DEN0004949MA - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Registration date: January 8, 1952. Advertised on September 29, 1955

GERMAN PATENT OFFICE

The invention relates to a method of treating plants for the purpose of controlling Pathogens by means of substances that have an internal chemotherapeutic effect. The fabrics penetrate the plants, spread through them and make them immune, at least less susceptible to it the attack of pathogens. In many cases the same remedies also have a curative effect, if the Plants were already attacked. Usually immunity persists for a few weeks, e.g. B. about 3 weeks after the substances have been absorbed by the plants.

There are certain indications that the substances in living plants are undergoing a transformation and that immunity and / or healing are only brought about by certain transformation products while the original substances do not need to have any effect per se. But it is certain that in practice a particularly beneficial effect is achieved in that the substances are in the plants themselves penetration. . :

Substances have already been proposed as internal chemotherapeutic agents, especially for protection of plants against fungal diseases. In the literature, such substances are mostly called system fungicides in analogy to the system insecticides, which also penetrate the plants and use them for insects and render poisonous to related animal parasites such as mites.

: Compared to the usual pesticides that do not or hardly penetrate the plant the internal chemotherapeutic agents the big ones

509 562/168

N 4949 IVa / 451

Advantage dal! also those parts that develop after the application of the control agent, like new shoots, nut, flowers, fruits, etc., immune in many cases for a period of time graze.

The chemotherapeutic agents of the invention can be used either individually or in combination with one another or with other fungitoxic, viritoxischcii, insecticidal or acaricidal substances are used

to be whose chemotherapeutic effect can be an internal or an external, whereby wetting agents and optionally also adhesives can be added. Also combinations with systemic insecticidesii and / or plant foods and / or plant honeys are possible.

Suitable wetting agents are, for example, alkyl sulfates, Alkylarylsulfonates, sulfosuccinates, ethers Polyethylene glycol and alkyl phenols. (loud results were achieved when using a tech-

ao iiischen mixture of sodium alkyl sulfates in amounts of 0.01 to 0.05 percent by weight. As far as the substances as an emulsion or suspension, z. B. in water are used, solvents such as T) Ie, emulsifiers, Enmlsionstabilisierungsmittel and the like., Can be added. In addition, substances can also be added which enable unusually high doses to be used without the occurrence of phytotoxic symptoms. It is well known that z. 15. Glucose Toinatenptlanzen against damage (by certain substances with a phytotoxic effect in high concentrations, such as urea. The chemotherapeutic substances according to the invention can be administered in various ways, such as 1>. 1. Application of the substances to above or below ground Parts of the plants or on the seeds, e.g. introduction of the substances into the soil near the roots, 3. direct introduction of the substances into the i'llau / .en, e.g. through boreholes or through incisions in parts of the plant.

In all cases it depends on the fabrics To give the opportunity to penetrate the plants themselves. The application has proven to be particularly effective on parts of the plants above ground, for example by spraying, the substances are wrung into the Testicles, care must be taken that the solution is brought in as close as possible to the roots, or sufficiently Select high concentrations, otherwise the active substances will be reduced by the soil constituents can be absorbed or the substances under certain circumstances undergo chemical or microbiological transformation could be exposed before they penetrate the plants.

The plants to be treated are preferably sprayed with aqueous solutions of the active ingredients that are 0.01 to 1 percent by weight, preferably 0.1 to 0.5 percent by weight of these substances may contain. Sometimes there are even lower ones Concentrations effective; under certain circumstances, if no phytotoxicity occurs, also higher concentrations can be used. Usually it is precisely with regard to phytotoxicity working with low concentrations is recommended.

The proof that the agents applied to the plants had penetrated the inside of the plant and exerted their effect from there was provided by artificially irrigating some of the treated plants so that every trace of the agent still present was washed off. It was found that the irrigated plants, as well behaved as the treated with the agent, but after 'not irrigated plants.

According to the invention, compounds are used as substances for combating pathogens which are derived from compounds with the formula CH ₁ N ₂ S, in the molecules of which the carbon atom is connected to both the nitrogen atoms and the sulfur atom, but not to any of the four hydrogen atoms by substituting one or more of the hydrogen atoms, where at least one of the substituents should be an acyl group.

The compounds to be used according to the invention are therefore any substituted acylthiourea compounds or acylisothiourea compounds.

It has been suggested to use thiourea compounds to be used as such for fungicidal purposes, but not in particular acylated thiourea derivatives. The invention was based on the knowledge that compounds of this type and their isomers are particularly suitable for the control of pathogens in plants and that they are an internal have chemotherapeutic effects.

According to the invention, compounds are preferably used are used which satisfy one of the following general formulas:

n (

\ R ₁ or \ R ₂ or \ Y C - = --- S. C - SX C-- SX I.
k Y NY Il
N \ R ₂ R.,

in which X = an optionally substituted, no ζ. H. halogenated acyl group, Y = a hydrogen atom or an optionally substituted, e.g. B. halogenated hydrocarbon radical which z. B. may be an alkyl or aryl group, or an optionally substituted, z. B. Halogenated acyl group. R ₁ and R ₂ = hydrogen atoms or optionally substituted, e.g. B. halogenated hydrocarbon radicals which z. B. can be alkyl or aryl groups.

As substituents in the groups X, Y, R ₁ and R ₂ , in addition to halogens, which are particularly suitable, also z. B. NO ₂ , SO ₃ H, OH and NH _{2 may be} present.

Good results have been achieved in particular with those compounds in which R ₁ and R _{2 were} both hydrogen atoms.

562/168

N 4949 IVa / 451

For practical reasons, primarily water-soluble compounds of the type mentioned come into consideration. Solubility in water is a water solubility of at least o, oi / ₀ ° understood, although this lower limit is not sharply drawn. As is well known, the water solubility generally decreases with the number of carbon atoms present in the molecule. As a rule, therefore, substances will be all the more suitable in the context of the present invention

ίο have fewer carbon atoms in the molecule. Substances with more than 9 carbon atoms will generally not be sufficient in terms of water solubility unless the water solubility is promoted by introducing hydrophilic groups, for example the SO ₃ H group.

In general, preference is given to using compounds in which the acyl group X and optionally

.. ·, also Y, apart from halogen atoms and others Substituents, of the formula

.0

Alc

are, wherein Alk represents an 'alkyl group. In particular methyl, ethyl, propyl and isopropyl groups come into consideration for this alkyl group. The alkyl group can be substituted, in particular halogenated, as can be seen from what has been said above. Chlorinated alkyl groups which do not contain any other substituents are preferred especially those in which the terminal carbon atom or branched alkyl groups, such as for example the isopropyl group, one or more of the terminal carbon atoms 1, 2 or preferably Carry 3 chlorine atoms. Good successes have also been achieved when in connections, in which both X and Y were acyl groups, only one of these two groups was terminally chlorinated and finally also with compounds in which the two alkyl groups contained in the acyl groups X and Y do not have any Substituents, including no chlorine atoms, contained.

When there is only one acyl group, i. H. so,

the fact that only X represents such a group gives good results both when the group is terminally chlorinated as well as if it contains no substituents at all.

Compounds having the acyl group of an aromatic acid, e.g. B. benzoic acid, on the sulfur atom showed interesting side effects, which are discussed in more detail in the example.

It should be noted in this connection that some of the halogenated compounds that can be used according to the invention are not stable because they are soon after or already during manufacture cyclize. This is the case, for example, with monochloroacetylthiourea. Are well resistant

- _: In general, the compounds which are completely halogenated at the terminal carbon atom, such as. B. Trichloroacetylthiourea.

If Y represents an aryl group, the phenyl group is particularly suitable, if desired. if with the solubility-promoting substituents, such as — S0 ₃ H.

If Y represents an alkyl group, these are terminally chlorinated or not substituted at all Alkyl groups are preferred, as in the case of the subgroup Alk when Y is an acyl group. So you prefer terminally chlorinated or unsubstituted methyl, ethyl, propyl and isopropyl groups.

As can be seen from the above, combinations of the groups X and Y are preferably always selected in which the total number of carbon atoms in the molecule is not greater than nine. Very good results have been achieved with compounds in which not only R ₁ and R ₂ , but also Y was a hydrogen atom, in particular with chlorinated acetylthioureas, such as trichloroacetylthiourea, and chlorinated or unsubstituted acetylisothioureas in which the acetyl group is bonded to the sulfur atom such as acetylisothiourea.

Compounds in which the acyl groups are not derived from a lower fatty acid, but are derived from monoalkyl esters of carbonic acid, d. H. so, connections with Acyl groups of the formula

, 0

- c;

where Alk has the same meaning as before. In this context, S-carboethoxythiourea should be used in particular be mentioned.

Of course, the active compounds according to the invention do not need to be used in pure form get. Inactive admixtures may be present, which during the technical; Manufacture. Mixtures of active compounds can also be used like them are easy to manufacture from technical products.

The active compounds can also be used in the form of salts. With the isothiourea derivatives the hydrochloric acid salts have generally proven their worth.

The effectiveness of the new plant protection products relates to a wide variety of pathogens, some of which are of great practical importance in the following list will:

Latin name
of German name
the Most important plants,
where the sick Pathogen illness occurrence nc
can Cladosporium Brown spots Tomato plants fulvum illness Septoria apii Celery plants ¹² ° graveolentis Phytophthora Herb and Potato plants, infestans Tuber rot tomatoes (Potato plant 125 illness) 509 562/168

N 4949 IVa / 451

Latin name

of
Crane virus

('olletotrieliuin
Lindenuilliiaiuun

Kxobasidium
vexans

Krysiphaeeae
¹ S (various
Species)

Uredinales

(different
αο species)

Fusariuni

(different
Species)

Ceratoslomella
iihni

Pseudo] Ilonas
(different
Species, e.g. B.
Agrobacteriiun
tuniefacieiis)

German name

the
illness

Focal spot disease

. »Blister blight« (English
Surname)

mildew

rust

Wilted sickness

Dutch elm deseasc

Bacterial cancer

Most important plants in which the disease can occur

Brown bean plants (Phoseolus vulgaris L)

Tea plants

Various plants, e.g. B. apple trees

Cereals

Cucumber plants

Elm trees

Tomato and many other plants

The list is of course not exhaustive. The pathogens mentioned are all fungi, except for the last one, which is bacteria.

The activity of the agents according to the invention could usually most conveniently be determined in the following manner will:

Test plants were sprayed with an aqueous solution of the inventive agent until the Liquid drained from the leaves. After the spray liquid has dried, usually after about For 2 days, the plants were exposed to the infection with the pathogen.

In all cases, some of the test plants were first artificially irrigated with tap water, to which 0.2 percent by weight of a mixture of sodium alkyl sulfonates was added. Through this the remains of the spray liquid were completely removed.

Depending on the species of the test plants and the fungus, the infection took place through inoculation or by placing the plants in a contaminated environment, namely in a greenhouse, which contained plants attacked by the pathogen. The circumstances were like that every time chosen that, for comparison, plants that remained untreated soon became ill.

After some time, the ratio of the leaf surface attacked by the disease to the total leaf surface in the treated and untreated plants was determined. If the quotient of these two numbers is subtracted from 1, a quantity is obtained which is a measure of the degree of suppression of the pathogen. Furthermore, this quantity, expressed as a percentage, is called the degree of suppression. The point in time at which the determination of the degree of suppression, as just defined, was carried out was chosen in each case so that all plants that remained untreated showed clear symptoms of the disease. As a rule, the leaf surface areas are not measured, but are estimated with the required accuracy. In this way, a trained person can determine the degree of suppression with an accuracy of about 5 ° / _0. This accuracy is sufficient because, in general, the results obtained in biological experiments can only be reproduced within fairly wide limits.

The invention is explained below using a few examples:

example 1

Tomato plants were treated with aqueous solutions of some active compounds at various concentrations splattered. Spraying continued until the solutions drained from the leaves.

Two days later, the plants were placed in a room heavily infected with Cladosporium fulvum spores brought. The table below shows the degree of suppression after 14 days.

formula C) Connection used Concentration of
injected solution Oppressive Surname (Weight percent) Degree II \ cu. Acetylthiourea _ 50 0.1 72 N C 0.2 86 I. o, 3 100 C S 0.4 96 NILE

562/168

N 4949 IVa / 451

formula

Connection name used

Concentration of
injected solution
(Weight percent)

Degree of oppression

N — c:

C = S
NH ₀

, 0

CH,

ν- c;

C = S

NC '
H

.0

CH ₃
.0

Triacetylthiourea (addition product of mono- and diacetylthiourea)

0.1

0.2

o, 4

90

60

100

98

CH ₉ Cl

N-chloroacetyl N'phenylthiourea

0.05

80

N-valeroylthiourea

0.05

80

(CH ₂ ) ₃ - CH ₃

Example 2

Brown beans plants (Phaseolus vulgaris L), about 3 weeks old, were, sprayed with an o, 5 ° / ₀ solution of Trichloracetylthioharnstoff, which was mixed with 0.1% of a mixture of sodium alkyl sulfates. Two days later the plants were inoculated with Colletotrichum Lindemathianum.

The assessment took place after 3 weeks. All the "blind test" plants showed a strong attack of the focal spot disease, in contrast to the treated plants, which had remained completely healthy. The degree of suppression was 100 ° / _0th

The trichloroacetylthiourea

NHCOCCl ₃

NH ₂

which has not yet been described in the literature, was produced by heating trichloroacetic anhydride and thiourea in a benzene solution in molar amounts, without any claim for protection being made. The trichloroacetylthiourea which separated out on cooling was recrystallized from alcohol (melting point 145 to 146 ^° ).

Example 3

Pseudomonas tumefaciens is a bacterium that causes tumors on both woody and herbaceous plants. It has been found that these tumors can be combated by external treatment with aqueous solutions of the active substances according to the invention. After three weeks, a ioo% strength recovery was achieved when tomato plants with Acetylthioharnstorf and Triacetylthioharnstoff were treated, both 3 ° / ₀ sodium concentration in o. No phytotoxic symptoms were noticed.

An equally good success was observed after treatment with an o, 5 ° / ₀ solution of S-Acetylisothioharnstoff (as hydrochloric acid salt), NH,

C = NH

HCl

SCOCH ₃

Example 4 A 0.3% solution of S-acetylisothiourea

hydrochloric acid salt, C = NH -HCl \ SCOCHo

509 562/168

N 4949 IVa / 451

was sprayed on about 2t) cm high celery plants. Two days later, the plants were liiniib in a moist greenhouse. r brought, together with one Row not sprayed with celery plants. Then the l'flanzin with spores of Septoria apii graveoleiitis grin,], ft. 3 weeks later the Judged effect. Degree of suppression 80%.

Example 5

The roots of cucumber plants (1 month old) were soaked for 4 to 5 hours in a solution of ".". V / o S-Carboethoxyisothiourea

/ NH ₂

I hydrochloric acid salt, C ^ Nile · HCl

^N SCO-OCJl ₅

and then.} up to 7 days in pots with sterilized sand with the addition of nutrient salts placed. The plants were then removed from the pots and the root system was 4 to 5 Hours immersed in a spore suspension of Fusarium (various types), after which she is again in sterilized sand. Many of the plants treated in this way showed up after 3 weeks no wilting yet, while the · blind test ..- plants had almost all died or one showed severe yellowing and had become limp.

" ₀ Example 6

Kino series apple seedlings (20 cm high) in pots was sprayed with an aqueous solution of 0.1% triacetylthiourea with an addition of 0.1% by weight of a mixture of sodium alkyl sulfates as a wetting agent. 80 ecm of liquid was used per cjiii. 3 days later, the plants were placed in a greenhouse and inoculated with spores of apple mildew. After 3 weeks, the level of infestation was determined by the leaves at the tip which had meanwhile unfolded. A degree of suppression of So ⁰ I ₀ was achieved.

Example 7

From six three-year-old ancestral trees (about 2 m high, variety hollandica), gives way: in concrete troughs with

1 were planted in · 'fashions, two trees were drilled in the trunk to the core. A gunun cannula was inserted into the resulting small opening (diameter 3 mm), which by means of a rubber tube with a small storage vessel in which an _{0.02 "/ 0} aqueous solution of S-carboethoxyisothiourea (hydrochloric acid salt) was located, The solution was found in the course of

2 days completely absorbed by the plant. 2 days after the end of the recording these were Trees on the trunk inoculated with a suspension of spores from some breeds of Ceratostomella ulmi.

For two trees aluminizing 1 2 were injected a o, i ° / ₀ solution of the same active compound at 50 cm depth between the roots, while 231 of the same solution were poured on the floor above. 4 days later, the trees treated in this way and the two trees that remained untreated were also inoculated. The untreated trees showed clear symptoms of Dutch elm disease 3 and especially 6 weeks after the inoculation, while all the treated trees were completely healthy.

Example 8

Various plants were used with results similar to the previous examples Combating various pathogens with acylthioureas or their salts, for example with S-benzoylisothiourea

NH.,

CS-COC ₀ H,

NH-HCl

treated.

The side effect (incidentally also on the healthy comparison plants) was clearly insecticidal Property of the agent used, which, as far as has been observed, especially those acylthiourea derivatives !! comes, in which the hydrogen atom sitting on the sulfur through a directly to an aromatic nucleus, in particular one Benzene nucleus, bound acyl group is replaced (see above formula).

Since plant-damaging insects, such as lice, etc., contribute indirectly to the spread of plant diseases by weakening the resistance of the plants and possibly spreading the pathogens to parts not yet infested, the insecticidal properties determined of certain agents falling within the scope of the invention mean a welcome \ ^; strengthening their effectiveness in combating pathogens.

In addition, it should be noted that the substances proposed according to the invention in experimental direct application to the fungus control, for example, of fungi and microbes at most show only a weak effect. When using the compounds according to the invention with induction an internal chemotherapeutic effect, on the other hand, that in the above examples was particularly good Effect achieved.

Claims (9)

PATENT CLAIMS: _Jlo I. Use of compounds preferably present in water-soluble form, which the general formulas / X / Ri / R ₁ n: n: : = --- S or C-SX or C-SX N-- Y NO, correspond, where X is an optionally substituted, preferably terminally halogenated, in particular chlorinated acyl group, Y a hydrogen 562/168 4949 IVa / 451 atom, an optionally substituted, preferably terminally halogenated, especially chlorinated acyl group or an optionally substituted, preferably terminally halogenated, especially chlorinated hydrocarbon radical and R ₁ and R _{2 represent} hydrogen atoms or optionally substituted, preferably terminally halogenated, especially chlorinated hydrocarbon radicals, for the purpose of treating plants Fight against pathogens. 2. Use of S-acylisothiourea compounds for the purposes of claim i, in particular in the form of their hydrochloric acid salts. 3. Use of by the presence of two optionally substituted acyl groups in the Molecule-labeled substances for the purposes of claim 1. 4. Use of characterized by the presence of not more than 9 carbon atoms in the molecule Substances for the purposes of address i. 5. Use of acetylthiourea or its derivatives chlorinated in the acetyl group for the purposes of claim 1. 6. Use of triacetylthiourea for the purposes of claim 1. 7. Use of S-acetylisothiourea, in particular in the form of one of its salts, for the purposes of claim 1. 8. Use of S-carboethoxyisothiourea, especially in the form of one of its salts, for the purposes of claim 1. 9. Use of substances according to claim 1 to 8, characterized in that the substances in aqueous solution in a concentration of 0.01 to 1, preferably 0.1 to 0.5 percent by weight Above-ground parts of the plant are applied, preferably sprayed on.