DE1667873C - Fungicidal agent with prophylactic and curative effectiveness - Google Patents

Description

to

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 required for use in practical crop protection 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 has 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.

It is applied in a known manner, for example by spraying or spraying the in water suspended or erauled active substance, as well as by dusting the usual solid carrier materials, such as kieselguhr, talc, chalk, kaolin. The addition ensures that it is more surface-active Substances, e.g. B. alkylarylsulfonates, fatty alcohol sulfates, such as sodium lauryl sulfates (Texapon) a more even distribution on the plants. The Γύ <· the preparation of the spray mixtures used Mixtures usually contain 50 to 80% active substance. The remaining shares apply to Wetting agents and carrier materials. If the agent is used in powder form, it consists only of 5 to 50% from 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 applied together. By combining the active ingredients, in addition to the Increasing the prophylactic effect also gives the mixture a curative effect. It is advantageous to use mixtures of the known fungicides and the one according to the claims Produce active ingredient in the ratio range from 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. Pr of ft, G. SoIf, Journal für p.aktiscU Chemie. Vol. 24, pp. 38 to 73. 19MV

example 1

In order to compare different thiophene derivatives with regard to their fungicidal effectiveness and Plant tolerance / u obtained, various tests shown in Table 1 were carried out.

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 (approx. 0.03 ml) are placed in areas marked with paraffin rings on the C3 object slide 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 compatibility and curative effectiveness Infestation with powdery mildew fungi

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 The naked eye can clearly be seen, the plants are watered with a. 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 I.
Comparison of some thiophene derivatives

Active ingredient

Tetrachloro thiophene

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

Spore germ test
(% Germ inhibition)

50 ppm

0% 0%

Plant compatibility
1000 ppm

Plant completely destroyed Plant completely destroyed

Curative effect of powdery mildew
1000 ppm

I 667 873

continuation

Active ingredient Spore germ test
(% Germ
hecnmung)
SO ppm Plant compatibility
1000 ppm ! Curative effect of powdery mildew
1 OUOpDm Β / ΚΜίηίΓΟ-Ι, δ-αίςηΙοί -
thiophene
^ S-Dinitro-S ^ 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
Spore germ test with Alternaria tenuis

The individual compounds are dissolved in acetone, then in the same solvent Concentration series produced. Small amounts (about 0.03 ml) are marked with paraffin rings Sites applied to microscope slides. After evaporation of the solvent is on the same Place a drop of Alternaria spore suspension

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 Germ inhibition compared to the control (acetone without the addition of a fungicide) determined.

Table 2 Inhibition of spore germs by thiophene derivatives

Active ingredient

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 containing the active ingredient in various concentrations, injected. After the spray coating has dried on, the plants are coated 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
ppm Downy mildew
Wine Percent befa
Phytophthora
tomato 1
Real one
cucumber mildew
wheat 2000 0 0 0 0 800 10 0 0 10 . 400 20th 10 10 25th 80 25th 25th 30th 60 Untreated 100 100 100 100

Mortality in% 100 « 100 10000 pp; .i 50 KX) 0 game 4 23 0 0 0 64 100 0 100 100 100 at

Curative effect of 2,5-dinitro-3,4-d> chlorothiophene

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 Botrytis
■ Wine, grapes 500
250
100
Untreated 3
2
3
0 3
2
0
+

Table 5
! Curative effectiveness in powdery mildew fungi

Conc. cucumber rose wheat Apple Oak Wine 3 ppm • 5000 3 2 4000 3 3000 3 2500 2 2 3 3 2000 3 1250 3 2 2 1000 3 1 2 1 3

IO

Conc.
ppm cucumber rose wheat Apple Oak Wine 800
500
Inconvenient
acts 2
1 0 0 O IO IO Legend for the
+ = Infestation labels 4 and
increased. 5

0 = infestation remained the same,

1 = slightly reduced infestation,

2 = infestation significantly weaker,

3 = infestation completely eliminated.

Claims (1)

Patent claim: Fungicidal agent with prophylactic and curative effectiveness to combat phyxopathogenic Fuze, characterized that the active ingredient is 2 ^ -Dinitro-3,4-dichlorothiophene, optionally in combination with other fungicidal active ingredients.