Soil disease inhibitor

Abstract

The purpose of the present invention is to provide a highly safe soil disease inhibitor capable of effectively inhibiting onset of soil disease.　The present invention relates to a soil disease inhibitor containing S-allylcysteine ​​or a salt thereof. The soil disease inhibitor according to the present invention preferably further contains an amino acid or a salt thereof. By applying, to the soil, the soil disease inhibitor according to the present invention, soil disease may be suppressed.

Description

Soil disease inhibitor

[0001] The present invention relates to a soil disease inhibitor.

[0002] Plants are susceptible to various diseases caused by plant pathogens such as bacteria, fungi, viruses, etc. Soil-borne diseases, which are one type of plant disease, are also called soil-borne diseases, and are a general term for diseases in which the plant pathogens live in the soil and parasitize the roots or stems of cultivated crops, causing root rot, yellowing of above-ground parts, wilting, damping-off, etc.

[0003] Soil-borne diseases occur frequently when the same crop is cultivated continuously. This is because the plant pathogens form numerous durable bodies such as sclerotia that remain in the soil and parasitize the same crop again when it is cultivated, rapidly increasing the density of the pathogen. The occurrence of these soil-borne diseases is the main cause of the continuous crop damage that has become a problem in vegetable cultivation areas in recent years. Moreover, because there are few effective pesticides against soil-borne diseases and they are difficult to control, they have become extremely important diseases in agriculture.

[0004] For example, measures to suppress soil diseases such as Fusarium wilt and bacterial wilt include cultivating resistant varieties or grafted seedlings and fumigating soil using chemical fumigants. However, when cultivating resistant varieties or grafted seedlings, pathogenic races that overcome the disease resistance of the resistant varieties or grafted seedlings often appear, making it impossible to suppress the onset of the disease. On the other hand, soil fumigation using chemical fumigants has problems such as the chemical fumigants generally being highly toxic and causing a large environmental burden, and their effectiveness against Fusarium wilt and bacterial wilt is unstable. Therefore, there is a need for the development of a soil disease inhibitor that can effectively suppress the onset of soil diseases while being safe and having a low environmental burden.

[0005] Furthermore, the possibility of biological control using antagonistic microorganisms has also been discussed. For example, Patent Document 1 describes a soil disease inhibitor that selectively and remarkably proliferates in soil a microorganism that has excellent antagonistic ability against potato scab pathogens, while also inhibiting the proliferation of pathogenic fungi. However, Patent Document 1 only describes the inhibitory effect against potato scab pathogens, and does not mention any effectiveness against other soil diseases. Therefore, there is a need for a soil disease inhibitor that can more effectively inhibit the onset of soil diseases and is highly safe.

[0006] Japanese Patent Application Publication No. 6-287097

[0007] An object of the present invention is to provide a soil disease inhibitor that can effectively suppress the onset of soil diseases and is highly safe.

[0008] The present inventors have conducted extensive research to solve the above problems and have found that S-allylcysteine ​​or a salt thereof can effectively suppress the onset of soil-borne diseases. Based on these findings, further research has led to the completion of the present invention.

[0009] That is, the present invention is as follows. Item 1. A soil disease inhibitor containing S-allylcysteine ​​or a salt thereof. Item 2. The soil disease inhibitor according to Item 1, further containing an amino acid or a salt thereof. Item 3. The soil disease inhibitor according to Item 2, wherein the amino acid or salt thereof is an amino acid having a charged side chain and / or an amino acid having a polar, uncharged side chain or a salt thereof. Item 4. The soil disease inhibitor according to Item 3, wherein the amino acid having a charged side chain or a salt thereof is glutamic acid or a salt thereof. Item 5. The soil disease inhibitor according to Item 3, wherein the amino acid having a polar, uncharged side chain or a salt thereof is one or more amino acids or salts thereof selected from the group consisting of cysteine, serine, and asparagine. Item 6. The soil disease inhibitor according to Item 2, wherein the amino acid or salt thereof contains one or more amino acids or salts thereof selected from the group consisting of cysteine, glutamic acid, serine, and asparagine. Item 7. Item 7. A method for suppressing soil diseases, comprising supplying the soil disease inhibitor according to any one of Items 1 to 6 to a plant or its periphery. Item 8. A method for applying the soil disease inhibitor according to any one of Items 1 to 6 to a plant or its periphery. Item 9. A method for enhancing the soil disease suppression effect by applying an amino acid or a salt thereof to a soil disease inhibitor containing S-allylcysteine ​​or a salt thereof. Item 10. A method for using S-allylcysteine ​​or a salt thereof to suppress soil diseases. Item 11. A method for using S-allylcysteine ​​or a salt thereof, and an amino acid or a salt thereof, to suppress soil diseases. Item 12. A method for using an agrochemical formulation containing S-allylcysteine ​​or a salt thereof, and an amino acid or a salt thereof, to suppress soil diseases. Item 1-1. A soil disease inhibitor containing S-allylcysteine ​​or a salt thereof. Item 2-1. Item 1-1. The soil disease inhibitor according to Item 1-1, further comprising an amino acid or a salt thereof. Item 3-1. The soil disease inhibitor according to Item 2-1, wherein the amino acid or salt thereof is an amino acid having a charged side chain and / or an amino acid having a polar, uncharged side chain or a salt thereof. Item 4-1. The soil disease inhibitor according to Item 3-1, wherein the amino acid having a charged side chain or a salt thereof is glutamic acid or a salt thereof.Item 5-1. The soil-borne disease inhibitor according to Item 3-1 or 4-1, wherein the amino acid having an uncharged polar side chain or a salt thereof is one or more amino acids or salts thereof selected from the group consisting of cysteine, serine, and asparagine. Item 6-1. The soil-borne disease inhibitor according to any one of Item 2-1 to 5-1, wherein the amino acid or a salt thereof contains one or more amino acids or salts thereof selected from the group consisting of cysteine, glutamic acid, serine, and asparagine. Item 7-1. A method for suppressing soil-borne diseases, comprising supplying the soil-borne disease inhibitor according to any one of Item 1-1 to 6-1 to a plant or its vicinity. Item 8-1. A method for applying the soil-borne disease inhibitor according to any one of Item 1-1 to 6-1 to a plant or its vicinity. Item 9-1. A method for enhancing soil-borne disease suppression effect by applying an amino acid or a salt thereof to a soil-borne disease inhibitor containing S-allylcysteine ​​or a salt thereof. Item 10-1. A method for using S-allyl cysteine ​​or a salt thereof to suppress soil-borne diseases. Item 11-1. A method for using S-allyl cysteine ​​or a salt thereof, and an amino acid or a salt thereof to suppress soil-borne diseases. Item 12-1. A method for using a pesticide formulation containing S-allyl cysteine ​​or a salt thereof, and an amino acid or a salt thereof to suppress soil-borne diseases.

[0010] According to the present invention, it is possible to provide a soil disease inhibitor that can effectively suppress the onset of soil-borne diseases and is highly safe. Furthermore, according to the present invention, it is possible to provide a soil disease inhibitor that does not cause phytotoxic symptoms.

[0011] FIG. 1 is a set of photographs showing the state in which cucumber seedlings grown in different types of soil are inhibited from developing cucumber fusarium wilt disease by a Fusarium disease inhibitor.

[0012] The soil disease inhibitor according to the present invention will be described below.

[0013] The soil-borne disease inhibitor of the present invention contains S-allyl cysteine ​​or a salt thereof. S-allyl cysteine ​​is a type of amino acid formed by the degradation of proteins. Natural S-allyl cysteine ​​generally has the chemical structure shown in the following general formula, and its official name is S-allyl-L-cysteine.

[0014]

[0015] In the present invention, S-allylcysteine ​​may be S-allylcysteine ​​having the above structure, or an optical isomer thereof, or a mixture of the optical isomers.

[0016] In this specification, the form of the salt is not particularly limited, and the counter ion may be either a cation or anion. Examples of salts include ammonium salts; alkali metal salts (sodium salts, potassium salts, lithium salts, etc.), alkaline earth metal salts (calcium salts, etc.), salts of metals other than alkali metals and alkaline earth metals (magnesium salts, aluminum salts, iron salts, zinc salts, copper salts, nickel salts, etc.), halides (fluorides, chlorides, etc.), carboxylate salts (acetates, etc.), organic amine salts (dibenzylamine salts, glucosamine salts, ethylenediamine salts, diethylamine salts, triethylamine salts, dicyclohexylamine salts, diethanolamine salts, tetramethylammonium salts, etc.). The soil-borne disease inhibitor of the present invention preferably contains an alkali metal salt of S-allylcysteine ​​as the salt of S-allylcysteine, and more preferably contains sodium S-allylcysteine.

[0017] S-allylcysteine ​​is an amino acid known to be contained in garlic, and its safety has been confirmed. Therefore, even if a soil disease inhibitor containing S-allylcysteine ​​or its salt is applied to soil cultivation, etc., it will not have an adverse effect on the environment.

[0018] Furthermore, since S-allylcysteine ​​or a salt thereof is less expensive than conventional plant disease control agents, agricultural producers can use the soil-based disease inhibitor of the present invention with peace of mind. Furthermore, the soil-based disease inhibitor of the present invention can be used by a very simple method such as irrigation.

[0019] S-allylcysteine ​​or a salt thereof can be produced by known methods. For example, S-allylcysteine ​​can be produced by a production method comprising a heating step in which at least one selected from the group consisting of Allium plants, juice of said plants, and extracts of said plants, in which endogenous alliinase has been inactivated, is heated at a specific temperature of 20 to 75°C. Alliinase is an enzyme endogenous to Allium plants and is known to convert alliin contained in Allium plants into allicin, an odorous component. By using Allium plants in which endogenous alliinase has been inactivated as a raw material, it is possible to suppress the reduction of alliin in the raw material. Furthermore, by suppressing the production of allicin, the odor characteristic of Allium plants can be reduced.

[0020] More than 700 species of Allium plants are known as raw materials, and any can be used as long as it can produce S-allylcysteine. As Allium (Allium genus) plants, those containing alliin are preferred. Specific examples of Allium plants include garlic, onion, wild garlic, Chinese chive, Chinese chive, Chinese chive, Japanese leek, Japanese shallot, wild shallot, chives, Japanese shallot, chives ... Among these, from the viewpoint of containing high concentrations of sulfur-containing amino acids such as alliin, garlic (Allium sativum L.), onion (Allium cepa L.), chives (Allium schoenoprasum L.), rakkyo (Allium chinense G. Don), wild garlic (Allium victorialis subsp. platyphyllum), etc. are preferred, and garlic (Allium sativum L.) is more preferred. One type of Allium plant may be used alone, or two or more types may be used in combination.

[0021] The Allium plant may be subjected to the heating step after being inactivated as is, or cut, crushed, ground, powder, etc. of the plant may be inactivated and then subjected to the heating step. The Allium plant cut, crushed, ground, or powder can be obtained by cutting, crushing, grinding, or powdering the Allium plant. The method for cutting, crushing, grinding, or powdering is not particularly limited as long as it is a known cutting, crushing, grinding, or powdering method. For example, the plant can be cut, crushed, ground, or powdered using a crusher, mixer, food processor, pulverizer, or the like to appropriately obtain the cut, crushed, ground, or powder of the plant.

[0022] The juice of Allium plants can be prepared using, for example, a filter press, a juicer mixer, or the like. The juice can also be prepared by filtering the ground product using a filter cloth or the like. The cut, crushed, crushed, and squeezed juice of Allium plants may be diluted or concentrated. Examples of diluted products include those obtained by diluting the cut, crushed, crushed, squeezed, or other products of the plant with water at a ratio of about 1 to 50. Examples of concentrated products include those obtained by concentrating the cut, crushed, crushed, squeezed, or other products of the plant at a ratio of 1 to 100 by means of freeze concentration, vacuum concentration, or the like. The cut, crushed, crushed, squeezed, or other products of Allium plants may be frozen.

[0023] S-allyl cysteine ​​can be efficiently obtained by heat-treating the Allium plant or the like whose endogenous alliinase has been inactivated. Note that by heat-treating the Allium plant or the like whose endogenous alliinase has been inactivated at the above-mentioned specific temperature, S-allyl cysteine ​​can be efficiently obtained without adding a reducing agent or the like (e.g., enzyme, reducing compound, etc.) that reduces alliin in the Allium plant.

[0024] Alliin is a sulfur-containing amino acid, a derivative of cysteine, and a natural sulfoxide found in fresh garlic and other Allium plants. For example, when fresh garlic is cut or grated, alliin is converted to allicin by alliinase. Allicin is responsible for garlic's unique aroma. Natural alliin generally has the structure shown in the general formula below, and its official name is L-alliin. Alliin has an asymmetric center at the carbon-2 position and a sulfur atom, and theoretically, four isomers exist, but only two exist naturally: (+)-L-alliin and (-)-L-alliin.

[0025]

[0026] From the viewpoint of promoting the production of S-allylcysteine, in the heating step, the Allium plant or the like in which endogenous alliinase has been inactivated needs to be heated at a temperature of 20 to 75° C. The heating temperature is preferably 25 to 65° C., more preferably 25 to 55° C., and even more preferably 30 to 45° C.

[0027] Furthermore, it is even more preferable to perform an additional heating step after performing the heating step within the above temperature range. That is, it is preferable to perform the heating step in two stages. For example, it is preferable to perform a heat treatment in the temperature range of 25 to 55°C for 10 to 30 hours as the first heating step, and then perform heating in the temperature range of 45 to 90°C, more preferably in the temperature range of 50 to 75°C, for 10 to 50 hours as the second heating step. In this way, performing the heating step in two stages allows the production reaction to proceed more efficiently, and S-allylcysteine ​​can be obtained more efficiently in a shorter time than if the first heating step were performed for a longer period of time. Note that if the first heating step is heated above 75°C, S-allylcysteine ​​is not substantially produced. However, when the heating step is performed in two stages, as long as the first heating step is heated at a temperature not exceeding 75°C, S-allylcysteine ​​can be efficiently obtained even if the second heating step is heated at a temperature exceeding 75°C.

[0028] The heating step may be performed with stirring or by leaving the mixture to stand. The stirring method is not particularly limited, and examples thereof include stirring using a stirring blade, a mixer, a stirrer, etc.

[0029] The pH of the Allium plant or the like in the heating step is preferably about pH 2 to 12, more preferably pH 4 to 12, and even more preferably pH 7 to 9. The heating time varies depending on the type and amount of the raw material used, but is usually preferably set in the range of about 1 to 48 hours.

[0030] Before the heating step, the method may further include a deactivation step of deactivating alliinase contained in at least one selected from the group consisting of the Allium plants, the juice of the plants, and the extracts of the plants.

[0031] The method for deactivating the endogenous alliinase is not particularly limited as long as it can inactivate the enzymatic activity of the alliinase endogenous to Allium plants. Examples of the method for deactivating the endogenous alliinase include heat treatment, acid treatment, alkali treatment, etc., which raise the internal temperature of the Allium plants to 60°C or higher, with heat treatment being preferred. Specific examples of heat treatment methods for raising the internal temperature of the Allium plants to 60°C or higher in the deactivation treatment include hot water heating treatment, steam heating treatment, microwave heating treatment, etc., with microwave heating treatment being preferred. The Allium plants, etc., in which the endogenous alliinase has been inactivated by the deactivation step can be obtained, and then subjected to the heating step.

[0032] After the heating step, an isolation step can be carried out to separate S-allylcysteine ​​from the crude product. The isolation step can be carried out by a conventional isolation procedure such as filtration, centrifugation, concentration, extraction, etc. Furthermore, in order to increase the purity of S-allylcysteine, a purification step can be carried out to purify S-allylcysteine. The purification step can be carried out by a conventional purification procedure such as column chromatography, recrystallization, etc. Furthermore, the crude product can be dried to obtain a solid (powder, granules, etc.) containing S-allylcysteine. Examples of drying methods include freeze-drying and spray-drying. Commercially available S-allylcysteine ​​can also be used.

[0033] The soil disease inhibitor of the present invention may consist only of the above-mentioned active ingredients, but may also contain amino acids, adjuvants, etc. in addition to the above-mentioned active ingredients depending on the formulation, application mode, etc. described below.

[0034] The content of the active ingredient in the soil disease inhibitor can be appropriately determined depending on the formulation, application mode, etc., as described below. For example, the concentration of S-allylcysteine ​​or a salt thereof in the soil disease inhibitor of the present invention is typically about 0.1 mg / L to 50 g / L, preferably about 0.1 mg / L to 5000 mg / L, and more preferably about 0.1 mg / L to 500 mg / L. Even when applied at such low concentrations, the soil disease inhibitor of the present invention can improve the soil disease inhibitory effect on the plant to be protected. Note that application of the soil disease inhibitor of the present invention to a plant body only once throughout the entire cultivation period of the plant body can sufficiently improve the soil disease inhibitory effect on the plant to be protected, but multiple applications are also preferred to fully enhance the soil disease inhibitory effect.

[0035] The formulation of the soil-borne disease inhibitor of the present invention is not particularly limited as long as it is an agriculturally acceptable formulation, and examples of the formulation include liquid formulations, solid formulations, dust formulations, granules, wettable powders, flowable formulations, emulsifiable concentrates, pastes, and dispersants.

[0036] The soil disease inhibitor of the present invention preferably further contains an amino acid or a salt thereof in addition to S-allylcysteine ​​or a salt thereof. This amino acid does not include S-allylcysteine. When the soil disease inhibitor of the present invention contains S-allylcysteine ​​or a salt thereof and an amino acid or a salt thereof, or when it contains an adjuvant described below in addition to S-allylcysteine ​​or a salt thereof and an amino acid or a salt thereof, it can also be referred to as a soil disease inhibitor composition.

[0037] The amino acid is not particularly limited, and α-amino acids, β-amino acids, γ-amino acids, etc. Examples of the amino acid include alanine (Ala), asparagine (Asn), aspartic acid (Asp), arginine (Arg), cysteine ​​(Cys), glutamic acid (Glu), glutamine (Gln), glycine (Gly), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), proline (Pro), serine (Ser), threonine (Thr), tryptophan (Trp), tyrosine (Tyr), valine (Val), β-alanine, and γ-aminobutyric acid.

[0038] The amino acids may be either L- or D-isomers, or may be a mixture containing L- and D-isomers in any ratio. In general, L-isomers are cheaper and more readily available than D-isomers. Furthermore, as will be explained in detail in the Examples below, soil disease inhibitors using L-isomers have been confirmed to have significant effects. For these reasons, it is possible to configure soil disease inhibitors with all amino acids in the L-isomer.

[0039] In the broadest sense, naturally occurring amino acids can be broadly divided into hydrophilic (polar) and hydrophobic (nonpolar) amino acids based on the chemical characteristics of each amino acid's side chain. The hydrophilic (polar) amino acids are further divided into amino acids with charged side chains and amino acids with polar, uncharged side chains. The charged side chain amino acids include aspartic acid (Asp), glutamic acid (Glu), arginine (Arg), histidine (His), and lysine (Lys). The charged side chain amino acids can also be divided into acidic amino acids (aspartic acid (Asp) and glutamic acid (Glu)) and basic amino acids (arginine (Arg), histidine (His), and lysine (Lys)). The polar, uncharged side chain amino acids are also called neutral amino acids. The amino acids having polar, uncharged side chains (neutral amino acids) include asparagine (Asn), glutamine (Gln), serine (Ser), threonine (Thr), and cysteine ​​(Cys).

[0040] The hydrophobic (non-polar) amino acids include alanine (Ala), isoleucine (Ile), leucine (Leu), methionine (Met), valine (Val), phenylalanine (Phe), tryptophan (Trp), tyrosine (Tyr), glycine (Gly), and proline (Pro). The hydrophobic (non-polar) amino acids can also be divided into amino acids with aliphatic side chains (alanine (Ala), isoleucine (Ile), leucine (Leu), methionine (Met), and valine (Val)), amino acids with aromatic side chains (phenylalanine (Phe), tryptophan (Trp), and tyrosine (Tyr)), and other amino acids (glycine (Gly) and proline (Pro)).

[0041] The amino acid is preferably an amino acid having a charged side chain and / or an amino acid having a polar, uncharged side chain. The amino acid having a charged side chain is preferably glutamic acid. The amino acid having a polar, uncharged side chain is preferably one or more amino acids selected from the group consisting of cysteine, serine, and asparagine. Furthermore, the amino acid preferably contains one or more amino acids selected from the group consisting of cysteine, glutamic acid, serine, and asparagine.

[0042] In this specification, the form of the salt is not particularly limited, and the counter ion may be either a cation or anion. For example, examples of the salt include inorganic salts (ammonium salts, etc.); alkali metal salts (sodium salts, potassium salts, lithium salts, etc.), alkaline earth metal salts (calcium salts, etc.), metal salts (magnesium salts, aluminum salts, iron salts, zinc salts, copper salts, nickel salts, etc.), halides (fluorides, chlorides, etc.), carboxylates (acetates, etc.), organic amine salts (dibenzylamine salts, glucosamine salts, ethylenediamine salts, diethylamine salts, triethylamine salts, dicyclohexylamine salts, diethanolamine salts, tetramethylammonium salts, etc.).

[0043] The soil-borne disease inhibitor of the present invention preferably contains an alkali metal salt of an amino acid as the salt of the amino acid, and more preferably contains a sodium salt of an amino acid.

[0044] The concentration of the amino acid or its salt in the soil disease inhibitor is preferably 1 to 5000 mg / L, more preferably 1 to 1000 mg / L, and even more preferably 1 to 500 mg / L when applied to plants or their surroundings.

[0045] From the viewpoint of improving solubility, the mass ratio of S-allylcysteine ​​or a salt thereof to the amino acid or a salt thereof is preferably (S-allylcysteine ​​or a salt thereof):(amino acid or a salt thereof) 1:1000 to 1000:1, more preferably 1:100 to 100:1, and even more preferably 1:10 to 10:1.

[0046] The soil disease inhibitor of the present invention may further contain an adjuvant, if necessary. Examples of such adjuvants include surfactants used as dispersants, wetting agents, spreading agents, and wetting agents, inert carriers, binders, tackifiers, thickeners, colorants, antifreeze / reconstitution agents, anticaking agents, disintegrants, antidegradants, pH adjusters, and light stabilizers. Furthermore, since soil disease inhibitors are generally formulated into forms convenient for agricultural use, adjuvants can be incorporated into an appropriate inert carrier at appropriate ratios, if necessary. Examples of dosage forms include suspensions (flowable formulations), emulsion suspensions (EW formulations), oil suspensions (OD formulations), suspoemulsions (SE), microemulsions (ME), emulsifiable concentrates, liquid formulations, wettable powders, water dispersible granules, granules, dusts, tablets, and pack formulations.

[0047] The soil disease inhibitor of the present invention is a composition that is applied to the periphery of a target plant and is highly effective by promoting the growth of bacteria that suppress the growth of soil disease pathogens (e.g., Fusarium fungi). The formulation when applied to the periphery of a plant is not particularly limited, and the composition can be prepared in any form, such as a liquid, powder, or granule.

[0048] It is preferable to use a surfactant as the adjuvant. Examples of surfactants that can be used include those that are soluble in water, such as nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants. Examples of nonionic surfactants include sorbitan fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene fatty acid esters, glycerin fatty acid esters, polyoxyalkylene glycerin fatty acid esters, polyglycerin fatty acid esters, polyoxyalkylene polyglycerin fatty acid esters, sucrose fatty acid esters, resin acid esters, polyoxyalkylene resin acid esters, polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenyl ethers, alkyl (poly)glycosides, and polyoxyalkylene alkyl (poly)glycosides. Examples of nonionic surfactants that are preferable include ether group-containing nonionic surfactants that do not contain nitrogen atoms, and ester group-containing nonionic surfactants. Particularly preferred examples of the nonionic surfactant include ester group-containing nonionic surfactants containing an oxyalkylene group, such as polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene fatty acid esters, polyoxyalkylene glycerin fatty acid esters, and polyoxyalkylene polyglycerin fatty acid esters; and ether group-containing nonionic surfactants having a sugar skeleton and no nitrogen atom, such as alkyl (poly)glycosides.

[0049] Examples of cationic surfactants include alkyltrimethylammonium salts (e.g., stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, etc.); alkylpyridinium salts (e.g., cetylpyridinium chloride, etc.); distearyldimethylammonium chloride dialkyldimethylammonium salts; poly(N,N'-dimethyl-3,5-methylenepiperidinium) chloride; alkyl quaternary ammonium salts; alkyldimethylbenzylammonium salts; alkylisoquinolinium salts; dialkylmorphonium salts; POE-alkylamines; alkylamine salts; polyamine fatty acid derivatives; amyl alcohol fatty acid derivatives; benzalkonium chloride; benzethonium chloride, etc. Examples of anionic surfactants include carboxylic acid surfactants, sulfonic acid surfactants, sulfate ester surfactants, and phosphate ester surfactants. Examples of carboxylic acid surfactants include fatty acids having 6 to 30 carbon atoms or salts thereof, polycarboxylic acid salts, polyoxyalkylene alkyl ether carboxylates, polyoxyalkylene alkylamide ether carboxylates, rosin acid salts, dimer acid salts, polymer acid salts, tall oil fatty acid salts, etc. Examples of sulfonic acid surfactants include alkylbenzene sulfonates, alkyl sulfonates, alkylnaphthalene sulfonates, naphthalene sulfonates, diphenyl ether sulfonates, condensate salts of alkylnaphthalene sulfonic acid, and condensate salts of naphthalene sulfonic acid. Examples of sulfate surfactants include alkyl sulfate salts, polyoxyalkylene alkyl sulfate salts, polyoxyalkylene alkylphenyl ether sulfate salts, tristyrenated phenol sulfate salts, polyoxyalkylenedistyrenated phenol sulfate salts, and alkyl polyglycoside sulfate salts. Examples of phosphate surfactants include alkyl phosphate salts, alkylphenyl phosphate salts, polyoxyalkylene alkyl phosphate salts, and polyoxyalkylene alkylphenyl phosphate salts. Examples of the salts include metal salts (such as Na, K, Ca, Mg, and Zn), ammonium salts, alkanolamine salts, and aliphatic amine salts.As the anionic surfactant, a carboxylic acid surfactant and a phosphate ester surfactant are preferred.

[0050] Examples of amphoteric surfactants include amino acid surfactants, betaine surfactants, imidazoline surfactants, and amine oxide surfactants. Examples of amino acid surfactants include acylamino acid salts, acyl sarcosinates, acyloylmethylaminopropionates, alkylaminopropionates, and acylamidoethyl hydroxyethyl methyl carboxylates. Examples of betaine surfactants include alkyl dimethyl betaines, alkyl hydroxyethyl betaines, acylamidopropyl hydroxypropyl ammonia sulfobetaine, acylamidopropyl hydroxypropyl ammonia sulfobetaine, and ricinoleic acid amidopropyl dimethyl carboxymethyl ammonia betaine. Examples of imidazoline surfactants include alkyl carboxymethyl hydroxyethyl imidazolinium betaines and alkyl ethoxy carboxymethyl imidazolium betaines. Examples of amine oxide surfactants include alkyl dimethyl amine oxides, alkyl diethanol amine oxides, and alkyl amidopropyl amine oxides. The above surfactants may be used alone or in combination.

[0051] The concentration of the surfactant in the soil disease inhibitor is preferably 1 mg / L to 5000 mg / L, more preferably 1 mg / L to 1000 mg / L, and even more preferably 1 mg / L to 500 mg / L, when applied to plants or their surroundings.

[0052] From the viewpoint of improving solubility, the mass ratio of S-allylcysteine ​​or a salt thereof to the surfactant (S-allylcysteine ​​or a salt thereof):(surfactant) is preferably 1:1000 to 1000:1, more preferably 1:100 to 100:1, and even more preferably 1:10 to 10:1.

[0053] In the present invention, soil-borne diseases of plants can be suppressed by supplying a soil-borne disease inhibitor containing S-allylcysteine ​​or a salt thereof to plants or their surroundings.

[0054] The soil diseases targeted by the soil disease inhibitor of the present invention are diseases caused by pathogens living in the soil that invade and grow through parts of plants that come into contact with the soil, such as roots, rhizomes, and stems. Soil diseases are also sometimes referred to as soil-borne diseases. Types of pathogens include viruses, bacteria, and filamentous fungi (molds). Examples of diseases caused by viral parasites include wheat stripe disease. Examples of diseases caused by bacterial parasites include bacterial wilt and soft rot. Examples of diseases caused by filamentous fungi include wilt, fusarium wilt, damping-off, root rot, yellows, and verticillium wilt caused by fungi of the genus Fusarium, Rhizoctonia, and Verticillium, as well as soybean stem rot caused by fungi of the genus Phytophthora.

[0055] The soil disease inhibitor of the present invention has excellent inhibitory effects against diseases caused by Fusarium fungi (hereinafter referred to as Fusarium disease), soybean stem rot, bacterial wilt, etc. Fusarium disease is a soil disease caused by pathogenic Fusarium fungi. Examples of pathogenic Fusarium fungi include Fusarium oxysporum and F. solani. The Fusarium fungi mainly invade plants through their roots and proliferate within their xylem, inhibiting water flow and causing symptoms such as leaf yellowing and wilting, and sometimes causing plant death. Well-known examples of Fusarium diseases include tomato wilt, fusarium wilt of cucumber, melon, watermelon, sweet potato, etc., strawberry yellows, and pumpkin damping-off. Fusarium diseases also include yellows of radish, cabbage, turnip, and komatsuna; wilt of onions and spinach; root rot of lettuce and salad; dry rot of chives; lotus root rot; and banana Panama disease. Soybean stem rot is a disease caused by a filamentous fungus, the genus Phytophthora. This pathogen is pathogenic only to soybeans. It occurs from the seedling stage immediately after germination to the mature stage. Infection begins before germination and causes non-germination. At the seedling stage, water-soaked streaks or oval lesions appear mainly at the base of the stem, later forming large brown to dark brown lesions and developing into damping-off. In soybeans that have grown further, the roots or the base of the stem are affected, resulting in root rot symptoms. Bacterial wilt is a disease caused by the pathogenic bacterium Ralstonia solanacearum species complex. Plants infected with the bacterial wilt disease rapidly wilt and die.

[0056] The target plants of the soil disease inhibitor of the present invention are not particularly limited. Useful plants for which the soil disease inhibitor of the present invention can be used are not particularly limited, and include, for example, Solanaceae plants such as tomato, eggplant, bell pepper, chili pepper, potato, etc.; Poaceae plants such as rice, barley, wheat, rye, corn, sugarcane, etc.; Leguminosae plants such as soybean, adzuki bean, broad bean, pea, kidney bean, peanut, etc.; Rosaceae plants such as apple, pear, peach, plum, cherry, strawberry, rose, etc.; Brassicaceae plants such as cabbage, broccoli, Chinese cabbage, radish, turnip, komatsuna, etc.; Cucurbitaceae plants such as pumpkin, cucumber, Japanese cantaloupe, watermelon, melon, etc.; Amaryllidaceae plants such as onion, leek, garlic, chive, etc.; Shiso plants such as perilla, basil, thyme, lavender, etc. Examples of suitable plants include: Amaranthaceae (e.g., spinach, sugar beet, etc.); Apiaceae (e.g., carrot, parsley, etc.); Asteraceae (e.g., lettuce, burdock, chrysanthemum, etc.); Convolvulaceae (e.g., sweet potato, etc.); fruit trees (e.g., citrus fruits, grapes, chestnuts, almonds, bananas, etc.); root vegetables (e.g., taro, lotus root, etc.); processing crops (e.g., cotton, hemp, hops, olives, rubber, coffee, tea, etc.); pasture grasses (e.g., orchard grass, sorghum, timothy, clover, alfalfa, etc.); turfgrass (e.g., Korean grass, bentgrass, etc.); ornamental crops (e.g., pepper, ginger, etc.); flowering plants (e.g., carnation, orchid, etc.); garden trees (e.g., ginkgo, cherry trees, aucuba, etc.); forest trees (e.g., Abies sachalinensis, spruce trees, pines, hiba, cedar, cypress, cypress, etc.). The target of the soil-borne disease inhibitor is not limited to the entire plant body, but may be at least one of the plant organs (e.g., flower, leaf, fruit, stem, or root).

[0057] The application mode of the soil disease inhibitor of the present invention is not particularly limited as long as it is a known mode of use for pesticides or fertilizers (or a mode to be developed in the future), and examples include spraying, dripping, painting, mixing or dissolving in the plant growth environment (in soil, solid medium, etc.).

[0058] The present invention includes a method for suppressing soil-borne diseases, which comprises supplying the above-mentioned soil-borne disease inhibitor to plants or the surrounding area of ​​the plants (such as the soil where the plants grow). By using this method, the onset of soil-borne diseases can be effectively suppressed.

[0059] The soil disease inhibitor of the present invention is highly safe and has almost no restrictions on its use, and can be used appropriately by conventionally known methods. For example, if it is a liquid formulation, it can be applied to the surroundings of plants by spraying or irrigation. If it is a granular or powder formulation, it can be applied to the surroundings of plants by spraying or burying.

[0060] The application amount of the soil-based disease inhibitor of the present invention may vary depending on the concentration of the active ingredient, application time, application frequency, plant type, cultivation density, growth stage, application method, etc. The application amount for foliar spray is preferably 100 L / ha to 7000 L / ha. The application amount for soil drench is preferably 100 L / ha to 50000 L / ha. The number of applications is not particularly limited and may be one or more times, and can be set appropriately depending on the occurrence or signs of disease.

[0061] The present invention will be specifically explained below with reference to examples and test examples, but the technical scope of the present invention is not limited to these examples.

[0062] Test Example 1 (Examples 1 to 11 and Comparative Examples 1 and 2): Confirmation of soil disease suppression effect (cucumber Fusarium wilt) To 40 g of soil containing microorganisms, 6.68 mL of a 0.000548% (0.034 mM) aqueous solution of S-allylcysteine ​​(Example 1), a 1:1 mixture of a 0.000548% aqueous solution (0.034 mM) of S-allylcysteine ​​and a 0.034 mM aqueous solution of each amino acid (Examples 2 to 11), or a mixture of equal volumes of an aqueous amino acid solution and sterilized water (Comparative Example 1) was administered, and the soil was cultured at 25°C for 1 week. As a control, soil to which the same volume of sterilized water was administered instead of the aqueous amino acid solution was also prepared (Comparative Example 2). In a plant test tube having a diameter of 3 cm and a height of 12 cm, 6 g of the above-mentioned S-allylcysteine-added soil (Example 1), S-allylcysteine ​​and amino acid-added soil (Examples 2 to 11), or control soil (Comparative Examples 1 and 2) was placed, and a spore suspension (approximately 3 × 10 ４The soils were irrigated with 2 mL of fertilizer (250-fold diluted Hyponex (registered trademark), N:P:K = 6:9:5) and 2 mL of fertilizer (250-fold diluted Hyponex (registered trademark), N:P:K = 6:9:5) was applied to the plant test tubes. The test tubes were then cultured in an artificial climate chamber at 25°C with a 12-hour photoperiod for 4 weeks. During the culture period, the disease status of the cucumber seedlings was observed daily and evaluated using the following four-level disease index: 0: no symptoms; 1: yellowing or mild wilting of cotyledons or browning of xylem vessels was observed; 2: yellowing or browning of stems was observed; 3: wilting before emergence, or systemic wilting or death.

[0063] Based on this disease index, the area under the disease progress curve (AUDPC) was calculated using the following formula. In this test, 10 seedlings were used in each section and the experiment was repeated three times. Formula: AUDPC = Σ [(disease index i + disease index i-1) x (ti-ti-1) x 0.5] *Disease index i and disease index i-1 are the disease indexes at time points ti and ti-1, ti and ti-1 are the number of consecutive days, so ti-ti-1 = 1.

[0064] The effectiveness was evaluated by comparing the mean difference of AUDPC (Area under the disease progress curve) using network meta-analysis (random effects model). The evaluation results are shown in Tables 1 and 2. Note that when the median point (standardized mean difference) is less than 0 (a negative value), it indicates that disease occurrence was suppressed compared to the control soil (Comparative Example 2).

[0065]

[0066] <Results> From Table 1, it was confirmed that the soil disease inhibitor of Example 1 containing S-allylcysteine ​​has a significant inhibitory effect against Fusarium wilt, which is a type of soil disease.

[0067]

[0068] <Results> From Table 2, it was confirmed that the soil disease inhibitors of Examples 2 to 11, which contain S-allylcysteine ​​and various amino acids, also have a significant inhibitory effect against Fusarium wilt, which is a type of soil disease.

[0069] Test Example 2 (Examples 12 and 13): Effect of differences in soil on soil-borne disease suppression effect A soil-borne disease suppressant containing S-allylcysteine ​​and glutamic acid (Example 12) and a soil-borne disease suppressant containing S-allylcysteine ​​and asparagine (Example 13) were used to evaluate the effect of differences in soil on soil-borne disease suppression effect. The soil-borne disease suppressant in Example 12 was an aqueous solution obtained by mixing a 0.034 mM aqueous solution of S-allylcysteine ​​and a 0.034 mM aqueous solution of glutamic acid in a 1:1 ratio. The soil-borne disease suppressant in Example 13 was an aqueous solution obtained by mixing a 0.034 mM aqueous solution of S-allylcysteine ​​and a 0.034 mM aqueous solution of asparagine in a 1:1 ratio. Sterile water was used in Comparative Example 3.

[0070] (Pot test) Equal amounts of sieved field soil (water content approximately 35%) and commercially available horticultural soil (Nanaka Ichiban (registered trademark), manufactured by Ibigawa Kogyo Co., Ltd.) were mixed. 25.05 mL of the soil disease inhibitor of Example 12 or the soil disease inhibitor of Example 13 was administered to 150 g of the soil. As a control, soil to which the same amount of sterilized water was administered instead of the soil disease inhibitor was also prepared (Comparative Example 3). These soils were then cultured at 25°C for one week. Next, 300 g of the soil to which the soil disease inhibitor had been added (Example 12 or 13) or the control soil (Comparative Example 3) was placed in a plastic pot (length 9 cm x width 9 cm x height 8 cm), and a spore suspension (approximately 3 x 10 spores) of the cucumber fusarium wilt fungus (Fusarium oxysporum cucumerinum specialis) was added. ５ The pots were inoculated with 10 mL of 100 spores (100 spores / mL). 10 mL of autoclaved vermiculite was layered on top of the inoculated pots, and four germinated cucumber seeds were sown and then covered with a small amount of autoclaved vermiculite. These pots were cultivated in an artificial climate chamber (25°C, 12-hour photoperiod) for 4 weeks. During the cultivation period, the plants were watered with an appropriate amount of tap water once every two days. The disease development status of the cucumber seedlings was observed and evaluated over time.

[0071] Three types of soil, Soil A, Soil B, and Soil C, which differ in biological and physicochemical properties, were used for the evaluation. Soil A is a sandy muddy soil collected from a vegetable field in Gifu Prefecture. Soil B is a sandy muddy soil collected from a grassland in Gifu Prefecture. Soil C is a black soil collected from a vegetable field in Tottori Prefecture. The evaluation items were the disease index shown below, and the disease severity and AUDPC values ​​using this index.

[0072] In this embodiment, the disease index was determined as follows. Cucumber seeds were sown in each plant test tube, inoculated with cucumber fusarium wilt fungus, and cultured for 21 days in an artificial climate chamber at 28°C with a 12-hour photoperiod. During this time, a soil-borne disease inhibitor (Example 12 or 13) combining S-allylcysteine ​​and another amino acid, or an equal amount of sterilized water (Comparative Example 3) instead of the soil-borne disease inhibitor, was irrigated and cultured. After culture, the cucumber seedlings were collected, and the disease severity was calculated using the values ​​quantified into a three-level disease index. The disease index evaluation criteria are as follows: 0: no symptoms; 1: mild wilting; 2: damping off or death before emergence. The disease severity was calculated using the following formula: Disease severity = Σ (disease index × number of seedlings) / 10 × 100%

[0073] Based on the severity scores, AUDPC (Area under the disease progress curve) was calculated and the mean difference was evaluated. The following formula was used to calculate AUDPC:

[0074] Here, n is the total number of tests, Y is the disease severity at the time of testing, and X is the number of growing days.

[0075] Table 3 and Figure 1 show the AUDPC values ​​(unitless) when a soil-based disease inhibitor containing S-allylcysteine ​​and glutamic acid (Example 12) and a soil-based disease inhibitor containing S-allylcysteine ​​and asparagine (Example 13) were applied to soil A, soil B, and soil C, respectively. Comparative Example 3 shows the AUDPC value when sterilized water was applied. Figure 1 also shows photographs (as substitutes for drawings) showing the growth status of cucumber seedlings when soil-based disease inhibitors were applied to soil A, soil B, and soil C.

[0076]

[0077] <Results> As can be seen from Table 3 and Figure 1, although differences in the degree of effectiveness depending on the type of soil disease inhibitor were observed for each type of soil, both the soil disease inhibitor containing S-allylcysteine ​​and glutamic acid (Example 12) and the soil disease inhibitor containing S-allylcysteine ​​and asparagine (Example 13) were confirmed to have a significant inhibitory effect on cucumber Fusarium wilt.

[0078] Test Example 3 (Examples 14 to 18 and Comparative Example 4) The concentration suitable for irrigation of a soil disease inhibitor containing a combination of S-allylcysteine ​​and glutamic acid was examined.

[0079] To verify the optimal concentration, aqueous solutions of S-allylcysteine ​​and glutamic acid were added to sterilized water at five concentrations: 0.00344 mM, 0.0344 mM, 0.344 mM, 3.44 mM, and 34.4 mM. The results of the verification test using a random effects model are shown in Table 4.

[0080]

[0081] <Results> As shown in Table 4, the aqueous solution (Example 14) in which 0.00344 mM each of S-allylcysteine ​​and glutamic acid was added to sterilized water had the highest inhibitory effect on cucumber Fusarium wilt, and the inhibitory effect decreased as the concentration increased. However, it was clear that a certain level of effect was obtained even when the highest concentration of 34.4 mM aqueous solution (Example 18) was used.

[0082] Test Example 4 (Examples 19 to 21 and Comparative Example 5) For soil disease inhibitors containing S-allyl cysteine ​​(sometimes abbreviated as SAC) and glutamic acid (sometimes abbreviated as Glu), the optimal blend ratio of S-allyl cysteine ​​and glutamic acid was investigated.

[0083] For the verification, the following three types of aqueous solutions containing S-allylcysteine ​​and glutamic acid were used. Example 19: SAC:Glu=1:1 SAC (0.034 mM) + Glu (0.034 mM) Example 20: SAC:Glu=4:1 SAC (0.055 mM) + Glu (0.014 mM) Example 21: SAC:Glu=1:4 SAC (0.014 mM) + Glu (0.055 mM) That is, the effects of suppressing Fusarium wilt were verified using three types of aqueous solutions: an aqueous solution with a molar ratio of S-allylcysteine ​​to glutamic acid of 1:1 (Example 19), an aqueous solution with a molar ratio of 4:1 (Example 20), and an aqueous solution with a molar ratio of 1:4 (Example 21). Note that a similar verification was performed using sterilized water (Comparative Example 5) as a control.

[0084] Table 5 shows the AUDPC values ​​when cucumber seedlings and Fusarium oxysporum f. sp. were cultured for 14 days.

[0085]

[0086] <Results> From Table 5, it was confirmed that the aqueous solution containing S-allylcysteine ​​and glutamic acid in a molar ratio of 1:1 (Example 19) and the aqueous solution containing S-allylcysteine ​​and glutamic acid in a molar ratio of 1:4 (Example 21) have a high disease suppression effect.

[0087] Test Example 5 (Example 22 and Comparative Example 6): Soybean Stem Rot 16.7 mL of an aqueous solution of S-allylcysteine ​​adjusted to 0.034 mM was applied to 200 g of mixed soil (field soil: commercially available seedling soil: vermiculite = 1:1:1 (mass ratio)) and cultured at 25°C for 1 week (Example 22). The same amount of sterilized water was applied to the control soil (Comparative Example 6). 120 mL of each soil was placed in a pot, and germinated soybean seeds were sown therein. Next, 10 mL of a zoospore suspension (35-100 zoospores / mL) of Phytophthora sojae (Phytophthora sojae) was irrigated around the soybean seeds, followed by water irrigation to create a submerged state, and the soybeans were cultured for 5 days in a climate chamber at 23°C under a 16-hour light / 8-hour dark cycle. Five seedlings were used for each plot. After cultivation, the degree of browning of the roots of the soybean seedlings was evaluated using the following disease index of 0 to 4: 0: no symptoms; 1: less than 1 / 4 of the roots browned; 2: 1 / 4 to less than 1 / 2 of the roots browned; 3: 1 / 2 to less than 3 / 4 of the roots browned; 4: 3 / 4 or more of the roots browned. Furthermore, the disease severity and control value were calculated based on the disease severity index. The disease severity was calculated using the following formula.

[0088] Formula: Disease severity = Σ (disease index × number of seedlings) × 100 / (number of plants surveyed × 4)

[0089] The results of the disease incidence and control value are shown in Table 6. The control value is the rate of reduction in the disease incidence in Example 22 (SAC group) relative to Comparative Example 6 (control group).

[0090]

[0091] <Results> From Table 6, it was confirmed that the soil disease inhibitor of Example 22 containing S-allylcysteine ​​has a significant inhibitory effect against soybean stem rot, which is a type of soil disease.

[0092] Test Example 6 (Examples 23 and 24, and Comparative Examples 7 and 8): Bacterial wilt of tomato Next, it was confirmed whether or not the soil-borne disease inhibitor of the present invention has an inhibitory effect on bacterial wilt of tomato.

[0093] A test to confirm the inhibitory effect on tomato bacterial wilt was carried out as follows. A 0.0344 mM S-allylcysteine ​​aqueous solution alone (Example 23) and a 0.0344 mM mixed aqueous solution of S-allylcysteine ​​and glutamic acid (Example 24) were each administered (3.34 mL / 40 g) to sieved field soil, followed by incubation at 25°C for one week. Similarly, soil was also prepared by administering a glutamic acid aqueous solution alone (Comparative Example 7). As a control, soil was administered and incubated with sterilized water (Comparative Example 8). Plant test tubes (2.5 cm diameter, 10 cm height) were filled with 6 g of soil treated with the soil disease inhibitor (Example 23, Example 24, or Comparative Example 7) or soil treated with sterilized water (Comparative Example 8), inoculated with 2 mL of a cell suspension (optical density OD600nm = 0.1) of bacterial wilt disease bacteria (Ralstonia pseudosolananacealum) by drenching, and then layered with 3.4 g of sterilized vermiculite. Five germinated tomato seeds (cultivar Ponterosa) were sown and covered with a small amount of sterilized vermiculite. These test tubes were placed in a climate chamber (28°C, 12-hour photoperiod) and cultured for 10 days.

[0094] Ten days after sowing, the tomato seedlings were harvested and evaluated based on the degree of disease severity using a three-level disease index. The evaluation criteria are as follows: 0: No symptoms; 1: Slight necrosis observed only in the cotyledons; 2: Pre-emergence damping-off or hypocotyl necrosis, systemic wilting or withering. Furthermore, based on the disease index, the disease severity was calculated using the following formula:

[0095] Formula: Disease severity = Σ (disease severity index × number of seedlings) / 10 × 100%

[0096] The average disease severity of bacterial wilt for each soil disease inhibitor obtained in the confirmation test is shown in Table 7.

[0097]

[0098] <Results> As shown in Table 7, the soil disease inhibitor containing S-allylcysteine ​​alone (Example 23) and the soil disease inhibitor containing S-allylcysteine ​​and glutamic acid (Example 24) were confirmed to have a significant effect in suppressing bacterial wilt in tomatoes, compared to the control, sterilized water (Comparative Example 8).

[0099] <Production Example> Among the soil disease inhibitors of the present invention, a soil disease inhibitor containing S-allylcysteine ​​and glutamic acid will be described in detail below.

[0100] Production Example 1 In Production Example 1, a soil disease inhibitor in the form of a liquid formulation was produced. The composition is shown below: S-allyl-L-cysteine ​​(manufactured by Tokyo Chemical Industry Co., Ltd.) 0.17 parts by mass L-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.17 parts by mass Water 96.56 parts by mass Propylene glycol (manufactured by Toho Chemical Industry Co., Ltd.) 3.00 parts by mass 1,2-benzisothiazolin-3-one 0.10 parts by mass (PROXEL (registered trademark) GXL(S), manufactured by Lonza)

[0101] The method for producing the soil-borne disease inhibitor in the form of a liquid formulation is as follows: (Step 1) S-allyl-L-cysteine ​​and L-glutamic acid are dissolved in water. (Step 2) Propylene glycol and 1,2-benzisothiazolin-3-one are added to the aqueous solution obtained in Step 1, and the mixture is stirred and mixed. The specific production method is as follows: 0.17 parts by mass each of S-allyl-L-cysteine ​​(manufactured by Tokyo Chemical Industry Co., Ltd.) and L-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) are dissolved in 96.56 parts by mass of tap water, to which 3.0 parts by mass of propylene glycol (manufactured by Toho Chemical Industry Co., Ltd.) and 0.1 parts by mass of 1,2-benzisothiazolin-3-one (trade name: PROXEL (registered trademark) GXL(S), manufactured by Lonza) are added, and the mixture is stirred and mixed to obtain a liquid formulation.

[0102] Production Example 2 In Production Example 2, a soil disease inhibitor in the form of a granule was produced. The composition is shown below. S-allyl-L-cysteine ​​(manufactured by Tokyo Chemical Industry Co., Ltd.) 0.02 parts by mass L-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.02 parts by mass Water 5.50 parts by mass Dioctyl sodium sulfosuccinate 0.03 parts by mass (trade name: Newcol (registered trademark) 291PG, manufactured by Nippon Nyukazai Co., Ltd.) Granular pumice 99.93 parts by mass (trade name: Kagalite (registered trademark) K-2, manufactured by Kagalite Kogyo Co., Ltd.)

[0103] The method for producing the soil-borne disease inhibitor in the form of a granule is as follows: (Step 1) S-allyl-L-cysteine ​​and L-glutamic acid are dissolved in water. (Step 2) Dioctyl sodium sulfosuccinate is added to the aqueous solution obtained in Step 1, and the mixture is stirred and mixed. (Step 3) The liquid obtained in Step 2 after mixing is impregnated into granular pumice. (Step 4) The impregnated granular pumice is dried at 80°C. The specific production method is as follows: 0.02 parts by mass each of S-allyl-L-cysteine ​​(manufactured by Tokyo Chemical Industry Co., Ltd.) and L-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) is dissolved in 5.5 parts by mass of tap water, and 0.03 parts by mass of dioctyl sodium sulfosuccinate (trade name: Newcol 291PG, manufactured by Nippon Nyukazai Co., Ltd.) is added to the solution and mixed by stirring. The obtained liquid was impregnated into 99.93 parts by mass of granular pumice (trade name: Kagalite K-2, manufactured by Kagalite Kogyo Co., Ltd.), and then dried at 80°C to obtain granules.

[0104] Production Example 3 In Production Example 3, a soil disease inhibitor in the form of a dust formulation was produced. The composition is shown below: S-allyl-L-cysteine ​​(manufactured by Tokyo Chemical Industry Co., Ltd.) 0.02 parts by mass L-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.02 parts by mass Potassium sulfate (manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) 99.96 parts by mass

[0105] The soil disease inhibitor in the form of a dust formulation can be produced by mixing and stirring S-allyl-L-cysteine, L-glutamic acid, and potassium sulfate. The specific production method is as follows: 0.02 parts by mass each of S-allyl-L-cysteine ​​(manufactured by Tokyo Chemical Industry Co., Ltd.) and L-glutamic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 99.96 parts by mass of potassium sulfate (manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) were placed in a plastic bag and shaken to obtain a dust formulation.

[0106] In the following Test Example 6, an example will be described in which the liquid soil disease inhibitor obtained in Production Example 1 was used to inhibit Fusarium wilt, a type of soil disease.

[0107] Test Example 6 (Example 25, Comparative Example 9, and Reference Example 1): Strawberry Yellows The soil disease inhibitor obtained in Production Example 1 was used to evaluate the inhibitory effect on strawberry yellows, a type of Fusarium disease. The soil disease inhibitor was used in the following manner. Fusarium oxysporum forma specialis lycopersici, the causal agent of strawberry yellows, was cultured to a concentration of 2.8 × 10 ５ The soil was then applied to a plot of 0.4 m ２ After one month, 500 ml of a 1000-fold diluted solution of the soil disease inhibitor obtained in Production Example 1 was drenched at 2 L / ml ２ The soil was mixed with the test soil to prepare the soil of Example 25.

[0108] As Reference Example 1, the inhibitory effect on strawberry chlorosis was evaluated using "Benlate (registered trademark) wettable powder (manufactured by Sumitomo Chemical Garden Products Co., Ltd.)," a formulation containing methyl 1-(butylcarbamoyl)benzimidazol-2-ylcarbamer. The method for using "Benlate wettable powder" is as follows. During the same period, a 500-fold diluted solution of "Benlate wettable powder" was applied at 2 L / m ２ The mixture was then mixed with the test soil to prepare the soil of Reference Example 1.

[0109] Furthermore, the soil was used as Comparative Example 9 (control area) without any treatment to inhibit Fusarium disease after irrigation with the pathogen.

[0110] Eight days after the preparation of the soil of Example 25 and the soil of Reference Example 1, ten strawberry seedlings were planted in each of the soils of Example 25, Reference Example 1, and Comparative Example 9 (control), and the condition of the seedlings was evaluated every week from one week after planting until the sixth week. The evaluation items were disease severity and control value. Phytotoxicity was also visually observed during the evaluation.

[0111] The disease severity was calculated using a disease index based on the observation of the appearance of the strawberry seedlings. The disease index was quantified into the following five levels: 0: No symptoms 1: Slightly malformed and yellowing of leaflets 2: Typical symptoms such as malformed and yellowing of leaflets 3: Shrunken and wilting of plant 4: Withered The formula for calculating the disease severity is shown below.

[0112] Formula: Disease severity = Σ (number of diseased plants by severity x index) x 100 / (number of plants surveyed x 4)

[0113] The control value is the rate of reduction in the disease incidence of strawberries in the soils of Example 25 and Reference Example 1 relative to the strawberries in Comparative Example 9 (control group).

[0114] The evaluation results of the inhibitory effect are shown in Table 8 below.

[0115]

[0116] <Results> As shown in Table 8, it was confirmed that the soil disease inhibitor of Example 25 was more effective in suppressing the onset of strawberry chlorosis than the substance of Comparative Example 9 (control group) and Reference Example 1. Furthermore, no phytotoxic symptoms were observed with the soil disease inhibitor of Example 25.

[0117] Test Example 7 (Example 26, Comparative Example 10, and Reference Example 2): Cucumber Fusarium Wilt Using the soil disease inhibitor obtained in Production Example 1, a test was carried out to confirm the inhibitory effect on cucumber Fusarium Wilt, a type of Fusarium disease. The soil disease inhibitor was used as follows. Fusarium oxysporum, the causal agent of cucumber Fusarium Wilt, was cultured at 30°C for 2 weeks. 500 g of the culture solution was mixed with 1 kg of sterilized soil, and the mixture was applied to a plot of 1.8 m2 in soil. ２ The test soil was mixed with the soil disease inhibitor obtained in Production Example 1 at a rate of 2 L / ml, to prepare a test soil. ２The mixture was then mixed with the soil to prepare the soil of Example 26. Cucumber seedlings were planted in this soil of Example 26.

[0118] For reference, 150 ml of a 1000-fold diluted solution of Benlate (registered trademark) wettable powder was irrigated into the test soil per cucumber seedling to prepare the soil for Reference Example 2. Cucumber seedlings were planted in the soil of Reference Example 2. Furthermore, as Comparative Example 10 (control), cucumber seedlings were planted in test soil that had not been subjected to the treatment for inhibiting Fusarium wilt.

[0119] The inhibitory effect on cucumber Fusarium wilt disease was evaluated based on the disease incidence and control value of the cucumber seedlings. At the same time, phytotoxicity was observed with the naked eye.

[0120] The disease severity was calculated using the same formula as in Test Example 6, based on a disease index quantified by observing the wilting symptoms of cucumber seedlings and the degree of vascular bundle discoloration of cut stems. The disease index was quantified using the following five-level scale: 0: No browning observed. 1: Browning observed in less than 1 / 3 of the vascular bundles. 2: Browning observed in 1 / 3 to 2 / 3 of the vascular bundles. 3: Browning observed in 2 / 3 or more of the vascular bundles. 4: Vine splitting symptoms occurred and the plant died.

[0121] The control value was defined as the reduction rate of the disease incidence in the soil of Example 26 and Reference Example 2 relative to that of Comparative Example 10 (control). The evaluation results of the inhibitory effect are shown in Table 9 below.

[0122]

[0123] <Results> As shown in Table 9, it was confirmed that the soil disease inhibitor of Example 26 was more effective in suppressing the onset of cucumber Fusarium wilt than the substance of Comparative Example 10 (control group) and Reference Example 2. Furthermore, no phytotoxic symptoms were observed with the soil disease inhibitor of Example 26.

[0124] Test Example 8 (Examples 27 to 29, Comparative Example 11, and Reference Example 3): Sweet potato fusarium wilt The soil disease inhibitor obtained in Production Example 1 was used to evaluate the inhibitory effect on sweet potato fusarium wilt. The test soil was cultured with 5 × 10 Fusarium oxysporum forma specialis batatas, the pathogen of sweet potato fusarium wilt. ４bud-cell / ml and applied to the soil at 1 L / ml ２ The soil was irrigated at a rate of 1000 ml / min.

[0125] The soil disease inhibitors were used as follows: Six days after the test soils were prepared, the soil disease inhibitors obtained in Comparative Example 10 (control) and Production Example 1 were diluted 100 times (Example 27), 1,000 times (Example 28), and 10,000 times (Example 29) to prepare three types of solutions, and these solutions were applied to the different test soils at 2 L / m ２ The mixture was then mixed with the soil to prepare three types of soil for the examples. Sweet potato seedlings were planted in the soil.

[0126] In Reference Example 3, the bases of sweet potato seedlings were immersed in a 500-fold diluted solution of Benlate (registered trademark) wettable powder for 30 minutes before planting, and then planted in test soil. In Comparative Example 11 (control), sweet potato seedlings were planted in test soil that had not been treated to suppress Fusarium wilt.

[0127] The evaluation was carried out 120 days after planting. The evaluation items were the degree of browning of xylem vessels and the control value. At the time of evaluation, phytotoxicity was also observed with the naked eye.

[0128] The disease severity was calculated based on the xylem browning index, which was calculated by observing the browning state of the xylem vessels of cut sweet potato stems and quantifying it. The degree of xylem browning was quantified using the following five-level evaluation criteria: 0: No xylem browning. 1: Less than one-third of the xylem vessels are browned. 2: One-third to two-thirds of the xylem vessels are browned. 3: Two-thirds or more of the xylem vessels are browned. 4: Death The formula for calculating the degree of xylem browning is shown below.

[0129] Formula: Degree of vessel browning = Σ (vessel browning index x number of plants with each index) / (number of plants surveyed x 4) x 100

[0130] The control value was defined as the rate of reduction in the degree of xylem browning in the soil of Examples 27 to 29 and Reference Example 3 relative to Comparative Example 11 (control). The evaluation results of the inhibitory effect are shown in Table 10 below.

[0131]

[0132] <Results> As shown in Table 10, it was confirmed that the soil disease inhibitors of Examples 27 to 29 were more effective in suppressing the onset of sweet potato Fusarium wilt than the substance of Comparative Example 11 (control) and Reference Example 3. Furthermore, no phytotoxic symptoms were observed with these soil disease inhibitors of Examples 27 to 29.

[0133] Test Example 9 (Example 30, Comparative Example 12, and Reference Example 4): Spinach wilt The inhibitory effect on spinach wilt, a type of Fusarium disease, was evaluated using the soil disease inhibitor obtained in Production Example 1. The test soil was prepared by culturing Fusarium oxysporum forma specialis spinaciae SP1 strain, the causal agent of spinach wilt, in a bran or soil medium at 25°C for 3 weeks and mixing it with horticultural potting soil "Soil Friend (registered trademark)" (manufactured by Sanken Soil Co., Ltd.) at a mass ratio of 1:5.

[0134] The method for using the Fusarium disease inhibitor is as follows: The test soil is thinly spread on a sheet, and a solution obtained by diluting the soil disease inhibitor obtained in Production Example 1 1000 times is applied at a rate of 2 L / ml. ２ The soil was mixed with the soil to prepare the soil of Example 30. After filling a cell tray with the soil of Example 30, spinach was sown.

[0135] For reference, test soil was filled into a cell tray, and then 2 L / m of Benlate (registered trademark) wettable powder diluted 1000 times was applied. ２ The soil was used as Reference Example 4. Spinach was sown in the soil of Reference Example 4. Furthermore, as Comparative Example 12 (control), spinach was sown in test soil that had not been subjected to the treatment for inhibiting Fusarium wilt.

[0136] The inhibitory effect on spinach wilt was evaluated by the seedling establishment rate of spinach 15 days after application of the soil-based disease inhibitor and the rate of wilted or dead plants 38 days after application of the soil-based disease inhibitor. The reduction rate of wilting or dead plants in the soil of Example 30 and Reference Example 4 compared to Comparative Example 12 (control) was defined as the control value. At the same time, phytotoxicity was observed with the naked eye. The evaluation results of the inhibitory effect are shown in Table 11 below.

[0137]

[0138] <Results> As shown in Table 11, it was confirmed that the soil disease inhibitor of Example 30 was more effective in suppressing the onset of spinach wilt than the substance of Comparative Example 12 (control) and Reference Example 4. Furthermore, no phytotoxic symptoms were observed with the soil disease inhibitor of Example 30.

[0139] Test Example 10 (Example 31, Comparative Example 13, and Reference Example 5): Lotus Root Rot A test to confirm the inhibitory effect on lotus root rot, a type of Fusarium disease, was carried out using the soil disease inhibitor obtained in Production Example 1. The soil disease inhibitor was used as follows. Fusarium oxysporum, the pathogen of lotus root rot, was cultured in a soil bran medium at 25°C for 32 days under dark conditions to prepare test soil. A 1000-fold diluted solution of the soil disease inhibitor obtained in Production Example 1 was added to the test soil at a concentration of 2 L / ml. ２ The mixture was mixed into the soil to prepare the soil of Example 30. Lotus roots were planted in the soil of Example 31.

[0140] In Comparative Example 13 (control group), lotus roots were planted in test soil that had not been treated to inhibit Fusarium wilt. Also, lotus roots were planted in soil that had not been inoculated with the pathogen causing lotus root rot, and grown under the same conditions to check for rot.

[0141] Lotus root tubers were harvested 157 days after planting, and the inhibitory effect on Fusarium disease was evaluated based on the diseased tuber rate (%), which is the percentage of tubers infected with lotus root rot. The control value was calculated from the average diseased tuber rate. At the same time, phytotoxicity was observed with the naked eye. The inhibitory effect evaluation results are shown in Table 12 below.

[0142]

[0143] As shown in Table 12, the inhibitory effect of the soil-borne disease inhibitor of Example 31 on lotus root rot was confirmed. In addition, no phytotoxic symptoms were observed with the soil-borne disease inhibitor of Example 31.

[0144] Test Example 11 (Examples 32 to 35 and Comparative Example 14): Banana Panama Disease A test to confirm the inhibitory effect on banana Panama disease, a type of Fusarium disease, was carried out using the soil disease inhibitor obtained in Production Example 1. The test soil was inoculated with Fusarium oxysporum forma specialis cubense, the causal fungus of banana Panama disease, and 12 banana seedlings aged 2 months were planted per plot.

[0145] The soil disease inhibitor was used as follows. Two types of solutions were prepared by diluting the soil disease inhibitor obtained in Production Example 1 1000 times and 5000 times. These were then applied to banana seedlings at the following four levels of application. Example 32 (Plot 1): 2 L of the 1000-fold diluted solution was applied once per banana plant. Example 33 (Plot 2): 4 L of the 1000-fold diluted solution was applied once per banana plant. Example 34 (Plot 3): 2 L of the 1000-fold diluted solution was applied three times at monthly intervals per banana plant. Example 35 (Plot 4): 2 L of the 5000-fold diluted solution was applied once per banana plant.

[0146] As Comparative Example 14 (control), a plot was set up in which no soil disease inhibitor was treated.

[0147] Banana stems were cut 180 days after planting, and the discoloration of each corm was observed to evaluate the disease index for each banana plant. The disease index was calculated according to the following criteria established by INIBAP (International Network for the Improvement of Banana and Plantain): 1: No discoloration of xylem 2: Discoloration limited to the junction of the root and rhizome 3: Less than one-third of xylem is browned 4: One-third to two-thirds of xylem is browned 5: More than two-thirds of xylem is browned 6: Total discoloration of the tissue Based on the evaluation results, the disease index was calculated using the following formula.

[0148] Formula: Disease severity = Σ (evaluation index x number of banana plants with each index) / (total number of plants x 6) x 100

[0149] At the same time, the symptoms of phytotoxicity were visually confirmed. The evaluation results of the inhibitory effect are shown in Table 13 below.

[0150]

[0151] <Results> As shown in Table 13, the inhibitory effect of the soil-borne disease inhibitors of Examples 32 to 35 on banana Panama disease was confirmed. Furthermore, no phytotoxic symptoms were confirmed with these soil-borne disease inhibitors of Examples 32 to 35.

[0152] The soil disease inhibitor of the present invention has been described in detail above, but the soil disease inhibitor described in the claims can contain various substances other than those described in the examples and usage examples, the compounding ratio of the substances can be changed as appropriate, and a known dosage form can be selected. As a method for providing the soil disease inhibitor of the present invention, the use of a liquid formulation has been particularly described in detail, but it can also be applied to the soil in the form of a dust or granule as described in the examples.

[0153] The soil disease inhibitor of the present invention can be used as a substitute for agricultural chemicals, a soil improver, etc.

Claims

1. A soil disease inhibitor containing S-allylcysteine ​​or a salt thereof.

2. The soil disease inhibitor according to claim 1, further comprising an amino acid or a salt thereof.

3. A soil disease inhibitor according to claim 2, wherein the amino acid or its salt is an amino acid or its salt having a charged side chain and / or an amino acid or its salt having a polar, uncharged side chain.

4. A soil disease inhibitor according to claim 3, wherein the amino acid or salt thereof having a charged side chain is glutamic acid or a salt thereof.

5. A soil disease inhibitor as described in claim 3, wherein the amino acid or salt thereof having a polar, uncharged side chain is one or more amino acids or salts thereof selected from the group consisting of cysteine, serine and asparagine.

6. The soil disease inhibitor according to claim 2, wherein the amino acid or salt thereof contains one or more amino acids or salts thereof selected from the group consisting of cysteine, glutamic acid, serine and asparagine.

7. A method for suppressing soil diseases, comprising supplying the soil disease inhibitor according to any one of claims 1 to 6 to a plant or its surroundings.

8. A method for applying the soil disease inhibitor according to any one of claims 1 to 6 to a plant or its surroundings.

9. A method for enhancing the soil disease inhibitory effect by applying an amino acid or a salt thereof to a soil disease inhibitor containing S-allylcysteine ​​or a salt thereof.

10. A method for using S-allylcysteine ​​or a salt thereof to suppress soil-borne diseases.