JP4621867B2 - Plant disease control agent, method for producing the same, pesticide and fertilizer - Google Patents

Description

  The present invention relates to a plant disease control agent comprising a licorice-derived component, liquiritigenin or isoliquitigenin as an active ingredient, a method for producing the same, an agrochemical and a fertilizer.

Licorice has long been known as a herbal medicine, and is now used mainly as a raw material for food sweeteners, pharmaceuticals and quasi drugs. In particular, glycyrrhizin, which is a water-soluble component, has excellent pharmacological actions such as anti-inflammatory action, anti-ulcer action, and anti-allergic action, and thus is widely used in foods, pharmaceuticals, cosmetics, and the like. The antibacterial action of licorice and its components against gram-positive bacteria is already known (see Non-Patent Documents 1 to 3). Moreover, the soil improvement agent (refer patent document 1) which mix | blended the licorice extract, the plant growth promoter containing a licorice extract, and the fertilizer using this plant growth promoter (refer patent document 2) are proposed.
However, since the current licorice extract has insufficient antibacterial properties against phytopathogenic bacteria, a more effective one has been desired.

JP-A-8-245959 JP 2000-309502 A Tsukiyama Ryoichi, "Food and Development", 2002, 37, 6, p59-61 Kenzo Okada “Chem. Pharm. Bull.”, 1989, Vol. 9, p2528-2530 Sachio Demizu “Chem. Pharm. Bull.”, 1988, Vol. 9, p 3474-3479 "14th revised Japanese Pharmacopoeia commentary", Yodogawa Shoten, June 27, 2001 “Food Additives Official Manual”, Yodogawa Shoten, June 9, 1999

  The present invention has been made in view of the above circumstances, and has an antibacterial action against a wide range of phytopathogenic fungi, and a plant disease control agent comprising a licorice-derived component, liquiritigenin, or isoliquitigenin as an active ingredient that can control plant diseases. And a method for producing the same, and an agricultural chemical and a fertilizer containing a plant disease control agent.

  In order to achieve the above-mentioned object, the present inventor has intensively studied on the antibacterial action against several phytopathogenic fungi that are problematic in agriculture. As a result, licorice was extracted with water under neutral to alkaline conditions, the precipitate obtained by acid treatment of this extract was ethanol-extracted, and the resulting ethanol extract was subjected to activated carbon decolorization, and then glycyrrhizin The antibacterial action was found in the crystallization mother liquor after the crystallization of, and the present invention was achieved.

  Furthermore, the present inventors have found that the component having an antibacterial action is liquiritigenin or isoliquitigenin, and have made the present invention.

  Conventionally, what is said to be a general licorice extract is obtained by hot water or hydrous alcohol extraction, and there are many glycyrrhizin content of about 5 to 25% by mass and flavonoid content of about 1 to 5% by mass (non-existing). (See Patent Documents 4 and 5). In addition, the method used for producing a derivative of glycyrrhizin usually used an alkali extraction and crystallized crystallized material, and the mother liquor from which the crystallized material was removed was usually discarded. On the other hand, it is a new finding by the present inventors that the mother liquor that has been discarded so far has an antibacterial action against plant pathogens.

Therefore, the present invention
[1]. Plant disease control characterized by comprising a crystallization mother liquor after crystallization of glycyrrhizin from an activated carbon decolorization solution of an ethanol extract of a precipitate formed by acid treatment of a neutral or alkaline water extract of licorice Agent,
[2]. Plant diseases include rice blast, seed rot, coat blight or scab, cucumber anthracnose or brown spot, tomato leaf mold, gray mold, ring rot or brown ring rot, eggplant The plant disease control agent according to [1], wherein the plant disease control agent is a soy mildew disease, a watermelon vine blight, a spinach wilt disease or a bell pepper spot disease,
[3]. An agrochemical comprising the plant disease control agent according to [1] or [2],
[4]. A fertilizer comprising the plant disease control agent according to [1] or [2],
[5]. Licorice is extracted with water under neutral or alkaline conditions, and the precipitate obtained by acid treatment of this extract is extracted with ethanol. The resulting ethanol extract is subjected to activated carbon decolorization, and then glycyrrhizin is crystallized. And a method for producing a plant disease control agent characterized by collecting the crystallization mother liquor.

  ADVANTAGE OF THE INVENTION According to this invention, a highly safe plant disease control agent which uses a licorice origin component, liquiritigenin, or isoliquitigenin as an active ingredient, its manufacturing method, an agricultural chemical, and a fertilizer can be provided.

Hereinafter, the present invention will be described in more detail.
The first invention of the present invention is based on the crystallization mother liquor after crystallization of glycyrrhizin from the activated carbon decolorization solution of the ethanol extract of the precipitate generated by acid treatment of the neutral or alkaline water extract of licorice. It is a plant disease control agent.

  The licorice used as the raw material for the plant disease control agent of the present invention is a plant belonging to the genus Glycyrihiza, for example, G. glabra, G.G. uralensis, G. et al. inflata and the like can be used. It is preferable to use inflata. Moreover, although any site | part of a root, a rhizome, a leaf, and a stem can be used as a raw material, it is preferable to use a root and / or a rhizome as a raw material. These may be raw or dried, but use dry roots and dry rhizomes, which are raw materials for industrially produced glycyrrhizin, as raw materials. be able to. In addition, licorice is often called with the name of the production area, and examples thereof include Tohoku licorice, Northwest licorice, Xinjiang licorice, Mongolian licorice, Russian licorice, and Afghanistan licorice.

  As extraction conditions for obtaining the plant disease control agent of the present invention, water extraction is carried out under neutral to alkaline conditions with respect to the above licorice. Usually, the pH of the water extract is preferably 7 to 11, particularly preferably 9 to 10. The extraction temperature may be cold water, hot water or hot water, but is preferably 5 to 100 ° C, particularly preferably 50 to 100 ° C. For adjusting the pH, ammonia, sodium hydroxide, potassium hydroxide, or the like can be used. Although extraction time changes with extraction temperature, it is 1 to 72 hours normally, and 2 to 24 hours are especially preferable.

  Next, the precipitate obtained by acid-treating the above extract is subjected to ethanol extraction, and the obtained ethanol extract is subjected to activated carbon decolorization treatment, and then glycyrrhizin is crystallized to obtain a crystal mother liquor.

  In the acid treatment, an acid solution such as sulfuric acid, hydrochloric acid, nitric acid or the like is used to perform precipitation treatment at an acid pH of 2 to 4, thereby precipitating glycyrrhizin or the like. Separate the precipitate and filtrate by filtration. 2 to 10 parts by mass, preferably 1 to 5 parts by mass of ethanol are added to 100 parts by mass of the resulting precipitate to obtain an ethanol extract. The extract is stirred and filtered. 2 to 10% by mass, preferably 1 to 5% by mass of activated carbon is added to the obtained filtrate, and reflux extraction is performed. Thereafter, filtration is performed using a filter aid such as celite, diatomaceous earth, pearlite, etc., and alkaline water such as ammonia water, sodium hydroxide, potassium hydroxide is added to adjust the pH to 4.0 to 7.0, preferably pH 5.0 to Adjust to 5.5. Further, glycyrrhizin is crystallized by allowing to stand at 3 to 10 ° C., preferably 5 to 7 ° C. for 1 to 5 days, preferably 2 days, and then filtered to remove the crystallized glycyrrhizin.

  In this case, the amount of glycyrrhizin in the extract obtained by drying the ethanol extract is 10 to 30% by mass per solid. In the above crystallization step, 20 to 50% by mass, particularly 30 to 40% by mass, of this glycyrrhizin is crystallized and removed so that the crystallization mother liquor after the crystallization step is dried. The glycyrrhizin content in the extract is preferably 5 to 20% by mass, particularly 8 to 15% by mass per solid.

  The plant disease control agent of the present invention comprises the above-mentioned crystallization mother liquor, but the crystallization mother liquor can be used as it is, and can also be used after being concentrated by a conventional method. Moreover, it can also be used as a powder or solid substance of a tan licorice extract by drying the extract by an appropriate method.

  The glycyrrhizin content of the plant disease control agent of the present invention is preferably 5 to 20% by mass, particularly preferably 8 to 15% by mass, and the content of flavonoids (liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin) is 5 to 25% by mass, particularly 10 to 20% by mass is preferred per solid. The flavonoid content of the plant disease control agent of the present invention is about 2 to 20 times that of the conventional licorice extract, which is a high content. In the present invention, the glycyrrhizin content is comparable to that of the conventional licorice extract, but has a high antibacterial activity because it contains a high content of flavonoids. The glycyrrhizin content and the flavonoid content are determined by the measurement methods described in the examples below.

  The plant disease control agent of the present invention has an antibacterial action against phytopathogenic fungi, and in particular has an antibacterial action against phytopathogenic fungi (generally filamentous fungi) belonging to eukaryotes. Pathogenic fungi belonging to eukaryotes invade many crops such as cereals, potatoes, beans, vegetables, fruit trees, flowers, special crops, forage crops, and the number of diseases reported so far (combinations of crops and pathogens) Is over 3,000. The main pathogens are rice blast fungus (Pyricularia oryzae), seed rot fungus (Pythium graminicura), rice blast fungus (Rhizoctonia bully burdock), , Sesame leaf blight fungus (Cochliobolus miyabeanus), seedling blight fungus (Rhizopus oryzae), wheat red mold fungus (Fusarium graminic ivy fungus) Various kinds of vegetables Gray mold fungus (Botrytis cinerea), powdery mildew fungus (example: Sphaerotheca friginea), mycorrhizal fungus (example: sclerotia sclerotole) Colletotrichum orbiculare), plague (e.g., Phytophsola melonis), Fusarium fungus causing various diseases (e.g., Fusarium oxysporum: Fusarium oxysporum), individually , Ring-rot disease fungus (Alta Ria solani: Alternaria solani), brown ring-shaped fungus (Corynespora casicola), spot fungus (Stemphyllium lycopersicii): Stemphylilium lycopersici Mycovelocinella natrashi (mycovelosiella natrassii), brown rot fungus (paracercospora genula: Paracercospora genula), cucumber (including watermelon, etc.) downy mildew (pseudoperosporus cubensis) pora cassiicola), vine blight fungus (Didimelella brioniae), spotted fungus of green pepper (Circospora capsici), spinach wilt fungus (Fusarium oxysporum formaspecies spinasum): Fusarium sp. spinciae), in fruit trees, apple leaf spot deciduous fungus (Alternaria marii), black rot fungus (Venturia inequalis), pear black spot fungus (Alternaria chrysiana fungus), : Gymnosporangium asiatium), black spot fungus of citrus (Diaporte citri), fungus of green mold (Penicillium itaricum), piromycetes of grapesviticola) and the like. Among these, rice blast fungus, seed rot fungus, coat blight fungus or leafy seedling fungus, cucumber anthracnose fungus or brown leaf fungus, tomato leaf mold fungus, gray mold fungus, ring mold fungus or brown ring fungus, eggplant The plant-controlling agent of the present invention is particularly effective against Japanese smut fungus, watermelon vine blight, spinach wilt or green pepper spot disease.

  The second invention of the present invention is a plant disease control agent comprising liquiritigenin and / or isoliquetiginin as an active ingredient. The method for obtaining liquiritigenin and isoliquitigenin is not particularly limited. As for liquiritigenin and isoliquitigenin, a purified commercially available product may be used, or it may be extracted from plants such as licorice, rakkyo, and alfalfa. It does not specifically limit as an extraction method, It can extract by adjusting suitably extraction temperature and time with organic solvents, such as water or ethanol. Purification can be performed by, for example, liquid-liquid partition extraction, various chromatographies, membrane separation, and the like. In addition, liquiritigenin and isoliquiritigenin are crystallized after glycyrrhizin is crystallized from an activated carbon decolorization solution of an ethanol extract of a precipitate formed by acid treatment of a neutral or alkaline water extract of licorice. The mother liquor may be obtained by purification by silica gel column chromatography.

  In the plant disease control agent containing liquiritigenin and / or isoliquitigenin as an active ingredient, the plant diseases and pathogenic bacteria may be the same as described above.

  The plant disease control agent of the present invention can be used as an agrochemical or a fertilizer as it is or mixed with any agrochemical component or a fertilizer component. Examples of other components include surfactants, emulsifiers, extenders, humectants and the like. The dosage form is not particularly limited, but it can be a liquid, water solvent, powder, granule, wettable powder, emulsion, flowable, microcapsule, and the like. As a method of use, a method of spraying these as they are or after diluting with water can be mentioned.

    The plant disease control agent of the present invention can be formulated by mixing with a compound fertilizer containing three elements of nitrogen, phosphoric acid and potassium, and sprayed on the field, thereby enabling disease control and fertilization simultaneously. In addition, foliar spray fertilizer (liquid or powder compound fertilizer) etc. is processed into a mixed preparation, and these are dissolved in water and sprayed directly onto the leaves of the crop to simultaneously control disease and fertilize. Can do. Furthermore, by mixing and formulating with trace element fertilizers containing the required trace elements such as manganese, boron, iron, copper, zinc, molybdenum, chlorine, nickel, etc., disease control and trace element deficiency Can be solved at the same time. In addition, it can also be used by mixing with various organic fertilizers.

  When used as an agrochemical or fertilizer, a plant comprising a crystallization mother liquor after crystallization of glycyrrhizin from an activated carbon decolorization solution of an ethanol extract of a precipitate produced by acid treatment of a neutral or alkaline water extract of licorice The blending amount in the case of a disease control agent is preferably 0.1 to 90% by mass in the total amount of the agricultural chemical, more preferably 1 to 50% by mass, and preferably 0.1 to 90% by mass in the total amount of fertilizer. 1-50 mass%. The blending amount in the case of a plant disease control agent containing liquiritigenin and / or isoliquitigenin as an active ingredient is preferably 0.1 to 90% by mass, more preferably 1 to 50% by mass, and the total amount of fertilizer. 0.1-90 mass% is preferable, More preferably, it is 1-50 mass%.

  The plant disease control agent of the present invention is free from the appearance of drug-resistant bacteria and side effects due to chemically synthesized pesticides, and can be used with confidence. Furthermore, since there is no effect on the human body and the environment due to the residue of the drug, it can greatly contribute to disease control for plants such as vegetables, trees and flowers.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In the following examples, “%” is mass% unless otherwise specified.

[Example 1]
The rhizome of licorice (Glycyrrhiza inflata) was crushed into chips. 1.0 kg of this licorice chip was extracted overnight with 10 L of 3% aqueous ammonia (pH 10), and then separated into solid and liquid. The obtained extract was subjected to an acid precipitation treatment with a 1% sulfuric acid solution to precipitate glycyrrhizin and the like, and the filtrate was separated into a precipitate and an extract filtrate. Among these, 1 L of ethanol was added to the precipitate, stirred at room temperature for 1 hour, and filtered using celite. Activated carbon 60g was added to the obtained filtrate, and reflux extraction was performed at room temperature for 1 hour. Then, filtration using celite was performed. Ammonia water was added to the obtained filtrate to adjust the pH to 5.0 to 5.5. The filtrate was allowed to stand at 5 ° C. for 2 days to crystallize glycyrrhizin, and then centrifuged to separate the crystals and the filtrate. The obtained filtrate was concentrated under reduced pressure, neutralized to about 7.0 with sodium carbonate, further concentrated under reduced pressure, and spray-dried to obtain 150 g of a licorice extract as a yellow-brown extract powder. As a result of performing HPLC analysis on this licorice extract, the glycyrrhizin content was 11%, and the flavonoids (liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin) content was 15%. Of the flavonoids content of 15%, the liquiritigenin content was 5%, and the isoliquitigenin content was 3%.

[Comparative Example 1]
The rhizome of licorice (Glycyrrhiza inflata) was crushed into chips. After extracting 1.0 kg of this licorice chip overnight with 10 L of water, it was solid-liquid separated, concentrated under reduced pressure, and spray-dried to obtain 250 g of a licorice extract as a brown extract powder. As a result of performing HPLC analysis on this licorice extract, the content of glycyrrhizin was 10%, and the content of flavonoids (liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin) was 1.5%. Of the flavonoids content of 1.5%, the liquiritigenin content was 0.1%, and the isoliquitigenin content was 0.05%.

  About the obtained licorice extract, antibacterial action evaluation with respect to the following plant pathogenic bacteria and an inoculation test were performed. The results are also shown in Tables 2-5.

The HPLC analysis conditions for glycyrrhizin content, liquiritigenin content, liquiritin content, isoliquitigenin and isoliquiritin content are shown below.
(1) Glycyrrhizin
<HPLC conditions>
Column: Nucleosil-II 5C18 HG
Solvent: Acetic acid: Acetonitrile (volume ratio) = 60: 40
Flow rate: 1.0 mL / min
Detection: 254 nm
Temperature: 40 ° C
Injection volume: 20 μL
(2) liquiritigenin, liquiritin
<HPLC conditions>
Column: Nucleosil-II 5C18 HG
Solvent: Acetonitrile: Water: Acetic acid (volume ratio) = 20: 75: 5
Flow rate: 1.0 mL / min
Detection: 280 nm
Temperature: 45 ° C
Injection volume: 20 μL
(3) Isoliquiritigenin
<HPLC conditions>
Column: Nucleosil-II 5C18 HG
Solvent: acetonitrile: water: acetic acid (volume ratio) = 40: 55: 5
Flow rate: 1.0 mL / min
Detection: 350nm
Temperature: 45 ° C
Injection volume: 20 μL
(4) Isoliquelitin column: Nucleosil-II 5C18 HG
Solvent: Acetonitrile: Water: Acetic acid (volume ratio) = 20: 75: 5
Flow rate: 1.0 mL / min
Detection: 350nm
Temperature: 45 ° C
Injection volume: 20 μL

(1) Evaluation of antibacterial action It evaluated by measuring the hyphal elongation suppression rate on the culture medium with respect to a plant pathogenic microbe.
<Preparation of assay medium>
Using a 10% solution of licorice extract dissolved in 50% by volume ethanol, PDA medium (manufactured by Nissui) prepared as licorice extract at concentrations of 100 and 1000 μg / mL was prepared. 20 mL of the medium prepared in the petri dish was dispensed to prepare a medium for the licorice extract added section. The licorice extract was not added to the control medium.
<Preparation of disc>
Plant pathogens were pre-cultured at 25 ° C. for several days using a separately prepared PDA plate medium (medium amount 10 mL), and the mycelial tip was punched with a cork borer having a diameter of 5 mm to form a disk.
<Culture>
The disc was placed in the center of the assay medium with the mycelium side down and cultured at 25 ° C.
<Measurement of mycelial elongation>
In the control group, it was measured at the time when the mycelium was extended to about 70% of the petri dish. Using the center of the disk with a cross line drawn as a reference, the hypha diameter of each phytopathogenic fungus was measured. Using 2 to 4 petri dishes per concentration, the mycelial diameter was measured at 2 locations per petri dish, and these were averaged to calculate the average diameter. The hyphal elongation amount was calculated from the measurement result based on the following formula (1).
Mycelial elongation amount = [average diameter of mycelia (mm) −diameter of disk (5 mm)] / 2 (1)
<Inhibition rate of hyphal elongation>
The hyphal elongation suppression rate was calculated by the following formula (2). In addition, when the hyphal elongation suppression rate is minus, it indicates that the hypha in the added section has been elongated.

  Plant pathogenic strains include rice blast, seed rot, coat blight and leafy seedling, cucumber anthracnose and brown leaf disease, tomato leaf mold, gray mold and ring mold, eggplant soot mold The pathogens of the disease, watermelon vine blight, and spinach wilt were used.

(2) Inoculation test An evaluation was performed by measuring the number of lesions occurring.
<Target plant>
Rice (variety: Nipponbare), cucumber (variety: Tatsuro Taro), and tomato (variety: Strong Yoneju 2) were used.
Rice was transplanted into a 1/5000 Earl Wagner pot, cucumber and tomato in an unglazed pot (5 inches) and cultivated for 1 to 2 months, and used for the test when the plant height was extended to about 50 cm.
<Preparation of phytopathogenic spore solution>
The plant pathogenic strains used were rice blast, rice, brown spot and anthracnose for cucumber, brown ring disease for tomato, and spot disease for pepper.
Rice blast fungus was cultivated in oatmeal, and cucumber and tomato pathogens were transplanted to PDA medium and cultured at 25 ° C. Only for rice blast fungus, the aerial mycelium on the medium was removed with a paint brush, and further, spore formation promotion treatment such as drying of the medium was performed. After 1 to 2 weeks, the pathogenic spore formed on the surface of the culture medium was suspended in distilled water using a paint brush and filtered with quadruple gauze to prepare a spore suspension.
One drop (about 20 μL) of this spore suspension is dropped on a slide glass and examined under a microscope to prepare a spore solution of a phytopathogenic fungus with distilled water to a concentration of about 10 ⁴ cells / mL. It was.
<Test method>
An equal amount of an aqueous solution of licorice extract (2%) and a phytopathogenic spore solution were mixed to prepare a suspension so as to be 1% as a licorice extract. This suspension was sprayed with a small glass sprayer and a compressor in an amount of 20 to 60 mL per plant (about the amount of sprayed liquid dripping from the leaves). Three bowls were tested per treatment. Immediately, it was carried into a constant temperature inoculation box and kept moist for 2 days at 25 ° C. and 100% humidity. Then, it moved to the glass room and measured the number of lesions about one week later visually. In the control group, instead of the licorice extract aqueous solution, a suspension obtained by mixing equal amounts of distilled water and phytopathogenic spore solution was used.

<Calculation of index>
The average number of lesions was calculated from the number of lesions of each strain. Relative value when the average number of lesions in the category (control group) to which only plant pathogenic bacteria were added was 100 in the average number of lesions in the category (licorice extract addition group) sprayed with the suspension containing licorice extract. The index was calculated by the following formula (3).

From Table 1, the hyphal elongation inhibition rate in the licorice extract of Example 1 is significantly higher than the hyphal elongation inhibition rate in the licorice extract of Comparative Example 1. From Tables 2 to 6, the number of lesions in the licorice extract of Example 1 is significantly smaller than the number of lesions in the licorice extract of Comparative Example 1.
From these results, the licorice extract of Example 1 had a significantly stronger antibacterial action than the licorice extract of Comparative Example 1, and a significantly stronger plant disease control action was confirmed.

[Test Example 1]
In the same way as the above antibacterial action evaluation, measure the inhibition rate of mycelial elongation on the medium for the pathogens of tomato brown rot for each of the flavonoids liquiritigenin and isoliquiritigenin, and evaluate the antibacterial action Went. As for liquiritigenin and isoliquiritigenin, those purified by silica gel column chromatography from the licorice extract of Example 1 (purity 95%) were used.

  As shown in Table 7, the inhibition rate of hyphal elongation in liquiritigenin and isoliquiritigenin is both high, liquiritigenin is equivalent to the licorice extract of Example 1, and isoliquiritigenin compared to the licorice extract of Example 1. 1.7 times. Compared to the licorice extract of Comparative Example 1, the licorice extract of Example 1 has a significantly higher content of liquiritigenin and isoliquiritigenin. From these, it was confirmed that liquiritigenin and isoliquiritigenin are active ingredients showing plant disease control.

[Prescription Example 1]
An agricultural chemical having the following composition was prepared based on a conventional method.
10 parts of licorice extract of Example 1 5 parts of Kiraya extract 10 parts of ethanol
75 parts of water
100 copies in total

[Prescription Example 2]
A fertilizer having the following composition was prepared based on a conventional method.
Licorice extract of Example 1 1 part Seaweed powder 5 parts Shell powder 10 parts
84 parts of humus
100 copies in total

Claims (5)

  Plant disease control characterized by comprising a crystallization mother liquor after crystallization of glycyrrhizin from an activated carbon decolorization solution of an ethanol extract of a precipitate formed by acid treatment of a neutral or alkaline water extract of licorice Agent.   Plant diseases include rice blast, seed rot, coat blight or scab, cucumber anthracnose or brown spot, tomato leaf mold, gray mold, ring rot or brown ring rot, eggplant 2. The plant disease control agent according to claim 1, wherein the plant disease control agent is a soy mildew disease, a watermelon vine blight, a spinach wilt disease or a bell pepper spot disease.   An agrochemical comprising the plant disease control agent according to claim 1 or 2.   A fertilizer comprising the plant disease control agent according to claim 1 or 2.   Licorice is extracted with water under neutral or alkaline conditions, and the precipitate obtained by acid treatment of this extract is extracted with ethanol. The resulting ethanol extract is subjected to activated carbon decolorization, and then glycyrrhizin is crystallized. And collecting the crystallization mother liquor, and a method for producing a plant disease control agent.