Method for protecting soybeans from being infected by fungi

Description

The invention relates to a method for protecting soybean plants from being infected by specific harmful fungi, wherein the soybean plants, their seed or the soil is treated with a fungicidally effective amount of a synergistically active combination comprising a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole.

Over recent years, there has been an increase in fungal infections of soybean crops in South America , resulting in considerable harvest and yield losses. Though the abovementioned compounds are known to be fungicidal active, their fungi- cidal performance in soybeans is still not completely satisfactory in all respects.

Bixafen (IUPAC name: N-(3',4'-dichloro-5-fluorobiphenyl-2-yl)- 3-(difluoromethyl)-1- methylpyrazole-4-carboxamide)

is known from WO 03/070705 and can be prepared in the manner described therein.

N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4-carboxamide (common name Penflufen)

is known from WO 03/010149 and can be prepared in the manner described therein.

Fungicidal compositions of said and structurally related compounds with various other chemical compounds of different structual classes are known from WO 2005/034628 and WO 2005/041653, respectively.

However, the fungicidal performance of the known compositions against fungal pathogens in cereal plants, consisting of compound (I) or (II) and other active ingredients, are not completely satisfactory in all respects.

It has now been found that a combination comprising a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole has excellent activity against harmful fungi in soybean crops.

The compounds (I) and (II) can be present in various crystal modifications which may differ in their biological activity. Their use also forms part of the subject matter of the present invention.

Epoxiconazole and metconazole, their preparation and their action against harmful fungi are generally known to a person skilled in the art. Both compounds are commercially available (cf. , for example, www. alanwood.net/pesticides/index_cn_frame.html).

In one aspect of the invention, preference is given to a combination comprising bixafen (I) and epoxiconazole.

In another aspect of the invention, preference is given to a combination comprising bixafen (I) and metconazole.

In still another aspect of the invention, preference is given to a combination comprising N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4-carboxamide (II) and epoxiconazole.

In still another aspect of the invention, preference is given to a combination comprising N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4-carboxamide (II) and metconazole.

The combinations comprising a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole, are particularly suitable for controlling the following harmful fungi in soybean crops:

• Alternaria spp.,

• Cercospora kikuchi , • Cercospora sojina,

• Colletotrichum truncatum,

• Corynespora cassiicola.

• Microsphaera diffusa,

• Phakopsora meibomiae, • Phakopsora pachyrhizi and/or

• Septoria glycines .

In one aspect of the invention, the control of Alternaria spp. is particularly preferred.

In another aspect of the invention, the control of Cercospora kikuchi is particularly preferred.

In still another aspect of the invention, the control of Cercospora sojina is particularly preferred.

In still another aspect of the invention, the control of Colletotrichum truncatum is particularly preferred.

In still another aspect of the invention, the control of Corynespora cassiicola is particu- larly preferred.

In still another aspect of the invention, the control of Microsphaera diffusa is particularly preferred.

In still another aspect of the invention, the control of Phakopsora meibomiae is particularly preferred.

In still another aspect of the invention, the control of Phakopsora pachyrhizi is particularly preferred.

In still another aspect of the invention, the control of Septoria glycines is particularly preferred.

The soybean plants or seed treated with the combinations of a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole

may by wildlife types, plants or seed obtained by breeding and transgenic plants as well as their seed.

Bixafen and epoxiconazole or metconazole can be applied simultaneously, that is jointly or separately, or in succession, the sequence, in the case of separate application, generally not having any effect on the result of the control measures.

The harmful fungi are controlled by applying the combination comprising a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole by treating the seed, by spraying or dusting the plants or the soil before or after sowing of the plants, or before or after emergence of the plants.

The fungal diseases in in soybean crops are controlled advantageously by applying an aqueous preparation of a formulation comprising a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole, or formulations comprising the single components, to the above-ground parts of the plants, in particular the leaves, or, as a prophylactic on account of the high systemic effectiveness, by treating the seed or the soil.

Compound (I) and epoxiconazole or metconazole respectively compound (II) and ep- oxiconazole or metconazole are usually applied in a weight ratio of from 100:1 to 1 :100, preferably from 20:1 to 1 :20, in particular from 10:1 to 1 :10.

Though generally combinations of a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole are employed, further compounds active against harmful fungi or other pests, such as insects, arachnids or nematodes, or else herbicidal or growth-regulating active compounds or fertilizers may be added.

Accordingly, the invention also relates to fungicidal mixtures for controlling harmful fungi in soybean crops, which mixtures comprise, as active components, a combination of a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole, and

c) at least one futher active compound (III) as indicated above.

In the method according to the invention, the fungicidal composition can advantageously be applied together with other active compounds (III), for example herbicides, insecticides, growth regulators, further fungicides or else with fertilizers. Suitable further mixing partners of this nature are in particular:

• glyphosate, sulphosate, gluphosinate, tefluthrin, terbufos, chlorpyrifos, chloroethoxy- fos, tebupirimfos, phenoxycarb, diofenolan, pymetrozine, imazethapyr, imazamox, imazapyr, imazapic, imazaquin or dimethenamid-P, in particular glyphosate, sul- phosate, gluphosinate or dimethenamid-P;

• fipronil, imidacloprid, acetamiprid, nitenpyram, carbofuran, carbosulfan, benfura- carb, dinotefuran, thiacloprid, thiamethoxam, clothianidin, diflubenzuron, flufenoxuron, teflubenzuron, alpha-cypermethrin and metaflumizone, in particular fipronil, imidacloprid, acetamiprid, carbofuran, thiamethoxam, clothianidin, flufenoxuron, teflubenzuron, alpha-cypermethrin and metaflumizone.

Those other active compounds (III) mentioned above are usually employed in a weight ratio of from 100:1 to 1 :100, preferably from 20:1 to 1 :20, in particular from 10:1 to 1 :10, based on the amount of compound (I) or (II).

Most preferrably, the further active compound (III) is applied together with (I) or (II) and epoxiconazole or metconazole in synergistically effective amounts.

The mixtures, described above, of a) bixafen (I) or N-[2-(1 ,3-dimethylbutyl)-phenyl]-1 ,3-dimethyl-5-fluor-1 H-pyrazole-4- carboxamide (II) and b) epoxiconazole or metconazole with herbicides are used in particular in crops in which the sensitivity of the plants to these herbicides, in particular glyphosate and the above mentioned imidazolinone compounds, is reduced.

When applying a combination comprising a) compound (I) or (II) and b) epoxiconazole or metconazole, to soybean crops, the yields are increased considerably. Thus, the combinations comprising compound (I) and epoxiconazole or metconazole respec- tively compound (II) and epoxiconazole or metconazole may also be used to increase the yield. By virtue of the yield increase in combination with the excellent action against harmful fungi in soybean crops, the method according to the invention is of particular benefit to the farmer.

The combination comprising a) compound (I) or (II) and b) epoxiconazole or metcona- zole, with fungicidally, insecticidally and/or herbicidally active compounds (III) is applied by treating the fungi or the plants, materials or seeds to be protected against fungal attack or the soil with a fungicidally effective amount of the active compounds. Applica- tion can be both before and after the infection of the materials or plants with the fungi.

If compound (I) or (II) is used on its own, the application rates in the method according to the invention are from 0.01 to 1.5 kg of active compound per ha, depending on the type of effect desired.

In the treatment of seed, the amounts of active compound (I) or (II) required are generally from 1 to 1500 g, preferably from 10 to 500 g, per 100 kilograms of seed.

Depending on the desired effect, the application rates of the mixtures according to the invention are from 10 g/ha to 2500 g/ha, preferably from 50 to 2000 g/ha, in particular from 100 to 1500 g/ha.

The application rates for compound (I) or (II) are generally from 1 to 1000 g/ha, preferably from 10 to 750 g/ha, in particular from 20 to 500 g/ha.

The application rates for epoxiconazole, metconazole and, if desired, the further fungicidally, insecticidally and/or herbicidally active compound (III) are generally from 1 to 1500 g/ha, preferably from 10 to 1250 g/ha, in particular from 20 to 1000 g/ha.

In the treatment of seed, application rates of combinations according to this invention are generally from 1 to 2000 g/100 kg of seed, preferably from 1 to 1500 g/100 kg, in particular from 5 to 1000 g/100 kg.

For use in the method according to the invention, the compounds can be converted into the customary formulations, for example solutions, emulsions, suspensions, dusts, powders, pastes and granules. The use form depends on the particular intended purpose; in each case, it should ensure a fine and even distribution of the compound according to the invention.

The formulations are prepared in a known manner [cf., for example, US 3,060,084, EP- A 707 445 (liquid concentrates), Browning, "Agglomeration", Chemical Engineering, Dec. 4, 1967, 147-48, Perry's Chemical Engineer's Handbook, 4th edition, McGraw- Hill, New York, 1963, pages 8-57, WO 91/13546, US 4,172,714, US 4,144,050, US 3,920,442, US 5,180,587, US 5,232,701 , US 5,208,030, GB 2,095,558, US 3,299,566, Klingman, Weed Control as a Science, John Wiley and Sons, Inc., New

York, 1961 , Hance et al., Weed Control Handbook, 8th edition, Blackwell Scientific Publications, Oxford, 1989 and Mollet, H., Grubemann, A., Formulation technology, Wiley VCH Verlag GmbH, Weinheim (Germany), 2001 , 2. D. A. Knowles, Chemistry and Technology of Agrochemical Formulations, Kluwer Academic Publishers, Dordrecht, 1998 (ISBN 0-7514-0443-8)], for example by extending the active compound with solvents and/or carriers, if desired using emulsifiers, surfactants, dispers- ants, stabilizers, antifoams and antifreeze agents. For formulations for treating seed, color pigments (for example rhodamine B), binders and/or swelling agents may additionally be considered.

Solvents/auxiliaries suitable for this purpose are essentially:

- water, aromatic solvents (for example Solvesso ^® products, xylene), paraffins (for example mineral oil fractions), alcohols (for example methanol, butanol, pentanol, benzyl alcohol), ketones (for example cyclohexanone, gamma-butyrolactone), pyrrolidones (N-methylpyrrolidone, N-octylpyrrolidone), acetates (glycol diacetate), glycols, fatty acid dimethylamides, fatty acids and fatty acid esters. In principle, solvent mixtures may also be used.

- carriers such as ground natural minerals (for example kaolins, clays, talc, chalk) and ground synthetic minerals (for example finely divided silicic acid, silicates); emulsifiers such as nonionogenic and anionic emulsifiers (for example polyoxy- ethylene fatty alcohol ethers, alkylsulfonates and arylsulfonates) and dispersants such as lignosulfite waste liquors and methylcellulose.

Suitable for use as surfactants are alkali metal, alkaline earth metal and ammonium salts of lignosulfonic acid, naphthalenesulfonic acid, phenolsulfonic acid, dibutyl- naphthalenesulfonic acid, alkylarylsulfonates, alkyl sulfates, alkylsulfonates, fatty alcohol sulfates, fatty acids and sulfated fatty alcohol glycol ethers, furthermore condensates of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensates of naphthalene or of naphthalenesulfonic acid with phenol and formaldehyde, polyoxyethylene octylphenyl ether, ethoxylated isooctylphenol, octyl- phenol, nonylphenol, alkylphenyl polyglycol ethers, tributylphenyl polyglycol ether, tristearyl phenyl polyglycol ether, alkylaryl polyether alcohols, alcohol and fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, lignosulfite waste liquors and methylcellulose.

Substances which are suitable for the preparation of directly sprayable solutions, emulsions, pastes or oil dispersions are mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, furthermore coal tar oils and oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons, for example toluene, xylene,

paraffin, tetrahydronaphthalene, alkylated naphthalenes or their derivatives, methanol, ethanol, propanol, butanol, cyclohexanol, cyclohexanone, isophorone, highly polar solvents, for example dimethyl sulfoxide, N-methylpyrrolidone and water.

Suitable antifreeze agents are, for example, glycerol, ethylene glycol and propylene glycol.

Suitable antifoams are, for example, silicon stearates or magnesium stearates.

A suitable swelling agent is, for example, carrageen (Satiagel ^® ).

Binders serve to improve the adhesion of the active compound or the active compounds on the seed. Suitable binders are, for example, polyethylene oxide/polypropylene oxide copolymers, polyvinyl alcohol, polyvinylpyrrolidone, poly- (meth)acraylate, polybutene, polyisobutylene, polystyrene, polyethyleneamine, poly- ethyleneamide, polyethyleneimine (Lupasol ^® , Polymin ^® ), polyethers, polyurethanes, polyvinyl acetate and the copolymers of the above polymers.

Powders, materials for spreading and dustable products can be prepared by mixing or concomitantly grinding the active substances with a solid carrier.

Granules, for example coated granules, impregnated granules and homogeneous granules, can be prepared by binding the active compounds to solid carriers. Examples of solid carriers are mineral earths such as silica gels, silicates, talc, kaolin, attaclay, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground synthetic materials, fertilizers, such as, for example, ammonium sulfate, ammonium phosphate, ammonium nitrate, ureas, and products of vegetable origin, such as cereal meal, tree bark meal, wood meal and nutshell meal, cellulose powders and other solid carriers.

In general, the formulations comprise from 0.01 to 95% by weight, preferably from 0.1 to 90% by weight, of the active compound. The active compounds are employed in a purity of from 90% to 100%, preferably 95% to 100% (according to NMR spectrum).

For seed treatment, the formulations can be diluted 2 to 10 times, resulting in ready-to- use preparations comprising from 0.01 to 60% by weight of the active compound, preferably from 0.1 to 40% by weight of the active compound.

The following are examples of formulations: 1. Products for dilution with water

A) Water-soluble concentrates (SL, LS)

10 parts by weight of the active compound(s) are dissolved with 90 parts by weight of water or a water-soluble solvent. As an alternative, wetting agents or other auxiliaries are added. The active compound dissolves upon dilution with water. This gives a for- mulation having an active compound content of 10% by weight.

B) Dispersible concentrates (DC)

20 parts by weight of the active compound(s) are dissolved in 70 parts by weight of cyclohexanone with addition of 10 parts by weight of a dispersant, for example polyvi- nylpyrrolidone. Dilution with water gives a dispersion. The active compound content is 20% by weight.

C) Emulsifiable concentrates (EC)

15 parts by weight of the active compound(s) are dissolved in 75 parts by weight of xylene with addition of calcium dodecylbenzenesulfonate and castor oil ethoxylate (in each case 5 parts by weight). Dilution with water gives an emulsion. The formulation has an active compound content of 15% by weight.

D) Emulsions (EW, EO, ES) 25 parts by weight of the active compound(s) are dissolved in 35 parts by weight of xylene with addition of calcium dodecylbenzenesulfonate and castor oil ethoxylate (in each case 5 parts by weight). This mixture is added to 30 parts by weight of water by means of an emulsifying machine (e.g. Ultraturrax) and made into a homogeneous emulsion. Dilution with water gives an emulsion. The formulation has an active com- pound content of 25% by weight.

E) Suspensions (SC, OD, FS)

In an agitated ball mill, 20 parts by weight of the active compound(s) are comminuted with addition of 10 parts by weight of dispersants and wetting agents and 70 parts by weight of water or an organic solvent to give a fine active compound suspension. Dilution with water gives a stable suspension of the active compound. The active compound content in the formulation is 20% by weight.

F) Water-dispersible granules and water-soluble granules (WG, SG) 50 parts by weight of the active compound(s) are ground finely with addition of 50 parts by weight of dispersants and wetting agents and made into water-dispersible or water- soluble granules by means of technical appliances (for example extrusion, spray tower, fluidized bed). Dilution with water gives a stable dispersion or solution of the active compound. The formulation has an active compound content of 50% by weight.

G) Water-dispersible powders and water-soluble powders (WP, SP, SS, WS) 75 parts by weight of the active compound(s) are ground in a rotor-stator mill with addition of 25 parts by weight of dispersants, wetting agents and silica gel. Dilution with water gives a stable dispersion or solution of the active compound. The active com- pound content of the formulation is 75% by weight.

H) Gels (GF)

20 parts by weight of the active compound(s) are, with addition of 10 parts by weight of dispersants, 1 part by weight of gelling agent and 70 parts by weight of water or an organic solvent, comminuted in a bead mill to give a fine active compound suspension. Dilution with water affords a stabile suspension of the active compound. The formulation has an active compound content of 20 parts by weight.

2. Products to be applied undiluted

J) Dustable powders (DP, DS)

5 parts by weight of the active compound(s) are ground finely and mixed intimately with 95 parts by weight of finely divided kaolin. This gives a dustable product with an active compound content of 5% by weight.

K) Granules (GR, FG, GG, MG)

0.5 part by weight of the active compound(s) are ground finely and associated with 99.5 parts by weight of carriers. Current methods are extrusion, spray-drying or the fluidized bed. This gives granules with an active compound content of 0.5% by weight to be applied undiluted.

L) ULV solutions (UL)

10 parts by weight of the active compound(s) are dissolved in 90 parts by weight of an organic solvent, for example xylene. This gives a product with an active compound content of 10% by weight to be applied undiluted.

Suitable for seed treatment are in particular FS formulations. Typically, such an FS formulation comprises 1 to 800 g of active compound(s) per literl, 1 to 200 g of surfactant/I, 0 to 200 g of antifreeze/I, 0 to 400 g of binder/I, 0 to 200 g of color pigment/I and ad 1 liter of a solvent, preferably water.

The active compounds can be used as such, in the form of their formulations or the use forms prepared therefrom, for example in the form of directly sprayable solutions, powders, suspensions or dispersions, emulsions, oil dispersions, pastes, dustable products, materials for spreading, or granules, by means of spraying, atomizing,

dusting, spreading or pouring. The use forms depend entirely on the intended purposes; they are intended to ensure in each case the finest possible distribution of the active compounds according to the invention.

Aqueous use forms can be prepared from emulsion concentrates, pastes or wettable powders (sprayable powders, oil dispersions) by adding water. To prepare emulsions, pastes or oil dispersions, the substances, as such or dissolved in an oil or solvent, can be homogenized in water by means of a wetting agent, tackifier, dispersant or emulsifier. However, it is also possible to prepare concentrates composed of active substance, wetting agent, tackifier, dispersant or emulsifier and, if appropriate, solvent or oil, with these concentrates being suitable for dilution with water.

The active compound concentrations in the ready-to-use preparations can be varied within relatively wide ranges. In general, they are from 0.0001 to 10%, preferably from 0.01 to 1 %.

The active compounds may also be used successfully in the ultra-low-volume process (ULV), it being possible to apply formulations comprising over 95% by weight of active compound, or even to apply the active compound without additives.

Oils of various types, wetting agents, adjuvants, herbicides, fungicides, other pesticides, or bactericides may be added to the active compounds even, if appropriate, not until immediately prior to use (tank mix). These agents are typically admixed with the compositions according to the invention in a weight ratio of from 1 :100 to 100:1 , preferably from 1 : 10 to 10: 1.

Use examples

The active compounds were formulated separately as a stock solution having a con- centration of 10 000 ppm in dimethyl sulfoxide. Epoxiconazole was used as a commercial finished formulation and diluted with water to the stated concentration of active compound.

The measured parameters were compared to the growth of the active compound-free control variant (100%) and the fungus- and active compound-free blank value to determine the relative growth in % of the pathogens in the individual active compounds. These percentages were converted into efficacies.

An efficacy of 0 means that the growth level of the pathogens corresponds to that of the untreated control; an efficacy of 100 means that the pathogens were not growing.

The expected efficacies of active compound combinations were determined using Colby's formula (Colby, S. R. "Calculating synergistic and antagonistic responses of herbicide combinations", Weeds, ^5, pp. 20-22, 1967) and compared with the observed efficacies.

Colby's formula: E = x + y - x = y/100

E expected efficacy, expressed in % of the untreated control, when using the mixture of the active compounds A and B at the concentrations a and b x efficacy, expressed in % of the untreated control, when using the active compound A at the concentration a y efficacy, expressed in % of the untreated control, when using the active compound B at the concentration b

Example 1 - Activity against Cercospora sojina in the microtiter plate test The stock solutions were mixed according to the ratio, pipetted onto a microtiter plate (MTP) and diluted with water to the stated concentrations. A spore suspension of Cercospora sojina in an aqueous biomalt solution was then added. The plates were placed in a water vapor-saturated chamber at temperatures of 18 ⁰ C. Using an absorption photometer, the MTPs were measured at 405 nm 7 days after the inoculation.

Table 1

The test results depicted in Table 1 show that, by virtue of the strong synergism, the mixtures according to the invention are considerably more active than had been predicted using Colby's formula.

Example 2 - Activity against Corynespora cassiicola in the microtiter plate test The stock solutions were mixed according to the ratio, pipetted onto a micro titer plate (MTP) and diluted with water to the stated concentrations. A spore suspension of corynespora cassiicola in an aqueous biomalt solution was then added. The plates were placed in a water vapor-saturated chamber at a temperature of 18°C. Using an absorption photometer, the MTPs were measured at 405 nm 7 days after the inoculation.

Table 2

The test results depicted in Table 2 show that, by virtue of the strong synergism, the mixtures according to the invention are considerably more active than had been predicted using Colby's formula.