DE1017405B - Fungicidal pesticides with therapeutic efficacy - Google Patents

Description

Fungicidal pesticides with therapeutic efficacy All so far in the trade. fungicidal sprays and dusts - with the exception some mercury compounds - have against. Mushrooms, which invade the planters, nu, prophylactic effect. They only kill the mushrooms or their spores, which are on the plant surface .; fungi that have entered the plant are not included and pose a constant risk of renewed infection.

So there is no real healing effect. That means that a Attack can only be warded off successfully if the pesticide is in front the infection is on the leaves.

As a result, the prophylactic control has many weaknesses afflicted. The effect decreases with the degree of washing down by rain; fast after and is with the often imperfect: covering of the plant surface with the uniform, dense spray coating required for protective effect unreliable.

For many years this has given rise to the wish, similarly as in human and veterinary medicine to use substances derived from, the plant recorded and forwarded in the control system of the same. If of that The field of insecticides and herbicides is neglected when serving externally on that Applied to the leaf or taken up by the plant roots and transmitted systemically Substances are known and; are widely used in practice, so are In the fungicides sector there are a number of substances whose systemic Effect and forwarding has been proven. Target herbicidal growth substances; thereon to destroy plants. So the ability to penetrate the plant becomes used with destructive intent. Other growth substances that are also on the leaf be included, e.g. B. in fruit growing, should, for example, an early fall of, fruits #Terhimin or achieve the opposite (thinning) or with tomatoes z. B. bring about higher fertility and earlier maturity. Systemic island pesticides (substances passed on in the plant's control system), such as certain phosphoric acid esters, aim the. Sap of the plant for certain species of insects or spider mites, too poison. These intra-therapeutic insecticides are taken from both the roots as well as taken up by the leaves and forwarded systemically. The plants, tolerate the amount of active ingredient required for killing without harming themselves to suffer. The margin between the dose curativa and the dose toxiea is reilative great. This can easily be explained by the fact that plants and insects are not related are. If one looks at the relation of the fungus to the plant, then there is due to the Relationship - mushrooms belong to plants, - the assumption is close; that here the span between the dose curativa and the dose toxica is very small is. Accordingly, it is also understandable that attempts at systemic fungicides to get., encountered considerable difficulties.

These attempts dealt with the uptake of the fungicidal compounds through the roots or by means of injections into the water system herbaceous and woody plants .. The pathogens examined here belong - in the first place Line to the Fusarium and Botrytis species on tomatoes and cleaning lanes as well as to Ceratomella ulmi, the causative agent of Dutch elm disease. With the chemical used. links it succeeded more or less well, the pathogen's entrance into the plant! to prevent it from spreading in the plant. Slide practical Performing an interior; Therapy, about the roots, will probably only be limited Unifange;,. Z. B. in, greenhouses or high-quality Einzelin = dividuen perform permit. The latter also applies to injections.

A fight against the most important diseases in general crop protection However, because of the large number of plants to be treated: only by spraying or B-estäübürig see the plant surface possible.

Such a way of combating the fungal germs that have already penetrated the plant, only Venturia on pome fruit, was previously only possible by means of highly toxic mercury preparations, a number of which some are still effective, but only a few days after the infection started. Because. In view of the toxicity, however, the possibility of using preparations containing mercury is restricted to only a very small area of application. In the search for mercury-free agents, it has now been found that compounds of the general formula given below have a fungicidal intrapeutic effect which lasts over long periods of time, which is apparently due to the fact that the preparations penetrate the plants through the plant surface. Your general formula is where R1 and R2 denote the following radicals: alkyl, aralkyl, cycloalkyl, alkylthiocarbamate, which can contain halogen, --N 1121 - N 02, - OH or other groups, which in turn are optionally substituted, and where R1 and R2 are the same. , different or part of a ring. can be and one of the two can also mean H.

The carboxylic acid residue should be modified in a wide variety of ways can, so z. B. the residue of a saturated or unsaturated carboxylic acid, oxycarboxylic acid, Represent dicarboxylic acid and organic or inorganic salts, esters or amides thereof can.

In these compounds the fungicidal properties of the dithiocarbasnate group are systematically or internally through the linkage with a carboxylic acid group been made effective.

The fungiz, ida depth effect is not limited to the simple acid derivatives or their esters, but it can also be used, for. B. the compounds with acid amides or unsaturated acids, also the carboxylic acid derivatives of ethylene-bis-dithiocarbaanic acid, so generally compounds of the group According to the invention, the present invention relates to fungicidal crop protection agents which contain compounds of the above general formula.

These remedies have: in addition to the one described: intra-therapeutic Effect has the particular advantage that, when used in emulsion form, it has a lasting effect own while at the; fungicidal plant protection products that have been used up to now the increased rain washability made the emulsion form unsuitable.

The dialkyldithiocarbaminaacetic acids also have growth substance properties, which makes the areas of application for this part of the compounds mentioned for combating harmful fungal ice be restricted to those for whom this side effect does not bother.

Because of the already mentioned basic similarity between the The pest fungus to be combated and the plant to be protected is at your internal therapeutic level acting, fungicides of course also a phytotoxic effect to be expected .. you is actually in the Dialkyldithiocarbam.inoessigsäurers, the Dimethyldithiocarbaminpropionäure @, -butyric acid, etc. and its derivatives are quite considerable, but not in the case of these mentioned much lower.

In their ability to penetrate through the plant surface, results the possibility of having sufficient protective or healing effects at the site of the attack fungicidal concentration can be achieved without damaging the entire plant if one proceed accordingly carefully.

But it has now been found that, surprisingly, the formic acid derivatives, especially those of dialkyldithiocarbamic acid relatively very little are phytotoxic, so that it is special with them. is quite possible a fungicidal Protective effect without damaging the plant. reach.

These derivatives are therefore used as active ingredients for pesticides excellent usable, all the more so as they are moreover compared to the Acetic acid derivatives have a remarkably stronger effect, especially against Phytophthora on potatoes and tomatoes as well as against Plasmopara (Peronospora), have wine.

The compounds mentioned are prepared by methods that are customary for this purpose, e.g. B. by reacting halogenated carboxylic acids or their derivatives with the salts, in general alkali metal salts of the sulfur-containing compounds listed above, with esterification or other substitution being of course also possible after the condensation. It forms z. B. in the implementation of the Na salt of ethylene, -bisd: ithiocarbamic acid with dich, laracetic acid methyl ester, the following compound: The following compounds, the majority of which have not yet been described in the literature and. which have been found to be effective by us are as. Examples given: The following examples show comparative figures for the internal therapeutic and systemic effects. The evaluation of the effect is carried out according to comparative figures (VZ), the fungal growth in the untreated but infected plants (control) being set = 100 (unhindered growth). 0 means no growth of the mushrooms. The VZ values between 0 and 100 indicate the strength of the fungal growth, increasing from 0 to 100, which are determined up to VZ 50 on the basis of the number of infections and beyond that on the basis of estimates.

So you get z. B. a comparative figure of 31 (versus control = 100) when the leaf upper side of celery plants twice within 24 hours with an emulsion of 1000 ppm dimethyl-dithioca.rbamin.o@- ethyl formate sprayed in water and on the second day of treatment the underside of the leaf with a Spore suspension becomes infected by Septoria.

In another example, one obtains. a comparative figure of 13 (versus Control 100) when the leaf surface of grapevines with 1000 ppm of the methyl ester the di-isopropyldithiocarbamino-crotonic acid treated and after 2 days. the underside of the leaf is infected with a sporangia suspension of the downy mildew.

In the following experiments, the upper side of the leaf was sprayed three times at intervals of 1 day each with the specified active substance and concentration and the lower side of the leaf was infected on the last day of treatment. In these three experiments, the active ingredient was absorbed by the leaves and showed a good internal therapeutic effect compared to the known fungicides copper oxychloride and dimethyldithiocarbamine-acidic zinc. In this experiment, the active ingredient was absorbed by the roots and passed on systemically. The formic acid esters mentioned under Nos. 2 and 17 were neither phytotoxic nor did they show the effect of growth substances. _ _.

Claims (3)

PATENT CLAIMS: 1. Fungicidal crop protection agents with therapeutic properties, characterized in that they contain active ingredients of the general formula contain, where R1 and R2 are the following radicals: alkyl, aralkyl, cycloalkyl, alkylthiocarbamate, which can contain halogen, --NH2, _NO2, -OH or other groups, which in turn are optionally substituted, and where R1 and R2 are the same , can be different or components of a ring and one of the two can also be H; the carboxylic acid residue should be able to be modified in a wide variety of ways, e.g. B. can represent the remainder of a saturated or unsaturated carboxylic acid, oxycarboxylic acid, dicarboxylic acid and organic or inorganic salts, esters, amides. 2. Plant protection agent according to claim 1, characterized in that it Contain formic acid derivatives of dialkyldithiocarbamic acids. 3. Plant protection products according to claim 1 and 2, characterized in that they contain the active ingredients in emulsified Shape included.