JP2017165678A - Method for reducing fungus density of clubroot fungi and method for controlling clubroot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method in which an excellent control effect as compared to the conventional clubroot control method is exhibited.SOLUTION: Provided is, in a method for controlling clubroot in which a decoy crop plant selected from rye and sorghum is grown as a preceding plant, a method for controlling clubroot of brassicaceous plant by applying 3-[(3-bromo-6-fluoro-2-methyl-1H-indol-1-yl)sulfonyl]-N,N-dimethyl-1H-1,2,4-triazole-1-sulfonamide to crop growing soil before sowing, during sowing or after sowing of the decoy crop plant.SELECTED DRAWING: None

Description

  The present invention relates to a method for reducing the density of clubroot fungi in crop cultivation soil and a method for controlling clubroot of cruciferous crops.

  Brassicaceae vegetable root-knot disease (hereinafter referred to as root-knot disease) is one of the difficult-to-control soil diseases caused by the root-knot fungus (Plasmodiophora brassicae). Is an important disease that greatly reduces the yield and causes serious damage around the world.

  The root-knot fungus usually exists as dormant spores, which are durable in the soil, and when the root of the host plant (ie, cruciferous crop) grows in the vicinity, it germinates to become primary zoospores, Causes root hair infection (primary infection). After that, a zoosporangia is formed in the root hair, and then a secondary zoospore released from the soil again causes a cortical infection (secondary infection), which grows in the root cell and forms a nodule. Wake up. The next-generation dormant spores are contained in the formed root-kumps (affected roots), and will diffuse into the soil as the root-kumps rot.

  Conventionally, as a method of controlling root-knot disease, by promoting germination of dormant spores in the soil, planting of decoy crops (also called decoy plants) that are defined as plants that reduce fungus density, planting of resistant varieties, Methods such as the use of disease control materials such as calcareous materials such as lime nitrogen and organic materials such as chitin, and the use of biological pesticides such as chemically synthesized pesticides and microorganisms have been proposed and applied.

  For example, Patent Document 1 discloses amisulbrom (chemical name: 3-[(3-bromo-6-fluoro-2-methyl-1H-indol-1-yl) sulfonyl] -N, N-dimethyl-1H-1, 2,4-triazole-1-sulfonamide) shows a control effect against clubroot of cruciferous vegetables, and Patent Document 2 describes the above-mentioned amisulbromine into the cultivated soil during leaf radish cultivation. A method for reducing the density of the clubroot fungus in the soil for cultivating crops and a method for controlling the clubroot of crops are disclosed.

Japanese Patent Laying-Open No. 2005-082479 JP2013-203686A

  In the above-mentioned conventional methods for controlling clubroot, resistant varieties have become diseased, while decoy crops have been found to have a decrease in the density of clubroot bacteria at the planting site, but the fungus in the whole field Problems such as the inability to expect a density reduction effect remained. Disease prevention materials such as organic materials are considered to be problematic in terms of practical application, and chemical synthetic pesticides such as fursulfamide and fluazinam, which are currently widely used, can cause root-knot disease. Although it can be suppressed, there still remains a problem that the effect of reducing the bacterial density of the clubroot in the soil cannot be expected. Furthermore, the method of controlling root-knot disease by combining decoy crop cultivation using leaf radish as a decoy crop and the application of amisulbrom may reduce the bacterial density of the club-root fungus by inhibiting growth due to pest damage of leaf radish. However, there is a need for a more effective and fundamental new method for controlling root-knot disease.

  This invention is made | formed in view of such a situation, The objective is to provide the control method in which the control effect outstanding compared with the conventional control method of a clubroot was expressed.

  As a result of diligent research to solve the above problems, the present inventors have used rye or sorghum as a decoy crop, and in a general name, amisulbrom is added to a crop-cultivated soil before sowing, at the time of sowing or after sowing. By applying, it was found that the density of the clubroot fungus can be drastically reduced, and the control of the clubroot of the cruciferous crops can be effectively achieved, and the present invention has been completed.

  That is, the present invention relates to the following [1] to [2].

[1]
3-[(3-Bromo-6-fluoro-2-methyl-1H-indol-1-yl) sulfonyl] -N before, after or after sowing a decoy crop selected from the group consisting of rye and sorghum , N-dimethyl-1H-1,2,4-triazole-1-sulfonamide is applied to the crop-cultivated soil, thereby reducing the density of the clubroot fungus in the crop-cultivated soil.

[2]
In a method for controlling root-knot disease in which a decoy crop selected from the group consisting of rye and sorghum is cultivated as a preceding crop of cruciferous crops, 3-[(3-bromo-6 -Fluoro-2-methyl-1H-indol-1-yl) sulfonyl] -N, N-dimethyl-1H-1,2,4-triazole-1-sulfonamide by applying to crop-cultivating soil How to control clubroot.

  According to the method of the present invention, compared with the conventional method for controlling clubroot, the bacterial density of the clubroot in the crop cultivation soil can be greatly reduced, and a very excellent clubroot control effect is exhibited.

  The present invention uses rye or sorghum as a decoy crop, and 3-[(3-bromo-6-fluoro-2-methyl-1H-indol-1-yl) sulfonyl before sowing, after sowing or after sowing of the decoy crop. ] Applying -N, N-dimethyl-1H-1,2,4-triazole-1-sulfonamide (generic name: amisulbrom, hereinafter referred to by generic name in this specification) to crop-cultivated soil The present invention relates to a method for reducing the density of clubroot bacteria in soil.

The present invention also relates to a method for controlling root-knot disease in which rye or sorghum is cultivated as a decoy crop as a predecessor of a cruciferous crop, and amisulbrom is applied to the crop-cultivated soil before, during or after sowing the decoy crop. The present invention relates to a method for controlling clubroot of cruciferous crops.
[Decoy crop]
A decoy crop is defined as a plant that reduces germ density by promoting germination of dormant spores in the soil as described above, and examples of decoy crops in cruciferous crops include rye, sorghum and oats. be able to. Variety name dash is used for rye, roll name king for sorghum, and cultivar name Heiots for oats.

A decoy crop is usually treated by sown into the soil after growing.
[Brassicaceae crops]
The cruciferous crops that are subject to clubroot control include rape, Osaka Chinese cabbage, turnip, mustard greens, cauliflower, cabbage, Kyoto greens, watercress, kale, komatsuna, kohlrabi, edible vegetables (variety of mustard greens), Shandong greens, Sakana, Taasai, Kai-red radish, Japanese radish, Taisai, Takana, Chingensai, Karasai, Japanese mustard (Mizukakena), Rape blossoms, Nozawana, Chinese cabbage, Pakchoi, Nisatsu radish (Radesh), Japanese vegetable, Hiroshima vegetable , Broccoli, horse radish, mizukake vegetables, rocket salad (Lucora), sprouts, wasabi, etc.
[Application of amisulbrom to crop cultivation soil]
The forms of application of amisulbrom to crop-cultivated soil include soluble concentrate, emulsion (emulsifiable concentrate), wettable powder, water-soluble solvent, and water dispersible granule. ), Water soluble granule, suspension concentrate, concentrated emulsion, suspoemulsion, microemulsion, dustable powder, micro granule), granule, gel (gel) and the like, or those prepared by diluting this agrochemical formulation with water. When diluting, it is usually desirable to dilute 1 to 20000 times with water.

  In the above agricultural chemical preparation, the above compound (amisulbromine) is usually mixed with a suitable solid carrier or liquid carrier, and if desired, a surfactant, penetrant, spreading agent, thickener, antifreeze agent, binder, It can be obtained by adding various additives usually used in agricultural chemical formulations such as anti-caking agents, disintegrating agents, antifoaming agents, preservatives, and decomposition inhibitors.

Examples of solid carriers include quartz, kaolinite, pyrophyllite, sericite, talc, bentonite, acid clay, attapulgite, zeolite, and diatomaceous earth, and other inorganic minerals such as calcium carbonate, ammonium sulfate, sodium sulfate, and potassium chloride. Examples include salts, synthetic silicas and synthetic silicates, natural polymers such as wheat flour, starch, crystalline cellulose, carboxymethylcellulose, and gelatin, sugars such as glucose, mantose, lactose, and sucrose, and urea. Liquid carriers include, for example, ethylene glycol , Alcohols such as propylene glycol and isopropanol, aromatic hydrocarbons such as xylene, alkylbenzene and alkylnaphthalene, ethers such as butyl cellosolve, cyclohexanone, etc. Ketones, esters such as γ-butyrolactone, acid amides such as N-methylpyrrolidone and N-octylpyrrolidone, vegetable oils such as soybean oil, rapeseed oil, cottonseed oil and castor oil, and water.

  These solid and liquid carriers may be used alone or in combination of two or more.

Examples of the surfactant include the following (A), (B), (C), (D) and (E). Moreover, surfactant may be used independently or may use 2 or more types together.
(A) Nonionic surfactant:
(A-1) Polyethylene glycol type surfactant:
For example, polyoxyethylene alkyl (C _12-18 ) ether, ethylene oxide adduct of alkyl naphthol, polyoxyethylene (mono or di) alkyl (C _8-12 ) phenyl ether, polyoxyethylene (mono or di) alkyl ( _C8-12 ) Formalin condensate of phenyl ether, polyoxyethylene (mono, di or tri) phenyl phenyl ether, polyoxyethylene (mono, di or tri) benzyl phenyl ether, polyoxypropylene (mono, di or tri) Polymers of benzyl phenyl ether, polyoxyethylene (mono, di or tri) styryl phenyl ether, polyoxypropylene (mono, di or tri) styryl phenyl ether, polyoxyethylene (mono, di or tri) styryl phenyl ether , Polyoxyethylene polyoxypropylene block polymers, alkyl (C _{12 to 18)} polyoxyethylene polyoxypropylene block polymer ethers, alkyl (C _{8 to 12)} polyoxyethylene polyoxypropylene block polymer ether, polyoxyethylene bisphenyl Ether, polyoxyethylene resin acid ester, polyoxyethylene fatty acid (C _12-18 ) monoester, polyoxyethylene fatty acid (C _12-18 ) diester, polyoxyethylene sorbitan fatty acid (C _12-18 ) ester, glycerol fatty acid ester ethylene oxide adducts, castor oil ethylene oxide adduct, hydrogenated castor oil ethylene oxide adduct, alkyl (C _{12 to 18)} amine ethylene oxide adduct And fatty acid _{(C 12 to 18)} amide ethylene oxide adducts.
(A-2) Polyhydric alcohol type surfactant:
For example, glycerol fatty acid ester, polyglycerin fatty acid ester, pentaerythritol fatty acid ester, sorbitol fatty acid (C _12-18 ) ester, sorbitan fatty acid (C _12-18 ) ester, sucrose fatty acid ester, polyhydric alcohol alkyl ether and fatty acid alkanolamide Etc.
(A-3) Acetylene-based surfactant:
Examples thereof include acetylene glycol, acetylene alcohol, ethylene oxide adduct of acetylene glycol, ethylene oxide adduct of acetylene alcohol, and the like.
(A-4) Other surfactant:
Examples thereof include alkyl glycosides.
(B) Anionic surfactant:
(B-1) Carboxylic acid type surfactants: for example, polyacrylic acid, polymethacrylic acid, polymaleic acid, copolymers of maleic acid and olefins (such as isobutylene and diisobutylene), acrylic acid and itaconic acid Copolymer, methacrylic acid and itaconic acid copolymer, maleic acid and styrene copolymer, acrylic acid and methacrylic acid copolymer, acrylic acid and acrylic acid methyl ester copolymer, acrylic acid And vinyl acetate copolymer, acrylic acid and maleic acid copolymer, N-methyl-fatty acid (C _12-18 ) sarcosinate, carboxylic acids such as resin acid and fatty acid (C _12-18 ), and carboxylic acids thereof Examples include acid salts.
(B-2) Sulfate ester type surfactant:
For example, alkyl (C _12-18 ) sulfate, polyoxyethylene alkyl (C _12-18 ) ether sulfate, polyoxyethylene (mono or di) alkyl (C _8-12 ) phenyl ether sulfate, polyoxyethylene ( Mono- or di) alkyl sulfates of alkyl (C _8-12 ) phenyl ether, polyoxyethylene (mono, di or tri) phenyl phenyl ether sulfate, polyoxyethylene (mono, di or tri) benzyl phenyl ether sulfate , Polyoxyethylene (mono, di or tri) styryl phenyl ether sulfate, polyoxyethylene (mono, di or tri) styryl phenyl ether polymer sulfate, polyoxyethylene polyoxypropylene block polymer Sulfuric esters, sulfated oil, fatty acid ester sulfuric, sulfuric acid ester such olefination sulfated fatty acids and sulfated, and salts thereof sulfate.
(B-3) Sulfonic acid type surfactant:
For example, paraffin (C _12-22 ) sulfonic acid, alkyl (C _8-12 ) benzenesulfonic acid, formalin condensate of alkyl (C _8-12 ) benzenesulfonic acid, formalin condensate of cresol sulfonic acid, α-olefin ( _C14-16 ) sulfonic acid, dialkyl ( _C8-12 ) sulfosuccinic acid, lignin sulfonic acid, polyoxyethylene (mono or di) alkyl ( _C8-12 ) phenyl ether sulfonic acid, polyoxyethylene alkyl ( _{C12- 18} ) Ether sulfosuccinic acid half ester, naphthalene sulfonic acid (mono or di) alkyl (C _1-6 ) naphthalene sulfonic acid, formalin condensate of naphthalene sulfonic acid, (mono or di) alkyl (C _1-6 ) naphthalene sulfonic acid Formalin condensate, creosote Formalin condensates of sulfonate, alkyl (C _{8 to 12)} ether disulfonic acid, Igepon T (trade name), sulfonic acids such as a copolymer of polystyrene sulfonic acid and styrene sulfonic acid and methacrylic acid, and their acid Salt.
(B-4) Phosphate ester type surfactant:
For example, alkyl ( _C8-12 ) phosphate ester, polyoxyethylene alkyl ( _C12-18 ) ether phosphate ester, polyoxyethylene (mono or di) alkyl ( _C8-12 ) phenyl ether phosphate ester, polyoxyethylene ( Mono, di or tri) alkyl (C _8-12 ) phenyl ether polymer phosphoric acid ester, polyoxyethylene (mono, di or tri) phenyl phenyl ether phosphoric acid ester, polyoxyethylene (mono, di or tri) benzyl phenyl ether Phosphate ester, polyoxyethylene (mono, di or tri) styryl phenyl ether phosphate ester, polyoxyethylene (mono, di or tri) styryl phenyl ether polymer phosphate ester, polyoxyethylene polyoxypropylene block poly Over phosphoric esters of phosphatidylcholine, phosphoric acid esters, such as phosphatidylethanolamine imine and condensation phosphoric acid (e.g., tripolyphosphate, etc.), and salts of these phosphate esters.

Examples of the salt in the above (B-1) to (B-4) include alkali metals (lithium, sodium, potassium, etc.), alkaline earth metals (calcium, magnesium, etc.), ammonium and various amines (for example, alkylamine, cyclohexane). Alkylamine and alkanolamine).
(C) Cationic surfactant:
Examples thereof include alkylamine salts and alkyl quaternary ammonium salts.
(D) Amphoteric surfactant:
Examples thereof include betaine type surfactants and amino acid type surfactants.
(E) Other surfactants:
For example, silicone surfactants and fluorine surfactants can be used.

Table 1 below shows formulation examples of the agrochemical formulations applied to the soil in the method of the present invention. In the following formulation examples, “part” means part by mass.
[Table 1]

  In the present invention, it is usually preferable to apply amisulbrom to crop-cultivating soil, and it is preferably applied to the field before seeding the decoy crop. In this case, after the chemical spraying treatment, the chemical and soil are mixed. Is preferred. The treatment time of the drug is usually within one month before sowing, preferably within one week, and more preferably within three days.

  Also, not only the period before sowing, but also at the time of sowing and after sowing, but before the period of covering soil (spray or spray the drug on the seed (planting hole) or seeding groove seeded on the soil, and then cover the soil) In addition, it may be applied to a period after sowing and after covering (drug irrigation or spraying treatment on the soil surface of covering). The treatment time of the drug is usually within one week after sowing, preferably within three days, and more preferably within one day.

  The amount of the agrochemical active compound (Amisulbrom) is preferably 0.1 to 5000 parts by mass, more preferably 0.1 to 1000 parts by mass per 10 ares, or seed 1 of a decoy crop. The amount is preferably 0.000001 to 10 parts by mass per grain.

  The present invention is greatly characterized in that amisulbrom and a decoy crop are used in combination.

  The decoy crop promotes germination of dormant spores in the soil and induces root hair infections, but subsequent disease symptoms do not progress. In addition, the zoosporangium zoospores can survive only in living plants, and the root-knot fungus infected with decoy crops are killed at the same time that these plants die. In this way, the decoy crop inhibits the formation of new dormant spores by suppressing the formation of the root nodules by growing in the roots of the clubroot, resulting in the germination of the dormant spore density of the clubroot. The amount can be decreased by the amount of the change.

  On the other hand, the drug used in the present invention: amisulbrom is known as a compound that inhibits the Qi site of the mitochondrial electron transport system complex III, and these compounds are derived from zoosporangia especially when a clubroot infects a crop. It does not act on the release of zoospores, and is a compound excellent in inhibiting host infection by inhibiting the migration of zoospores and the germination of spore spores.

  For this reason, the combined use of decoy crops and amisulbrom sterilizes the zoospores (primary zoospores and secondary zoospores) produced by germination of clubroot induced by decoy crops, and the growth of decoy crops In addition, the decoy crops induce germination of the clubroot, and these germicides kill the germinated zoospores to achieve a dramatic reduction effect of the clubroot in the soil. .

The usefulness of the present invention will be specifically described in the following test examples. However, the present invention is not limited to these.
[Production of contaminated soil]
Add the dormant spore suspension prepared by adding water to the root-knot diseased roots to healthy soil so that the number of dormant spores per 1 g of soil (hereinafter abbreviated as fungal density) is 550,000, Contaminated soil was prepared.
[Cultivation of prototype (decoy crop)]
About 200 mL of the contaminated soil prepared above is put in a plastic bag, and 65 mg of amisulbrom powder (trade name: Oracle powder manufactured by Nissan Chemical Industries) containing 0.5% of an agrochemical active ingredient as a reagent agent (30 kg of drug) / Soil 10 are equivalent) was added and stirred about 30 times and filled into a 200 mL capacity styrene cup. Moreover, about 200 mL of contaminated soil was filled as it was into a 200 mL capacity styrene cup without mixing reagent reagents. In this way, two kinds of soil pots were prepared.

  The seeds of the decoy crop were sown in these two types of soil pots and grown for 4 weeks, and then the soil was recovered from each pot.

As a decoy crop, 6 seeds are used when rye (dash) is used, 4 seeds are used when sorghum (rolling) is used, and 6 seeds are used when oats (hay oats, new oats) are used. Grain seeds were sown in each of the pots.
[Preparation of observation sample for measurement of dormant spores of clubroot]
The collected soil was air-dried and then sieved with a 2 mm sieve as a test soil.

  To 1 g of the test soil, 20 mL of a 0.2 wt% sodium hexametaphosphate aqueous solution was added and stirred for 1 minute using a shaker. After adding 1 mol / L NaOH aqueous solution to this soil suspension and adjusting pH to 10, it stirred vigorously for 1 minute using the shaker. A 1 mol / L NaOH aqueous solution was again added to the soil suspension to adjust the pH to 10, followed by sonication for 10 minutes. The soil suspension was sieved with a 32 μm sieve, and the soil on the sieve was washed with water so that the passing liquid was 50 mL. After the obtained passing liquid was centrifuged, 45 mL of the supernatant was removed, and the remaining 5 mL was used as an observation sample.

  In addition to the above observation sample, the observation sample was prepared by the above method for soil that was contaminated using the above-mentioned contaminated soil, was not mixed with a reagent, and was not grown on a decoy crop for 4 weeks. A control example was used.

Two observation samples were prepared from each soil.
[Method for measuring dormant spores of root-knot fungus]
50 μL of each of the observation samples prepared by the above procedure is weighed and 50 μL of calcoflor white staining solution (manufactured by Sigma-Aldrich, 1 g / L calcoflor white M2R, 0.5 g / L Evans blue) is used as a staining solution. Was added to each and mixed. Drop 20 μL on a slide glass with 1 mm × 1 mm grid lines (manufactured by Matsunami), cover it with a cover glass of 24 × 36 mm, and exist in a 1 mm × 1 mm square grid with a fluorescence microscope (filter WU). The number of dormant spores of the clubroot fungus was counted for a total of 10 compartments. The bacterial density of the clubroot was calculated from the number of dormant spores in these 10 sections and the following formula. The average value of two samples of each soil was defined as the bacterial density.

(Calculation formula 1) Bumper fungus density
= Number of dormant spores in 10 sections × 0.5 × 3.24 × 10 ⁴
Further, the reduction rate (%) of the clubroot density of the clubroot was determined by the following formula using the density of the clubroot in the control example and the density of the clubroot in the example calculated by the above calculation formula 1. Calculated.

(Calculation formula 2) Reduction rate of clubroot fungus
= [(Bacterial density of control example-Bacterial density of calculation formula 1) / Bacterial density of control example] x 100
The results obtained are shown in Table 2.
[Table 2]

  As shown in Table 2, in Example 1 in which amisulbrom powder was used in combination with cultivation of rye as a decoy crop and in Example 2 in which sorghum was used as a decoy crop, 63.9% and 41. As a result, it was obtained that the present invention was reduced by 4%, and the present invention was excellent in the effect of reducing the bacterial density of the clubroot, and was useful as a method for controlling the clubroot.

Claims (2)

  3-[(3-Bromo-6-fluoro-2-methyl-1H-indol-1-yl) sulfonyl] -N before, after or after sowing a decoy crop selected from the group consisting of rye and sorghum , N-dimethyl-1H-1,2,4-triazole-1-sulfonamide is applied to the crop-cultivated soil, thereby reducing the density of the clubroot fungus in the crop-cultivated soil.   In a method for controlling root-knot disease in which a decoy crop selected from the group consisting of rye and sorghum is cultivated as a preceding crop of cruciferous crops, 3-[(3-bromo-6 -Fluoro-2-methyl-1H-indol-1-yl) sulfonyl] -N, N-dimethyl-1H-1,2,4-triazole-1-sulfonamide by applying to crop-cultivating soil How to control clubroot.