WO2012165266A1

WO2012165266A1 - Method for controlling plant diseases

Info

Publication number: WO2012165266A1
Application number: PCT/JP2012/063236
Authority: WO
Inventors: Munekazu Ogawa; Akihiro Nishimura; Masanari OHNO
Original assignee: Ishihara Sangyo Kaisha, Ltd.
Priority date: 2011-05-27
Filing date: 2012-05-17
Publication date: 2012-12-06
Also published as: UA112544C2; RU2013158187A; JP5940369B2; BR112013029836A2; TW201309200A; EP2713753A1; TWI544871B; AR086563A1; RU2580681C2; JP2013010743A

Abstract

The present invention provides a combination of agricultural and horticultural fungicides, which remarkably improves controlling effects against plant diseases. A method for controlling plant disease, which comprises applying (a) 3-(2,3,4-trimethoxy-6-methylbenzoyl)-5-chloro-2-methoxy-4-methylpyridine, (b) prochloraz, and (c) at least one fungicide selected from the group consisting of a sterol demethylation inhibitor (excluding prochloraz) and an electron transport complex II inhibitor, to plants.

Description

DESCRIPTION

TITLE OF INVENTION: METHOD FOR CONTROLLING PLANT DISEASES TECHNICAL FIELD

The present invention relates to a combination of agricultural and horticultural fungicides, which remarkably improves controlling effects against plant diseases.

Patent Document 1 discloses that a benzoylpyridine derivative which is an active ingredient in the present invention is useful as a fungicide and may be mixed with or used in combination with another fungicide as the case requires. Further, it is disclosed that a fungicidal composition having excellent synergistic effects is obtained when the benzoylpyridine derivative is combined with prochloraz or the like (Patent Document 2) or difenoconazole or the like (Patent Document 3).

However, they failed to specifically disclose a combination of three fungicides of 3-(2,3,4-trimethoxy-6-methylbenzoyl)-5-chloro-2-methoxy-4-methylpyridine, prochloraz and a specific fungicide.

PRIOR ART DOCUMENTS PATENT DOCUMENTS

Patent Document 1 : WO02/02527

Patent Document 2: WO2005/041663

Patent Document 3: WO2010/002026

DISCLOSURE OF INVENTION TECHNICAL PROBLEM

Each of 3-(2,3,4-trimethoxy-6-methylbenzoyl)-5-chloro-2-methoxy-4- methylpyridine, prochloraz and a specific fungicide, which are active ingredients in the present invention, may be inadequate in its controlling effect against a specific plant disease, its residual effect may last only a relatively short time, or specific fungicide- resistant bacterium may emerge, and thus, depending upon the condition for application, it may practically have only an inadequate controlling effect against plant diseases. An object of the present invention is to provide a method for controlling plant diseases using a combination of fungicides, which remarkably improves controlling effects against plant diseases. SOLUTION TO PROBLEM

The present inventors have conducted a research to solve the above problems and as a result, found that by further combining a specific fungicide with 3-(2,3,4- trimethoxy-6-methylbenzoyl)-5-chloro-2-methoxy-4-methylpyridine and prochloraz, an unexpectedly excellent fungicidal effect can be obtained as compared with a case where the respective compounds are used alone, and accomplished the present invention.

That is, the present invention provides a method for controlling plant diseases, which comprises applying (a) 3-(2,3,4-trimethoxy-6-methylbenzoyl)-5-chloro-2- methoxy-4-methylpyridine (hereinafter sometimes referred to simply as a component (a)), (b) prochloraz (hereinafter sometimes referred to simply as a component (b)) and (c) at least one fungicide selected from the group consisting of a sterol demethylation inhibitor (excluding prochloraz) and an electron transport complex II inhibitor

(hereinafter sometimes referred to simply as a component (c)) in combination, to plants.

ADVANTAGEOUS EFFECTS OF INVENTION

The combination of fungicides of the present invention has stably high controlling effects against plant diseases and thus the method of the present invention is useful as a method for controlling plant diseases.

DESCRIPTION OF EMBODIMENTS

3-(2,3,4-Trimethoxy-6-methylbenzoyl)-5-chloro-2-methoxy-4-methylpyridine which is the component (a) in the present invention can be obtained by a production process as disclosed in the above Patent Documents 1 and 2. This is a compound known by a common name pyriofenone.

Prochloraz which is the component (b) in the present invention is a compound disclosed in The Pesticide Manual (15th edition; BRITISH CROP PROTECTION COUNCIL) at pages 928 to 929.

The sterol demethylation inhibitor (excluding prochloraz) which is the component (c) of the present invention may, for example, be a triazole compound such as azaconazole, bitertanol, bromuconazole, cyproconazole, difenoconazole, diniconazole, epoxiconazole, etaconazole, fenbuconazole, fluquinconazole, flusilazole, flutriafol, furconazole-cis, hexaconazole, imibenconazole, ipconazole, metconazole,

myclobutanil, penconazole, propiconazole, prothioconazole, simeconazole,

tebuconazole, tetraconazole, triadimefon, triadimenol or triticonazole;

a pyridine compound such as pyrifenox;

a piperazine compound such as triforine;

a pyridmine compound such as nuarimol or fenarimol; or

an imidazole compound such as oxpoconazole, imazalil, triflumizole or

pefurazoate. These are compounds disclosed in The Pesticide Manual (15th edition; BRITISH CROP PROTECTION COUNCIL) or SHIBUYA INDEX 15th edition (SHIBUYA INDEX RESEARCH GROUP) as fungicides.

Among them, a triazole compound or an imidazole compound is preferred.

More specifically, cyproconazole, difenoconazole, epoxiconazole, fluquinconazole, flusilazole, hexaconazole, imibenconazole, metconazole, penconazole, propiconazole, prothioconazole, simeconazole, tebuconazole, tetraconazole, triadimenol,

oxpoconazole or triflumizole is preferred, and cyproconazole, epoxiconazole, fluquinconazole, hexaconazole, metconazole, propiconazole, prothioconazole, tebuconazole or tetraconazole is more preferred.

The electron transport complex II inhibitor which is the component (c) in the present invention may, for example, be a pyrazolecarboxamide compound such as penthiopyrad, penflufen, furametpyr, bixafen, isopyrazam, sedaxane or fluxapyroxad; a pyridinecarboxamide compound such as boscalid;

a thiazolecarboxamide compound such as thifluzamide;

an oxathiin compound such as carboxin or oxycarboxin;

a pyridinyl-ethylbenzamide compound such as fluopyram;

a furancarboxamide compound such as fenfuram; or

a phenyl-benzamide compound such as flutolanil, mepronil or benodanil. These are compounds disclosed in The Pesticide Manual (15th edition; BRITISH CROP PROTECTION COUNCIL) or SHIBUYA INDEX 15th edition (SHIBUYA INDEX

RESEARCH GROUP) as fungicides.

Among them, a pyrazolecarboxamide compound, a pyridinecarboxamide compound or a pyridinyl-ethylbenzamide compound is preferred. More specifically, penthiopyrad, penflufen, bixafen, isopyrazam, boscalid, sedaxane, fluxapyroxad or fluopyram is preferred.

The components (a), (b) and (c) may be a salt. The salt may be any

agriculturally acceptable salt, and may, for example, be an alkali metal salt such as a sodium salt or a potassium salt; an alkaline earth metal salt such as a magnesium salt or a calcium salt; an ammonium salt such as a monomethylammonium salt, a dimethylammonium salt or a triethylammonium salt; an inorganic acid salt such as a hydrochloride, a perchlorate, a sulfate or a nitrate; or an organic acid salt such as an acetate, a fumarate or a methanesulfonate.

The method of the present invention is useful for controlling various plant diseases, such as blast, brown spot or sheath blight of rice (Oryza sativa, etc.);

powdery mildew, scab, rust, snow mold, snow blight, loose smut, eye spot, leaf spot or glume blotch of cereals (Hordeum vulgare, Tricum aestivum, etc.); melanose or scab of citrus (Citrus spp., etc.); blossom blight, powdery mildew, Alternaria leaf spot or scab of apple (Mai us pumila); scab or black spot of pear (Pyrus Pyrifolia, var. culta); brown rot, scab or Phomopsis rot of peach (Prunus persica, etc.); anthracnose, ripe rot, powdery mildew or downy mildew of grape (Vitis vinifera spp., etc.); anthracnose or leaf spot of Japanese persimmon (Diospyros kaki, etc.); anthracnose, powdery mildew, gummy stem blight of downy mildew of cucurbit (Cucumis melo, etc.); early blight, leaf mold or late blight of tomato (Lvcopersicon esculentum); Alternaria leaf spot of cruciferous vegetables (Brassica sp., Raphanus sp., etc); early blight or late blight of potato

(Solanum tuberosum); powdery mildew of strawberry (Fragaria, etc.); and gray mold or disease caused by Sclerotinia of various crops. It is particularly effective against plant diseases of cereals. Further, it is effective also for controlling soil diseases caused by plant pathogens such as Fusarium, Pvthium, Rhizoctonia. Verticillium and

Plasmodiophora.

The components (a), (b) and (c) in the present invention are, in the same manner as conventional agricultural chemicals, mixed with various adjuvants and formulated into various formulations such as a dust, granules, water dispersible granules, a wettable powder, a water-based suspension concentrate, an oil-based suspension concentrate, water soluble granules, an emu!sifiable concentrate, a soluble

concentrate, a paste, an aerosol and an ultra low-volume formulation. However, so long as the purpose of the present invention can be accomplished, any type of formulation which is commonly used in this field is applicable.

When these components are formulated, the components (a), (b) and (c) may be formulated as mixed together, or they may separately be formulated.

Such adjuvants include solid carriers such as diatomaceous earth, slaked lime, calcium carbonate, talc, white carbon, kaoline, bentonite, a mixture of kaolinite and sericite, clay, sodium carbonate, sodium bicarbonate, mirabilite, zeolite and starch; solvents such as water, toluene, xylene, solvent naphtha, dioxane, acetone,

isophorone, methyl isobutyl ketone, chlorobenzene, cyclohexane, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone and alcohol; anionic surfactants and spreaders such as a salt of fatty acid, a benzoate, an

alkylsulfosuccinate, a dialkylsulfosuccinate, a polycarboxylate, a salt of alkylsulfuric acid ester, an alkyl sulfate, an alkylaryl sulfate, an alkyl diglycol ether sulfate, a salt of alcohol sulfuric acid ester, an alkyl sulfonate, an alkylaryl sulfonate, an aryl sulfonate, a lignin sulfonate, an alkyldiphenyl ether disulfonate, a polystyrene sulfonate, a salt of alkylphosphoric acid ester, an alkylaryl phosphate, a styrylaryl phosphate, a salt of polyoxyethylene alkyl ether sulfuric acid ester, a polyoxyethylene alkylaryl ether sulfate, a salt of polyoxyethylene alkylaryl ether sulfuric acid ester, a polyoxyethylene alkyl ether phosphate, a salt of polyoxyethylene alkylaryl phosphoric acid ester, and a salt of a condensate of naphthalene sulfonate with formalin; nonionic surfactants and spreaders such as a sorbitan fatty acid ester, a glycerin fatty acid ester, a fatty acid polyglyceride, a fatty acid alcohol polyglycol ether, acetylene glycol, acetylene alcohol, an oxyalkylene block polymer, a polyoxyethylene alkyl ether, a polyoxyethylene alkylaryl ether, a polyoxyethylene styrylaryl ether, a polyoxyethylene glycol alkyl ether, a polyoxyethylene fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, a polyoxyethylene glycerin fatty acid ester, a polyoxyethylene hydrogenated castor oil, and a polyoxypropylene fatty acid ester; and vegetable and mineral oils such as olive oil, kapok oil, castor oil, palm oil, camellia oil, coconut oil, sesame oil, corn oil, rice bran oil, peanut oil, cottonseed oil, soybean oil, rapeseed oil, linseed oil, tung oil, and liquid paraffins. Such adjuvants may be selected from those known in this field so long as the purpose of the present invention can thereby be accomplished. Further, various additives which are commonly used, such as a filler, a thickener, an anti-settling agent, an anti-freezing agent, a dispersion stabilizer, a phytotoxicity reducing agent, and an anti-mold agent, may also be employed. The blend ratio of the active ingredient compounds to the various adjuvants is usually from 0.005:99.995 to 95:5, preferably from 0.2:99.8 to 90:10. In the actual application of such a formulation, it may be used as it is, or may be diluted to a predetermined concentration with a diluent such as water, and various spreaders may be added thereto, as the case requires.

Further, in the present invention, other agricultural chemicals such as a fungicide, an insecticide, a miticide, a nematicide, a soil pesticide, an antivirus agent, an attractant, a herbicide and a plant growth regulating agent may further be used in combination, whereby more excellent effects may sometimes be obtained.

The active ingredient compounds of a fungicide in the above-mentioned other agricultural chemicals, include, for example, (by common names, some of them are still in an application stage, or test codes of Japan Plant Protection Association):

anilinopyrimidine compounds such as mepanipyrim, pyrimethanil and cyprodinil; triazolopyrimidine compounds such as 5-chloro-7-(4-methylpiperidin-1-yl)-6- (2,4,6-trifluorophenyl)[1 ,2,4]triazolo[1 ,5-a]pyrimidine;

pyridinamine compounds such as fluazinam;

azole compounds such as tricyclazole and probenazole;

quinoxaline compounds such as quinomethionate;

dithiocarbamate compounds such as maneb, zineb, mancozeb, polycarbamate, metiram, propineb and thiram;

organic chlorine compounds such as fthalide, chlorothalonil and quintozene;

imidazole compounds such as benomyl, thiophanate-methyl, carbendazim, thiabendazole, fuberiazole and cyazofamid;

cyanoacetamide compounds such as cymoxanil;

anilide compounds such as metalaxyl, metalaxyl-M (another name: mefenoxam), oxadixyl, ofurace, benalaxyl, benalaxyl-M (another name: kiralaxyl, chiralaxyl), furalaxyl, cyprofuram, isotianil and tiadinil; sulfamide compounds such as dichlofluanid;

copper compounds such as cupric hydroxide and oxine copper;

isoxazole compounds such as hymexazol;

organophosphorus compounds such as fosetyl-AI, tolclofos-methyl, S-benzyl 0,0-diisopropylphosphorothioate, O-ethyl S,S-diphenylphosphorodithioate, aluminum ethylhydrogen phosphonate, edifenphos and iprobenfos;

phthalimide compounds such as captan, captafol and folpet;

dicarboxyimide compounds such as procymidone, iprodione and vinclozolin; amide compounds such as silthiopham and fenoxanil;

benzamide compounds such as zoxamide;

piperidine compounds such as fenpropidin;

morpholine compounds such as fenpropimorph and tridemorph;

organotin compounds such as fentin hydroxide and fentin acetate;

urea compounds such as pencycuron;

cinnamic acid compounds such as dimethomorph and flumorph;

phenyl carbamate compounds such as diethofencarb;

cyanopyrrole compounds such as fludioxonil and fenpiclonil;

strobilurin compounds such as azoxystrobin, kresoxim-methyl, metominostrobin, trifloxystrobin, picoxystrobin, oryzastrobin, dimoxystrobin, pyraclostrobin, fluoxastrobin, enestroburin, pyraoxystrobin and pyrametostrobin;

oxazolidinone compounds such as famoxadone;

thiazolecarboxamide compounds such as ethaboxam;

valinamide compounds such as iprovalicarb and benthiavalicarb-isopropyl;

acylamino acid compounds such as methyl N-(isopropoxycarbonyl)-L-valyl- (3RS)-3-(4-chlorophenyl)- -alaninate (valiphenalate);

imidazolinone compounds such as fenamidone;

hydroxyanilide compounds such as fenhexamid;

benzenesulfonamide compounds such as flusulfamide;

oxime ether compounds such as cyflufenamid;

anthraquinone compounds;

crotonic acid compounds;

antibiotics such as validamycin, kasugamycin and polyoxins; guanidine compounds such as iminoctadine and dodine;

quinoline compounds such as tebufloquin;

thiazolidine compounds such as flutianil;

sulfur compounds such as sulfur;

and other compounds such as pyribencarb, isoprothiolane, pyroquilon, diclomezine, quinoxyfen, propamocarb hydrochloride, chloropicrin, dazomet, metam- sodium, metrafenone, UBF-307, diclocymet, proquinazid, amisulbrom (another name: amibromdole), mandipropamid, fluopicolide, carpropamid, meptyldinocap, N-[(3',4'- dichloro-1 ,1 -dimethyl)phenacyl]-3-trifluoromethyl-2-pyridinecarboxamide, N-[(3',4'- dichloro-1 ,1 -dimethyl)phenacyl]-3-methyl-2-thiophenecarboxamide, N-[(3',4'-dichloro- 1 ,1 -dimethyl)phenacyl-1 -methyl-3-trifluoromethyl-4-pyrazolecarboxamide, N-[[2'- methyl-4'-(2-propyloxy)-1 , 1 -dimethyl]phenacyl]-3-trifluoromethyl-2- pyridinecarboxamide, N-[[2'-methyl-4'-(2-propyloxy)-1 ,1 -dimethyl]phenacyl]-3-methyl-2- thiophenecarboxamide, N-[[2'-methyl-4'-(2-propyloxy)-1 ,1-dimethyl]phenacyl]-1-methyl- 3-trifluoromethyl-4-pyrazolecarboxamide, N-[[4'-(2-propyloxy)-1 , 1 -dimethyl]phenacyl]- 3-trifluoromethyl-2-pyridinecarboxamide, N-[[4'-(2-propyloxy)-1 , 1 -dimethyl]phenacyl]-3- methyl-2-thiophenecarboxamide, N-[[4'-(2-propyloxy)-1 ,1-dimethyl]phenacyl]-1-methyl- 3-trifluoromethyl-4-pyrazolecarboxamide, N-[[2'-methyl-4'-(2-pentyloxy)-1 , 1 - dimethyl]phenacyl]-3-trifluoromethyl-2-pyridinecarboxamide, N-[[4'-(2-pentyloxy)-1 ,1- dimethyl]phenacyl]-3-trifluoromethyl-2-pyridinecarboxamide, ferimzone, spiroxamine, fenpyrazamine, ametoctradin, S-2200, ZF-9646, BCM-061 and BCM-062.

The active ingredient compounds of insect pest control agents, such as the insecticide, the miticide, the nematicide and the soil insect pesticide in the above- mentioned other agricultural chemicals, include, for example, (by common names, some of them are still in an application stage, or test codes of Japan Plant Protection Association):

organic phosphate compounds, such as profenofos, dichlorvos, fenamiphos, fenitrothion, EPN, diazinon, chlorpyrifos, chlorpyrifos-methyl, acephate, prothiofos, fosthiazate, cadusafos, disulfoton, isoxathion, isofenphos, ethion, etrimfos, quinalphos, dimethylvinphos, dimethoate, sulprofos, thiometon, vamidothion, pyraclofos,

pyridaphenthion, pirimiphos-methyl, propaphos, phosalone, formothion, malathion, tetrachlorvinphos, chlorfenvinphos, cyanophos, trichlorfon, methidathion, phenthoate, ESP, azinphos-methyl, fenthion, heptenophos, methoxychlor, parathion, phosphocarb, demeton-S-methyl, monocrotophos, methamidophos, imicyafos, parathion-methyl, terbufos, phosphamidon, phosmet and phorate;

carbamate compounds, such as carbaryl, propoxur, aldicarb, carbofuran, thiodicarb, methomyl, oxamyl, ethiofencarb, pirimicarb, fenobucarb, carbosulfan, benfuracarb, bendiocarb, furathiocarb, isoprocarb, metolcarb, xylylcarb, XMC and fenothiocarb;

nereistoxin derivatives, such as cartap, thiocyclam, bensultap and thiosultap- sodium;

organic chlorine compounds, such as dicofol, tetradifon, endosulfan, dienochlor and dieldrin;

organic metal compounds, such as fenbutatin oxide and cyhexatin;

pyrethroid compounds, such as fenvalerate, permethrin, cypermethrin, deltamethrin, cyhalothrin, tefluthrin, ethofenprox, flufenprox, cyfluthrin, fenpropathrin, flucythrinate, fluvalinate, cycloprothrin, lambda-cyhalothrin, pyrethrins, esf en vale rate, tetramethrin, resmethrin, protrifenbute, bifenthrin, zeta-cypermethrin, acrinathrin, alpha-cypermethrin, allethrin, gamma-cyhalothrin, theta-cypermethrin, tau-fluvalinate, tralomethrin, profluthrin, beta-cypermethrin, beta-cyfluthrin, metofluthrin, phenothrin and flumethrin;

benzoylurea compounds, such as diflubenzuron, chlorfluazuron, teflubenzuron, flufenoxuron, triflumuron, hexaflumuron, lufenuron, novaluron, noviflumuron, bistrifluron and fluazuron;

juvenile hormone-like compounds, such as methoprene, pyriproxyfen, fenoxycarb and diofenolan;

pyridazinone compounds, such as pyridaben;

pyrazole compounds, such as fenpyroximate, fipronil, tebufenpyrad, ethiprole, tolfenpyrad, acetoprole, pyrafluprole and pyriprole;

neonicotinoids, such as imidacloprid, nitenpyram, acetamiprid, thiacloprid, thiamethoxam, clothianidin, nidinotefuran, dinotefuran and nithiazine;

hydrazine compounds, such as tebufenozide, methoxyfenozide, chromafenozide and halofenozide;

pyridine compounds, such as flonicamid; tetronic acid compounds, such as spirodiclofen;

strobilurin compounds, such as fluacrypyrim;

pyrimidinamine compounds, such as flufenerim;

dinitro compounds;

organic sulfur compounds;

urea compounds;

triazine compounds;

hydrazone compounds;

other compounds, such as buprofezin, hexythiazox, amitraz, chlordimeform, silafluofen, triazamate, pymetrozine, pyrimidifen, chlorfenapyr, indoxacarb, acequinocyl, etoxazole, cyromazine, 1 ,3-dichloropropene, diafenthiuron, benclothiaz, bifenazate, spiromesifen.spirotetramat, propargite, clofentezine, metaflumizone, flubendiamide, cyflumetofen, chlorantraniliprole, cyenopyrafen, pyrifluquinazone, fenazaquin, amidoflumet, chlorobenzoate, sulfluramid, hydramethylnon, metaldehyde, HGW-86, AKD-1022, ryanodine, pyridalyl and verbutin. Further, it may be mixed with or used in combination with microbial agricultural chemicals, such as Bacillus thuringiensis aizawai, Bacillus thuringiensis kurstaki, Bacillus thuringiensis israelensis, Bacillus thuringiensis japonensis, Bacillus thuringiensis tenebrionis or insecticidal crystal proteins produced by Bacillus thuringiensis, insect viruses, etomopathogenic fungi, and nematophagous fungi: antibiotics or semisynthetic antibiotics, such as avermectin, emamectin benzoate, milbemectin, milbemycin, spinosad, ivermectin, lepimectin, DE- 175, abamectin, emamectin and spinetoram; natural products, such as azadirachtin, and rotenone; and repellents, such as deet.

In the present invention, various application methods may be employed, and may properly be used depending upon various conditions such as the crop plants to be treated, the application method, the type of the formulation, the dose, etc, and the following methods may be mentioned.

(1 ) Separate formulations of the component (a), the component (b) and the

component (c) are applied to the crop plants to be treated as they are, after diluted to a predetermined concentration with e.g. water, or after various additives (such as a surfactant, a vegetable oil or a metal oil) are added as the case requires.

(2-1) A formulation of the component (a) and the component (b) mixed together, and a formulation of the component (c), are applied to the crop plants to be treated as they are, after diluted to a predetermined concentration with e.g. water, or after various additives (such as a surfactant, a vegetable oil or a mineral oil) are added as the case requires.

(2-2) A formulation of the component (a) and the component (c) mixed together, and a formulation of the component (b), are applied to the crop plants to be treated as they are, after diluted to a predetermined concentration with e.g. water, or after various additives (such as a surfactant, a vegetable oil or a mineral oil) are added as the case requires.

(2-3) A formulation of the component (b) and the component (c) mixed together, and a formulation of the component (a), are applied to the crop plants to be treated as they are, after diluted to a predetermined concentration with e.g. water, or after various additives (such as a surfactant, a vegetable oil or a mineral oil) are added as the case requires.

(3) The component (a), the component (b) and the component (c) are mixed together to prepare a formulation, which is applied to the crop plants to be treated as it is, after diluted to a predetermined concentration with e.g. water, or after various additives (such as a surfactant, a vegetable oil or a mineral oil) are added as the case requires.

In the above application methods (1) and (2-1) to (2-3), the respective

formulations may be mixed when diluted to a predetermined concentration with e.g. water so that they are applied to the crop plants to be controlled simultaneously, or they may be applied continuously or with an appropriate interval. In order to obtain effects of the present invention more effectively, it is preferred to apply the component (a), the component (b) and the component (c) simultaneously.

The concentrations of the components (a), (b) and (c) of the present invention cannot generally be defined, as they vary depending upon the crop plants to be treated, the application method, the type of the formulation, the dose, etc. However, the concentration of the component (a) is preferably from 0.1 to 2,000 ppm, more preferably from 0.4 to 700 ppm, the concentration of the component (b) is preferably from 1 to 5,000 ppm, more preferably from 3 to 3,000 ppm, and the concentration of the component (c) is preferably from 0.5 to 2,500 ppm, more preferably from 0.8 to 1 ,500 ppm, in the case of foliar treatment. In the case of soil treatment, the concentration of the component (a) is preferably from 10 to 500 g/ha, more preferably from 30 to 200 g/ha, the concentration of the component (b) is preferably from 50 to 2,000 g/ha, more preferably from 100 to 1 ,000 g/ha, and the concentration of the component (c) is preferably from 10 to 2,000 g/ha, more preferably from 40 to 1 ,000 g/ha.

The appropriate mixing weight ratio of the components (a), (b) and (c) is such that per 1 part by weight of the component (a), the amount of the component (b) is preferably from 1 to 100 parts by weight, more preferably from 1 to 50 parts by weight, particularly preferably from 1 to 20 parts by weight, and the amount of the component (c) is preferably from 0.1 to 100 parts by weight, more preferably from 0.1 to 50 parts by weight, particularly preferably from 0.1 to 20 parts by weight.

In the present invention, the formulation or a diluted product thereof may be applied by an application method which is commonly used, such as spraying (such as spraying, jetting, misting, atomizing, powder or grain scattering, or dispersing in water), soil application (such as mixing or drenching) or surface application (such as coating, powdering or covering). Further, it may be applied also by a so-called ultra low- volume application method. In this method, the formulation may be composed of 100% of the active ingredients.

Now, preferred embodiments of the present invention will be described, but it should be understood that the present invention is by no means thereby restricted.

[1] A method for controlling plant diseases, which comprises applying the

component (a), the component (b) and the component (c), to plants.

[2] A method for controlling plant diseases, which comprises applying a composition containing the component (a) and the component (b), and the component (c), to plants.

[3] A method for controlling plant diseases, which comprises applying a composition containing the component (a) and the component (c), and the component (b), to plants.

[4] A method for controlling plant diseases, which comprises applying a composition containing the component (b) and the component (c), and the component (a), to plants.

[5] The method according to any one of the above [1] to [4], wherein as the component (c), the sterol demethylation inhibitor is a triazole compound, a pyridine compound, a piperazine compound, a pyrimidine compound or an imidazole compound, and the electron transport complex II inhibitor is a pyrazolecarboxamide compound, a pyridinecarboxamide compound, a thiazolecarboxamide compound, an oxathiin compound, a pyridinyl-ethylbenzamide compound, a furancarboxamide compound or a phenyl-benzamide compound.

[6] The method according to any one of the above [1] to [4], wherein as the component (c), the sterol demethylation inhibitor is a triazole compound or an imidazole compound, and the electron transport complex II inhibitor is a

pyrazolecarboxamide compound, a pyridinecarboxamide compound or a pyridinyl- ethylbenzamide compound.

[7] The method according to any one of the above [1] to [4], wherein the component (c) is at least one member selected from the group consisting of cyproconazole, difenoconazole, epoxiconazole, fluquinconazole, flusilazole, hexaconazole,

imibenconazole, metconazole, penconazole, propiconazole, prothioconazole, simeconazole, tebuconazole, tetraconazole, triadimenol, oxpoconazole, triflumizole, penthiopyrad, penflufen, bixafen, isopyrazam, boscalid, sedaxane, fluxapyroxad and fluopyram.

[8] The method according to any one of the above [1] to [4], wherein the component (c) is at least one member selected from the group consisting of cyproconazole, epoxiconazole, fluquinconazole, hexaconazole, metconazole, propiconazole, prothioconazole, tebuconazole, tetraconazole, triadimenol, oxpoconazole,

penthiopyrad, boscalid, sedaxane, fluxapyroxad and fluopyram.

[9] The method according to any one of the above [1] to [8], wherein the component (b) is applied in an amount of from 1 to 100 parts by weight, and the component (c) is applied in an amount of from 0.1 to 100 parts by weight, per 1 part by weight of the component (a).

[10] The method according to any one of the above [1] to [9], wherein the component (a), the component (b) and the component (c) are applied to plants simultaneously.

[11] The method according to any one of the above [1] to [10], which is a method for controlling plant diseases of cereals.

The present invention further includes fungicidal compositions and use of a combination of fungicides. Preferred embodiments of such a case will be described below. However, it should be understood that the present invention is by no means thereby restricted.

[12] A fungicidal composition comprising the component (a), the component (b) and the component (c).

[13] A fungicidal composition comprising the component (a) and the component (b), to be used in combination with the component (c).

[14] A fungicidal composition comprising the component (a) and the component (c), to be used in combination with the component (b).

[15] A fungicidal composition comprising the component (b) and the component (c), to be used in combination with the component (a).

[16] Use of a combination of the component (a), the component (b) and the

component (c) to control plant diseases.

[17] Use of a combination of a composition comprising the component (a) and the component (b), with the component (c), to control plant diseases.

[18] Use of a combination of a composition comprising the component (a) and the component (c), with the component (b), to control plant diseases.

[19] Use of a combination of a composition comprising the component (b) and the component (c), with the component (a), to control plant diseases.

EXAMPLES

Now, the present invention will be described in further detail with reference to

Test Examples. However, it should be understood that the present invention is by no means thereby restricted.

TEST EXAMPLE 1 : Test on preventive effect against wheat powdery mildew

Wheat (cultivar: Norin-61) was cultivated in a plastic pot having a diameter of 7.5 cm, and when it reached 1.5-leaf stage, a chemical solution having each test compound adjusted to a predescribed concentration, was applied by a spray gun in an amount of 5 ml/seedling. After the chemical solution dried, conidia of Erysiphe graminis were dusted and inoculated and maintained in a constant temperature chamber at 20°C. From 6 to 8 days after the inoculation, the area of sporulation was investigated, the control value was determined in accordance with the following calculation, and the results are shown in Tables 1 to 6. The area of sporulation in non-treated plot was obtained in the same manner as the treated plot except that water was spread by a spray gun instead of the chemical solution.

Control value=(1 -a/b)x100

a: Area of sporulation in treated plot, b: area of sporulation in non-treated plot Expected values (control values) by use in combination were calculated in accordance with the following Colby's formula. When the experimental value is higher than the expected value, the fungicidal composition of the present invention has a synergistic effect against wheat powdery mildew. Expected values by the Colby's formula in such cases are also shown in brackets ( ) in Tables 1 to 6.

Colby's formula=(x+y+z)-(xy+xz+yz)/100+xyz/10000

x: Control value in single use of the component (a)

y: Control value in single use of the component (b)

z: Control value in single use of the component (c)

(Table 1)

Control value

Concentration

(ppm) Single Component (a)+component use (b)+component (c)

Component (a) 0.4 1.5 -

Component (b) 3.1 0 -

Oxpoconazole 1.6 0 30.4(1.5)

Tebuconazole 3.1 18.9 65.2(20.1)

Component Tetraconazole 3.1 0 91.3(1.5)

(c) Propiconazole 3.1 0 91.3(1.5)

Cyproconazole 1.6 0 88.4(1.5)

Hexaconazole 3.1 0 91.3(1.5)

(Table 2)

Control value

Concentration

Single

(ppm) Component (a)+component use (b)+component (c)

Component (a) 0.4 43.8 -

Com ponent (b) 3.1 32.6 -

Component

Fluquinconazole 12.5 21.3 91.6(70.2)

(c) (Table 3)

Control value

Concentration

Single Component (a)+component (ppm)

use (b)+component (c)

Component (a) 0.4 0 -

Component (b) 3.1 0 -

Component

Prothioconazole 3.1 0 25.7(0)

(Table 4)

(Table 5)

(Table 6)

TEST EXAMPLE 2: Test on preventive effect against wheat glume blotch

Wheat (cultivar Norin-61 ) was cultivated in a plastic pot having a diameter of 7.5 cm, and when it reached 1.5-leaf stage, a chemical solution having each test compound adjusted to a predescribed concentration was applied by a spray gun in an amount of 5 ml/seedling. After the chemical solution dried, a suspension of conidia of Septoria rodorum was sprayed and inoculated and maintained in an inoculation box (humidity of at least 95%) at 20°C for 1 day, and then maintained in a constant temperature chamber at 20°C. From 9 to 11 days after the inoculation, the lesion area was investigated, and the control value was determined in the same manner as in Test Example 1. The results are shown in Tables 7 to 9. The lesion area in non- treated plot was determined in the same manner as the treated plot except that water was spread by a spray gun instead of the chemical solution.

Further, expected values by the Colby's formula are also shown in bracket ( ) in

Tables 7 to 9.

(Table 7)

Control value

Concentration

(ppm) Single Component (a)+component use (b)+component (c)

Component (a) 100 0 -

Component (b) 31 0 -

Tebuconazole 15 0 60.5(0)

Component Tetraconazole 31 0 60.5(0)

(c) Propiconazole 63 0 60.5(0)

Cyproconazole 8 0 60.5(0)

(Table 8)

Control value

Concentration

Single

(ppm) Component (a)+component use (b)+component (c)

Component (a) 100 0 -

Com ponent (b) 30 0 -

Epoxiconazole 15 36.1 87.2(36.1)

Hexaconazole 63 0 64.9(0)

Component Triadimenol 30 0 64.9(0)

(c) Fluquinconazole 15 0 64.9(0)

Metconazole 15 0 87.2(0)

Prothioconazole 15 0 80.8(0)

(Table 9)

Control value

Oncenii llOn

(ppm) Single Component (a)+component use (b)+component (c)

Component (a) 100 0 -

Component (b) 31 63.8 -

Component Penthiopyrad 31 0 92.2(63.8)

(c) Boscalid 31 0 94.8(63.8) The entire disclosure of Japanese Patent Application No. 2011-118691 filed on May 27, 2011 including specification, claims and summary is incorporated herein by reference in its entirety.

Claims

1. A method for controlling plant disease, which comprises applying (a) 3-(2,3,4- trimethoxy-6-methylbenzoyl)-5-chloro-2-methoxy-4-methylpyridine, (b) prochloraz, and (c) at least one fungicide selected from the group consisting of a sterol demethylation inhibitor (excluding prochloraz) and an electron transport complex II inhibitor, to plants.

2. The method according to Claim 1 , wherein as the component (c), the sterol demethylation inhibitor is a triazole compound, a pyridine compound, a piperazine compound, a pyrimidine compound or an imidazole compound, and the electron transport complex II inhibitor is a pyrazolecarboxamide compound, a

pyridinecarboxamide compound, a thiazolecarboxamide compound, an oxathiin compound, a pyridinyl-ethylbenzamide compound, a furancarboxamide compound or a phenyl-benzamide compound.

3. The method according to Claim 1 , wherein as the component (c), the sterol demethylation inhibitor is a triazole compound or an imidazole compound, and the electron transport complex II inhibitor is a pyrazolecarboxamide compound, a

pyridinecarboxamide compound or a pyridinyl-ethylbenzamide compound.

4. The method according to Claim 3, wherein (c) is at least one member selected from the group consisting of cyproconazole, difenoconazole, epoxiconazole,

fluquinconazole, flusilazole, hexaconazole, imibenconazole, metconazole,

penconazole, propiconazole, prothioconazole, simeconazole, tebuconazole,

tetraconazole, triadimenol, oxpoconazole, triflumizole, penthiopyrad, penflufen, bixafen, isopyrazam, boscalid, sedaxane, fluxapyroxad and fluopyram.

5. The method according to Claim 1 , wherein the concentration of the component (a) is from 0.1 to 2000 ppm, the concentration of the component (b) is from 1 to 5,000 ppm, and the concentration of the component (c) is from 0.5 to 2500 ppm, in the case of foliar treatment.

6. The method according to Claim 1 , wherein the concentration of the component (a) is from 10 to 500 g/ha, the concentration of the component (b) is from 50 to 2,000 g/ha, and the concentration of the component (c) is from 10 to 2,000 g/ha, in the case of soil treatment.

7. The method according to Claim 1 , wherein the component (b) is applied in an amount of from 1 to 100 parts by weight, and the component (c) is applied in an amount of from 0.1 to 100 parts by weight, per 1 part by weight of the component (a).

8. A fungicidal composition comprising (a) 3-(2,3,4-trimethoxy-6-methylbenzoyl)-5- chloro-2-methoxy-4-methylpyridine, (b) prochloraz, and (c) at least one fungicide selected from the group consisting of a sterol demethylation inhibitor (excluding prochloraz) and an electron transport complex II inhibitor.