NO130906B - - Google Patents

Description

Antifungal agent.

It is known that a compound with the general formula

where X and Y mean oxygen or sulphur, R,

R', R" and R'" mean hydrogen or alkyl groups and Rl optionally means at least one halogen atom and/or alkyl groups, can be used as an active ingredient together with a contact insecticide with the formula:

wherein Ar, and Ars mean aromatic groups which may bear the same or different non-salt-forming substituents, and V and W mean halogen or hydrogen, in an agent for controlling vermin, especially insects. Furthermore, it is known that compounds of the general formula

wherein X means chlorine or bromine, R! means an alkyl group and R2, R3 and R4 means hydrogen or an alkyl, aralkyl or cycloalkyl group and n means an integer from 3

to 5, are effective against spider mites, aphids and the "Mexican bean beetle" and against mosquitoes,

like for example. bean meal.

Furthermore, it has been described that compounds with the general formula

wherein R 1 means a negatively substituted phenyl group, e.g. a nitrophenyl-, carbethoxy-phenyl- carbethoxynitrophenyl, aldehyde ph-

nyl or chlorophenyl group, R 2 and R 3 mean alkoxy or alkyl groups or residues of aliphatic amines, have insecticidal properties.

The invention relates to an agent for combating fungi, in particular powdery mildew, and the agent is characterized by the content of a compound with the general formula

as active ingredient, where X denotes an oxygen or sulfur atom.

As you know, a large number of effective compounds against fungi have been described, but which, due to more or less strong phytotoxic properties, are not relevant for the practical control of fungi on plants. The plants would then be too severely damaged.

It has been determined that the agents according to the invention are not at all or essentially not phytotoxic and are therefore particularly suitable for combating fungi, and especially powdery mildew on plants, such as e.g. barley, apples and grapes.

The compounds are tested for their fungicidal effect as described in the following: Young plants of barley (Hordeum vulgare) were grown at a temperature of 15 to 18° C in small flowerpots up to a length of approx. 7 cm. They were then sprayed with acetone solutions with different contents of the compounds to be tested. The solutions used contained 1000, 100 and 10 parts by weight of active compound in 1,000,000 parts by weight of acetone. Seven plants in a single pot were simultaneously sprayed with 0.2 cm<3> solution. Immediately after spraying, the plants were pollinated with viable conidia from Erysiphe graminis. This took place in such a way that the pots of the entire experimental series are simultaneously arranged under a spacious bell and in this room the powdery mildew conidia are distributed by means of an air current that sweeps over heavily infected leaves of barley. You let it all stand for a while, whereby the conidia settle evenly on the plants. These were then brought into a room, in which the temperature was 18 to 20° C and the relative humidity approx.

90 per cent, under continuous lighting with

fluorescent lamps (white light) with an intensity of approx. 3000 Lux. Five days after inoculation, clear spots of powdery mildew had formed on the test plants, which showed abundant spore formation.

Each plant's degree of attack was assessed with a number in the range from 0 to 10, where 0 = no attack and 10 means: the entire leaf stung.

The experiments were carried out three times, so that for each used concentration of the investigated compounds 21 observations are obtained, which were summed up.

As all compounds could not be examined in one and the same test series, the degree of attack of each plant was always compared with that caused by means of 2,4-dinitro-6-(r-methylheptyl)-1-phenylcrotonate. In this way, the dose was always brought clean which, as well as with the compound to be examined, which also with the phenylcrotonate derivative resulted in 50 percent protection of the plant.

As a measure of the effect of an investigated compound, the quotient of the relevant dose of phenylcrotonate and the relevant dose of the investigated compound which gave 50 percent protection was now chosen. The numbers found in this way are mentioned in column h in Table I. The higher such a number is, the greater the fungicidal effect of the investigated compounds in question.

In this table, the first column contains the sample number, the second mentions the substituents X, the third column the chlorinated benzene ring and the last column the effect against Erysifpaceae in relation to the effect of 2,4-dinitro-6-(1'-methylheptyl)-1 -phenylcrotonate (on barley plants) as expressed above.

Young plants of creeping beans, tomatoes, oats and beetroot were treated with solutions containing 1% by weight in acetone of the compounds in the agents according to the invention, resp. it was known bis(N,N-dimethylamido)-pentachlorophenylthiophosph that in a dosage of 10 kg/ha and it then turned out that the compounds in the agents according to the invention produced no difference whatsoever between untreated and treated plants, while that after the treatment with the known compound a slight leaf burn occurred.

An agent according to the invention can be processed in the usual ways.

For this purpose, the active compounds are mixed with solid or liquid carriers and possibly dissolved therein, if desired, enriched with dispersing, emulsifying or wetting agents. Preparations obtained in this way can either be showered out, atomized or atomized in the air, as such or emulsified or dispersed in a liquid, e.g. water. Of the various topical preparations into which the active compounds can be processed, mention can be made of the so-called mixed oils, spray and atomizing powders. These forms are only mentioned by way of example and the invention is not limited to them.

To prepare mixed oils, the active compounds are dissolved in a suitable solvent, which is itself poorly soluble in water, and an emulsifier is added to this solution. Suitable solvents are e.g. xylol, toluene, dioxane. petroleum destillates which are rich in aromatic compounds, e.g. solvent naphtha, distilled tar oil, further tetralin, cyclohexane or mixtures of these liquids. As emulsifiers, alkyl phenoxy polyglycol ethers, polyoxyethylene sorbitan esters of fatty acids or polyoxyethylene sorbitol esters of fatty acids can be used. A number of these types of emulsifiers are known under the trade names "Triton", "Tween" and "Atlox".

The concentration of the active compound in the liquid to be mixed with water is not bound to narrow limits. It can e.g. vary from 2 to 50 percent by weight. Before these solutions are used, the mixed oil is emulsified in water and this emulsion is showered out. Generally, the concentration of the active compound in these aqueous emulsions is between 0.01 and 0.5% by weight.

Spray powders can be prepared by mixing and grinding the active compounds with a solid inert carrier, usually in the presence of a dispersing and/or wetting agent. Before use, the spray powder is dispersed in a liquid, preferably in water, and the resulting dispersion is atomized. It is important that the spray powder consists of small particles, in order to prevent the atomiser's opening from being blocked during use. It therefore pays to use a fine powdered substance as carrier. If desired, the mixture of the carrier substance, the active compound and possibly present excipients is therefore also ground.

As carriers, e.g. considering pipe clay, diatomaceous earth, kaolin, dolomite, chalk, talc, gypsum, betonite, attapulgite, silicic acid, celite, wood flour, tobacco dust or ground coconut shells. Suitable dispersants are lignin sulphonates and naphthalene sulphonates. As a wetting agent, e.g. usable fatty alcohol sulphates, alkylaryl sulphonates or fatty acid condensation products, e.g. known under the trade name "Igepon".

The concentration of the active compound is also not bound within narrow limits in the case of spray powders. Concentrations between 10 and 80 percent by weight are usually chosen.

The atomizing powder can be prepared by placing an active compound on a solid carrier as such or dissolved in a solvent. During use, the preparation thus obtained is atomized in the air in a dry or finely powdered state. These powders can also be produced using suitable lighter carriers in the manner described for the production of spray powders. As carrier substances, the products mentioned above are relevant for the production of spray powders. Generally, the concentration of active compounds in nebulizers is lower than in the spray powders or mixed oils, but higher than the concentrations in dispersions or emulsions that can be obtained by diluting the spray powders or mixed oils with liquid. The dusting powders often contain 1 to 20% by weight of active compound. Finally, it can be mentioned that the mixed oils, spray powders or atomizing powders according to the invention can be prepared by mixing two mixed oils (or spray and atomizing powders) that each contain one of the active compounds).

A spray powder can be produced by mixing 25 parts by weight of bis(N,N-dimethylamido) pentachlorophenyl phosphate, 68 parts by weight of dolomite, 2 parts by weight of oleylamidomethyl taurate and 5 parts by weight of sodium lignin sulphonate and then grinding to an average particle size of less than approx. 10 microns.

An atomizing powder is produced, e.g. in that 3 parts by weight of bis(N,N-dimethylamido)-pentachlorophenyl phosphate, 7 parts by weight of diatomaceous earth and 90 parts by weight of dolomite are ground after mixing to an average particle size of less than approx. 10 microns.

To produce a mixed oil, e.g. 10 parts by weight of bis(N,N-dimethylamido) pentachlorophenyl phosphate in a mixture of 12 parts by weight of dioxane, 6 parts by weight of polyoxyethylene sorbitan fatty acid ester and 72 parts by weight of xylol. When poured into water, such a mixed oil by itself produces exclusively stable emulsions.

Comparison tests have been carried out with the compound bis(N,N-dimethylamido)-pentachlorophenylthionophosphate according to British patent no. 673 877 with the compound in the agents according to the invention, as the effect has been tested against barley powdery mildew (Erysiphe graminis). It then turned out that the compounds in the agents according to the invention were 10-20 times as strong as the known compound according to the aforementioned British patent.

In the experiments to determine the phytotoxic effect of the compounds, young plants of creeping beans, tomatoes, oats and beetroot were treated with solutions of the various compounds. It then turned out that the two compounds in the agents according to the invention were not phytotoxic, while the known above-mentioned thionophosphate was slightly phytotoxic.

Claims (1)

Means for combating fungi, in particular powdery mildew, characterized by a content of a compound of the general formula as active substance, where X denotes an oxygen or sulfur atom.