Methods and uses of preventing fungal diseases in plants

Abstract

The present invention relates to a method of preventing or reducing Septoria disease and / or rust disease in a plant, use of a composition in such a method, and a kit comprising a composition for such a method and use.

Description

[0001] METHODS AND USES OF PREVENTING FUNGAL DISEASES IN PLANTS

[0002] Field of the Invention

[0003] The present invention relates to a method of preventing or reducing Septoria disease and / or rust disease in a plant, use of a composition comprising yeast extract as a plant fungicide, and a kit comprising a yeast extract.

[0004] Background of the Invention

[0005] During their growth and after harvest, crops are exposed to the negative impact of pathogenic microorganisms. Pathogenic microorganisms consist of bacteria, archaea, protozoa, algae, fungi, viruses and multicellular animal parasites. Fungal diseases cause significant damage to crops and crop yields are significantly reduced as a result.

[0006] Fungal diseases have devastating effects on the global harvests of cereal crops. Cereal crops include wheat (e.g. spring wheat, winter wheat), maize, barley, rice, triticale and rye. Wheat is a cereal crop that is a staple food throughout the world. Wheat is produced on more land area than any other food crop across the globe. World trade in wheat is greater than for all other crops combined.

[0007] Septoria diseases and rust are two of the major fungal diseases that destroy cereal crops. Septoria disease includes two variants: Septoria tritici blotch and Septoria nodorum blotch. Septoria tritici blotch disease is caused by the pathogenic fungus Zymoseptoria tritici (also known as Septoria tritici and Mycosphaerella graminicola). Septoria nodorum blotch disease is caused by the pathogenic fungus Septoria nodorum (also known as Leptosphaeria nodorum). Septoria leaf blotch is the number one economic disease problem for wheat production in the UK and Europe.

[0008] Rusts are fungal plant pathogens of the order Pucciniales. There are more than 7,000 identified species of rust fungi. The three main types of rust that affect cereal crops are: yellow rust (also known as stripe rust); brown rust (also know as wheat leaf rust) and black rust (also known as stem rust). Yellow rust is caused by the pathogenic fungus Puccinia striiformis. Brown rust is caused by the pathogenic fungus Puccinia triticina. Black rust is caused by the pathogenic fungus Puccinia graminis. Rust is one of the other major fungal diseases that impact global wheat growth.

[0009] There is a huge global sale of chemical fungicides directed towards treating these Septoria diseases and rust diseases. The use of chemical fungicides has resulted in resistance evolution in the pathogens, such that no single fungicide is completely effective in protecting against these diseases. Similarly, when using genetic modification to breed wheat with genetic resistances to these pathogenic fungi, the resistances are quickly overcome by the fungus. Thus, there is currently no effective fungicide strategy for protecting cereal crops, such as wheat, from fungal diseases such as Septoria diseases and rust.

[0010] In recent years, use of synthetic chemical fungicides have been phased out due to environmental concerns. As a result, the ability to control Septoria diseases and rust in crops is increasingly difficult.

[0011] In view of the above, there is a need for new ways to provide environmentally benign crop protection against Septoria diseases and rust.

[0012] Summary of the Invention

[0013] A first aspect of the present invention relates to a method of preventing or reducing Septoria disease and / or rust disease in a plant, comprising applying a composition comprising yeast extract to the plant.

[0014] In an aspect, the plant may be a cereal crop. The cereal crop may be at least one selected from wheat, maize, barley, rice, triticale and rye.

[0015] In an aspect, the Septoria diease may be Septoria tritici blotch and / or Septoria nodorum blotch. The rust disease may be at least one selected from yellow rust, brown rust and black rust.

[0016] In an aspect, the amount of yeast extract in the composition may be equal to or greater than 0.1 weight %, for example greater than or equal to 0.5 weight %, preferably greater than or equal to 1.0 weight %, more preferably greater than or equal to 2.5 weight %, even more preferably greater than or equal to 5.0 weight % based on the total volume of the composition.

[0017] In an aspect, the amount of yeast extract in the composition may be 0.5 to 99.5 weight %, for example 1 .0 to 95 weight %, preferably 2.5 to 90 weight %, more preferably 5.0 to 85 weight % based on the total volume of the composition.

[0018] In an aspect, the composition may include a solvent and the solvent may be at least one selected from water, an alcohol, a ketone and an ether.

[0019] In an aspect, the composition may further include an additive selected from a peptone, dextrose and / or a surfactant.

[0020] In an aspect, the surfactant may be at least one selected from polysorbate 20, polysorbate 80, poloxamer 188, polyoxyethylene fatty acid esters, polyoxyl 35 castor oil, sorbitan monolaurate and trisiloxane organosilicone copolymers.

[0021] A second aspect of the present invention relates to the use of a composition comprising yeast extract in the method above.

[0022] A third aspect of the present invention relates to the use of a composition comprising yeast extract as a plant fungicide. The plant fungicide is used to reduce or prevent at least one of Zymoseptoria tritici, Leptosphaeria nodorum, Puccinia striiformis, Puccinia triticina and Puccinia graminis..

[0023] In an aspect, the plant may be a cereal crop. The cereal crop may be at least one selected from wheat, maize, barley, rice, triticale and rye.

[0024] In an aspect, the amount of yeast extract in the composition may be equal to or greater than 0.1 weight %, for example greater than or equal to 0.5 weight %, preferably greater than or equal to 1.0 weight %, more preferably greater than or equal to 2.5 weight %, even more preferably greater than or equal to 5.0 weight % based on the total volume of the composition. In an aspect, the amount of yeast extract in the composition may be 0.5 to 99.5 weight %, for example 1 .0 to 95 weight %, preferably 2.5 to 90 weight %, more preferably 5.0 to 85 weight % based on the total volume of the composition.

[0025] In an aspect, the composition may include a solvent and the solvent may be at least one selected from water, an alcohol, a ketone and an ether.

[0026] In an aspect, the composition may further include an additive selected from a peptone, dextrose and / or a surfactant.

[0027] In an aspect, the surfactant may be at least one selected from polysorbate 20, polysorbate 80, poloxamer 188, polyoxyethylene fatty acid esters, polyoxyl 35 castor oil, sorbitan monolaurate and trisiloxane organosilicone copolymers.

[0028] A third aspect of the present invention relates to a kit of parts for use according to the method or use as defined herein, including a yeast extract and instructions on how to apply the yeast extract to a plant to prevent or reduce fungal disease.

[0029] Brief Description of the Drawings

[0030] This invention will now be described, by way of example only, in reference to the accompanying drawings, in which:

[0031] Figure 1 demonstrates the set up for the wheat seedling Septoria infection assay.

[0032] Figures 2A and 2B demonstrate that yeast extract containing media treatments provide resistance to leaf infection by the Septoria fungus (Zymoseptoria tritici).

[0033] Detailed Description of the Invention

[0034] Due to the increased resistance of fungi to fungicides and the phasing out of many chemical fungicides on the market, the damage to crops, particularly wheat, is significant. Providing a cheap, non-toxic fungicide to treat fungal diseases, such as Septoria disease and / or rust disease, would increase global crop yield and reduce waste. The present invention is concerned with providing a method for preventing or reducing fungal diseases in plants. The present invention is based on the unexpected discovery that a composition including yeast extract acts as a fungicide. In particular, it has been found that a composition including yeast extract prevents or reduces Septoria disease and / or rust disease in cereal crops, particularly wheat.

[0035] Yeast extract is derived from yeast. Yeast extract comprises the cell contents of yeast without the cell walls. In other words, yeast extract consists of the cell contents of yeast. Yeast extract is the at least partially hydrolysed contents of a yeast cell having had the cell wall removed (i.e. no cell wall is present in yeast extract).

[0036] The production of yeast extract comprises three key steps: fermentation, disruption of the cell, and separation.

[0037] During fermentation, yeast is grown in the presence of a sugar source. During disruption, the yeast cell wall is broken down and the compounds inside the yeast cells (intracellular compounds) are released. Typically, in the food industry, thermal autolysis is used. This involves heating the yeast cells to a temperature of 45 to 55 °C. During autolysis, the digestive enzymes of the yeast cell break the intracellular compounds down into simpler compounds by hydrolysis. Other specialised disruption methods can also be used to break the yeast cell walls, such as mechanical disruption, enzymatic lysis, and treatment with organic solvents. Some of these methods do not result in the hydrolysis of the intracellular compounds. Therefore, disruption is not limited to autolysis, or more specifically thermal hydrolysis. During separation, the intracellular compounds of the broken yeast cells are isolated from the cell walls by centrifugation and / or filtration. The yeast extract consists of the intracellular components of the yeast cells. The yeast extract may be subjected to washing and drying. Yeast extracts are provided in liquid, paste or powder form.

[0038] The compounds present in yeast extract may include, but are not limited to, proteins, nucleic acids, polysaccharides, minerals and vitamins. The proteins may include peptides and free-amino acids, such as glutamic acid. The vitamins may include B vitamins, such as vitamin B-12. The nucleic acids may include ribonucleic acid (RNA), oligonucleotides and nucleotides. The polysaccharides may include oligosaccharides, chitin mannans and glucans. The exact composition of yeast extract varies based on the species of yeast, the production conditions and process times. The yeast extract may be autoclaved (e.g. the yeast extract may not include functional proteins).

[0039] Yeast extract is a water-soluble natural ingredient derived from fresh yeast. Yeast extract is a by-product of the food and brewing industries and is referred to as “spent yeast”. Yeast extract produced as a by-product in the food industry typically derives from the common bakers’ or brewers’ yeast, Saccharomyces cerevisiae. Other yeast species may also be used to make yeast extract, such as Candida utilis, Candida tropicalis, and Kluyveromyces marxianus. After brewing and / or baking, spent yeast is hydrolysed to produce yeast extract. Yeast extract is a natural by-product of the food industry. Yeast extract is generated in large amounts at low costs by the food industry. The source of yeast extract, yeast, is abundantly available. Yeast extract is non-toxic and consumed by humans and animals and is present in many commercial food products.

[0040] Yeast extract is a readily available, environmentally friendly, non-toxic ingredient. Using yeast extract as the active ingredient of a fungicide composition represents an effective and low-cost way of preventing fungal diseases (e.g. Septoria tritici blotch) from damaging crops and reducing crop yields.

[0041] The present invention is based on the unexpected discovery that a composition comprising yeast extract protects crops against Septoria disease. It is proposed that the yeast extract acts as a fungicide by upregulating the plant immune system.

[0042] The present invention is concerned with providing a method of preventing or reducing fungal disease in a plant, comprising applying a composition comprising yeast extract to the plant.

[0043] The plant may be a cereal crop. The cereal crop may be at least one selected from wheat, maize, barley, rice, triticale and rye. Preferably, the cereal crop is wheat.

[0044] The fungal disease may be a Septoria disease or a rust disease. The Septoria disease may be Septoria tritici blotch and / or Septoria nodorum blotch. The rust disease may be at least one selected from yellow rust, brown rust and black rust. Preferably, the fungal disease is Septoria tritici blotch and / or rust. More preferably, the fungal disease is Septoria tritici blotch. The amount of yeast extract in the composition may be greater than or equal to 0.1 weight %, greater than or equal to 0.2 weight %, greater than or equal to 0.3 weight %, greater than or equal to 0.5 weight %, greater than or equal to 0.5 weight %, greater than or equal to 0.6 weight %, greater than or equal to 0.7 weight %, greater than or equal to 0.8 weight %, greater than or equal to 0.9 weight %, greater than or equal to 1.0 weight %, greater than or equal to 1.5 weight %, greater than or equal to 2.0 weight %, greater than or equal to 2.5 weight %, greater than or equal to 3.0 weight %, greater than or equal to 3.5 weight %, greater than or equal to 4.0 weight %, greater than or equal to 4.5 weight %, greater than or equal to 5.0 weight % based on the total volume of the composition.

[0045] The amount of yeast extract in the composition may be 0.1 to 100 weight % based on the total volume of the composition. For example the amount of yeast extract in the composition may be 0.2 to 100 weight %, 0.3 to 100 weight %, 0.4 to 100 weight %, 0.5 to 100 weight %, 0.6 to 100 weight %, 0.8 to 100 weight %, 0.9 to 100 weight %, 1 .0 to 100 weight %, 1.5 to 100 weight %, 2.0 to 100 weight %, 2.5 to 100 weight %, 3.0 to 100 weight %, 3.5 to 100 weight %, 4.0 to 100 weight %, 4.5 to 100 weight %, or 5.0 to 100 weight %. The amount of yeast extract in the composition may be 0.5 to 99.5 weight % based on the total volume of the composition.

[0046] The amount of yeast extract in the composition may be 1.0 to 95 weight % based on the total volume of the composition. For example, the amount of yeast extract in the composition may be 1.5 to 95 weight %, 2.0 to 95 weight %, 2.5 to 95 weight %, 3.0 to 95 weight %, 3.5 to 95 weight %, 4.0 to 95 weight %, 4.5 to 95 weight %, or 5.0 to 95 weight % based on the total volume of the composition.

[0047] The amount of yeast extract in the composition may be 2.5 to 90 weight % based on the total volume of the composition. For example, the amount of yeast extract in the composition may be 3.0 to 90 weight %, 3.5 to 90 weight %, 4.0 to 90 weight %, 4.5 to 90 weight %, or 5.0 to 90 weight % based on the total volume of the composition. The amount of yeast extract in the composition may be 5.0 to 85 weight % based on the total volume of the composition. The amount of yeast extract defined in the passages above is in terms of the weight of the yeast extract in the composition as a percentage of the total volume of the composition (w / v %).

[0048] The composition may include a solvent. The solvent may be at least one selected from water, alcohols, ketones, ethers and hydrocarbons or mixtures thereof.

[0049] The solvent may be an alcohol. For example, the solvent may be selected from ethanol, isopropanol, glycerol, propylene glycol, benzyl alcohol, and polyethylene glycol. Preferably, the solvent may be C1-C12 alkyl alcohol (e.g. C2-C12 alkyl alcohol). For example, the solvent may be a Ci-Ce alkyl alcohol (e.g. C2-C6 alkyl alcohol).

[0050] The solvent may be a ketone. For example, the solvent may be selected from acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone.

[0051] The solvent may be an ether. For example, diethyl ether.

[0052] Preferably, the solvent may be water. The water may be sterile water that contains no microorganisms.

[0053] The composition may be applied to the plant before or after exposure to a fungus. Preferably, the composition is applied to the plant before exposure to the fungus.

[0054] The composition may be applied to the plant by sprays, drips and / or other forms of liquid application. A composition as described herein may be applied to a plant, including plant leaves, shoots, roots, or seeds. Preferably, the composition as described herein may be applied to a foliar surface of a plant.

[0055] As used herein, the term "foliar surface" broadly refers to any green portion of a plant having surface that may permit absorption, including petioles, stipules, stems, bracts, flowerbuds, and leaves.

[0056] The compositions may be applied to the foliar surfaces of the plant using any conventional system for applying liquids to a foliar surface. For example, application by spraying will be most convenient. Any conventional atomisation method can be used to generate spray droplets, including hydraulic nozzles and rotating disk atomisers. In other instances, alternative application techniques, including application by brush or by ropewick, may be utilised.

[0057] The composition may further comprise an additive. The additive may be a peptone, dextrose and / or a surfactant. Preferably, the composition may comprise a peptone, dextrose and a surfactant.

[0058] Agricultural compositions are often formulated and transported in a concentrated form, which is subsequently diluted by the user before application. The presence of small amounts of a surfactant facilitates this process of dilution. Thus, at least one carrier in a composition as described herein may be a surfactant agent.

[0059] A surfactant may be an emulsifying agent, a dispersing agent or a wetting agent; it may be non-ionic or ionic. Examples of suitable surfactant include the sodium or calcium salts of polyacrylic acids and lignin sulfonic acids; the condensation of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and / or propylene oxide; fatty acid esters of glycerol, sorbitol, sucrose or pentaerythritol; condensates of these with ethylene oxide and / or propylene oxide; condensation products of fatty alcohol or alkyl phenols, for example p-octylphenol or p- octylcresol, with ethylene oxide and / or propylene oxide; sulfates or sulfonates of these condensation products; alkali or alkaline earth metal salts, preferably sodium salts, of sulfuric or sulfonic acid esters containing at least 10 carbon atoms in the molecule, for example sodium lauryl sulfate, sodium secondary alkyl sulfates, sodium salts of sulfonated castor oil, and sodium alkylaryl sulfonates such as dodecylbenzene sulfonate; polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxide; and organosilicone copolymers, for example trisiloxane organosilicone copolymers. Preferably, the surfactant may be at least one selected from polysorbate 20 (polyoxyethylene (20) sorbitan monolaurate), polysorbate 80 (polyoxyethylene (20) sorbitan monooleate), poloxamer 188, polyoxyl 35 castor oil, sorbitan monolaurate and trisiloxane organosilicone copolymers. More preferably, the surfactant may be polysorbate 20.

[0060] Peptones are a water-soluble protein hydrolysates made by incomplete hydrolysis of proteins. The amount of surfactant in the composition may be 0.001 to 1 .0 weight % based on the total volume of the composition. For example, the amount of surfactant in the composition may be 0.01 to 0.9 weight %, 0.02 to 0.8 weight %, 0.03 to 0.7 weight %, or 0.04 to 0.6 weight % based on the total volume of the composition. The amount of surfactant in the composition may be about 0.05 weight % based on the total volume of the composition.

[0061] According to another aspect of the invention, there is provided the use of a composition comprising yeast extract as a plant fungicide.

[0062] The term “fungicide” as used herein is a chemical that kills or prevents the growth of fungi and their spores.

[0063] The plant fungicide may be used to reduce or prevent the growth of at least one of Zymoseptoria tritici, Leptosphaeria nodorum, Puccinia striiformis, Puccinia triticina and Puccinia graminis. Preferably, the fungicide may be used to reduce or prevent the growth of Zymoseptoria tritici.

[0064] Examples

[0065] The invention will now be illustrated by means of the following examples, it being understood that these are intended to explain the invention, and in no way to limit its scope.

[0066] Wheat leaf infection assays

[0067] A preliminary experiment indicated that treatment of leaves with LB broth (LB broth (Lennox) - LB Formedium product number LBX0102) offered some protection to wheat leaves against fungal disease. Control treatments (fungal spores + treatment with sterile water + 0.05 % w / v Tween20) gave the anticipated complete leaf area necrosis at 21 days per infection. Necrosis was noticeably reduced if LB broth was used as a secondary treatment. This suggested that a component of LB might be imparting leaf protection. One component of LB is YE, which is present at 1% w / v. Wheat leaf infection assays were conducted to determine which component of the media was providing protection. Wheat seeds (cultivar Riband) were sown into standard soil containing fertiliser. Seedlings were grown in air-conditioned glasshouse for 17 to 21 days (16 hours a day at 20 °C: 8 hour night at 14 °C) until emergence of the third leaf. Five days prior to leaf inoculation, fungal spores stored at -80 °C in 50% w / v glycerol were streaked onto Yeast Extract Peptone Dextrose Agar (YPD) plates, and incubated in the dark for 5 days at 16 °C. Fungal inoculation of the second leaves of each seedling was performed as described in Keon, etal., (Molecular Plant-Microbe Interactions; 2007, 20 (2), pp. 178-193) and illustrated in Figure 1. The second leaves were inoculated with a Zymoseptoria tritici (formerly called Mycosphaerella graminicola - isolate IPO323) spore suspensions streaked from YPD plates into sterile water + 0.05% w / v of Tween20 (polysorbate 20) to a density of 1 x 106spores I ml. Spore suspensions were applied by spraying using small handheld pump-action perfume bottles until run-off (complete leaf wetting). Additional media or Yeast Extract (YE) solutions were applied via the same means 1 hour after spore application. The trays containing the inoculated fixed leaves were then placed inside plastic boxes to generate high humidity for 72 hours before removal. Disease levels were monitored for 21 days from the inoculation date with photographs taken periodically and at the final date (21 days post infection).

[0068] The following commercially available media were used; (1) Yeast Extract Peptone Dextrose Broth - YPD Formedium product number CCM0210; (2) LB broth (Lennox) - LB Formedium product number LBX0102; (3) Potato Dextrose Broth (PDB) - PDB Formedium product number PDB0102; (4) Czapek-Dox Broth (CDB) - CDB Oxoid product number CM95; (5) Yeast Extract - YE Sigma Y1625.

[0069] Other broths were also tested to see if they provided protection against Septoria tritici blotch disease: YPD, which contains YE at 5% w / v and two other rich media, which contain no YE, namely CDB and PDB. LB was also included in these assays to confirm the original observations.

[0070] Figure 2A shows the results of these treatments on fungal infection levels of wheat leaves photographed 21 days (3 weeks) after treatments. The symbol “n” in Figure 2A denotes the number of times the same result was achieved in an independently replicated experimental unit (e.g. in separate plants). Figure 2A demonstrates a noticeable reduction in disease level when LB treatment was included. However, an even stronger effect was seen upon YPD treatment, which has YE present at 5% w / v therein. In contrast, treatment with both broths lacking YE provided no disease protection relative to untreated controls, with full leaf necrosis observed in all cases. This gave further credence to the idea that the YE component was responsible for the disease protection.

[0071] To test this further the disease assays were repeated using only commercial YE not in broth form. Solutions containing yeast extract at 5% w / v (same as in YPD) and 1 % as in LB were tested. The results of these treatments are shown in Figure 2B. “n” has the same meaning as in Figure 2A. Both the 5% w / v and the 1% w / v offered protection to levels equivalent to YPD and LB, with 5% w / v YE offering more protection than 1 % w / v YE. This indicates a dose response relationship between the amount of yeast extract present and the level of protection afforded. Both autoclaved and non-autoclaved yeast extract solutions offered the same levels of protection suggesting that the active component(s) are unlikely to be proteins.

[0072] This demonstrates that media containing yeast extract and pure yeast extract solutions both offer protection against Septoria tritici blotch disease. It is expected that this protection would extend to rust diseases, as rust pathogens infect the plant in a similar way to Septoria disease.

[0073] While the foregoing disclosure provides a general description of the subject matter encompassed within the scope of the present invention, including methods, as well as the best mode thereof, of making and using this invention, the following examples are provided to further enable those skilled in the art to practice this invention and to provide a complete written description thereof. However, those skilled in the art will appreciate that the specifics of these examples should not be read as limiting on the invention, the scope of which should be apprehended from the claims and equivalents thereof appended to this disclosure. Various further aspects and embodiments of the present invention will be apparent to those skilled in the art in view of the present disclosure.

[0074] “and / or” where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example, “A and / or B” is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein.

[0075] Unless context dictates otherwise, the descriptions and definitions of the features set out above are not limited to any particular aspect or embodiment of the invention and apply equally to all aspects and embodiments, which are described.

Claims

CLAIMS:

1. A method of preventing or reducing Septoria disease and / or rust disease in a plant, comprising applying a composition comprising yeast extract to the plant.

2. The method according to claim 1 , wherein the plant is a cereal crop.

3. The method according to claim 1 or claim 2, wherein the cereal crop is at least one selected from wheat, maize, barley, rice, triticale and rye.

4. The method according to any one of claims 1 to 3, wherein the Septoria diease is Septoria tritici blotch and / or Septoria nodorum blotch.

5. The method according to any one of claims 1 to 4, wherein the rust disease is at least one selected from yellow rust, brown rust and black rust.

6. The method according to any one of claims 1 to 5, wherein the amount of yeast extract in the composition is greater than or equal to 0.1 weight %, for example greater than or equal to 0.5 weight %, preferably greater than or equal to 1.0 weight %, more preferably greater than or equal to 2.5 weight %, even more preferably greater than or equal to 5.0 weight % based on the total volume of the composition.

7. The method according to any one of claims 1 to 6, wherein the amount of yeast extract in the composition is 0.5 to 99.5 weight %, for example 1.0 to 95 weight %, preferably 2.5 to 90 weight %, more preferably 5.0 to 85 weight % based on the total volume of the composition.

8. The method according to any one of claims 1 to 7, wherein the composition includes a solvent and the solvent is at least one selected from water, an alcohol, a ketone and an ether.

9. The method according to any one of claims 1 to 8, wherein the composition further comprises an additive selected from a peptone, dextrose and / or a surfactant.

10. The method according to claim 9, wherein the surfactant is at least one selected from polysorbate 20, polysorbate 80, poloxamer 188, polyoxyethylene fatty acid esters, polyoxyl 35 castor oil, sorbitan monolaurate and trisiloxane organosilicone copolymers.

11. Use of a composition comprising yeast extract in the method according to any preceding claim.

12. Use of a composition comprising yeast extract as a plant fungicide, wherein the plant fungicide is being used to reduce or prevent the growth of at least one of Zymoseptoria tritici, Leptosphaeria nodorum, Puccinia striiformis, Puccinia triticina and Puccinia graminis.

13. The use according to claim 12, wherein the plant is a cereal crop.

14. The use according to claim 12 or claim 13, wherein the cereal crop is at least one selected from wheat, maize, barley, rice, triticale and rye.

15. The use according to any one of claims 12 to 14, wherein the amount of yeast extract in the composition is greater than or equal to 0.1 weight %, for example greater than or equal to 0.5 weight %, preferably greater than or equal to 1.0 weight %, more preferably greater than or equal to 2.5 weight %, even more preferably greater than or equal to 5.0 weight % based on the total volume of the composition.

16. The use according to any one of claims 12 to 15, wherein the amount of yeast extract in the composition is 0.5 to 99.5 weight %, for example 1.0 to 95 weight %, preferably 2.5 to 90 weight %, more preferably 5.0 to 85 weight % based on the total volume of the composition.

17. The use according to any one of claims 12 to 16, wherein the composition includes a solvent and the solvent is at least one selected from water, an alcohol, a ketone and an ether.

18. The use according to any one of claims 12 to 17, wherein the composition further comprises an additive selected from a peptone, dextrose and / or a surfactant.

19. The use according to claim 18, wherein the surfactant is at least one selected from polysorbate 20, polysorbate 80, poloxamer 188, polyoxyethylene fatty acid esters, polyoxyl 35 castor oil, sorbitan monolaurate and trisiloxane organosilicone copolymers.

20. A kit of parts for use according to the method of any one of claims 1 to 10 or the use of any of claims 11 to 19, comprising a yeast extract and instructions on how to apply the yeast extract to a plant to prevent or reduce Septoria disease and / or rust disease.

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