JPS59157003A - Plant blight controlling agent - Google Patents

Abstract

PURPOSE:To provide a safe and pollution-free plant blight controlling agent exhibiting remarkable effect to various plant blights such as melanose, scab and canker of citrus, anthracnose of cucumber, etc. without causing environmental pollution, by using 6,7-dimethoxycoumarin as an active component. CONSTITUTION:6,7-Dimethoxycoumarin of formula is used as an active component. The above active compound is applied directly or in an arbitrary form such as granules, powder, emulsifiable concentrate, etc. by using proper solid carrier, liquid carrier, emulsifying and dispersing agent, etc. The amount of the active component in the agent is preferably about 10-90% for emulsifiable concentrate, wettable powder, etc., and about 0.1-10% for powder, oil solution, etc. The above active component can be prepared by (1) grinding the citrus fruit peel inoculated with the blight of melanose, (2) extracting with acetone and filtering the extract, (3) removing acetone from the filtrate, (4) dispersing the extract in distilled water, and (5) adsorbing with active carbon followed by elution and fractionation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plant disease control agent characterized by containing 6,7-simethoxycoumarin as an active ingredient.

Conventional plant disease control agents act directly on pathogenic bacteria on A1a objects to prevent the occurrence of diseases. Zunawachi...
A drug exhibits its control effect only after it comes into contact with pathogenic bacteria and is absorbed. However, the prefecture's control agents sprayed with 111 sprays are quickly washed away by raindrops, so their residual effectiveness is short.

On the other hand, if 4V<a drug remains on an object for a long period of time, there is a concern about contamination of raw materials due to crop residue.

From this point of view, 41f' (, Phytoalexin d
(Although the research on ``i'' has been attracting attention, its mechanism of action has not yet been clarified. Therefore, in view of the above-mentioned purpose, the present inventors conducted intensive research and found that citrus plants infected with citrus black spot fungus 6,7- present in pericarp and leaves
The inventors succeeded in isolating cymethoxycoumarin and discovered that this compound exhibits a strong control effect against various plant pathogenic bacteria, leading to the completion of the plant disease control agent of the present invention.

The active ingredient of the present invention is biosynthesized in the host plant through the metabolic relationship between the host plant and plant pathogenic bacteria, and is recognized to be involved in the regulatory action of the plant itself. There is no fear of this, and it has the characteristics of an extremely safe and non-polluting pesticide.

The discovery of the above-mentioned active ingredient stems from the discovery that the black spot fungus that invades the pericarp and new leaves of citrus trees is trapped within the epidermal cells of the citrus tree that it first reaches and dies. When researching the reason why the black spot fungus dies immediately after invasion, we found new knowledge that citrus persimmons produce antibacterial substances when invaded by pathogens, and this action kills the pathogens. Based on this knowledge, we succeeded in extracting the substance from -6°≦, citrus fruits such as pericarp, and 1i11 texture. That is, the pericarp inoculated with the black spot 6 bacteria is ground and extracted with acetone. After P filtration, acetone is removed from the P solution, and the extract is suspended in distilled water and adsorbed on activated carbon. After adsorption, the eluate was eluted with acetone, the eluate was concentrated, and fractionated using thin layer chromatography and column chromatography. Recrystallization from enal ether isolates white needles.

It was confirmed from physical properties that the crystal thus obtained was a compound having a first-order borrowed formula.

Molecular weight: 206 Melting point: 145.5-146.5°C As a result, the active ingredient compound of the present invention was consistent with 6,7-somethoxycoumarin (Tadabe Araki, Yakugaku Zasshi, 1928, p p
437: E. J. Corey et al.

Chemistry & Industry, 195
4. See PP 1294).

The plant disease control agent of the present invention can be used to control various diseases such as black spot, scab, and canker of citrus, anthracnose of cucumber, gray mold of strawberry, rice blast, and sesame leaf slime, as shown in the test examples described below. It is highly effective against plant diseases.

When applying the plant disease control agent of the present invention, the above-mentioned active ingredient compound may be applied directly, or a suitable solid carrier, liquid carrier, emulsifying dispersant, etc. Used for granules, powders, emulsions, irrigation agents,
It can be formulated and applied in any form such as an aphrodisiac, an oil, a spray, or a smoke propellant.゛These carriers include clay, kaolin, bentonite, acid clay, diatomaceous earth, calcium carbonate, solids such as nitrocellulose, starch, gum arabic, etc., and liquid carriers such as water, methanol, and ethanol. , acetone, trimethylformamide, ethylene glycol, and the like. In addition, auxiliary agents commonly used in formulations, such as sulfur aβ esters of mild alcohols, polyoxyethylene alkyl allyl ethers, alkyl-allyl ethers, etc.
Polyethylene glycol ether, alkyl allyl sorbitan monolaurate, alkyl allyl sulfonate, alkyl sulfone m salt, alkylaryl sulfonate, quaternary ammonium salt, polyalkylene oxide, sodium lignin sulfonate, dinaphthyl methanesulfone Acid soda, lecithin, sucrose fatty acid ester, sorbitan fatty acid ester, monoglyceride, polypropylene glycol fatty acid ester, etc. can be blended as appropriate.The blending ratio of active ingredients is 10 to 90% as an emulsion, hydrating agent, etc. The appropriate amount is 0.1 to 10 qlj for powders, powders, oils, etc.
These degrees may be increased or decreased as appropriate depending on the purpose of use.

Furthermore, the drug of the present invention can be used with other fungicides, herbicides, insecticides,
It can be used by appropriately mixing it with fertilizer substances, soil conditioners, etc.

Next, Examples of the plant disease control agent of the present invention will be shown.

Example 1 (Irrigation agent) 6.80 parts of 7-simethoxycoumarin, 10 parts of monoglyceride, 5 parts of starch, and 5 parts of sodium caseinate are mixed and ground to obtain an irrigation agent. Use by diluting it approximately 2000 times with water.

Example 2 (Irrigation agent) 80 parts of 6.7-cymethoxycoumarin, 2 parts of white carbon, 2 parts of ligninsulfonic acid sodium salt, 4 parts of polyoxyethylene alkyl ether, and 12 parts of clay were mixed and ground to make 11 parts of water solution. get.

Dilute it approximately 2000 times with water and use it! 1
3 (Powder) 25 parts of a mixture of 6.80 parts of 7-simethoxycoumarin, 10 parts of monoglyceride and 10 parts of starch are mixed with 75 parts of talc to obtain a powder.

Example 4 (emulsion) 40 parts of 6.7-simethoxycoumarin, 10 parts of glyceride
1 part, 5 parts of sodium caseinate, 15 parts of methanol and 50 parts of water are mixed and dissolved to obtain an emulsion.

Example 5 (Emulsion) 6. An emulsion is obtained by mixing and dissolving 40 parts of 7-cymethoxycoumarin, 5 parts of polyoxyethylene alkyl allyl ether, and 5 parts of sodium phonate, 20 parts of methanol, and 30 parts of water.

Next, the plant disease control effect of the agent of the present invention will be specifically explained using test examples, and the control agent was used at the concentration used in actual use.

Test Example 1 (Citrus black spot control test) A mandarin orange branch for product Y was placed in a test tube, sterilized in an autoclave, and then inoculated with black spot bacteria.The test tube was kept in the dark at 25°C for 5 days, and then placed in a glass tube. The plants were moved to a greenhouse to form petiospores and petiospores. After that, distilled water (10=2) was added and shaken to obtain a spore suspension solution (pediospore e: 5
x 106/ml). New shoots of approximately 3-year-old seedlings of Satsuma mandarin (2 to 4 #f in 6-inch pots) were used as test plants,
Old branches are cut off from the base, 10 to 20 grains of mixed fertilizer are applied, and the new shoots that have grown out are tested after about 2 to 5 weeks. A drug (an irrigation agent prepared according to Example 1) diluted to a predetermined concentration is uniformly spread over 2e+-40a. Then, the spore suspension was spray-inoculated and kept in a greenhouse (R, H,
After maintaining the seedlings at a temperature of 100 elp (25° C.), they were cultivated in a glass greenhouse, and after 21 days, the number of lesions was investigated on all leaves of the new shoots.

Number of lesions: 1-50 (1), 51-150 (2), 15
The disease was investigated separately for 1 or more (3) and no disease (0), and the disease severity was determined using the following formula and the control value (CH) was calculated.
nl, n2, and n3 are the onset degree of 1.2.5, respectively.
The number of leaves, N indicates the total number of leaves. ) The results are shown in Table 1.

Table 1 1) Comparative agent: Zinc ethylene bisdithiocarbamate (
→ indicates no chemical damage.

Test Example 2 (Citrus scab control test) The scab fungus overwinters in lesions formed on citrus leaves, roots, fruits, etc., and the following spring, when it rains, it scatters with raindrops and spreads.

Therefore, the following test was conducted. A leaf of a Satsuma mandarin orange with lesions formed on it was immersed in a test chemical (an irrigation agent prepared according to Example 2) diluted to a predetermined concentration. After air drying,
After 4 days of treatment, kept in the greenhouse, about 5 of the unshu mandarin oranges planted in pots
0 (: Hanged on In. After that, rain was made with an artificial rain device (20 rrrm/hr, 2 hours) 0
After rain treatment, greenhouse for 2 days (R, 8,100%, 25℃)
After keeping the plants at a constant temperature, they were transferred to a glass greenhouse and cultivated, and after 21 days, the number of lesions was counted and the control value was determined. The method for calculating the control value was in accordance with Test Example 1. The results are shown in Table 2.

Table 2 (Thiophanate-Methyl) 70% Hydrating Powder Test Example 3 (Citrus Canker Control Test) Similar to scab, canker is found in lesions formed on citrus leaves, roots, fruits, etc. It overwinters, and the following spring, when it rains, it is blown away and spread by raindrops.

Therefore, a test was conducted in the same manner as in Test Example 2 using unshiu mandarin orange leaves with canker lesions. However, the emulsion of Example 4 was used as the test drug. The method for calculating the control value was in accordance with Test Example 1. The results are shown in Table 3.

Table 5 3) Synthetic agent: Copper hydroxide 809G (C
uS2 Section) Test Example 4 (Cucumber anthrax disease control trial) Cucumber (variety: Sagami Hanshiro) seedlings grown between 2 and Ai (
A predetermined 0 degree centrifugal agent (emulsion of Example 5) was uniformly sprayed in an amount of 500 ml per 25 pots (2 to 5 plants in 2-inch pots) and dried. Incubate cucumber anthrax pathogens in slant culture medium for 2" at 8℃, 1
Cultured for weeks to form spores, and the spores were suspended in pure water (spore concentration = 6 x 106 cells/ml) 50
ml was sprayed and inoculated to the above-mentioned cucumber seedlings in 5 blocks of 25 pots using a spray gun. After inoculation, the plants were allowed to develop disease in a greenhouse for 2 days, and the number of lesions was examined 5 days later. The control value was calculated according to the following formula.

The results are shown in Table 4.

Table 4 Test I Example 5 (Strawberry gray mold control test) A prescribed concentration of the drug (hydration oJ of Example 1) was applied to the fruits of potted strawberries (variety: Danner, fruiting stage) in 5 pots! 7100 mJ was uniformly sprayed and dried.

Gray mold fungus (BojrytlsCln) was cultured on potato juice flat medium and formed by BLB lamp treatment.
eroa) spores were suspended in distilled water (spore concentration 6X).
106 cells (7 ml)) 1001 nl was spray-inoculated onto the above-mentioned strawberry fruit using a spray gun. After inoculation, the plants were kept moist for 4 days, and after the onset of disease, the number of rotten fruits in each plot was investigated. The control value was calculated according to the following formula.

The results are shown in Table 5.

Table 5 5) Comparative agent: polyoxin complex (2j?1096 as rioxin) Test Example 6 (Rice blast control test #) Diameter 6. Rice (variety Nijukoku) was grown in a greenhouse in Od synthetic resin pots with 10 plants per pot, and at the fourth leaf stage, a prescribed gj degree of chemical (according to the powder in Example 3) was applied to the fence. sprayed on the body. Spores of the rice blast fungus that were separately cultured in a rice husk medium (containing powdered yeast, extract, soluble starch, sugar, and rice husks) were suspended in water (spore strength: 4X).
A total of 105 cells/ml was sprayed uniformly onto the fence and placed in a constant temperature and humidity box at a temperature of 27C and humidity of 95C or higher to induce disease.

On the 5th day of inoculation, the duration of the lesions on the leaves was determined, and the control value was calculated according to the following formula.

The results are shown in Table 6.

Table 6 Test Example 7 (Rice. Toma leaf blight control test) Diameter 6. In a Qtm synthetic resin pot, 10 plants per pot were grown in a greenhouse, and at the 7th leaf stage, a predetermined concentration of the chemical (the irrigation agent of Example I) was applied to the fence. was dispersed.

Sesame leaf blight spores separately cultured on a PSA plate medium were suspended in water (spore concentration: 3 x 10'/ml)%
This was uniformly sprayed and inoculated onto the above-mentioned rice plants, and placed in a constant temperature and humidity box at a temperature of 26° C. and a humidity of 100% to induce disease. Five days after inoculation, the number of lesions per leaf was determined.

The calculation method was based on Test Example 6. The results are shown in Table 7. Table 7 (Discussion) As is clear from the above test examples, the active ingredient compound of the present invention exhibits extremely excellent control effects against a wide range of various plant diseases. It also showed sufficient pest control effect even at low concentrations.

Patent applicant: RIKEN

Claims (1)

[Claims] 6. A plant disease control agent characterized by containing 7-simethoxycoumarin as an active ingredient.