WO1993012659A1

WO1993012659A1 - Agricultural use of certain compounds, compositions and methods for producing said compounds

Info

Publication number: WO1993012659A1
Application number: PCT/DK1992/000387
Authority: WO
Inventors: Jens Breinholt; Ruby Ione Nielsen
Original assignee: Novo Nordisk A/S
Priority date: 1991-12-20
Filing date: 1992-12-18
Publication date: 1993-07-08
Also published as: IL104156A0; TW273501B; JPH08504165A; ZA929909B; AU3345093A; EP0637916A1

Abstract

Use of compounds of general formula (I), wherein R1 and R2 are methyl or hydrogen, R3 is: cyclohexyl, cyclohexenyl, or phenyl substituted in the para position, R4 is hydrogen, carboxy alkoxycarbonyl, optionally mono- or plurisubstituted, all three R5 groups are hydrogen or methyl; X is oxygen or imino; and Y is a direct bond or a group -CONHCH(CH3)-; and wherein the carbon atom bridging X and Y may be in the L- or D-configuration, and derivatives thereof for treating plants in the fields of agri- and horticulture, especially as fungicides. The compounds are producible by cultivation of a strain of the fungus Curvularia sp., or Septoria sp., and optional chemical modification. The compounds may also be used for controlling fungi in the preservation of wood, paints, cosmetics, and edible products.

Description

Title: AGRICULTURAL USE OF CERTAIN COMPOUNDS, COMPOSI- TIONS AND METHODS FOR PRODUCING SAID COMPOUNDS

FIELD OF THE INVENTION

This invention relates to the use of certain compounds in agriculture or horticulture, compositions containing said compounds, and the use of such compositions for controlling fungi in valuable crops, and in the preservation of wood and timber, paints, cosmetics, foods and feeds, methods for producing the fungicidally active compounds, and microorganisms capable of producing said compounds.

BACKGROUND OF THE INVENTION Certain compounds have been disclosed in European Publication No. EP 360 760 (Sandoz AG), published 28.3.1990. These compounds are disclosed as having interesting pharmacological properties, especially for use as chemotherapeutic drug resistance reversing and to some extent immunosuppressant and antiinflammatory agents. It is also stated that the compounds have an antifungal activity in animals against yeast and yeast-like species causing systemic attacks. The publication contains only reference to one test against Candida, and indicates that the com- pounds also may have activity against yeast like species causing systemic attacks in animals. No reference is made to which of the 82 exemplified compounds were tested for this activity, but in EP 360 760 it is stated that the most preferred compound can be represented by the formula: cyclo-[Pec-MeVal-Val-MeAsp-MeIle-MeIle-Gly-MeVal-TyrOMe-D-Lact](Example 1, first compound). This compound is together with some other related compounds according to EP 360 760 produced by the fungal genus Septoria.

For a number of years it has been known that various microorganisms produce metabolites exhibiting biological activity so as to be useful as biocides for combating diseases and pests.

Especially it has been known that some species of the genus Curvularia produce dif- ferent metabolites exhibiting biological activity, in particular as phytotoxins. However, none of these metabolites are known to be fungicides. C. lunata (Wakk.) Boed was found to produce at least two phytotoxins. They cause necrotic spots on plant leaves even when they are highly diluted. (F. Macri and A. Vianello, Physio- logical Plant Pathology 8:325-331, 1976). The toxins are phytotoxins and are non host specific. Host specific toxins have been isolated from culture filtrates of C. pallescens Boedijn and from diseased host leaves attacked by this species (Olufolaji, Cryptogamie Mycol. 7(4):335-342, 1986). These toxic substances gave chlorotic spots to maize plants. They later became necrotic similar to in-vivo symptoms ofthe disease caused by C. pallescens.

Curvularin, a macrocyclic metabolite, has been isolated from a Curvularia species (O. C. Musgrave, J. Chem Soc, 1956, 4301) and from C. lunata (Coombe et al, Aust. J. Chem. 21:783, 1968). The compound has the composition C₁₆H₂₀O₅ (mole- cular weight 292.3) and has the formula 1 below:

Crude curvularin was isolated as colourless or pale yellow-brown crystals.

Neither curvularin nor the crude filtrates from Curvularia showed anti-bacterial activity (against Bacillus subtilis, Escerichia coli, and Staphylococcus aureus) or anti-fungal activity (spore germination test with Penicillium digitatum).

None of the above compounds are useful for combating plant diseases and pests because they are strong phytotoxins.

As indicated above metabolites from the mold genus Curvularia known in the prior art all have exhibited a strong phytotoxic activity, but it has now surpri- singly been found that fu ngi belonging to said genus also produce metabolites that exhibit strong antifungal activity, and that are substantially without phytotoxic activity. One example thereof is our unpublished International Patent Application No. PCT/DK91/00273, wherein compounds of the general formulae 2 and 3

(2)

cyclo-[Pec-MeAsρ-MeVal-Val-MeVal-MeIle-Gly-MeVal-TyrOMe-D-Lact] (2)

(3)

cyclo-[Pec-MeVal-Val-MeAsρ-MeVal-MeIle-Gly-MeVal-TyrOMe-D-Lact] (3), wherein each amino acid residue and the lactate residue independently may occur in L- or D-form, and derivatives thereof, are disclosed.

SUMMARY OF THE INVENTION

It has now surprisingly been found that such compounds as disclosed in EP 360 760 exhibit strong fungicidal activity against plant pathogens, especially fungi.

The invention consequently in its first aspect relates to the use of said compounds for combating or controlling plant diseases, especially fungal attack.

Also the invention relates to the use of said compounds as preservatives and/or additives to control fungi in foods and feeds, timber and wood, paints, growth media, cosmetics, etc.

In a third aspect of the invention it relates to fungicidal compositions for use in the field of agriculture or horticulture comprising the above compounds in combination with suitable excipients, such as diluents, carriers, etc.

Within the context of the invention it is also contemplated to combine the com- pounds in question with known biocides for making up novel combination com- positions.

Furthermore the invention in a fourth aspect relates to methods of combating plant diseases by application of compositions comprising the above compounds to infested areas. The present invention in a still further aspect relates to the production of com- pounds having the general formula I defined below, by a) cultivation of a species belonging to the genus Curvularia, subsequent recovery of at least one active component of formula Ia from the biomass and the fermentation medium, and optionally modifying the active compound to obtain a desired compound of formula I.

The compound directly produced has as indicated the structure Ia

(Ia)

wherein all the amino acid residues are in the L-form and the lactate residue is in the D-form, and is apparently identical to Compund 1 of Example 1 in EP

360760.

Specifically the invention relates to processes for the production of the com- pounds indicated above. These processes comprise use of specific microorganisms as well as chemical processes for full or semi synthetic production of said com- pounds. The invention also relates to the use of microorganisms, especially of the genera Septoria and Curvularia, producing the aforementioned compounds as fungicidal compositions.

Lastly the invention relates to an isolated pure culture of the microorganism Curvularia sp.(IMl CC No. 346564).

DEPOSITION OF MICROORGANISM

For the purpose of describing this invention in detail a strain of the fungus Cur- vularia sp (IMI CC No.346564) has been deposited with the International Mycological Institute Collection (IMI CC), Ferry Lane, Kew, Surrey TW9 3AF, England, for the purposes of patent procedure on the date indicated below. IMI CC being an international depository under the Budapest Treaty affords perma- nence of the deposit in accordance with rule 9 of said treaty.

Deposit date 29-4-1991

Depositor's ref. 33 855

IMI CC designation IMI CC No.346564

IMI CC No. 346564 belongs to the class Deuteromycetes, sub-class Hyphomyce- tidae and family Dematiaceae. The fungus is a species of the genus Curvularia and was isolated from a leaf sample.

BRIEF DESCRIPTION OF THE DRAWING The invention is described in further detail below with reference to the drawings, wherein Fig. 1 shows the 400 MHz ¹H -NMR spectrum of the isolated compound BK 230 in CDCl₃, and

Fig. 2 shows a 100 MHz ¹³C-NMR spectrum of the isolated compound BK 230 in CDCl₃.

DETAILED DESCRIPTION OF THE INVENTION

The present invention in its first aspect relates to the agricultural use of certain known compounds.

The compounds can be represented by the formula I

(I)

Wherein one of R1 and R2 is methyl and the other is hydrogen or methyl;

R3 is: cyclohexyl, cyclohexenyl, or phenyl substituted in the para position by a group -OR6, wherein -OR6 is hydroxy, alkoxy, alkenyloxy, acyloxy, geranyloxy, alkoxycar- bonyloxy, aralkoxycarbonylmethoxy, aralkoxy or aralkoxy substituted by a lower alkyl group or halogen;

R4 is hydrogen, carboxy alkoxycarbonyl, optionally mono- or plurisubstituted by aryl, alkenyloxycarbonyl, alkeninyloxycarbonyl, benzyloxycarbonyl, aryloxycar- bonyl, trimethylsilylethoxycarbonyl, formyl, alkylcarbonyl or aralkylcarbonyl; all three R5 groups are the same and are hydrogen or methyl;

X is oxygen or imino; and

Y is a direct bond or a group -CONHCH(CH₃)-;

with the proviso that when R5 is methyl, then R1 and R2 are methyl and R4 is other than carboxy; and

wherein the carbon atom bridging X and Y may be in the L- or D-configuration.

Formula I may alternatively be represented as formula I' cyclo[R5Gly-MeVal-A-B-Pec-MeVal-R5Val-D-R2Ile-RlIle] I' Wherein Me is methyl attached to the nitrogen atom in the carbamoyl group, R1,

R2, and R5 are defined as above, and are attached to the nitrogen atom in the carbamoyl group;

A is -N(R5)CH(CH₂R3)CO- , wherein R3 and R5 are as defined above;

B is -X-CH(CH₃)-Y- , wherein X and Y are as defined above;

Pec is L-pipecoloyl; and

D is -N(CH₃)CH(CH₂R4)CO- , wherein R4 is defined as above and the asyme- tric carbon atom has the S-configuration.

Alkoxy as such or as part of a substituent preferably is of 1 to 4 carbon atoms. Alkenyloxy preferably is of 3 to 5 carbon atoms. Acyloxy preferably is of 2 to 5 carbon atoms in the alkyl or alkylene portion thereof. In aryl as a substituent or as part of a substituent the aryl group preferably is phenyl. When it is substituted it preferably is monosubstituted, preferably in the para position. When it is plurisubstituted it preferably is disubstituted, preferably in the meta and para positions. Aryl preferably is unsubstituted. Halogen preferably is of atomic number of from 9 to 35, it preferably is chlorine or bromine.

Alkoxycarbonyl preferably is of 2 to 10 carbon atoms, expecially of 4 to 9 carbon atoms. Alkenyloxycarbonyl preferably is of 4 to 10 carbon atoms, expecially of 4 to 6 carbon atoms.

A naturally-occurring amino acid is any amino acid found in nature, preferably an amino acid found in proteins unless indicated otherwise, especially an α-amino acid, and includes e.g. glycine, proline and serine.

Alkyl preferably is of 1 to 6 carbon atoms. Lower alkyl preferably is of 1 to 4 carbon atoms, especially methyl. Alkyl of 1 to 4 carbon atoms preferably is methyl, isopropyl or tert-butyl. Alkenyl preferably is of 3 to 5 carbon atoms, it especially is allyl. Hydroxy alkyl preferably is of 1 to 4 carbon atoms. It especial- ly is hydroxymethyl; however, when it is bound to a nitrogen atom it preferably is of 2 to 6 carbon atoms and the hydroxy group preferably is separated from the nitrogen atom by at least 2 carbon atoms. Dialkylaminoalkyl preferably is of 1 to 4 carbon atoms in the alkyl parts and of 2 to 4 carbon atoms in the aminoalkyl part, it especially is 3-(dimethylamino)propyl. Furylmethyl preferably is 2- fiirylmethyl. Alkoxycarbonylalkyl preferably is of 1 to 4 carbon atoms in the alkoxy part and of 2 to 4 carbon atoms in the carbonylalkyl part. Trialkylsilyl- oxyalkyl preferably is of 1 to 4 carbon atoms in the alkyl parts bound to the silicium atom and of 2 to 4 carbon atoms in the alkylene part. Acyl as such or as part of a substituent preferably is alkylcarbonyl, preferably of altogether 2 to 4 carbon atoms. Optionally substituted acyloxy methyl preferably is of 1 to 4 carbon atoms in the acyloxy part; if substituted is preferably is substi- tuted at the ω carbon atom, preferably by carboxy or 2-carboxyphenyl. Alkyl as part of a substituent such as dialkylaminomethyl preferably is of 1 to 4 carbon atoms, it especially is methyl. Halogenomethyl preferably is chloromethyl.

Compounds of this class of organic structures with the formula I are known from EP 360 760 discussed above.

Although these compounds closely related or identical to the compounds indicated by this invention are disclosed in EP 360 760. The compounds as described there would not be considered for agronomical use. This is due to the high toxicity (approximately 100 mg/kg p.o.) and low antifungal activity (dosage 25 to 300 mg/kg, daily dosage of 300 to 3000 mg) indicated, and as exemplified towards Candida on pages 47 to 49 of EP 360 760. Furthermore EP 360 760 only indicates pharmaceutical usage of these com- pounds. Consequently the surprising specificity and activity for the agronomical use of the same compounds indicated by the present invention can in no way be inferred from EP 360 760.

According to the invention the compounds are to be used in agriculture as fun- gicidally active agents, and the invention therefore in its second aspect relates to fungicidally active compositions comprising said compounds of formula I in admixture with agronomically acceptable diluents and/or excipients. Depending on the circumstances such as the crop wherein fungi are to be com- bated, the environmental conditions or other factors, a composition of the invention in addition to said fungicidally active compounds may also contain other active ingredients such as other biocides, such as fungicides, pesticides, herbicides, insecticides, nematicides, acaricides, or plant nutrients, plant growth regulators, or fertilizers.

Examples of other fungicides which according to the invention can be combined with the active compounds include especially ergosterol biosynthesis inhibitors ("EBIs"). These are generally imidazoie or triazole derivatives and examples include those known by the common names prochloraz, triadimefon, propiconazo- le, diclobutrazol, triadiminol, flusilazole, flutriafol, myclobutanil, penconazole, quinconazole, imazalil and diniconazole. Examples of non azole EBIs include nuarimol, fenarimol, fenpropimorph, tridemorph and fenpropidine. Other fungi- cides which can be combined with the enzyme preparation of the invention include anilides, e.g. carboxin, metalaxyl, fu ralaxyl, oftirace, benalaxyl, mepro- nil, flutolanil, pencycuron and oxadixyl; benzimidazoles, e.g. benomyl and carbendazim; carbamates, e.g. maneb, mancozeb and propamocarb; dicarboximi- des, e.g. iprodione, vinclozolin and procymidone; phosphorus derivatives, e.g. pyrazophos, tolclofos-methyl and fosetyl aluminum; and miscellaneous com- pounds, including dithiocarbamates, bisdithiocarbamates, imidazoles, triazoles, phathalonitriles, polyhalogenalkylthio compounds, iminoctadine, guazatine, dicloran, chlorothalonil, pyrifexox, ethirimol, cymoxanil, phenyl pyrroles, thiocyofenes, pyrimidines, and anilazine.

A fungicidal composition according to the invention having a fungicidally active compound of formula I as its active ingredient may for agronomical and/or horti- cultural applications be formulated by mixing the active principle with suitable inert and compatible carriers or diluents to obtain a composition of the type generally used in agricultural compositions such as a wettable powder, an emul- sifiable concentrate, a concentrated emulsion, a granular formulation, a water soluble powder, an alginate, a xanthan gum and/or an aerosol. As solid carriers bentonite, diatomaceous earth, apatite, gypsum, talc, pyrophyllite, vermiculite, ground shells, and clay may be mentioned. A surface active agent may also be added with the purpose of producing a homogeneous and stable formulation.

The diluent or carrier in the composition of the invention can as indicated be a solid or a liquid optionally in association with a surface-active agent, for example a dispersing agent, emulsifying agent or wetting agent. Suitable surface-active agents include anionic compounds such as a carboxylate, for example a metal car- boxylate of a long chain fatty acid; an N-acylsarcosinate; mono- or di-esters of phosphoric acid with fatty alcohol ethoxylates or salts of such esters; fatty alcohol sulphates such as sodium dodecyl sulphate, sodium octadecyl sulphate or sodium cetyl sulphate; ethoxylated fatty alcohol sulphates; ethoxylated alkylphenol sul- phates; lignin sulphonates; petroleum sulphonates; alkyl aryl sulphonates such as alkyl-benzene sulphonates or lower alkylnaphthalene sulphonates, e.g. butyl- naphthalene sulphonate; salts of sulphonated naphthalene-formaldehyde conden- sates; salts of sulphonated phenol-formaldehyde condensates; or more complex sulphonates such as the amide sulphonates, e.g. the sulphonated condensation product of oleic acid and N-methyl taurine or the dialkyl sulphosuccinates, e.g. the sodium sulphonate of dioctyl succinate. Non-ionic agents include condensation products of fatty acid esters, fatty alcohols, fatty acid amides or fatty-alky 1- of alkenyl-substituted phenols with ethylene oxide, fatty esters of polyhydric alcohol ethers, e.g. sorbitan fatty acid esters, condensation products of such esters with ethylene oxide, e.g. polyoxyethylene sorbitan fatty acid esters, block copolymers of ethylene oxide and propylene oxide, acetylenic glycols such as 2,4,7, 9-tetra- ethyl-5-decyn-4,7-diol, or ethoxylated acetylenic glycols. Examples of a cationic surface-active agent include, for instance, an aliphatic mo- no-, di-, or polyamine as an acetate, naphthenate or oleate; an oxygen-containing amine such as an amine oxide or polyoxyethylene alkylamine; an amide-linked amine prepared by the condensation of a carboxylic acid with a di- or polyamine; or a quaternary ammonium salt.

The compositions of the invention can take any form known in the art for the formulation of agrochemicals, for example, a solution, a dispersion, an aqueous emulsion, a dusting powder, a seed dressing, a dispersible powder, an emulsifi- able concentrate or granules. Moreover, it can be in a suitable form for direct ap- plication or as a concentrate or primary composition which requires dilution with a suitable quantity of water or other diluent before application.

An emulsifiable concentrate comprises the active ingredient dissolved in a water- immiscible solvent which is formed into an emulsion with water in the presence of an emulsifying agent. A dusting powder comprises the active ingredient intimately mixed and ground with a solid pulverulent diluent, for example, kaolin.

A granular solid comprises the active ingredient associated with similar diluents to those which may be employed in dusting powders, but the mixture is granu- lated by known methods. Alternatively it comprises the active ingredient absorbed or adsorbed on a pre-granular diluent for example, Fuller's earth, attapulgite or limestone grit.

Wettable powders, granules or grains usually comprise the active ingredient in admixture with a suitable surfactant and an inert powder diluent such as china clay. Another suitable concentrate is a flowable suspension concentrate which is formed by grinding the active ingredient with water or other liquid, a wetting agent and suspending agent.

It is contemplated that the active compound according to the invention may be applied in concentrations ranging from about 0.001 μg/ml to 750 mg/ml, prefer- ably from 1 μg/ml to 10 mg/ml, for use in controlling fungi in plants.

According to the invention the concentration of the active compounds of formula I in the compositions of the invention may vary within a wide range depending on the type of formulation and the field of application. In its fourth aspect the invention relates to methods of combating fungi in plants, wherein an effective amount of a fungicidally active compound of formula I according to the invention is applied to a region to be treated.

In connection with this aspect the compositions of the invention may for agrono- mical or horticultural uses be applied to a region to be treated either directly to the soil as a pre-emergence treatment to the seed surface as a seed dressing or to the foliage or fruits of the plants as a post-emergence treatment. Depending on the crop and circumstances the treatment may be postponed until seeds or fruits appear on the plants, wherein fungi are to be controlled.

The active preparation or the compositions of the invention can be applied directly to the plant by, for example, spraying or dusting either at the time when the fungus has begun to appear on the plant or before the appearance of fungus as a protective measure. In both such cases the preferred mode of application is by foliar spraying. It is generally important to obtain good control of fiingi in the early stages of plant growth as this is the time when the plant can be most severely damaged. The spray or dust can conveniently contain a pre-or post- emergence herbicide, a mixture of other pesticides, plant growth regulators or fertilizers, if this is thought necessary.

Sometimes, it is practicable to treat the roots of a plant before or during planting, for example by dipping the roots in a suitable liquid or solid composition. When the active preparation of the invention is applied directly to the plant a suitable rate of application is from 0.001 to 50 kg per hectare, preferably from 0.05 to 5 kg per hectare.

In the method of the invention the active preparation of the invention alone or in combination with a conventional biocide can also be applied to seeds or habitat. Thus the preparation can be applied direcdy to the soil before, at or after drilling so that the presence of active ingredient in the soil can control the growth of fiingi which may attack seeds.

The compositions may be applied in amounts corresponding to from about 1 g to about 100 kg fungicidally active compound per hectare.

When the soil is treated directly the active preparation (alone or in admixture with the conventional biocide) can be applied in any manner which allows it to be intimately mixed with the soil such as by spraying, by broadcasting a solid form of granules, or by applying the active ingredient at the same time as drilling by inserting it in the same drill as the seeds. A suitable application rate is within the range of from 0.01 to 50 kg per hectare, more preferably from 0.05 to 5 kg per hectare.

The concentration of the fungicidally active compounds in the compositions of the present invention when used alone or in combination with a conventional fungi- cide, as applied to plants is preferably within the range from about 0.001 to about 30 per cent by weight, especially 0.01 to 3.0 per cent by weight. In a primary composition the amount of active compound can vary widely and can be, for example, in the range from about 5 to about 95 per cent by weight of the compo- sition.

The concentration of the other fungicidally active ingredient in the mixed com- position of the present invention, as applied to plants is preferably within the range of 0.001 to 50 per cent by weight, especially 0.01 to 10 per cent by weight. In a primary composition the amount of other active ingredient can vary widely and can be, for example, from 5 to 80 per cent by weight of the composi- tion.

Although the present invention has been described in detail in connection with controlling fungi in plants, it is also anticipated that the fungicidally active com- pounds of the invention may be used for the preservation of wood by adding said compounds to wood preservation and/or impregnation compositions. Also, the active compounds according to the invention may be useful as a fungicide and preservant in paints - both to prevent growth in the paint during storage, and growth on the painted object such as the plastered surface of a house.

Further according the invention the fungicidally active compounds may due to their low toxicity be used for the preservation of cosmetics, foods and feeds, or other such items where the compounds may be added subsequent to any cooking process.

Also, the fungicidally active compounds of the invention may be used as fungi- cidal additive to growth media for various microorganisms such as E. coli, and Pseudomonas aeroginosa. As indicated above the invention relates in a further aspect to the production of compounds of the general formula I as defined above, by a) cultivation on suitable nutrient media under suitable conditions of a species belonging to the genus Curvularia,

b) subsequent recovery of an active component of formula Ia as defined above from the biomass and the fermentation medium, and

c) optionally modifying the active compound to obtain a desired compound of formula I. The compound of formula Ia was isolated as a metabolite from a novel species of the genus Curvularia, Curvularia sp. (IMI CC No. 346564) and is apparently identical to compound 1 of Example 1 in EP 360 760.

Guidance for producing other compounds of formula I using the compound of formula Ia as starting material (step c) can thus be found in EP 360760 whereto reference is made in its entirety.

The compound of formula Ia may be prepared by aerobic cultivation on suitable nutrient media under conditions hereinafter described with a strain of a fungus belonging to the genus Curvularia, especially the fungus Curvularia sp. (IMI CC 346564), and thereafter recovering the active component from the fermentation medium.

The natural metabolite may subsequently be modified chemically in order to obtain various derivatives thereof. The derivatives may be produced in order to improve certain properties with the metabolite such as its solubility in aqueous media, its hydrophobicity, hydrophilicity, stability, specificity, etc. Derivatives of the compound produced or related compounds and methods for producing such derivatives hereto are disclosed in detail in EP 360 760, which is hereby incorporated by reference in its entirety.

A specific type of derivatives from the compound of formula I are such com- pounds wherein the lactone ring has been opened.

Although this aspect of the invention discussed herein below, principally deals with the specific strain IMI CC 346546, it is well known in the art that the properties of microorganisms may be varied naturally and artificially. Thus all strains belonging to the genus Curvularia including variants, recombinants and mutants, whether obtained by natural selection, produced by the action of mutat- ing agents such as ionizing radiation or ultraviolet irradiation, or by the action of chemical mutagens such as nitrosoguanidine, are included in this invention.

It is well known that a fungus is able to produce closely related metabolites (cf. compounds of formulae III and IV in our unpublished International Patent Ap- plication No. PCT/DK91/00273 (formulae 2 and 3 above), or see EP 360 760, where three related compounds were produced by the same fungus) of the same or similar activity, but with minor differences in chemical structure. The present invention is therefore meant also to encompass the production of such closely related compounds produced by the same fungus and their use in agriculture or horticulture as fungicides.

Description of the strain

Colonies: grey, cottony, sometimes zonate.

Conidiophores: Single to aggregated, simple, straight to flexuous, geniculate above. Conidia: acropleurogenous, 2-4 septate when mature, smooth, but becom- ing verrucose on the large central cell, mostly curved, concolourous or with central cell more pigmented than the other cells, mostly 20-39 μm long and 11- 14μm thick in the broadest part. IMI CC 346564 is 4 septate like C. verruciformis, but differs from it in the size of the conidia. The conidia of C. verruciformis are 16-26 μm x 8-12 μm in size. IMI CC 346564 is a new species in the genus Curvularia. It belongs to the class Deuteromycetes, sub-class Hyphomycetidae and family Dematiaceae.

EXAMPLES The invention is illustrated in the following examples which are to be construed as indicating certain embodiments of the invention as defined in the appended claims. The examples should in no way be interpreted as limiting for the scope of the invention.

Example 1 Cultivation of the strain.

The fungus may be grown on agar slants containing the following ingredients in grams/litre: yeast extract 4.0

potassium dihydrogen phosphate 1.0

magnesium sulphate heptahydrate 0.1

glucose 15

Bacto (Difco Laboratories, Detroit, USA) agar 20

The substrate is autoclaved at 121 °C for 20 or 40 minutes and will, hereinafter, be referred to as YPG agar. Slants contain 12ml YPG agar and after inoculation they are incubated at 20 - 25°C for 7 days or longer.

Surface cultivation

The fungicide was produced by surface cultivation on a semi-solid medium consisting of the following ingredients: 30 g wheat bran in a 500 ml Erlenmeyer flask, 45 ml liquid medium (yeast extract 0.4%, potassium dihydrogen phosphate 0.1 %, magnesium sulphate heptahydrate 0.05%, demineralised water). This was sterilized by autoclaving at 121 °C for 40 minutes. Each flask was inoculated with about 10⁶ spores from a YPG agar slant previous- ly inoculated with IMI CC No. 346564.The flasks were incubated at 25°C for 7 - 14 days after which time the active compound was extracted with an organic solvent, e.g. ethanol, methanol, ethylacetate and acetone.

Extraction of the compound

To each flask was added 200 ml methanol and this was shaken at 18°C over- night. The mycelium and unused substrate were then removed by centrifugation. The supernatant was analyzed for fungicidal activity.

The fungicide can also be produced in submerged cultures in media containing other sources of carbon and nitrogen assimilable by the micro-organism and generally low levels of inorganic salts. In addition, the media may be supple- mented with trace metals, although if complex sources of carbon and nitrogen are used, they are usually present in the complex sources.

Submerged cultivation 1.

A substrate for shake flasks was prepared with the following ingredients per litre: 4.0 g yeast extract, 1.0 g potassium di-hydrogen phosphate, 0.1 g magnesium sulphate heptahydrate, 15 g glucose and 0.1 g Pluronic™ L61 (BASF, Federal Republic of Germany) and demineralized water. Sterilization took place at 121°C for 20 minutes. A 500 ml Erlenmeyer flask with 100 ml of substrate was inocu- lated with 10⁶ spores from a YPG agar slant previously inoculated with Curvu- laria sp. IMI CC No.346564.

The flasks were shaken at 230 rpm at 25°C for 3-14 days whereafter the active ingredient was extracted with 100 ml ethanol, methanol, ethylacetate or acetone or any other suitable organic solvent as indicated above.

Submerged cultivation 2.

A substrate was prepared with the following ingredients per 500ml Erlenmeyer flask:

wheat bran 10 g

tap water 90 ml

dilute salts 50 ml

(dilute salts = ammonium hydrogen phosphate (66 mg), potassium dihydrogen phosphate (68 mg), dipotassium hydrogen phosphate (87 mg), calcium chloride.2 hydrate (7.4 mg), and magnesium chloride.6 hydrate (10 mg) made up to 1 litre with distilled water).

The substrate was sterilized at 121°C for 20 minutes. Each flask was inoculated with about 10⁶ spores from a YPG agar slant previously inoculated with IMI CC No. 346564. The flasks were incubated at 25°C for 7 - 14 days after which time the active compound was extracted with 200 ml of an organic solvent, e.g.

ethanol, methanol, ethylacetate and acetone.

Example 2 Bioassay

10⁶ spores of Botrytis cinerea were added to 50 ml of dilute salts. This was mixed with 50 ml YPG agar at a temperature which favoured the viability of Botrytis spores in the temperature range from about 30°C to about 45°C. 12 ml of this mixture were poured in 9 cm petri dishes and allowed to solidify. 1 - 5 holes of 4 mm diameter were punched in the agar and 15 μl of the extract was put in each hole.

The petri dishes were incubated at 20 - 25°C for 2 days. The fungicide in the extract inhibited the growth of Botrytis and a rather diffuse zone appeared around the hole - the larger the zone the stronger the fungicide. The extract under these conditions produced a zone of 30 - 42 mm. Under a stereo microscope, it could be seen that the fungus is present but normal growth had been inhibited. The mycelium appeared as large vesicles, suggesting a particular type of mode of action.

Example 3 Mammalian pathogenicity

Culture broth containing the fungicide, viable spores and mycelium showed no effect on mice, intraperitoneally applied at the rate of 20 ml per kg body weight. The broth contained approximately 1x10⁶ viable counts/ml. Example 4

Fungicidal activity

The active ingredient has been found to have an inhibitory effect on the growth of the following microorganisms:

Class Ascomycetes, genus Venturia, e.g. V. inequalis

Genus Monilinia, e.g. M. fructigena

M. fructicola

Genus Erysiphe, e.g. E. graminis

Genus Saccharomyces, e.g. S.cerevisiae

Form-genus Aspergillus, e.g. A. fumigatus

A. niger

Form-genus Penicillium, e.g. P. digitatum

Class Deuteromycetes, Genus Botrytis, e.g. B. cinerea

Genus Phoma, e.g. P. lingam

Genus Ascochyta, e.g. A. pisi

Class Basidiomycetes, Genus Puccinia, e.g. P. recondita

Example 5

Isolation and characterization of BK 230

500 ml of the methanolic extract from Example 1 or 2 is concentrated under reduced pressure to 115 ml and after acidification (pH 4, IM HCl) extracted with 6 x 50 ml ethylacetate. The combined organic phases are dried by cooling to - 18°C and removal of the separated ice by filtration.

After evaporation to dryness the residue is taken up in 4 ml of ethylacetate and chromatographed over silica (200 x 40 mm Merck Silica gel 60, 63-200μ). The column is eluted with one bed volume of ethylacetate-hexane (EA-Hex) 1:1, EA- Hex 2:1, EA, EA-methanol 9: 1, EA-methanol 1: 1 and methanol. The active compound is present in the fraction eluted with ethylacetate-methanol 1 : 1 and is purified further by reversed phase chromatography (ODS, H₂O-Acetonitrile (0.05% TFA) gradient), yielding 20 mg of pure compound as a colorless powder.

Crystallized from methanol the compound has the following physico-chemical properties:

Mp: 210-215°C

Optical rotation [α]_D: (CHCl₃, c=0.5) -229° MH⁺ (PDMS): 1126 (Plus minus one mass unit)

Total hydrolysis (6N HCl. 110°C, 24h - hydrolysis not complete) yields Lactic acid(1), Glycine(1), Valine(1), N-Methyl-Valine(2), N-Methyl-Isoleucine(2), Pipecolic acid(1), N-Methyl-Aspartic acid(1) and O-Methyl-Tyrosine, identified by GC/MS as n-butyl ester-triflouroacetyl derivatives.

Analysis: Found C: 60.42 Calculated for C: 60.78

H: 8.12 C₅₆H₉₁N₉O₁₄ H: 8.14

N: 10.89 N: 11.19

¹H- and ¹³C-NMR spectra are shown in Fig.1 and Fig.2. Example 6

Activity against Botrytis cinerea

Tomato plants (Lycopersicon esculentum cv. "First in Field", 3 weeks old) were each sprayed with 0.30 ml of a solution using a handhold "Aerograph 63" sprayer. The solutions contained decreasing concentrations from 1000 μg/ml to 1 μg/ml of the purified active ingredient dissolved in 70 % (v/v) ethanol and a control containing no active ingredient. The plants were dried for 24 hours before they were inoculated with a spore suspension containing 5x10⁵ spores of B. cinerea per ml in 25 % (v/v) autoclaved grape fruit juice. The inoculation was carried out with a hand held sprayer ("Wagener W 50" type 0237). To allow for optimal conditions for the fungus the plants were incubated at high humidity in the darkness at 19°C for five days and subsequently scored for the level of B. cinerea infection.

No phytotoxicity was observed from spraying the active ingredient on the plants. Results:

1000 ug/ml a.i: 100 % protection (no attack from the pathogen)

100 ug/ml a.i.: 100 % protection

10 ug/ml a.i.: 100 % protection

1 ug/ml a.i.: 100 % protection

0 a.i.: 0 % protection (plants heavily infected) Example 7

Activity against Erysiphe graminis f.sp. hordei (Powdery mildew)

Residual protective activity.

Host: Hordeum vulgare (Barley, var. Catrin Carlsberg) Barley plants (1 week old) were sprayed to run off with a liquid suspension using a handhold sprayer (Bink Bullows 900). The solution was a methanol extract (see above) containing about 100 μg/ml a.i. The plants were kept 24 hours in a glass- house to dry before they were inoculated with conidia spores by shaking leaves from diseased plants over them (concentration around 100 spores/mm²). The infected plants were then incubated in a controlled environment room (16 hours light (6.000 lux) at 22-24°C and 8 hours dark) at 15-17°C.

A similar test was performed using the compound of formula 2 (BK202) as active ingredient in the concentration level.

After 7-9 days the assessment was done: BK230 gave approximately 90% and BK202 approximately 90% protection to Powdery mildew caused by Erysiphe graminis f.sp. hordei.

Example 8

Activity against Puccinia recondita f.sp. tritici

Residual protective activity.

Host: Triticum aestivum (Wheat, var. Anja Pajbjerg) Wheat plants (1 week old) were sprayed to run off with a liquid solution using a handhold sprayer (Bink Bullows 900). The solution was a methanol extract (see above) containing about 100 μg/ml a.i. The plants were kept 24 hours in a glass- house to dry before they were inoculated with a spore suspension containing 5x10⁵ spores per ml. The inoculation was carried out with a handhold atomizer (Wagner, Pico Bel). The plants were then incubated at 20°C in a dark polythene bag for 24 hours. Thereafter the polythene bag was removed and the plants were placed in a controlled environment room (16 hours light (10.000 lux) and 8 hours dark) at 18-22°C. After 10-12 days the assessment was done:

BK230 gave approximately 90% protection to Leaf rust caused by Puccinia recondita f.sp. tritici.

Claims

PATENT CLAIMS

1. Use of an active compound produced by a fungus belonging to the genus Septoria or Curvularia and derivatives thereof for treating plants.

2. Use according to claim 1 wherein said fiingus is the strain S 42508/F (NRRL 15761) or the strain 33 855 QMI CC No.346564).

3. Use of a compound having the general formula I,

(I)

wherein one of R1 and R2 is methyl and the other is hydrogen or methyl;

R3 is: cyclohexyl, cyclohexenyl, or phenyl substituted in the para position by a group -OR6,

wherein -OR6 is hydroxy, alkoxy, alkenyloxy, acyloxy, geranyloxy, alkoxycar- bonyloxy, aralkoxycarbonylmethoxy, aralkoxy or aralkoxy substituted by a lower alkyl group or halogen; R4 is hydrogen, carboxy alkoxycarbonyl, optionally mono- or plurisubstituted by aryl, alkenyloxycarbonyl, alkeninyloxycarbonyl, benzyloxycarbonyl, aryloxycarb- onyl, trimethylsilylethoxycarbonyl, formyl, alkylcarbonyl or aralkylcarbonyl; all thre R5 groups are the same and are hydrogen or methyl;

X is oxygen or imino; and

Y is a direct bond or a group -CONHCH(CH₃)-_;

wherein the carbon atom bridging X and Y may be in the L- or D-configuration, and derivatives thereof for treating plants.

4. A fungicidal composition for agronomical use comprising as an active ingredient a compound having the general formula I as defined in claim 3.

5. A fungicidal composition for agronomical use comprising as an active ingredient a compound having the general formula Ia

wherein each amino acid residue and the lactate residue independently may occur in L- or D-form, or derivatives thereof, preferred are the compounds wherein all the amino acid residues are in the L-form and the lactate residue is in the D- form; and derivatives thereof.

6. The composition of claim 4 or 5, wherein said compound is present in an amount of from 0.001 μg/ml to 100 μg/ml.

7. A fungicidal composition comprising as an active ingredient a fungus of a species belonging to the genus Curvularia or genus Septoria.

8. The composition of claim 7, wherein the fungus is Curvularia sp. (IMI

CC No. 346564).

9. A fungicidal composition comprising as an active ingredient a compound having the general formula I as defined in claim 3, or derivatives thereof in combination with other biocidal agents.

10. A fungicidal composition comprising as an active ingredient a compound having the general formula Ia as defined in claim 5, or derivatives thereof in combination with other biocidal agents.

11. The composition of claim 9 or 10, wherein said other biocidal agent is chosen from the group comprising pesticides, such as fungicides, herbicides, insecticides, nematicides, acaricides or plant nutrients, plant growth regulators and fertilizers.

12. The composition of claim 11, wherein said other biocidal agent is another fungicide chosen from the group comprising ergosterol biosynthesis inhibitors ("EBIs", azoles or non-azoles), anilides, benzimidazoles, carbamates, dicarboximides, dithiocarbamates, bisdithiocarbamates, imidazoles, triazoles, phathalonitriles, polyhalogenalkylthio compounds, and phosphorous derivatives.

13. The composition of any of the claims 9 to 12, wherein said other active agent is present in an amount of 0.001 to 50% by weight, preferably 0.01 to 10% by weight.

14. A method of combating fungi at a locus infested or liable to be infested therewith, which comprises applying to said locus a composition according to any of the claims 4 to 13.

15. The method of claim 14, for combating fungi in plants, seeds, on timber, cosmetics, feeds and foods.

16. The method of claim 14 or 15, to control attacks from fungal species belonging to the classes Ascomycetes, Deuteromycetes, or Basidiomycetes.

17. The method of claim 14, 15, or 16, to control attacks from fungal species belonging to the classes Ascomycetes, or Deuteromycetes, e.g. to the genera Venturia, Monilinia, Erysiphe, Saccharomyces, Aspergillus, Penicillium, Botrytis, Phoma, Ascochyta, or Puccinia.

18. The method of claim 17, to control attacks from fiingal species belong- ing to the genus Botrytis, especially Botrytis cinerea.

19. The method of claim 17, to control attacks from fungal species belong- ing to the genus Erysiphe, especially E. graminis.

20. The method of claim 17, to control attacks from fungal species belong- ing to the genus Puccinia especially P. recondita.

21. A process for the production of compounds having the general formula I as defined in claim 3, and derivatives thereof by

a) cultivation on suitable nutrient media under suitable conditions of a

species belonging to the genus Curvularia,

b) subsequent recovery of an active component of formula Ia as defined in claim 3 from the biomass and the fermentation medium, and

c) optionally modifying the active compound to obtain a desired compound of formula I.

22. The process of claim 21, wherein the active compound has the formula Ia, and is obtained directly in step (b).

23. The process of any of the claims 21 to 22, wherein the microorganism is Curvularia sp. (IMI CC No. 346564).

24. Use of a compound as defined in claim 3 for the preservation of wood or timber.

25. Use of a compound as defined in claim 3 for the preservation of paints.

26. Use of a compound as defined in claim 3 for the preservation of cosme- tics.

27. Use of a compound as defined in claim 3 for the preservation of foods and feeds.

28. Use of a compound as defined in claim 3 as in additive to growth

29. An isolated pure culture of the microorganism Curvularia sp. (IMI CC No. 346564).