JP2003040715A - Control method for disease damage of field crop by spraying aqueous solution of hypochlorous acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an effective control method for disease damage of field crops, with reduced harmful effects to human health and reduced economic cost. SOLUTION: This control method for the disease damage of field crops sprays an aqueous solution that includes hypochlorous acid and has a specific effective chlorine concentration and a specific pH (2.0 to 8.0). This invention provides an effective control method for disease damage of field crops, with reduced harmful effects to human health and reduced economic cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling diseases of agricultural products by spraying an aqueous solution of hypochlorous acid on agricultural products and sterilizing them.

[0002]

2. Description of the Related Art Conventionally, a large amount of pesticides have been used for controlling diseases of agricultural products such as cucumber spot bacterial disease, cucumber powdery mildew, cucumber downy mildew, Chinese cabbage soft rot and the like. Examples of these pesticides include copper agents, oxytetracycline agents, kasugamycin agents, propenazole agents, and polycarbamate agents for cucumber spot bacterial disease, and copper agents, streptomycin agents, and oxytetracycline agents for Chinese cabbage soft rot. Agents, etc. are used (Agricultural chemical application list, 1991 version, supervised by the Ministry of Agriculture, Forestry and Fisheries, Agricultural Chemicals Inspection Office, published by Japan Plant Protection Association).

Some pesticides of this kind are harmful to the human body,
There are concerns about the health effects of vegetables and other consumers and producers. Particularly in greenhouse cultivation, a large amount of pesticide is used in a closed space, and thus there is a great fear of impairing the health of workers. For this reason, it is known to use an acidic aqueous solution for the purpose of reducing the amount of pesticide sprayed.
No. 194109), a method for controlling diseases of agricultural crops, which is not sufficient in controlling the disease bacteria, is more effective and has less adverse effects on health, has been desired.

[0004]

[PROBLEMS TO BE SOLVED BY THE INVENTION] It is an object of the present invention to provide a method for controlling diseases of agricultural crops, which has less adverse effects on human health, can remove other kinds of diseases, and is inexpensive.

[0005]

SUMMARY OF THE INVENTION The present invention is a method for controlling crop diseases, in which an aqueous solution containing hypochlorous acid water is sprayed on crops to kill pathogenic fungi on the leaves. The effective chlorine concentration of the hypochlorous acid aqueous solution is 1 to 1000 ppm, and the pH is adjusted to 2.0 to 8.0. Effective chlorine concentration is 2
0-800 ppm is more preferable, 50-500 ppm
Is most preferred. The pH of the hypochlorous acid aqueous solution is more preferably 4.0 to 7.2, and most preferably 5.0 to 7.2. Hypochlorous acid may be supplied as a hypochlorite or a hypochlorous acid aqueous solution, or may be generated by electrolysis of a chloride ion-containing aqueous solution. Sodium hypochlorite is preferred as the hypochlorite.

The pH of the aqueous solution of hypochlorous acid is adjusted by adding an inorganic acid such as hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, or an organic acid such as acetic acid, formic acid, citric acid and tartaric acid. Is preferred. It is also possible to add an alkali such as sodium hydroxide. Acids include hydrochloric acid, phosphoric acid,
Acetic acid, citric acid and tartaric acid are more preferable, hydrochloric acid, phosphoric acid and acetic acid are further preferable, and hydrochloric acid is particularly preferable. When adjusting these pHs, it is preferable to dilute both the acid and the alkali with water. In particular, when adjusting the pH to be between 5.0 and 7.0, it is preferable to use a sufficiently diluted acid.

An aqueous solution of acid and alkali, an aqueous solution of hypochlorous acid (preferably an aqueous solution of sodium hypochlorite) and water are mixed to prepare an aqueous solution of hypochlorous acid having a predetermined concentration and pH. This preparation may be carried out in advance or just before use. However, since hypochlorous acid in the aqueous solution of hypochlorous acid is unstable with respect to heat, light and an oxidizing agent, it is preferable to put it in a closed container, shield it from light and store it at a low temperature. Further, in order to accurately adjust the concentration of each composition to a predetermined value, it is preferable to use a mixing device capable of adjusting the addition amount with high precision. With this device, the hypochlorous acid aqueous solution can be prepared immediately before use. In that case, it is also possible to mix an aqueous solution of acid or alkali with an aqueous solution of hypochlorous acid (preferably an aqueous solution of sodium hypochlorite) and water, or to preliminarily dilute to a predetermined concentration with water. It is also preferable to mix two kinds of solutions of an aqueous solution of acid or alkali and an aqueous solution of hypochlorous acid (preferably an aqueous solution of sodium hypochlorite). These solutions are sealed containers, preferably in the form of cartridges.

It is preferable to prepare the above-mentioned hypochlorous acid aqueous solution by electrolyzing water containing chlorine ions. At that time, salts such as sodium chloride and / or potassium chloride can be added. Further, the electrolysis can be carried out in a diaphragm electrolyzer or a non-diaphragm electrolyzer. In the case of a diaphragm electrolyzer, patent type application number 63-30
The technology described in 0998 is preferably used. Further, in the case of the diaphragmless electrolytic cell, the technique described in Patent Registration 2619756 is preferably used. For these electrolysis methods, the methods described in "Basics and Utilization Technologies of Electrolyzed Water" (Masaki Matsuo, Gihodo Publishing Co., Ltd., issued January 25, 2000) can be preferably used.

It is also preferable to use a pH buffer solution to adjust the pH of the hypochlorous acid aqueous solution. pH
When a buffer solution is used, the bactericidal effect can be continued for a long period of time. A pH buffer solution is the change in pH (hydrogen ion concentration) when an acid or base is added to the solution.
This solution is smaller than the change in pH when an acid or base is added to pure water. The pH buffer solution can be obtained by mixing an acid, a base, or a salt thereof. Water-soluble acids, bases,
Any salt is preferably used. Of course, it is necessary to consider safety depending on the application.

Any antiseptic solution of the present invention can be preferably used as long as it has the effect of reducing the above-mentioned fluctuation of pH. As examples thereof, any of those described on pages II-336 to II-339 of the 4th edition of the revised edition of the Chemical Handbook (September 1993, Maruzen Publishing Co., Ltd.) can be preferably used. Examples of preferable pH buffers will be given below, but the present invention is not limited thereto.

The pH buffer solution of the present invention is potassium chloride,
Alkali halides such as sodium chloride, amino acids such as glycine, alanine, valine, leucine, isoleucine and cystine, inorganic acids such as hydrochloric acid, boric acid and phosphoric acid, lactic acid,
Malic acid, tartaric acid, citric acid, formic acid, butyric acid, acetic acid, succinic acid, diethylparbituric acid, potassium hydrogen phthalate, potassium hydrogen phthalate, sodium hydroxide, potassium hydroxide, potassium dihydrogen phosphate, diphosphoric acid. Sodium hydrogen, dipotassium hydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, tripotassium phosphate, sodium citrate, potassium citrate, sodium dihydrogen citrate, potassium dihydrogen citrate, sodium tetraborate,
Potassium tetraborate, sodium tartrate, potassium tartrate, sodium lactate, potassium lactate, sodium acetate,
Potassium acetate, sodium dimethylparbiturate, potassium dimethylparbiturate, (2,4,6-trimethylpyridine), tris (hydroxymethyl) aminomethane, (2-amino-2-methyl-1,3-propane) Diol), tris (hydroxymethyl) aminomethane,
It is preferably an aqueous solution containing at least two kinds of compounds in (3- [4- (2-hydroxyethyl) -1-propanesulfonic acid]).

The pH buffer solution of the present invention is (potassium hydrogen phthalate / hydrochloric acid), (potassium chloride / hydrochloric acid), (potassium hydrogen phthalate / sodium hydroxide), (potassium dihydrogen phosphate / sodium hydroxide). , (Glycine / sodium chloride / hydrochloric acid), (glycine / sodium chloride / sodium hydroxide), (sodium citrate / hydrochloric acid),
(Sodium citrate / sodium hydroxide), (sodium tetraborate / hydrochloric acid), (potassium dihydrogen phosphate / disodium hydrogen phosphate), (potassium citrate / citric acid), (potassium dihydrogen citrate / hydrochloric acid) ), (Potassium dihydrogen citrate / sodium hydroxide), (succinic acid / sodium tetraborate), (potassium dihydrogen citrate / sodium tetraborate), (potassium dihydrogen phosphate / sodium tetraborate), (Tartaric acid / sodium tartrate), (lactic acid / sodium lactate), (acetic acid / sodium acetate), (sodium dimethylparbiturate / sodium acetate / sodium chloride / hydrochloric acid), (sodium dimethylparbiturate / hydrochloric acid), ( Disodium hydrogen phosphate / citric acid), (citric acid / potassium dihydrogen phosphate / boric acid / diethyl parbituric acid) Trisodium phosphate), (boric acid / citric acid, trisodium phosphate),

(2,4,6-trimethylpyridine / hydrochloric acid), (tris (hydroxymethyl) aminomethane / hydrochloric acid), (2-amino-2-methyl-1,3-propanediol / hydrochloric acid), (citric acid / Potassium dihydrogen phosphate /
Sodium tetraborate / tris (hydroxymethyl) aminomethane / potassium chloride / hydrochloric acid), (citric acid / potassium dihydrogen phosphate / sodium tetraborate / tris (hydroxymethyl) aminomethane / potassium chloride / sodium hydroxide), (3- [4- (2-hydroxyethyl) -1
-Propanesulfonic acid] / sodium hydroxide / sodium chloride) (the combination in () indicates the combination)
It is preferable that the aqueous solution contains at least one of the above.

The pH buffer solution of the present invention comprises (potassium hydrogen phthalate / sodium hydroxide), (potassium dihydrogen phosphate / sodium hydroxide), (sodium citrate / sodium citrate).
Sodium hydroxide), (potassium dihydrogen phosphate / disodium hydrogen phosphate), (potassium dihydrogen citrate / sodium hydroxide), (succinic acid / sodium tetraborate),
(Potassium dihydrogen citrate / sodium tetraborate),
(Potassium dihydrogen phosphate / sodium tetraborate), (lactic acid / sodium lactate), (acetic acid / sodium acetate),
(Disodium hydrogen phosphate / citric acid), (Boric acid / citric acid, trisodium phosphate), (Citric acid / potassium dihydrogen phosphate / sodium tetraborate / Tris (hydroxymethyl) aminomethane / potassium chloride / Hydrochloric acid), (citric acid / potassium dihydrogen phosphate / sodium tetraborate /
It is more preferable that the aqueous solution contains at least one kind of a combination of tris (hydroxymethyl) aminomethane / potassium chloride / sodium hydroxide (the inside of the parentheses indicates the combination).

The concentration of each component of these pH buffers is preferably any concentration as long as the required pH can be obtained. When used for a short period after opening, it is preferable that the concentration of each component of the pH buffer solution is low, and for the hand sanitizing solution used for a long period after opening, the concentration of each component is preferably high. The method of mixing the components can be used in any order.
The hypochlorous acid may be mixed either after completion of the pH buffer solution or before completion. The mixing of hypochlorous acid and pH buffer may be done at any time prior to use.

To the hypochlorous acid aqueous solution of the present invention, it is desirable to add a water-soluble dye, a UV absorber, a surfactant, and a water-soluble polymer compound for the purpose of preventing the decomposition of hypochlorous acid. . Also, the addition of a water-soluble polymer compound is preferable from the viewpoint of promoting the adhesion of the aqueous solution to the leaves of agricultural crops. As the water-soluble polymer compound, animal gelatin, vegetable starch, starch derivative, fibrin derivative, chitosan derivative,
Cellulose derivative, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, polyethylene oxide, partially saponified polyvinyl acetate, poly (styrene-ethylene oxide), poly (ethylene-
Vinyl alcohol)-(ethylene oxide) and the like are preferable.

It is also preferred to add thickeners. As the thickener, for example, silicate, montmorillonite, inorganic thickeners such as colloidal alumina and carboxymethyl cellulose, methyl cellulose, cellulose derivatives such as hydroxyethyl cellulose, casein, sodium caseinate, proteins such as ammonium caseinate,
Organic thickeners such as sodium alginate, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, polyether, and maleic anhydride copolymer are preferable.

Further, a dye may be contained in the hypochlorous acid aqueous solution in order to increase the stability. Azo, anthraquinone, indigo, phthalocyanine, carbonyl, quinonimine, methine, quinoline, and nitro dyes are all preferable. Color Index
The edible and natural dyes described in 1. are particularly preferable. Similarly, it is preferable to add an ultraviolet absorber for the purpose of increasing the stability of the disinfecting solution of the present invention. Any ultraviolet absorber may be used, but those having an absorption at 250 to 400 nm are preferable, and those having an absorption at 280 to 350 nm are more preferable. Specific examples thereof include esters of p-aminobenzoic acid and benzophenones. Further, it is preferable to add a polymerization inhibitor to the disinfecting solution of the present invention. Phenols, quinones, hydroquinones, hydrazines, benzene derivatives and the like are preferable as the polymerization inhibitor.

A spreading agent is preferably used in the hypochlorous acid aqueous solution of the present invention so that the aqueous solution adheres to and spreads on the leaves of agricultural products. As the spreading agent, any of anionic, cationic, nonionic and betaine surfactants and water-soluble polymers are preferably used. The concentration of spreading agent is 2
0 to 2000 ppm is preferable. Polyoxyethylene sorbitan ester, polyoxyethylene alkyl (or aryl) ether, polyoxyethylene fatty acid ester, polyglycerin fatty acid ester (for example, JP-A No.
000-327507 compound of general formula (1)), and the oxyethylene group-containing surfactant of general formula (1) described in JP-A 2000-1404. Nonionic surfactants such as nonionic surfactants obtained by adding 5 to 8 moles of ethylene oxide to a higher alcohol having 13 carbon atoms in average number of moles (JP-A-49-30539, JP-A-6-329503).
And linear alkylbenzene sulfonate, dialkyl succinate, lignin sulfonate, polynaphthyl sulfonate, sulfonate of lower alkyl ester of fatty acid (JP-A-2-167202), alkyl sulfosuccinate surfactant, etc. Anionic surfactant. Polyacrylic acid salts and chitosan having a deacetylation degree of 30% or more are preferably used.

It is preferable that the aqueous solution of hypochlorous acid is sprayed with a droplet size of 1 to 50 μm. The droplet size is more preferably 1 to 20 μm, particularly preferably 1 to 10 μm.

[0021]

Example 1 Hydrochloric acid diluted with water was added to an aqueous solution of sodium hypochlorite to adjust the pH to 5.7 to prepare an aqueous solution of hypochlorous acid of the present invention having an effective chlorine concentration of 100 ppm. This hypochlorous acid aqueous solution was sprinkled on cucumber seedlings grown in greenhouse. Rifampicin / nalidixic acid-resistant bacterium of a cucumber spot bacterial disease bacterium of the sprayed cucumber leaf was tested as an indicator bacterium. That is, the above-mentioned drug-resistant bacteria were spray-inoculated onto leaves sprayed with an aqueous solution of hypochlorous acid, the leaves were washed, and the viable count of drug-resistant bacteria in the washing solution was counted using a selective medium.
In the leaves sprayed with the aqueous solution of hypochlorous acid, no pathogenic bacteria survived immediately after spraying, and 8
In the day test, no survival of pathogenic bacteria was found in the leaves sprayed with the aqueous solution. It was revealed that the pathogenic bacteria were rapidly killed by the application of the aqueous solution of sodium hypochlorite of the present invention, and this bactericidal effect was maintained for at least 8 days after the application.

[0022]

Example 2 Example 1 was repeated except that the pH was changed to 4.5, 5.5, 6.0 and 6.5, and similar results were obtained.
However, if the mixing amount of hydrochloric acid is mistaken and the pH becomes too low, chlorine gas is generated. Therefore, pH 5.5 or higher is safer in this range.

[Example 3] Effective chlorine concentration of 50, 200, 300 pp
Example 1 and 2 were repeated except that m was set, and similar results were obtained.

Example 4 Spreading agent Alkyl sulfosuccinate based surface active agent is used at 100 ppm and effective chlorine concentration is 30, 50 pp.
Example 1 and 2 were repeated except that m was set, and the same result was obtained.

Claims (17)

[Claims] 1. A method for controlling diseases of agricultural crops, which comprises spraying an aqueous solution containing hypochlorous acid on agricultural crops. 2. The effective chlorine concentration of the hypochlorous acid aqueous solution is 1
The method for controlling agricultural plant diseases according to claim 1, wherein the control method is in the range of 1000 ppm and the pH is in the range of 2.0 to 8.0. 3. The effective chlorine concentration is 20 to 800 ppm.
The method for controlling a crop disease according to claim 2, wherein 4. The method for controlling agricultural crop diseases according to claim 2, wherein the pH is 4.0 to 7.2. 5. The pH of the aqueous solution containing hypochlorous acid is adjusted by adding at least one of inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid and nitric acid, and organic acids such as acetic acid, formic acid, citric acid and tartaric acid. The method for controlling a crop disease according to any one of claims 2 to 4, wherein the method is controlled. 6. The method for controlling a crop disease according to claim 5, wherein the pH of the hypochlorous acid-containing aqueous solution is adjusted by adding hydrochloric acid or acetic acid. 7. The method for controlling a crop disease according to claim 6, wherein the pH of the hypochlorous acid-containing aqueous solution is adjusted by adding hydrochloric acid. 8. The method for controlling a crop disease according to claim 1, wherein the aqueous solution of hypochlorous acid is prepared by electrolyzing water containing chlorine ions. 9. The method for controlling a crop disease according to claim 8, wherein the water added with sodium chloride and / or potassium chloride is electrolyzed. 10. The method for controlling agricultural plant diseases according to claim 8, wherein water is electrolyzed by a diaphragmless method. 11. The method for controlling a crop disease according to claim 8, wherein water is electrolyzed by a diaphragm method. 12. The pH of the aqueous solution containing hypochlorous acid is adjusted to pH.
The method for controlling agricultural plant diseases according to any one of claims 1 to 7, wherein the method is controlled by a buffering agent. 13. The pH buffer solution comprises an alkali halide such as potassium chloride and sodium chloride, an amino acid such as glycine, alanine, valine, leucine, isoleucine and cystine, an inorganic acid such as hydrochloric acid, boric acid and phosphoric acid, and lactic acid. , Malic acid, tartaric acid, citric acid, formic acid, butyric acid, acetic acid, succinic acid, diethylparbituric acid, potassium hydrogen phthalate,
Potassium hydrogen phthalate, sodium hydroxide, potassium hydroxide, potassium dihydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, disodium hydrogen phosphate,
Trisodium phosphate, tripotassium phosphate, sodium citrate, potassium citrate, sodium dihydrogen citrate, potassium dihydrogen citrate, sodium tetraborate, potassium tetraborate, sodium tartrate, potassium tartrate,
Sodium lactate, potassium lactate, sodium acetate, potassium acetate, sodium dimethylparbiturate, potassium dimethylparbiturate, (2,4,6-trimethylpyridine), tris (hydroxymethyl) aminomethane, (2-amino- 2-methyl-1,3-propanediol), tris (hydroxymethyl) aminomethane,
(3) [4- [2- (2-hydroxyethyl) -1-propanesulfonic acid]], which is an aqueous solution containing at least two or more types of compounds, and the control of agricultural crop diseases according to claim 12. Method. 14. The method for controlling diseases of agricultural crops according to claim 1, wherein the aqueous solution of hypochlorous acid contains a spreading agent. 15. The method for controlling a crop disease according to claim 14, wherein the spreading agent is an anionic surfactant. 16. The method for controlling diseases of agricultural crops according to claim 14, wherein the spreading agent is a nonionic surfactant. 17. A method for controlling a crop disease, which comprises spraying the hypochlorous acid aqueous solution according to claim 1 with a droplet size of 1 to 50 μm.