GB2269102A

GB2269102A - Plant fungicidal compositions

Info

Publication number: GB2269102A
Application number: GB9315727A
Authority: GB
Inventors: Basil Terence Grayson; Alan John Sampson
Original assignee: SHELL INT RESEARCH; Shell Internationale Research Maatschappij BV
Current assignee: SHELL INT RESEARCH; Shell Internationale Research Maatschappij BV
Priority date: 1992-07-31
Filing date: 1993-07-29
Publication date: 1994-02-02
Also published as: FR2694161B1; JPH0687704A; GB9315727D0; DE4325558A1; FR2694161A1

Abstract

A fungicidal composition comprises as active ingredient a compound of general formula: <IMAGE> in which: R represents alkyl or optionally substituted cycloalkyl or phenyl, X represents a nitrogen atom or a -CH- group; Y preferably represents a grouping -OCH2-, -CH=CH- or -CH2 CH2 -; and Zm represents O-3 substituents; and an aliphatic alcohol alkoxylate, for example an ethoxylate, with an average of 5-9 ethylene oxide units per molecule, of a C9-15 aliphatic alcohol, as activity enhancing adjuvant.

Description

2269102 FUNGICIDAL COMPOSITIONS This invention relates to novel fungicidal

compositions, to their use, and to their preparation. The invention relates in particular to novel fungicidal compositions which incorporate 1-hydroxyethyl azole compounds as disclosed in U.S. Patent No. 4723984.

It has now been discovered that the fungicidal activity of the aforementioned compounds is enhanced to a surprising and significant extent by the co-application to a plant to be treated, of an adjuvant selected from a particular class, namely aliphatic alcohol alkoxylates. Such alkoxylates are substantially non-phytotoxic.

Moreover, they are very suitable for the development of practical formulations.

In accordance with a first aspect of the present invention, there is provided a fungicidal composition which comprises a compound of general formula:

OH 1 Y-C - R 1 52 ZW in which:

R represents an alkyl radical, an optionally substituted cycloalkyl radical or an optionally substituted phenyl radical; c X represents a nitrogen atom or a CH group; Y represents a grouping -OCH2- , -CH2CH2:- or -CH=CH-; Z represents a halogen atom, an alkyl, cycloalkyl, alkoxy, alkylthio, haloalkyl, haloalkoxy or haloalkylthio radical, an optionally substituted phenyl radical, an optionally substituted phenoxy radical, an optionally substituted phenylalkyl radical or an optionally substituted phenylalkoxy radical; and 5 m is 0, 1, 2 or 3; or an acid addition salt or a metal salt complex thereof; and an alkoxylate of an aliphatic alcohol. In accordance with a second aspect of the present invention, there is provided a method of combating a fungus at a locus, comprising treating the locus with a composition of the first aspect. The locus may be an agricultural or horticultural locus.

The locus may be plants subject to fungal attack, seeds of such plants or the medium in which plants are growing or are to be grown. The method may comprise combating a fungus already present at a locus and/or prophylactic fungicidal treatment at a locus. The composition may be used to control a large number of fungal diseases of plants, for example Erysiphe, Puccinia, Rhynchosporium, Pyrenophora and Septoria. In particular, the plants may suitably be cereals, especially wheat or barley plants, because of the control achievable by the method of the invention against infestations of the fungi B17siphe graminis (powdery mildew) and Leptosphaerla nodorum (septoria).

Preferably, the method according to the invention involves the foliar treatment of plants with the composition.

Preferably, the method of the invention comprises treating the locus with an aqueous composition which comprises a compound of general formula I and an alkoxylate of an aliphatic alcohol.

A preferred alkoxylate of an aliphatic alcohol is based on alkoxy units having 2 carbon atoms, thus being an ethoxylate, or 2 and 3 carbon atoms, thus being a mixed ethoxylatelpropoxylate. An ethoxylate is preferred. Such alcohol alkaxylates are available from various sources or may be prepared by alkoxylating a suitable aliphatic alcohol under known conditions.

In preferred aliphatic alcohol alkoxylates for use in the present invention, the alkoxylate chain may have at least 5 alkoxy moieties, suitably from 5 to 25 alkoxy moieties, preferably from 5 to 15, and most preferably from 5 to 9.

In preferred alcohol alkoxylates for use in the present invention, the alcohol moiety is derived from a C9-,, aliphatic alcohol, preferably a C9-15 aliphatic alcohol. As is well known, such alcohols are normally available in the form of mixtures. However, it may be stated that, in the context of the present invention, preferred alcohols are primary or predominantly primary, straight chain or predominantly straightchain, alcohols and with one hydroxy group or predominantly with one hydroxy group. They may be saturated or unsaturated but are preferably saturated alcohol alkoxylates, or alcohol alkoxylates in which saturated alcohol moieties predominate. The terms "predominate" and "predominantly" denote "more than 50% by weight" and, preferably, "at least 80% by weight".

Alcohol alkoxylates in which the alcohol is of vegetable. animal or mineral oil origin can be used.

In a method in accordance with the invention, the presence of an alkoxylate of an aliphatic alcohol may substantially reduce the quantity of a compound of general formula I which needs to be applied to a locus to obtain a given level of fungicidal activity. In practice, a compound of general formula I may suitably be applied to a locus in an amount in the range 10 - 600 g/ha, preferably 50 - 300 g/ha. The adjuvant may suitably be applied to a locus in an amount in the range 60 - 2000 g/ha, preferably 300 - 1500 g/ha.

Whilst a composition comprising an aliphatic alcohol alkoxylate and a compound of general formula I may have other fungicidal applications, it is likely to be of primary benefit for therapeutic foliar applications. Activity can be enhanced or broadened by co-application of a further fungicidal compound, suitable examples being dithianon, chlorothalonil and fenpropimorph. Preliminary tests have indicated that the enhancement effect which the alkoxylate adjuvant has on a compound of general formula I remains, when such a compound is also applied. Such a compound, when co-applied, may suitably be co-applied in an amount in the range 20 - 1200 g/ha, preferably 100 800 g/ha.

It may be desirable to co-apply further compound(s) to a said locus, for example an insecticide, acaricide, herbicide or nematocide, or a fertilizer.

In accordance with a further aspect of the present invention, there is provided an aqueous composition for use in the method of the invention, to be applied to a said locus. Such a composition may be prepared by mixing an aliphatic alcohol ethoxylate and a composition containing a compound of general formula I, taken from separate sources, in water in a tank; or., preferably, by adding, to water in a tank, a pre-mixed 'lone-pack" formulation containing both an aliphatic alcohol alkoxylate and a compound of general formula I. Such a pre-mixed formulation may most conveniently be a liquid or a wettable powder, the manufacture of each of which is entirely standard.

An antifoaming agent may be employed, if desired, in accordance with standard practice. An antifoaming agent may be a constituent of a "one-pack" formulation. When the aqueous composition is to be prepared by mixing an aliphatic alcohol ethoxylate, and a composition containing a compound of general formula I in a tank, and an antifoaming agent is desired, the antifoaming agent may conveniently be formulated with the ethoxylate component.

Conventionally, antifoaming agents are selected on the basis of compatibility with the formulation to be prepared; thus, for example, solubility of the antifoaming agent in the formulation has to be checked. Selection on such a basis is entirely routine in formulation technology. It was expected that, if needed, for the compositions of the present invention, and especially for the 'lone-pack" formulations, compatible, conventional antifoaming agents, including silicone-based products, would be suitable. However, it has been found that conventional agents such as silicone-based products are in fact not suitable for use with the compositions of the present invention.

Surprisingly, it has now been found that certain paraffinic oils, which are not conventional antifoaming agents, are not only compatible with compositions of the present invention but also provide useful antifoaming properties, where needed. It is therefore preferred that the composition of the present invention is used in conjunction with a paraf f inic oil as antif oaming agent, e. g. as an ingredient of the composition or by addition with the formulation ingredients in a tank mix with water.

Usually, paraffinic oils are derived from petroleum sources and are composed of paraffinic and aromatic, usually naphthenic, hydrocarbons. Suitable paraf f inic oils for use as antifoaming agents with compositions of the present invention, have a molecular weight in the range of from 140 to 180 and contain in the range of from 45 to 100%, preferably 50 to 100%, paraffinic hydrocarbons.

The concentration of the components in the aqueous composition may be calculated from the amount of a compound of general formula I and of alkoxylate it is desired to supply, and the rate of application of the composition (that is, the volume applied). Typically the rate of application of the composition may be 100-1000 llha. Thus, when the rate of application of the composition is to be 1000 llha, and that of a compound of general f ormula I and of the alkoxylate, 100 g/ha and 400 g/ha, respectively, the aqueous composition will contain 0.1 g/1 of a compound of general formula I and 0.4 g/1 of alkoxylate. Generally, the aqueous composition may contain 0.02-6.0 g/1 of a compound of general formula I and 0.08-20 g/1 alkoxylate.

In accordance with a further aspect of the present invention, there is provided a concentrate formulation containing an alkoxylate of an aliphatic alcohol and of a compound of general formula I, for dispersion or dissolution in water. Such a concentrate formulation may 7 suitably contain 5-200 g/kg, preferably 3-0-120 g/kg, of a compound of general formula I and 100-1000 g/kg, preferably 400-700 glkg, of adjuvant, the balance of the concentrate formulation being the usual types of further 5 materials.

With reference to compounds of general formula I, it will be appreciated that these will have optical isomers, because of the presence of an optical centre. The method of the invention may employ a compound of general formula I in the form of a single optical isomer, or in the form of a racemic mixture, or in the form of any other mixture of optical isomers. Similarly if Y represents the grouping -CH=CH- compounds of general formula I can additionally exist in two geometrical isomer forms, and the method of the invention may equally apply to an individual geometrical isomer, or to any geometrical isomer.mixture.

Preferred 1-hydroxyethyl azole derivatives used in the composition and method of the present invention are those in which R represents a straight-chain or branched alkyl radical with 1 to 4 carbon atoms, a cycloalkyl radical which has 3 to 7 carbon atoms and is optionally substituted by alkyl with 1 or 2 carbon atoms, or a phenyl radical which is optionally monosubstituted or polysubstituted by identical or different substituents, preferred substituents being: halogen, alkyl with 1 to 4 carbon atoms and haloalkyl with 1 or 2 carbon atoms and 1 to 5 identical or different halogen atoms (such as, in particular, fluorine and chlorine atoms). Z represents a halogen atom, a straight chain or branched alkyl radical with 1 to 4 carbon atoms, a cycloalkyl radical with 5 to 7 carbon atoms, an alkoxy or alkylthio radical with in each case 1 to 4 carbon atoms, a haloalkyl, haloalkoxy or haloalkylthio radical with in each case 1 or 2 carbon atoms and 1 to 5 identical or different halogen atoms (such as, in particular, fluorine and chlorine atoms), or a phenyl, phenoxy, phenylalkyl or phenylalkoxy radical, in each case optionally substituted, the phenylalkyl and phenylalkoxy radical having 1 or 2 carbon atoms in the alkyl part or in the alkoxy part and preferred substituents which may be mentioned being halogen and alkyl with 1 to 4 carbon atoms, and X, Y and m have the meanings indicated above.

Particularly preferred compounds of the formula I are those in which R represents a tert-butyl, isopropyl or methyl radical, or a cyclopropyl, cyclopentyl or cyclohexyl radical, in each case optionally substituted by methyl, or phenyl which is optionally monosubstituted or distributed by identical or different substituents selected from fluorine, chlorine, methyl and trifluoromethyl, Z represents a fluorine, chlorine or bromine atom, a methyl, tert-butyl, cyclohexyl, methoxy, methylthio, trif luoromethyl, trif luoromethoxy or trifluoromethylthio radical, or a phenyl, phenoxy, benzyl or benzyloxy radical, in each case optionally monosubstituted or disubstituted by identical or different substituents selected from fluorine, chlorine and methyl, and X, Y and a have the meanings indicated above.

Preferably m represents 1. Preferably Z,, represents a single substituent located at the 4-position. Most preferably Z, represents a 4-chloro substituent.

Specific compounds of general formula I which may be used in the composition and method of the present invention are stated in U.S. 4723984, which is incorporated herein by reference In an especially preferred compound of general formula I for use in the composition and method of the present invention Z, represents a 4-chloro moiety, Y represents a group -CH2-CH2-, X represents a nitrogen atom, and R represents a tert.-butyl group. This compound is known by the common chemical name tebuconazole.

The preparation of compounds of general formula I is described in U.S. Patent No. 4723984.

The invention extends to a method for the preparation of a composition as described herein.

The invention will now be further described with reference to the accompanying Examples.

Example 1 a) Materials The commercially supplied emulsif iable concentrate (EC) formulation of a compound of general formula I sold under the Trade Mark HORIZON and containing the active ingredient tebuconazole (CAS RN [107534-96-31 in a concentration of 250 g/1 was obtained.

The materials employed were the EC formulation HORIZON, an aliphatic alcohol ethoxylate, and tap water. The particular alcohol ethoxylate selected was DOBANOL 91-6 (Trade Mark) available from Shell.

This is an aliphatic alcohol ethoxylate. derived from mineral oil, having predominantly C9-,, primary alcohol moieties, and an average of 6 ethoxy units per molecule.

b) Plants Winter wheat, cv Hornet, were sown in 7 cm square pots. This resulted in establishment of 20 to 25 plants per pot. After 12 days, under normal glasshouse conditions (initially top watered, followed by automatic sub-irrigation; temperature of 20-25OC; 16 hour photoperiod, of daylight supplemented by mercury vapour lamps and/or sodium lamps as necessary), by which time the seedlings were at the 1-2 leaf stage, the plants were inoculated with ErysiRhe araminis fsp tritici from a stock infection.

Treatments were applied on day 13, usually about 28 hours after inoculation. Plants were then laid out in a controlled environment compartment of a greenhouse using a randomised double-block design to reduce variation due to placement. Watering was carried out by means of an automated sub-irrigation matting system.

c) PrCRaration and apRlication of spray solutions All test solutions were sprayed at four doses, the difference between doses being a factor of x2, the application rates being 25, 50, 100 and 200 g/ha of the active ingredient (a.i.) tebuconazole. A single quantity of the product was weighed out for all of the doses of the product. When adjuvant was added as a single a.i.: adjuvant ratio, the whole batch was prepared for the highest dose, then appropriate aliquots diluted with tap water to the correct concentrations for the lower doses. When adjuvant was added at a single dose per hectare for all treatments, the base formulation was made up at double the required concentration and then each dose diluted to the correct concentration using a stock solution of the adjuvant. All applications were made using a moving track sprayer fitted with a single flat-fan nozzle calibrated to give 400 llha of spray.

Four pots (replicates) were sprayed with each treatment.

In this Example 1 the alcohol ethoxylate adjuvant was added to give a single dose per hectare, 1 kg/ha, for all treatments.

d) Assessment Estimates of infection were made, f irstly after about one week, then after about two weeks. Usually the initial assessment was a score on a 0-9 scale, where 0 = no infection and 9 = very high infection of inoculated leaves. Later assessments were usually of percentage of leaf area infected by the mildew.

e) Results The results are presented in graphical form below.

The results after one week were analysed in standard manner using probit analysis to work out the ED90 figure, that is, the application rate of active ingredient required to give 90% control of the fungus, and the 95% fiducial limits. Those figures appear in Table 1 below.

12 7 days after treatment 6 D0BA-NOL at 1000 g/ha without DOBANOL 3 2 with DOBANOL 0 13 days after treatment 70 without DOBANOL % U) - infectedl 40-, - with DOBANOL 0 so 100 200 g/ha a.i.

Table i

EProductImixture ED% (g) 95% pid. lirlits "ixt 'S HORIZON alone 80 64-102 HO 1 HORIZON/DOBANOL at 1 32 22-444 H g/ I' Kg/hia Example 2

Further series of tests in accordance with those described in Example 1 were carried out, also using HORIZON as commercially available, but using dose rates of a.i. of 6.25, 12.5, 25 and 50 g/ha. However in these tests the DOBANOL was used both at a rate of 1 kg/ha, as above, and in a proportion of 10:1 parts by weight, of active ingredient. The ED90 results calculated from the results is shown in Table 2 below.

Table 2

Product/Mixture ED90 (g) 95% Fid. limits HORIZON alone 88 69-117 HORIZON/DOBANOL at 1 15 12-20 Kg/ha 1 IZON/DOBANOL at 32 25-41 1:10 =i It should be noted that the alcohol ethoxylate was added to a commercial, formulated, sample of the active ingredient. In this context the high level of enhancement of activity of a pre-formulated source of tebuconazole achieved by the use of an alcohol ethoxylate is surprising.

It should be noted that the use of capital letters in this specification to denote terms for materials indicates that those terms are, or are thought to be, trade marks.

It should be noted that the information which has been provided about the chemical constitution of the various materials designated by trade marks has been provided on the basis of common knowledge, and, where available, manufacturers' or distributors' information.

i T 1657

Claims

C L A I M S

1. A fungicidal composition which comprises a compound of general formula:

OH 1 Y -C - R 1 CH2 Z. N fill' 1 X N in which: R represents an alkyl radical, an optionally substituted cycloalkyl radical or an optionally substituted phenyl radical; X represents a nitrogen atom or a CH group; Y represents a grouping -OCH 2-1 -CH

2 CH 2- or -CH=CH-; Z represents a halogen atom, an alkyl, cycloalkyl, alkoxy, alkylthio, haloalkyl,haloalkoxy or haloalkylthio radical, an optionally substituted phenyl is radical, an optionally substituted phenoxy radical, an optionally substituted phenylalkyl radical or an optionally substituted phenylalkoxy radical; and m is 0, 1, 2 or 3; or an acid addition salt or a metal salt complex thereof; and an alkoxylate of an aliphatic alcohol. 2. A comkpsition as claimed in claim 1, wherein the alkoxylate comprises 5 to 25 alkoxy moieties.

3. A composition as claimed in any one of the preceding claims, wherein the alkoxylate is an ethoxylate or a mixed ethoxylate/propoxylate.

4. A composition as claimed in any one of the preceding claims, wherein the aliphatic alcohol is a c 9-18 aliphatic alcohol.

5. A composition as claimed in any one of the preceding claims, wherein the alcohol moiety is a primary alcohol moiety or, when there is a mixture of alcohol moieties, they are predominantly primary.

6. A composition as claimed in any one of the preceding claims, wherein the alcohol moiety is straight-chain or, when there is a mixture of alcohol moieties, they are predominantly straight-chain.

7. A composition as claimed in any one of the preceding claims, wherein the alcohol moiety has only one hydroxy group or, when there is a mixture of alcohol moieties, alcohol moieties with only one hydroxy group predominate.

is

8. A composition as claimed in any one of the preceding claims, wherein the alcohol moiety is saturated or, when there is a mixture of alcohol moieties, saturated alcohol moieties predominate.

9. A composition as claimed in any one of the zo preceding claims, wherein Z m represents a 4-chloro moiety, Y represents the grouping -CH 2-CH 2_ X represents a nitrogen atom and R represents a t-butyl group.

10. A composition as claimed in any one of the preceding claims, being a concentrate formulation for addition to water, and containing 5-200 g/kg of a compound of general formula I, and 100- 1000 g/kg of an alkoxylate of an aliphatic alcohol.

11. A method of combating a fungus at a locus, which method comprises treating the locus with a composition as claimed in any one of claims 1 to 9.

12. Use as a fungicide of a composition as claimed in any one of claims 1 to 9.

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