JPH05194109A - Method for controlling disease of crop by spraying acidic aqueous solution and method for reducing generation of chemical damage accompanied by spraying acidic aqueous solution - Google Patents

Abstract

PURPOSE:To provide a method for controlling the diseases of crops with a highly safe acidic aqueous solution exhibiting the same or higher controlling effect against the diseases of crops such as cucumbers or Chinese cabbages apart from Sands, and to provide a method for reducing the generation of chemical damages accompanied by the spraying of the acidic aqueous solution. CONSTITUTION:A method for controlling the diseases of crops by the spraying of an acidic aqueous solution comprises spraying an acidic aqueous solution exhibiting an antibacterial action against the pathogenic bacteria of crops such as cucumbers or Chinese cabbages on the crops to kill the pathogenic bacteria on the leaves of the crops and lover the pH of the surfaces of the leaves, thereby producing an environment not suitable for the growth of the pathogenic bacteria. A method for reducing the generation of the chemical damages accompanied by the spraying of the acidic aqueous solution comprises using the acidic aqueous solution mixed with a suitable amount of an alkyl-sulfosuccinic acid salt sticking agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention sprays an acidic aqueous solution on a crop to kill pathogenic fungi on the leaf surface and p.
The present invention relates to a method for controlling crop diseases by reducing H to create an environment unsuitable for the growth of pathogenic bacteria, and a method for reducing the occurrence of phytotoxicity associated with spraying an acidic aqueous solution.

[0002]

2. Description of the Related Art Heretofore, in this type, the following has been done. Pseudomonas syringae pv. Lac
Bacterial blight of cucumber caused by hrymans) and Erwinia carotovora subspices carotovora (Er
Chinese cabbage soft rot caused by winia carotovora subsp. carotovora) is currently controlled by pesticide application, but no other practical control method is found.

Pesticides applicable to cucumber spot bacterial disease are copper agents, oxytetracycline agents, kasugamycin agents, propenazole agents, and polycarbamate agents, and pesticides applied to Chinese cabbage soft rot disease are copper agents, streptomycin. There are few types of applicable pesticides, which are classified as either an agent or an oxytetracycline agent, based on the active ingredients (Agricultural Chemical Application List, 1991 version, supervised by the Ministry of Agriculture, Forestry and Fisheries, Agricultural Chemicals Inspection Agency, published by Japan Plant Protection Association).

The cucumber powdery mildew and cucumber downy mildew, which are the common diseases of cucumber, are also controlled by spraying a pesticide of a different kind from the above-mentioned spot bacterial disease. Sands [Plant Dis. Reptr., 61, 823
-827 (1977)] lowers the density of Erwinia amylovora, a pear burn disease fungus, on the leaf surface by spraying citric acid and tartaric acid, and also Pseudomonas syringae Pasovar syringe (Pseudomona).
s syringae pv. syringae) has been shown to be able to reduce the number of lesions on cowpea leaves, but there has been no report of successful commercialization.

In addition to Sands, the present invention has a safety which is equivalent to or more than that of commercially available pesticides against cucumber spot bacterial disease, cucumber powdery mildew, cucumber downy mildew and Chinese cabbage soft rot. The present invention aims to provide a new method for controlling crop diseases using an acidic aqueous solution as a so-called “soft pesticide”.

[0006]

The problems described in the prior art have the following problems. Pseudo-syringe Pasovar-Lacrimans
Bacterial blight of cucumber caused by monas syringae pv. lachrymans) and Erwinia carotovora subsp. caro
Chinese cabbage soft rot caused by tovora) is difficult to control, and once it occurs, it spreads rapidly and causes great damage. These diseases are currently controlled by spraying pesticides, but no other practical control method is found.

[0007] Pesticides applicable to cucumber spot bacterial disease are copper agents, oxytetracycline agents, kasugamycin agents, propenazole agents, and polycarbamate agents, and pesticides applied to Chinese cabbage soft rot disease are copper agents, streptomycin. There are few types of applicable pesticides, which are classified as either an agent or an oxytetracycline agent, based on the active ingredients (Agricultural Chemical Application List, 1991 version, supervised by the Ministry of Agriculture, Forestry and Fisheries, Agricultural Chemicals Inspection Agency, published by Japan Plant Protection Association). Therefore, there is always concern about the emergence of resistant bacteria associated with the continuous use of similar pesticides,
In particular, it has been reported that resistant bacteria have appeared in copper agents and streptomycin agents, which have been frequently used for many years. For example, Bender, etc. [Phytology
Opathology), Vol. 74, 1325 (1985)] and Sundin et al. [Phytopatho (Phytopatho
logy), 79, 861-865 (1989)] is a Pseudomonas syringe (Pseudomonas sy) that is resistant to copper agents.
ringae), and Hayashi and Sakata [Nikkei Shouho, 46
Vol. 409 (1980)] and Matsuzaki et al.
7, 297-300 (1981)] are Erwinia carotovora subsp. Ca that show resistance to streptomycin agents.
rotovora).

[0008] Also, among the control agents for cucumber powdery mildew and cucumber downy mildew, it has been reported that the control effect is reduced due to the occurrence of drug-resistant bacteria. Thus, there are few types of applied pesticides as seen from the active ingredients for cucumber spot bacterial disease and Chinese cabbage soft rot, and further,
Due to the emergence of resistant bacteria to some pesticides, the development of new pesticides effective against these crop diseases is strongly demanded. In the development of pesticides today, so-called "soft pesticides" that emphasize fast-decomposition and safety without environmental pollution
It has been put to practical use with some diseases such as "soy lecithin", which is strongly demanded for development and applied to powdery mildew of cucumber.

According to the present invention, an acidic aqueous solution is sprayed on a crop,
It is intended to lower the leaf surface pH and control crop diseases, and the active ingredient of the acidic aqueous solution according to the present invention is a novel compound that has not been used in conventional pesticides. As will be described later, among the active ingredients of the acidic aqueous solution according to the present invention, there are some organic acids contained in the living body, and these are fast degrading and safe without bioconcentration. Further, all the active ingredients of the acidic aqueous solution according to the present invention other than the above also correspond to ordinary substances, have high safety, and should be classified into the category of so-called "soft pesticides". As described above, with conventional pesticides, the emergence of drug-resistant bacteria is always a concern, but in the low pH environment on the leaf surface produced by the present invention, the pathogenic bacteria are killed in a short time. It is considered that a mutant having pH environmental resistance is difficult to develop. The present application has been made in view of such problems of the conventional technology, and an object of the present application is to provide a device capable of solving the above problems.

[0010]

In order to achieve the above object, the present invention is as follows. The first invention sprays an acidic aqueous solution having a bactericidal action against the pathogenic bacteria of the crop to the crop to kill the pathogenic bacteria on the leaf surface and lower the pH of the leaf surface to create an environment unsuitable for growth of the pathogenic bacteria. It is a method for controlling a crop disease by spraying an acidic aqueous solution configured as described above.

In this case, the following can be done. First, when the disease is cucumber spot bacterial disease, as the acidic aqueous solution, fumaric acid, fumaric acid and salts thereof,
Any of aqueous solutions of malic acid, malic acid and its salts, phthalic acid, maleic acid, citric acid and its salts, and calcium sulfate and ferric sulfate can be used.
When the disease is cucumber powdery mildew, any one of fumaric acid, fumaric acid and salts thereof, malic acid, malic acid and salts thereof, and phthalic acid may be used as the acidic aqueous solution. it can.

Further, when the disease is cucumber downy mildew, any one of the aqueous solutions of fumaric acid, phthalic acid, malic acid, ferric sulfate, citric acid and its salts, and calcium sulfate is used as the acidic aqueous solution. Or can be used.
In addition, when the disease is Chinese cabbage soft rot, as the acidic aqueous solution, phosphoric acid, phosphoric acid and maleic acid, phosphoric acid and ferric chloride solution, malonic acid, malonic acid and its salts, malonic acid and ferric chloride are used. Any one of ferric chloride, malonic acid, ferric chloride solution, and ferric chloride aqueous solution can be used.

A second aspect of the present invention is a method for reducing the occurrence of phytotoxicity caused by spraying an acidic aqueous solution, which is constituted by adding an appropriate amount of an alkylsulfosuccinate-based spreading agent to the acidic aqueous solution of the first aspect.

[0014]

EXAMPLES Details of examples will be described. Generally, bacteria are p
It grows well around H7, but at pH 4-5 or lower,
Not only does it stop growing, but it also dies rapidly. Cucumber spot fungus and Chinese cabbage soft-rot fungus inhabit the leaf surface of cucumber and Chinese cabbage, respectively, and invade into tissues through natural openings and wounds to cause diseases. The cucumber powdery mildew fungus and the cucumber downy mildew infect the cucumber leaves after air-borne infection and infect the leaves.

The present invention sprays an acidic aqueous solution to p
By lowering H and creating a low pH environment on the leaf surface where pathogens cannot survive, it is intended to control cucumber spot bacterial disease, cucumber powdery mildew, cucumber downy mildew and Chinese cabbage soft rot. First, using a cucumber seedling that is easy to handle as a test material, it was tested whether or not the pH of the leaf surface was lowered by spraying an acidic aqueous solution. When one of the acidic aqueous solutions was sprayed on cucumber leaves, the pH of the cucumber leaf washing solution was significantly lowered compared to that of non-sprayed leaves. Thereafter, the pH of the washing solution gradually increased with the lapse of days from spraying to washing, but it was lower than that of non-sprayed leaves even on the 7th day after spraying. (Table 1). From the above,
It was suggested that spraying of acidic aqueous solution markedly lowered the leaf surface pH.

[0016]

[Table 1]

Secondly, in order to clarify the survival status of pathogenic bacteria in cucumber leaves sprayed with an acidic aqueous solution, a test was carried out using rifampicin / nalidixic acid-resistant bacteria of bacterial spots of cucumber spots as indicators. That is, after spraying and inoculating the above-mentioned drug-resistant bacteria onto leaves sprayed with an acidic aqueous solution, the leaves were washed, and the viable cell count of the drug-resistant bacteria in the washing solution was counted using a selective medium.

As shown in Table 2, in the leaves sprayed with the acidic aqueous solution, the pathogenic bacteria could not survive at all immediately after spraying, and even in the leaves sprayed with the acidic aqueous solution 7 days before, the survival of the pathogenic bacteria was inhibited. Was done. Therefore, it was revealed that not only the pathogenic bacteria were rapidly killed in the leaves immediately after the application of the acidic aqueous solution, but also the bactericidal effect of the application of the acidic aqueous solution was maintained for at least 7 days after the application.

[0019]

[Table 2]

Thirdly, for cucumber spot bacterial disease,
An acidic aqueous solution showing an excellent bactericidal effect on the cucumber leaf surface was screened in an indoor test (Table 3).

[0021]

[Table 3]

Fourthly, an acidic aqueous solution having a high inhibitory effect on tissue rot caused by soft rot bacteria was screened in a laboratory test (Table 4).

[0023]

[Table 4]

Fifth, it was clarified that the addition of a commercially available alkylsulfosuccinate-based spreading agent to the acidic aqueous solution can reduce the occurrence of chemical damage caused by spraying the acidic aqueous solution (Table 5).

[0025]

[Table 5]

The above-mentioned name of the spreading agent is as described in 1989, Kumiai Agricultural Guide (Planning / Editing, Agricultural Technology Promotion Section, All Agriculture and Fertilizer Division), page 1340 "Classification of Surfactants for Spreading Agent and General Properties" Obeyed. The test spreader was Vesten (manufactured by Mikasa Chemical Industry Co., Ltd., registered by Ministry of Agriculture, Forestry and Fisheries No. 10).
No. 589), and the components of the present spreading agent are polyoxyethylene nonylphenyl ether 30.0%, sodium dioctylsulfosuccinate 7.0%, and methanol, water and the like 63.0%.

Sixth, mainly on the acidic aqueous solution screened in the laboratory test, a control test and proof of chemical damage reduction in house (cucumber spot bacterial disease, cucumber powdery mildew, cucumber downy mildew) and open field (chinese cabbage soft rot) The test was repeated. As a result, we found acidic aqueous solutions (there is no practical problem with phytotoxicity) with a control effect equal to or higher than the control pesticides on the market, and these were 8 types of acidic aqueous solutions effective against bacterial diseases of cucumber spots. , 5 kinds of acidic aqueous solution effective for cucumber powdery mildew, 5 kinds of acidic aqueous solution effective for cucumber downy mildew, and 8 kinds of acidic aqueous solution effective for Chinese cabbage soft rot.

1) Effect and phytotoxicity against cucumber spot bacterial disease An acidic aqueous solution having a predetermined concentration (Table 6) (Example Nos. 3 to 3 in Table 7)
7: 3 ml / 10 of alkylsulfosuccinate-based spreading agent
1) was sprayed on the foliage of a house-grown cucumber with a backpack type sprayer, and then cucumber spot bacterial disease (2.48 × 10 ⁷
cfu / ml) was spray-inoculated on the back surface of the top 5 developed leaves.
Then, the acidic aqueous solution was sprayed twice every approximately one week.
The spraying amount is 200 to 500 l / 10a. The disease onset was investigated almost one week after the final application. In addition, a commercially available kasugamycin / copper wettable powder, which is an applied pesticide for cucumber spot bacterial disease, was used as a control drug.

As shown in Table 7, the acidic aqueous solution showed almost the same or slightly superior control effect as that of the control drug kasugamycin / copper wettable powder. It should be noted that although spots of medicine were sometimes formed on the leaves of cucumber, this was considered to be practically acceptable.

[0030]

[Table 6]

[0031]

[Table 7]

2) Effects and phytotoxicity on Chinese cabbage soft rot and acidic aqueous solution of predetermined concentration (Table 8) on growing Chinese cabbage (silver polymulch cultivation) (Example Nos. 5 to 8 of Table 9: alkylsulfosuccinate-based spreader) (3 ml / 10 l) was sprayed on the back and back sprayer 4 to 5 times approximately once every week. The amount of spray is 100-200l / 10a. The disease onset was investigated almost one week after the final application. A commercially available streptomycin wettable powder, which is an agricultural chemical to which Chinese cabbage soft rot is applied, was used as a control drug.

As shown in Table 9, the acidic aqueous solution showed almost the same or slightly superior control effect as that of the streptomycin wettable powder as the control agent. Although spots were sometimes formed on the outer leaves of Chinese cabbage, it was considered that there was no problem in practical use.

[0034]

[Table 8]

[0035]

[Table 9]

3) Effect and phytotoxicity against cucumber powdery mildew A predetermined acidic aqueous solution (adding 3 ml / 10 l of an alkylsulfosuccinate-based spreading agent) is applied to the foliage of a house-cultivated cucumber by a backpack type sprayer at intervals of about 1 to 3 for about 1 week. Sprayed 5 times. The concentration of each acidic aqueous solution is the same as in Table 6. Spray amount is 100
~ 500l / 10a. A commercially available pesticide was used as a control drug. As a result, an acidic aqueous solution having a controlling effect almost equal to that of the commercially available pesticide used as a control was found (Tables 10 to 12). No drug damage was observed.

[0037]

[Table 10]

[0038]

[Table 11]

[0039]

[Table 12]

4) Effect and phytotoxicity on cucumber downy mildew A predetermined acidic aqueous solution (adding 3 ml / 10 l of alkylsulfosuccinate-based spreading agent) was applied to the foliage of house-grown cucumber for 3 to 3 weeks at about every 1 week with a backpack type sprayer. Sprayed 5 times. The concentration of each acidic aqueous solution is the same as in Table 6. Spray amount is 100
~ 500l / 10a. In addition, a commercially available pesticide was appropriately used as a control drug. As a result, depending on the type of commercially available pesticide tested, the control effect is slightly inferior to the commercially available pesticide,
An acidic aqueous solution capable of suppressing the development of cucumber downy mildew was found (Tables 13 to 14). No drug damage was observed.

[0041]

[Table 13]

[0042]

[Table 14]

The operation will be described together with the effects.

[0044]

Since the present invention is constructed as described above, it has the following effects. 1) Since the disease control method according to the present invention is a new crop disease control method that has never been put into practical use, the means for controlling crop diseases can be diversified and contribute to stable production of agricultural products. 2) The active ingredient of the acidic aqueous solution according to the present invention is a novel compound that has never been used for conventional pesticides, and can contribute to the increase of the bacterial disease controlling agents, which has been small in the past.

3) A part of the active ingredients of the acidic aqueous solution according to the present invention is contained in the living body, is rapidly degradable, does not undergo bioconcentration, and does not pollute the environment. All other active ingredients according to the invention are also common. Therefore, by applying the present invention to disease control,
It is possible to produce safer agricultural products. 4) Most of the active ingredients of agricultural chemicals currently on the market are complicated organic synthetic compounds, and the production cost thereof is high. On the other hand, each of the active ingredients of the acidic aqueous solution according to the present invention has a simple structure, and the production cost can be suppressed to a considerably low level by mass production.

5) Conventionally, there are many cases in which the control effect is lost due to the development of drug-resistant bacteria. However, in the low pH environment on the leaf surface produced by the present invention, it is considered that a mutant having low pH environment resistance is unlikely to develop, and thus the present invention can be applied to crop disease control for a long period of time.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display area A01N 37/10 8930-4H 59/06 Z 7106-4H 59/16 Z 7106-4H

Claims (10)

[Claims] 1. An environment unsuitable for the growth of pathogenic fungi is created by spraying an acidic aqueous solution having a bactericidal action against the pathogenic fungus of the crop onto the crop to kill the pathogenic fungus on the leaves and lowering the pH of the leaves. A method for controlling crop diseases by spraying an acidic aqueous solution. 2. The method for controlling a crop disease by spraying an acidic aqueous solution according to claim 1, wherein the disease is a cucumber spot bacterial disease. 3. The method for controlling a crop disease by spraying an acidic aqueous solution according to claim 1, wherein the disease is cucumber powdery mildew. 4. The method for controlling a crop disease by spraying an acidic aqueous solution according to claim 1, wherein the disease is cucumber downy mildew. 5. The method for controlling a crop disease by spraying an acidic aqueous solution according to claim 1, wherein the disease is Chinese cabbage soft rot. 6. The aqueous solution of fumaric acid, fumaric acid and its salt, malic acid, malic acid and its salt, phthalic acid, maleic acid, citric acid and its salt, calcium sulfate and ferric sulfate. Among these, the method for controlling a crop disease by spraying an acidic aqueous solution according to claim 2 using any one of them. 7. The acidic aqueous solution according to claim 3, wherein any one of fumaric acid, fumaric acid and its salts, malic acid, malic acid and its salts, and phthalic acid is used as the acidic aqueous solution. A method for controlling crop diseases by spraying. 8. The method according to claim 4, wherein any one of fumaric acid, phthalic acid, malic acid, ferric sulfate, citric acid and its salts, and calcium sulfate is used as the acidic aqueous solution. A method for controlling crop diseases by spraying an acidic aqueous solution. 9. The acidic aqueous solution includes phosphoric acid, phosphoric acid and maleic acid, phosphoric acid and ferric chloride solution, malonic acid, malonic acid and salts thereof, malonic acid and ferric chloride, malonic acid and ferric chloride. The method for controlling crop diseases by spraying an acidic aqueous solution according to claim 5, which uses one of ferric chloride and ferric chloride. 10. A method for spraying an acidic aqueous solution, comprising adding an appropriate amount of an alkylsulfosuccinate-based spreading agent to the acidic aqueous solution according to any one of claims 6 to 9. How to reduce the occurrence of chemical damage.