DE1667873B - Fungicidal agent with prophylactic and curative effectiveness - Google Patents

Description

IO

The fungicidal effectiveness of halogenated and / or nitrated thiophenes is known (USA patents 2 600 126 and 2 691 616). However, none of the thiophene compounds mentioned so far shows next to one sufficient fungicidal effectiveness also a door the use in practical plant protection required Plant compatibility.

It has now become a fungicidal agent with prophylactic and curative effectiveness for combating found phytopathogenic fungi, which is characterized in that it contains 2,5-dinitro-3,4-dichloro-thiophene as the active ingredient, optionally in combination with other fungicidal active ingredients.

It is surprising that 2,5-dinitro-3,4-dichloro-thiophene, which has not yet been proposed as a fungicidal agent, very good plant tolerance in addition to a strong prophylactic and curative effectiveness. Especially those curative property which the substance according to the invention has, for example, against botrytis, genuine and downy mildew, even with severe infection, is not one of the fungicides used to date known. The spores of fungal pests become very large as a result of the active ingredient according to the invention killed quickly (about an hour) and caused the mycelium to die.

In addition, reference can be made to the low toxicity of the claimed agent to warm blooded animals.

The application takes place in a known manner, for example by spraying or spraying the active ingredient suspended or emulsified in water, as well as by dusting the conventional solid carrier materials such as kieselguhr, talc, chalk, kaolin Means. The addition of surface-active substances such. B. alkylarylsulfonates, fatty alcohol sulfates, like sodium lauryl sulfate (Texapon) a more even distribution on the plants. The mixtures used for the preparation of the spray liquors usually contain 50 to 80% active substance. The remaining shares are accounted for by wetting agents and carrier materials. The means comes in powder form for use, it consists of only 5 to 50% of the claimed compound.

2,5-Dinitro-3,4-dichloro-thiophene can be used alone or with other known active ingredients, such as Dithiocarbamates, thiuram compounds or phthalimides can be used together. Through a combination of the active ingredients is added to the mixture in addition to increasing the prophylactic effect also conveys a curative effectiveness. It is useful to use mixtures of the known Fungicides and the active ingredient according to the claim in a ratio of 1: 1 to 4: 1.

The valuable properties of the active ingredient can only be seen in this, but not in its isomers. In addition, the replacement of the chlorine atoms with bromine brings about a substance with noticeably less curative properties Effectiveness and greater phytotoxicity.

The active ingredient according to the claims is preferably prepared by nitration of 3,4-dichlorothiophene (E. Profft, G. SoIf, Journal for Practical Chemistry, Vol. 24, pp. 38-73, 1964).

example 1

In order to compare different thiophene derivatives with regard to their fungicidal effectiveness and Various tests shown in Table 1 were carried out to obtain plant tolerance.

Spore germ test with Alternaria tenuis

The various thiophene derivatives are dissolved in acetone and brought to a concentration of 0.005% diluted. Small amounts (about 0.03 ml) are placed in areas marked with paraffin rings on microscope slides dripped on. After evaporation of the solvent, a drop of an Alternaria spore suspension is placed on the same spot upset. Incubation takes place overnight in a humid chamber at 25 ° C. After about 16 hours, the germinated or non-germinated spores are counted under the microscope and the percentage of germ inhibition compared to the control (acetone without the addition of a fungicide) determined.

Plant tolerance and curative effectiveness in case of powdery mildew infestation

Young cucumber plants are made with conidia from Erysiphe cichoracearum and wheat seedlings Conidia of Erysiphe graminis strongly infected. As soon as the infestation with these pests also for Can be clearly seen with the naked eye, the plants are treated with an aqueous suspension of the thiophene derivatives (1000 ppm active ingredient content) injected. The formulation from which the aqueous suspension is made was, had the following composition: 50% active ingredient, -20% cell pitch, 18% kaolin, 10% Chalk and 2% Texapon. The rating on plant tolerance and curative fungicidal effectiveness takes place after 2 days.

Table 1 Comparison of some thiophene derivatives

Active ingredient

Spore germ test
(% Germ inhibition)

50 ppm

Plant compatibility
1000 ppm

Curative effect of powdery mildew
1000 ppm

Tetrachloro thiophene

2,3,4-trichloro-5-nitro-thiophene

0% 0%

Plant completely destroyed
Plant completely destroyed

continuation

Active ingredient Sporenkcimiesi
(% Germ
inhibition)
50 ppm Plant compatibility
1000 ppm Kurniivc effect powdery mildew
1000 ppm 3,4-dinitro-2,5-dichloro
thiophene
2,5-dinitro-3,4-dichloro
thiophene
2,5-dinitro-3,4-dibromo
thiophene
Untreated I.
100%
100%
100%
0% very strong damage
no damages
minor damage
no damages Infestation a little weaker
Infestation completely eliminated
Infestation remained the same
Infestation increased

Example 2
Sporecim test with Alternaria tenuis

The individual compounds are dissolved in acetone, then concentration series are produced in the same solvent. Small amounts (about 0.03 ml) are placed on slides in areas marked with paraffin rings. After evaporation of the solvent, a drop of an Alternaria spore suspension is applied to the same place. Incubation takes place overnight in a humid chamber at 25 ^° C. After about 16 hours, the germinated or non-germinated spores are counted under the microscope and the percentage germ inhibition compared to the control (acetone without the addition of a fungicide) is determined.

Table 2 Inhibition of spore germs by thiophene derivatives

Active ingredient

Killing in % 10,000 ppm 50 100 1000 23 0 0 0 100 0 0 64 100 100 100 100 At. el 4 "pi

2,3,4,5-tetrachlorothiophene

3,4,5-trichloro-2-nitro-thiophene

2,5-dinitro-3,4-dichloro-thiophene

Example 3

Prophylactic effectiveness of 2,5-dinitro-3,4-dichloro-thiophene against phytopathogenic fungi

Test plants are given a suspension that contains the active ingredient in various concentrations, injected. After the spray coating has dried on, the plants are treated with a spore suspension of fungi sprayed or dusted with conidia of powdery mildew mushrooms. After infection has taken place, the test plants are placed in a greenhouse at high humidity. After 3 to 8 days depending on the type of plant the infestation is rated in comparison to the untreated but infected control.

Table 3

concentration Downy mildew Percent infestation Real one mildew ppm Wine Phytophthora cucumber wheat 0 tomato 0 0 2000 10 0 0 10 800 20th 0 10 25th 400 25th 10 30th 60 80 100 25th 100 100 Untreated 100

Curative effect of 2,5-dinitro-3,4-dichlorothiophene

For these experiments, plants were used that were either artificial under cultivation conditions had been infected, or showed significant fungal attack in their natural habitat. There were aqueous suspensions used in various concentrations. The formulation from which the aqueous Suspension was made, consisted of 50% active ingredient, 20% cell pitch, 18% kaolin, 10% chalk and 2% Texapon. The fungal attack was rated after 1 and 8 days. The values obtained are in the tables 4 and 5 reproduced.

Table 4

concentration
ppm Downy mildew
Wine, leaves ßotrytis
Wine, grapes 500
250
100
Untreated 3
2
3
0 3
2
0
-4-

Table 5
Curative effectiveness in powdery mildew fungi

Conc. cucumber rose wheat Apple E / ühe Wine ppm 5000 3 4000 3 3000 3 3 2500 2 2 3 3 200C 3 2 1250 3 2 2 1000 3 1 2 1 3

Legend for tables 4 and

+ = Infestation increased,

0 = infestation remained the same,

1 = slightly reduced infestation,

2 = infestation significantly weaker,

3 = infestation completely eliminated.

Conc. cucumber ...
rose wheat Apple Eiclk Wine ppm 800 2 2 500 I. 2 Un be acts + 0 -L 0 0

Claims (1)

Claim: Fungicidal agent with prophylactic and curative effectiveness to combat phytopathogenic Mushrooms, characterized that the active ingredient is 2,5-dinitro-3,4-dichlorothiophene, optionally in combination with other fungicidal active ingredients.