DD257576A1 - FUNGICIDAL AGENTS - Google Patents

Abstract

The invention relates to novel fungicidal compositions which contain, in addition to the usual auxiliaries and traeger substances as active ingredients a-thiocyanato-acetophenones of the general formula in which R is chlorine, bromine, hydrogen, a methyl or methoxy group, n is the numbers 1 or 2, X and Y is hydrogen or bromine.

Description

Field of application of the invention

The invention relates to fungicidally active α-thiocyanato-acetophenones for controlling fungal diseases on crop plants.

Characteristic of the known technical solutions

For control of fungal diseases on crops, salts of ethylene bis (dithiocarbamic acid), e.g. Maneb (US Pat. No. 2504,404, US Pat. No. 2,710,822), Mancozeb (US Pat. No. 2,504,404, Belg. Pat. No. 996,264) and Zineb (US Pat. No. 2,457,674).

Of great importance as fungicides are in addition to the metal salts of dimethyldithiocarbamic the thiuram derivatives, eg. As the Tetramethylthiuramdisulfid (US Patent 1972961).

The disadvantage of the metal salts of ethyl bis (dithiocarbamic acid) is that they have a phytotoxic effect on crops. Compared to fungi such as Fusarium culmorum, Botrytis cinerea and Alternaria tenuis they show only mediocre effects. Tetramethylthiuram disulfide has a very good action against Botrytis cinerea, on the other hand, the action against Phytophthora infestans unsatisfactory. Japanese Patent 7021,297 and East German Patent Nos. 92602, 209716 and 209955 describe the fungicidal effects of α-halogenated acetophenones. The compounds listed therein are also phytotoxic and show only minor effects on Fusarium culmorum, Botrytis cinerea and Altemaria tenuis. In DE-PS 2 823658 a-thiocyanato-acetophenones are claimed as bactericides. The listed compounds show little activity against fungi.

Object of the invention

The aim of the invention is to develop new fungicidal agents having a broad spectrum of activity with good plant tolerance for controlling fungal diseases on crop plants.

Explanation of the essence of the invention

This object is achieved in that the novel fungicidal compositions in addition to conventional excipients and carriers compounds of the general formula:

in which R = chlorine, bromine, hydrogen, a methyl or methoxy group

η the numbers 1 or 2

X and Y = hydrogen or bromine.

The new fungicides have a broader spectrum of activity and a higher fungicidal activity than the cited commercial preparations zineb and thiuram. The α-thiocyanato-acetophenones can be prepared by known processes by conversion of α-haloacetophenones by means of alkali thiocyanates or their subsequent bromination. Following these procedures, the following compounds listed in Table 1 were synthesized and tested for their fungicidal activity.

-2- ZS / O / D

Table 1: a-thiocyanato-acetophenones

C-SCIT

R connection R Ϊ X Y Fp ( ⁰ C) η 1 H br br 98 2 4-CI br br 102-103 3 4-Br br br 113-115 4 3,4-Cl ₂ br br 95 5 3,4-Cl ₂ H H 107-109 6 4-CH ₃ H br 81 7 4-OCH ₃ H br 115

embodiment example 1

Effect on different fungi in "in vitro" test:

The test fungi Alternaria tenuis, Botrytis cinerea and Fusarium culmum were inoculated on agar plates containing drug concentrations of 0.1%, 0.01% and 0.001% by weight. The evaluation took place on the 10th day according to the following rating scheme:

1 = no growth inhibition

2 = weak growth inhibition

3 = strong growth inhibition

4 = complete growth inhibition

The fungicidal action of the compounds according to the invention against o.g. Mushrooms are shown in Table 2.

Table 2

Medium credit score

Botrytis cinerea Alternaria tenuis Fusarium culmorum

0.1 0.01 0.001 0.1 0.01 0.001 0.1 0.01 0.001

(Wt%) (wt%) (wt%)

1 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0

2 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0

3 4.0 4.0 2.0 4.0 4.0 1.0 4.0 4.0 1.0

4 4.0 4.0 2.0 4.0 4.0 1.0 4.0 4.0 1.0

5 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0

6 4.0 4.0 4.0 3.0 1.0 1.0 4.0 3.0 1.0

7 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Zineb 4.0 1.0 1.0 4.0 4.0 1.0 4.0 1.0 1.0 thuuram 4.0 4.0 4.0 4.0 4.0 1.0 4.0 4.0 1.0

The results from Table 2 show that the compounds 1, 2, 5 and 7, especially at low application rates, are far superior to the comparison products zineb and thiuram in their action compared to the fungi mentioned.

Example 2

Fungicidal and bactericidal action of the agents according to the invention on potato tissue.

The compositions according to the invention were sprayed onto potato tissue. Subsequently, the infection was carried out with the causative agent of Erwinia carotovorum and the pathogen of the potato blight Fusarium spp.

It was evaluated according to the following rating scheme:

1 = no effect against the pathogen

2 = mean effect

3 = no infestation (tissue healthy)

Table 3

Effect of the agents according to the invention against Erwinia carotovorum and Fusarium spp.

Medium credit score

Erwinia carotovorum Fusarium spp.

0.5 0.1 0.5 0.1

Wt% AS wt% AS

4 3 2 3 3

5 2 2 3 3

7 3 3 2 2 '

Chlorine 2 2 3 3

amphenicol

Table 3 shows that compared to the comparison product chloramphenicol before all the compound 4 shows better effect, the means 5 and 7 show comparably good properties against the o.g. Pathogens.

Example 3

Action against Phytophthora infestans.

Tomato leaves were treated with a spray mixture containing 0.1% to 0.01% active ingredient of the compounds of the invention, which in turn was formulated into a water emulsifiable or suspendible form.

After the spray coating had dried, the infection was carried out with Phytophthora infestans. The incubation of the thus treated test plants was made C. and a relative atmospheric humidity of 90-100% at 2O ^0th

5 days later, the infestation of the following rating scheme was determined:

1 = severe infestation by P. i. as untreated 30%

2 = average infestation 11-30%

3 = low infestation 1-10%

4 = no infestation 0%

The converted results from the test are shown in Table 4.

Table 4

Effect of the agents according to the invention against Phytophthora infestans

medium Efficiency (4) 0.01% AS 0.1% AS 56.7 1 90.0 43.3 2 76.7 42.5 3 76.9 36.3 cn 73.6 23.4 Zineb 100.0

Phytotoxicity did not occur.

From Table 4 it can be seen that the compounds of the invention have better effect at the low application rate than the comparative product zineb, wherein the agent No. 1 stands out particularly.

The most effective compound (No. 1) was tested in practical application rates of intact tomato plants.

Table 5

Effect on intact tomato plants Average efficiency (%)

2.0kg / ha 1.0kg / ha 0.5kg / ha '0.25kg / ha

1 100.0 100.0 100.0 100.0

Zineb 100.0 100.0 80.0 23.4

Also from this.Tabelle shows that the compound of the invention 1 at lower application rates shows better effect than the commercial product zineb.

Claims (1)

Invention claim: Fungicidal agent, characterized in that, in addition to customary excipients and carriers, as active substances, compounds of the general formula in the R = chlorine, bromine, hydrogen, a methyl or methoxy group η = the numbers 1 or 2, X and Y = hydrogen or bromine mean, included.