after decomposing the active ingredient, safe pathogen control treatment can be performed.

Incidentally, raising the temperature of the soil is useful not only for increasing the treatment rate but also for promoting the decomposition of allyl isothiocyanate and methyl isothiocyanate after the treatment. The seemingly contradictory method of simultaneously proceeding the intended processing operation and the decomposition treatment of this active ingredient was made possible by the fact that the target treatment speed was 40 ° C. for 5 to 10 hours, whereas the decomposition speed was half-life. Is about 20 hours,
During the target processing time, the concentration of 80% or more of the initial concentration can be maintained on average. In the final stage of the treatment, if the temperature is set as high as possible, for example, 50 ° C. or more, and the concentration is significantly reduced in about 48 hours, it is safe to work. Findings of the fact that they can.
Therefore, according to the present invention, soil treatment at a depth of 15 to 30 cm in the ground is possible, and after the treatment, the atmospheric concentration of allyl isothiocyanate or methyl isothiocyanate is reduced to a level that does not interfere with agricultural work. It becomes possible.

The soil fumigant of the present invention exhibits an excellent soil pathogen control effect as described above.

Examples of applicable pests include nematodes such as sweet potato nematodes, soil nematodes, nematodes, nematodes nematodes, pine wood nematodes; Kaburayaga,
Spodoptera, Tamanaginiwawa, Nikameiga, Sankameiga, Nashinioshingui, Himadarameiga, Mamenomeiga, Inetomushimi, Cottonweed Beetle, Potato Moga, Monshiro Butterfly, Noshimedama Meiga, Tonen-koma-mogama, Tonen-moka-miga-mimi Lepidopteran pests such as scarf, chanohosoga, diamondback moth, iga; tobacco whitefly, whitefly, citrus whitefly, cotton aphid, snowy aphid, apple aphid, peach peach aphid, radish aphid, lycopodium aphid, beetle aphid , Citrus aphid, Grapevine aphid, Mugimid aphid, Potato beetle Buramushi, tea Roh green leafhopper, lid Ten leafhopper, small brown planthopper, brown planthopper, Sejirounka, leafhopper, Taiwan green rice leafhopper, white giant leafhopper, Rubiroumushi,
Olive stinkbug, San Jose scalebug,
Lepidopteran mosquitoes; , Colorado potato beetle, Tencybi beetle, weevil, beetle beetle, beetle beetle, kidney beetle, adzuki beetle, beetles
Coleopteran pests, such as scrofa scrofa, platypus beetle, etc .;
The double-legged insects such as Acalymophila, Chikaieka, Anopheles chinensis, Aedes albopictus, A. anemone, Soybean gall midge, Rice carabae, Rice scallop, housefly, black flies, onion fly, sea urchins, porphyra, and red porphyra; Thrips insects, such as thrips; black cockroaches, yamato cockroaches, brown cockroaches, brown cockroaches, oriental insect pests such as brown locusts, tosama grasshoppers, etc .; Acarina pests such as house dust mites, tsutsugamushi, and mites mites; other, fleas, head lice, and termites Yakeyasude, Guedj like.

The effective disease target of the soil fumigant of the present invention is sweet potato blight, vine wilt, purple scab, black bruise; potato scab, black bruise; cucumber seedling establishment Blight, vine rot, plague; melon spot rot;
Eggplant wilt, wilt; Tomato white wilt, wilt, wilt, wilt; Strawberry blight, wilt; Spinach wilt, wilt, root rot; Cruciferous vegetables Root rot, constriction, yellow rot, yellowing of carrot; root rot of carrot, dry rot; root rot of pea; white silk of kidney bean; yellow rot of celery; Diseases: Tobacco blight, plague, black root, dwarf; Carnation blight, wilt and other diseases caused by filamentous fungi and bacteria. In addition, there are various virus diseases, nematodes, scarab beetles, and black beetles. , Vignetting and the like.

The weeds to which the soil fumigant of the present invention is effective include legume weeds such as white clover, grasses, cyperaceae weeds, and broadleaf weeds.

[0060]

The present invention will now be described more specifically with reference to examples.

The degradation of the allyl isothiocyanate in water and the course of the decrease in the antibacterial effect were compared. (FIG. 1) (Reference Example 1: Degradability of Allyl Isothiocyanate in Water) First, allyl isothiocyanate (AIT)
5.025 g was diluted in 100 ml of ethanol to prepare a substrate stock solution. Next, 0.6 ml of the substrate stock solution was accurately weighed and placed in a Teflon (registered trademark) -coated 100 ml sealed glass bottle containing 20 ml of purified water to prepare a plurality of treatment solutions. The lid of the glass bottle containing each processing solution was tightly closed, and the mixture was stirred at 40 ° C and 60 ° C for up to 50 hours.

The amount of allyl isothiocyanate was measured for the treatment liquid every 5 hours up to 50 hours. 80 ml of ethanol was added to the treatment solution after a predetermined time, to obtain a sample for measurement. The residual amount of allyl isothiocyanate at each time was expressed as a percentage of the allyl isothiocyanate at 0 hour. In addition, the allyl isothiocyanate of the sample was measured under the following conditions.

GC graph operating conditions: Model: (GC-14B Co., Ltd. Shimadzu Corporation) Detector: FID Column: DB-WAX (J & W SCIENTIFI
C) Temperature: 220 ° C. of sample inlet and detector (Reference example 2: Efficiency of treating allyl isothiocyanate with pathogenic bacteria) As the pathogenic bacteria, Fusarium oxysporum was used.
Was used.

The above strain was grown on a Brix agar medium at 37 ° C.
C., and cultured for 24 hours. Using this culture, 10 ⁵ cf
100 μl of u / ml bacterial suspension was spread on the plate medium.

An allyl isothiocyanate solution 100 diluted to various concentrations with corn oil was placed inside the lid of a petri dish.
The filter paper to which μl was added was placed, and the plate medium was covered with the petri dish. This was placed in a plastic film bag having barrier properties, sealed, and cultured at 37 ° C. for 3 days to measure the minimum inhibitory concentration (MIC).

100 μl of the allyl isothiocyanate solution diluted to the MIC amount with corn oil was added to the inside of the petri dish lid, and the plate medium prepared in the same manner as above was covered with the petri dish. This is put in a plastic film bag having barrier properties and sealed, and the temperature is set to 40 ° C. or 6 ° C.
The cells were cultured at 0 ° C. for 50 hours.

The number of bacteria in the petri dish was measured every 5 hours. 50 ml of sterile physiological saline was added to the sample opened every 5 hours, treated with a stomacher (manufactured by Gunze Sangyo Co., Ltd.) for 2 minutes, and the number of bacteria was measured by an open pour method. Regarding the number of bacteria in the petri dish, the number of bacteria at each time was expressed as a percentage of the number of bacteria at 0 hour. The allyl isothiocyanate vapor in the gas phase was analyzed by GC (Shimadzu Corporation, GC-14A, detector FI) equipped with a DEGS column.
D).

Example 1 20 parts by mass of silicic anhydride and 40 parts by mass of magnesium aluminate metasilicate were mixed with 40 parts by mass of a 40% methylene chloride solution of allyl isothiocyanate.

The solvent contained was removed by vacuum drying at a temperature of 20 to 25 ° C. to obtain an allyl isothiocyanate-adsorbed powder. Next, the allyl isothiocyanate adsorption powder 40
Parts by mass, 35 parts by mass of calcium carbonate, 15 parts by mass of polyvinyl alcohol (manufactured by Shin-Etsu Chemical: PVA C-05 (granules)), 6 parts by mass of water-soluble hydroxypropyl cellulose (trade name: ECG, manufactured by Gotoku Yakuhin Co., Ltd.), magnesium stearate 2 parts by mass, 2 parts by mass of talc are mixed with a V-type mixer,
A soil fumigant having a diameter of 9 mm was produced with a tablet machine made by Hata Tekko.
The amount of allyl isothiocyanate of this sample A was 8.
It was 2% by mass.

A sample B was prepared by coating the surface of the above-mentioned soil fumigant with a 6% by mass aqueous solution of polyvinyl alcohol.
And The amount of allyl isothiocyanate of this sample B was 6.7% by mass.

(Example 2) Using the sample A and the sample B obtained in Example 1, a pot was tested in summer at an average outside temperature of 25 to 32 ° C. The pot is made of expanded polystyrene 5
Those having a size of 0 × 100 cm and a depth of 50 cm were used. For keeping the temperature warm, a warming agent was wound around 4 mm. Also,
A polyvinylidene chloride film was embedded on the inner surface of the container so that allyl isothiocyanate was not absorbed into the container. Next, after putting the soil to a depth of 45 cm, a sample was charged under the following conditions and mixed with the soil up to a depth of 25 cm. In Test Examples 1 to 7 and Comparative Example 1, 1.0 kg of lime nitrogen and 10 kg of rice hulls were charged and mixed to a depth of 25 cm. In Test Examples 8 to 13, lime nitrogen and rice husk were mixed to a depth of 25 cm without being charged.

After the above treatment, the surface of the soil was covered with a transparent multi-film, allowed to stand in the sunlight, water was added at a predetermined time shown in Table 1, and a soil sample was collected on the evaluation day shown in Table 1. The antibacterial effect was measured. The soil was sampled up to a depth of 30 cm from the soil surface.
The presence or absence of odor was also recorded at the time of sampling. Table 1 shows the results. The criteria for the effects in Table 1 are based on a 10-point evaluation of the disease-suppressing effect, ie, the disease-suppressing rate.

Results: In the season of strong sunlight, the treatment of sample A or sample B without addition of lime nitrogen and organic matter was performed only on the soil having a depth of 25 cm 12 days after the last stage of treatment, and the soil temperature was reduced after 12 days. The temperature reached 40 ° C, and a sufficient disease control effect was obtained. The odor hardly occurred 6 days after watering. In the case where no water was added, a slight odor was felt even after 12 days.

[0074]

[Table 1]

(Example 3) In the same manner as in Example 2, a pot was tested in April at an average outside temperature of 8 to 20 ° C. Table 2 shows the results.

Results: In the season when the solar heat was weak, the effect of adding organic matter and lime nitrogen was great.

[0077]

[Table 2]

Example 4 Silicic anhydride (Mizukasil, Mizusawa Chemical Co., Ltd.) (60 parts by mass) was mixed with 40 parts by mass of a methylene chloride solution containing 40% by mass of methyl isocyanate. The solvent was removed at a low temperature of 10 to 20 ° C. under vacuum to obtain a methyl isocyanate-adsorbed powder. Next, 50 parts by mass of methyl isocyanate-adsorbed powder, 37 parts by mass of polyvinyl alcohol (PVA SMR-10M manufactured by Shin-Etsu Chemical), 3 parts by mass of magnesium stearate, and 10 parts by mass of calcium phosphate
The mass was mixed and granulated by an extruder into granules having a diameter of 2-3 mm.

2 kg of the granules are mixed with 1 liter of a 5% by mass methylene chloride: methanol (1: 1) solution at 35 ° C.
And pan coated. This is designated as Sample C. Sample C contained 8.9% by weight of methyl isocyanate.

Example 5 A soil fumigant containing allyl isothiocyanate was obtained in the same manner as in Example 4 except that allyl isothiocyanate was used instead of methyl isocyanate. The soil fumigant is designated as Sample D. This sample D contained 9.4% by mass of allyl isothiocyanate.

Example 6 In April, an average temperature of 8 to 20 ° C. was used to evaluate the incidence of cancer types according to the following method.

In an area of 2.2 m × 1.8 m (3.96 m ² ), 100 kg / ear of straw, 10 kg / ear of lime nitrogen, and 30 kg / ear of sample C were mixed.
This will be referred to as E-ward. Further, a sample using the same amount of sample D instead of sample C was designated as section F. In addition, straw 100k
g / R and 10 kg / R of lime nitrogen were mixed, but none of the samples was mixed.
Further, a section to which neither straw nor lime was added was designated as a control section, section H.

After treating the soil with the sample under the above conditions, the soil surface was covered with a transparent multi-film. Two days later, water was injected. Eight days later, the multi-film was removed and allowed to stand. Five days after the removal of the multifilm, five melon seedlings were planted in each fraction. Three months later, all strains were dug up to measure the degree of cancer formation, and the incidence of cancer types was calculated. Table 3 shows the results.

Even in April, when the solar heat was weak, treatment of lime nitrogen and allyl isothiocyanate or methyl isothiocyanate could control cancerous diseases.

[0085]

[Table 3]

[0086]

The active ingredient used in the soil fumigant of the present invention starts to be decomposed by moisture. Therefore, when water is poured into the soil and the soil is fumigated, the active ingredient is sown immediately after the fumigation and cultivates larvae. can do.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing Reference Examples 1 and 2;
It is a figure which shows the hydrolytic property of the allyl isothiocyanate in water at 40 degreeC and 60 degreeC, and the time course of the pathogen treatment effect.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) A01N 25/18 103 A01N 25/18 103A 103B 25/34 25/34 Z (72) Inventor Susumu Kawano Isumi-gun, Isumi-gun, Chiba 1240 Machimatsumaru Inside Niho Kagaku Co., Ltd. (72) Inventor Yuki Kenmochi 1-2-1 Shibaura, Minato-ku, Tokyo Seavans N Building Kanematsu Co., Ltd. F-term (reference) 2B121 AA11 AA20 CB12 CC02 CC03 CC04 CC31 DA43 EA25 FA16 4H011 AA01 BA01 BB11 BC06 BC18 BC19 BC20 DA02 DA03 DC05 DE04 DE06 DH02 DH10

Claims (15)

[Claims] A soil fumigant containing 0.5 to 30% by mass of allyl isothiocyanate or methyl isothiocyanate is mixed into soil, the soil is covered with a multi-film, and then water is injected into the soil. There is a soil fumigation method. 2. Heating the soil before and / or after the irrigation after covering with the multi-film.
The soil fumigation method according to claim 1. 3. The soil fumigation method according to claim 2, wherein the method of heating the soil comprises adding lime nitrogen and organic matter to the soil. 4. The soil fumigation method according to claim 2, wherein the method of heating the soil is heating by solar heat. 5. The soil fumigation method according to claim 2, wherein the soil is heated by adding lime nitrogen and organic matter to the soil and heating by solar heat. 6. The soil fumigation method according to claim 2, wherein the method for heating the soil is to introduce steam or a heating gas into a pipe previously buried in the soil. 7. The soil fumigating method according to claim 1, wherein the soil fumigant is a granular material having allyl isothiocyanate or methyl isothiocyanate supported on a carrier. 8. The soil fumigating method according to claim 7, wherein the soil fumigant is formed by assembling the granules with a water-soluble binder. 9. The soil fumigant, wherein the aggregate is coated with polyvinyl alcohol and water-soluble cellulose.
The soil fumigation method according to claim 8. 10. A granular material having allyl isothiocyanate or methyl isothiocyanate supported on a carrier,
Soil fumigant. 11. A soil fumigant in which a granular material having allyl isothiocyanate or methyl isothiocyanate supported on a carrier is formed into an aggregate of granular materials with a water-soluble binder. 12. The soil fumigant according to claim 10, wherein the soil fumigant is obtained by further coating the granular material or the aggregate with polyvinyl alcohol or water-soluble cellulose. 13. The soil fumigant according to claim 11, wherein the aggregate further contains a disintegrant in addition to the granular material. 14. The soil fumigant according to claim 13, wherein the disintegrant is water-soluble hydroxypropylcellulose. 15. The soil fumigant according to claim 10, wherein the content of the allyl isothiocyanate or methyl isothiocyanate is 0.5 to 30% by mass.