CH685662A5 - Fungicidal compositions based inhibitors of sterol biosynthesis. - Google Patents

Description

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CH 685 662 A5

Description

The present invention relates to new fungicidal compositions based on sterol biosynthesis inhibitors.

More specifically, the invention relates to fungicidal compositions containing two fungicides which inhibit the biosynthesis of sterols belonging to the triazole family. These compounds are known and so far have been used separately to combat various classes of pathogenic fungi. The Applicants have now found that certain combinations of such fungicides give compositions exerting an unexpected synergistic fungicidal activity.

The compositions of the invention are therefore characterized in that they contain a first compound with fungicidal activity chosen from the group comprising a) cyproconazole and flutriafol, hereinafter designated component (a), and a second compound with fungicidal activity chosen from the group comprising b) inhibitors of sterol biosynthesis belonging to the triazole family, designated below component (b), components (a) and (b) being different from each other and being present in the compositions in amounts producing a synergistic fungicidal effect.

The sterol biosynthesis inhibitor class of the triazole family includes flutriafol, flusilazole, hexaconazole, triadimenol, propiconazole, epoxiconazole, fenbucona-zole, tetraconazole, bromuconazole, diniconazoie, difenoconazoie and tebuconazole; these compounds are all known and available on the market.

A preferred combination of the invention comprises cyproconazole and a triazole selected from group (b) indicated above. Particularly preferred combinations are those comprising cyproconazole and any of the components selected from the group consisting of flutriafol, flusilazole, propiconazole, difenoconazole and fenbuconazole. Another preferred combination includes flutriafol as component (a) and any of components (b) selected from the group consisting of tetracaconazole, tebuconazole and epoxiconazole. A specially preferred combination according to the invention comprises cyproconazole and flutriafol.

The fungicidal compositions of the invention are effective in combating a variety of fungi including Erysiphe graminis f. sp. hordei in barley, Erysiphe graminis f. sp. tritici in wheat, Co-chliobolus sativus in barley, Septoria nodorum and Septoria tritici in wheat and barley, Puccinia striiformis and Puccinia recondita in wheat, Drechslera teres in barley and Drechslera tritici-repentis in wheat .

The weight ratio of the first compound with fungicidal activity to the second compound with fungicidal activity depends on various factors such as the active ingredient concerned, the mode of application, the pathogenic fungus to be combated, the culture, the time of application, etc. In general, satisfactory results are obtained with compositions in which the weight ratio of component (a) to component (b) is from 1: 1 to 1: 4, more preferably from 1: 1 to 1: 2.

The overall amounts of the first compound with fungicidal activity and of the second compound with fungicidal activity which are suitable and effective from the fungicidal point of view, are between 50 and 100 g / ha of cultivated area. In general, satisfactory results are obtained by using from 20 to 100 g / ha of the first compound with fungicidal activity, more particularly from 60 to 80 g / ha, and from 40 to 150 g / ha of the second compound with fungicidal activity.

Although the formulation of the components of the combination in a combined form and the use of the porridges prepared from this combined form on the cultivated areas constitute the preferred embodiment of the invention, it is also possible to apply the components separately or as a mixture prepared extemporaneously in the spray tank from the separate concentrated forms of each of the components.

The application rate can also be expressed in terms of concentration. Spray mixtures intended for example for use on vines or cereals comprise from 50 to 250 g per hectolitre. Spray treatment usually includes foliar application until runoff. This generally corresponds to a spray volume of between 600 and 1000 liters per hectare of cultivated area, depending on the type of crop, the condition of the land, etc.

The compositions of the invention can be in any usual form, for example in the form of a twin pack or of an emulsifiable concentrate, of a soluble concentrate, of a wettable powder or of granules dispersible in the 'water. Such compositions can be formulated using adjuvants and formulation techniques known to those skilled in the art, for example by mixing the first fungicidal compound with the second fungicidal compound together with diluents and optionally other ingredients such as surfactants.

By the term "diluent" is meant any liquid or solid material acceptable in agriculture, including fillers, which can be added to the compounds with fungicidal activity to put them in an appropriate application or commercial form. Thinners are talc, kaolin, diatomaceous earth, mineral oil and water.

Spray formulations such as water dispersible concentrates or wettable powders may contain surfactants such as wetting agents and dispersing agents, for example the condensation product of formaldehyde with a naphthalenesulfonate, an alkylarylsulfonate , a ligninesulfonate, a fatty alcohol sulfate, an ethoxylated alkylphenol and an ethoxylated fatty alcohol.

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CH 685 662 A5

In general, the formulation comprises from 0.01 to 90% by weight of active materials, from 0 to 20% by weight of a surfactant acceptable in agriculture and from 10 to 99.99% of a solid or liquid diluent . The formulations can also contain additives such as pigments, thickeners, etc.

The formulations indicated below are representative of formulations suitable for use according to the invention, and are obtained by mixing and stirring according to the usual methods.

Formulation 1:

200 g / liter of cyproconazole,

200 g / liter of flutriafol,

55 g / liter of a mixture of nonionic polymeric emulsifying agents (for example a mixture of polyoxyalkylene glycolic ether / polyoxyethylene glycolic ether of alkylphenol),

66 g / liter of an anti-freeze agent (for example 1,2-propanediol),

3 g / liter of a thickening agent (for example xanthan gum),

1 g / liter of a bactericide (for example the sodium salt of 1,2-benzisothiazoline-3-one),

4 g / liter of an anti-foaming agent (for example a polysiloxane),

the rest being water.

Formulation 2:

25 g / liter of cyproconazole,

50 g / liter of flusilazole,

57 g / liter of an emulsifying agent (for example the phosphate of the polyoxythylene glycolic ether of nonylphenol),

96 g / liter of solvent (for example N-methyl-2-pyrrolidone),

the remainder being constituted by a solvent (for example polyethylene glycol).

Formulation 3: (Emulsifiable concentrate)

25 g / liter of cyproconazole,

100 g / liter of triadimenol,

74 g / liter of an emulsifying agent (for example the phosphate of the polyoxyethylene glycolic ether of nonylphenol),

92 g / liter of an emulsifying agent (for example the phosphate of an alkyl ether of polyoxyethylene glycol),

46 g / liter of a solvent (for example hexanol),

101 g / liter of a solvent (for example N-methyl-2-pyrrolidone),

the remainder being constituted by a solvent (a mixture of fatty alcohols Cg to Cu).

Formulation 4: (Wettable granules)

5% cyproconazole,

10% propiconazole,

15% of a dispersing agent (for example sodium ligninsulfonate),

70% of a filler (for example calcium or magnesium carbonate).

Combinations of active ingredients as indicated above are effective in combating various types of pathogenic fungi, including the following, as well as the symptoms associated therewith.

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Fungicide trials:

The effectiveness of the mixtures of the invention on various pathogenic fungi is demonstrated by the following tests:

In vivo tests:

Ervsihe graminis in wheat or orpe:

For 8-10 days, wheat or barley is grown in a mixture of peat and sand in plastic pots 6 cm in diameter. The plants are treated by spraying with aqueous solutions containing a compound A, a compound B or their mixtures (hereinafter called active ingredient) at various concentrations. The treatment includes a foliar spray until practically run off. After drying (24 hours), the plants are inoculated in an inoculation chamber with dried spores of Erysiphe graminis and then incubated at 20 ° C for 7 days in an incubation chamber ensuring a relative humidity of 60-80 %, with a daily exposure to light of 16 hours. The effectiveness of the active ingredient is determined by comparing the degree of fungal attack on the treated plants with that obtained on the untreated control plants, but which have been inoculated and incubated in a similar manner. The test is carried out with each active ingredient using 4 to 5 concentrations. This makes it possible to determine the experimental CE 90 value (CEgo exp.), That is to say the concentration of each active ingredient allowing 90% control of the infection.

Similar tests are carried out with Septoria nodorum on wheat. In these tests, the plants are inoculated by spraying a suspension containing 1 × 10 5 spores / ml.

The activity of each active ingredient against Puccinia striiformis or Puccinia recondita on wheat was carried out in a similar manner, but on detached leaves. Wheat plants are grown and sprayed according to the methods described above. After drying, the primary leaves are detached from the plants, inoculated in an inoculation chamber and incubated on agar and water for 20 days at 10 ° C.

In vitro tests:

The activity of each active ingredient against Septoria tritici, Septoria nodorum, Drechslera teres and Drechslera tritici-repentis was also determined in vitro. A PDA medium (agar medium based on potato and dextrose) is prepared and cooled to 55 ° C. Amounts of fungicidal solutions in water are added to obtain the following concentrations of PDA medium: 0.01, 0.1, 1, 10 and 100 ppm of active ingredient. PDA discs are taken from the growth front of the fungus colonies tested using a cork borer. These PDA disks are placed on the PDA media modified by the fungicide. Radial mycelial growth was measured after incubation for 7 days at 20 ° C in the dark and compared to growth on PDA free of fungicide. We calculate the EC 90 exp.

Calculation of the synergy effect:

The experimental results (CE 90 exp.) Are compared for a given weight ratio of compound A to compound B, with the corresponding theoretical CE 90, that is to say the concentration of the particular mixture allowing control at 90% of the infection calculated according to the Wadley method:

CE (A + B) 90 theoretical = a + b

a + b

CE (A) 90 exp. CE (B) 90 exp.

where a and b represent the ratios of compound A and compound B in the mixture and the indices (A), (B) and (A + B) refer respectively to the EC 90 values of compound A, of compound B and of the mixture a: b of compound A and compound B. In the case of a synergistic effect, the theoretical EC (A + B) 90 is greater than the experimental EC (A + B) 90, or

Synergy factor (FS) = CE (A + B) 90 theoretical> 1

CE (A + B) 90 experimental

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According to these tests, the mixtures of the invention exert an activity which is clearly greater than the sum of the activities of each of the active agents taken separately.

Claims (10)

Claims 1. A fungicidal composition, characterized in that it comprises a first compound with fungicidal activity chosen from the group comprising a) cyproconazole and flutriafol, hereinafter designated component (a), and a second compound with fungicidal activity chosen from the group comprising b) inhibitors of sterol biosynthesis belonging to the triazole family, designated below component (b), components (a) and (b) being different from each other and being present in the composition in amounts producing a synergistic fungicidal effect. 2. A fungicidal composition according to claim 1, characterized in that component (b) is chosen from flutriafol, flusilazole, hexaconazole, triadimenol, propiconazole, epoxiconazole, fenbuconazole, tetraconazole, bromuconazole , diniconazoie, difenoconazoie and tebuconazole. 3. A fungicidal composition according to claim 1 or 2, characterized in that component a) is cyproconazole. 4. A fungicidal composition according to claim 3, characterized in that component b) is flutriafol. 5. A fungicidal composition according to claim 3, characterized in that component b) is chosen from flutriafol, flusilazole, propiconazole, difenoconazoie and fenbuconazole. 6. A fungicidal composition according to claim 1 or 2, characterized in that component a) is flutriafol. 7. A fungicidal composition according to claim 6, characterized in that component b) is chosen from tetraconazole, tebuconazole and epoxi conazole. 8. A fungicidal composition according to claim 1, characterized in that it comprises a combination of cyproconazole and flutriafol. 9. A fungicidal composition according to any one of claims 1 to 8, characterized in that the weight ratio of component a) to component b) is of the order of 1: 1 to 1: 4. 10. A fungicidal composition according to claim 9, characterized in that the weight ratio of component a) to component b) is of the order of 1: 1 to 1: 2. 5