Composition and Method for Fighting Phytopathogenic Fungi

Abstract

A composition of active ingredients for fighting plant diseases, composed of at least two different active ingredients, selected from the group of stilbenes and/or derivatives thereof on the one hand and of the group of galloylated flavan-3-ols and/or derivatives thereof, and/or of the group of proanthocyanidins and/or derivatives thereof on the other hand. As an alternative, the at least two different active ingredients can be selected from the group of galloylated flavan-3-ols and/or derivatives thereof and/or from the group of proanthocyanidins and/or derivatives thereof. The novel mixtures have a higher effect than the individual components, there is a synergistic effect. The invention further relates to a method for fighting fungal plant diseases using the aforementioned active ingredients.

Claims

1. An active ingredient composition for fighting plant diseases, comprising: at least two different active ingredients selected from the group of stilbenes and/or their derivatives, and from the group of galloylated flavan-3-ols and/or their derivatives and/or from the group of the porathocyanidins and/or their derivatives.

2. An active ingredient composition for fighting plant diseases, comprising: at least two different active ingredients selected from the group of the galloylated flavan-3-ols and/or their derivatives and/or from the group of proanthocyanidins and/or their derivatives.

3. The active ingredient composition according to claim 1, wherein the at least two different active ingredients are intermixed in a ratio from 1:1 to 1:8.

4. The active ingredient composition according to claim 1, wherein the at least two different galloylated flavan-3-ols are epigallocatechin gallate and gallocatechin.

5. The active Active ingredient formulation comprised of a ready-to-use solution, an emulsifiable concentrate, an emulsion, a suspension, a spray powder, a soluble powder and/or a granulate of an active ingredient composition according to claim 1, and additional additives in form of adjuvants.

6. The active ingredient formulation according to claim 5, wherein the concentration of active ingredients in the active ingredient formulation is between 4 and 2000 ppm.

7. A method of using an active ingredient composition according to claim 1, wherein the phytopathogenic fungi to be attacked include one or more phytopathogenic fungi.

8. A method of fighting fungal plant diseases, comprising the steps of selecting at least two different active ingredients from the group consisting of stilbenes and/or derivatives thereof, and, from the group of galloylated flavan-3-ols and/or derivatives thereof and/or from the group of porathocyanidine and/or its derivatives, applying on a plant to be treated simultaneously, jointly, separately, or sequentially, as such or in their formulations.

9. A method of fighting fungal plant diseases, comprising the steps of selecting at least two different active ingredients selected from the group of galloylated flavan-3-ols and/or derivatives thereof and/or from the group of proanthocyanidins and/or derivatives thereof, applying on a plant to be treated simultaneously, jointly or separately, or in succession as such or in their formulations.

10. The method of claim 8, wherein the active ingredients or their formulations are also applied as a mixture, simultaneously, before or afterwards, with additional fungicides, bactericides, acaricides, nematicides, insecticides and/or further additional ingredients including herbicides, and/or with fertilizers and/or growth regulators.

11. The method according to claim 8, wherein the active ingredients are applied at a concentration in between 4 and 2000 ppm.

12. The active ingredient composition according to claim 3, wherein the at least two different active ingredients are intermixed in a ratio from 1:1 to 1:4,

13. The active ingredient composition according to claim 3, wherein the at least two different active ingredients are intermixed in a ratio from 1:1 to 1:2.

14. The active ingredient formulation according to claim 5, wherein the concentration of active ingredients in the active ingredient formulation is between 8 and 500 ppm.

15. The method according to claim 8, wherein the active ingredients are applied at a concentration in between 8 and 500 ppm.

16. The active ingredient composition according to claim 2, wherein the at least two different active ingredients are intermixed in a ratio from 1:1 to 1:8.

17. The active ingredient composition according to claim 1, wherein the at least two different galloylated flavan-3-ols are epigallocatechin gallate and gallocatechin.

18. The active ingredient composition according to claim 2, wherein the at least two different active ingredients are intermixed in a ratio from 1:1 to 1:4.

19. The active ingredient composition according to claim 2, wherein the at least two different active ingredients are intermixed in a ratio from 1:1 to 1:2.

Description

[0030] Further details, features and advantages of embodiments of the invention can be inferred from the following description of exemplary embodiments with reference to the accompanying drawings, which show in:

[0031] FIG. 1 the known general structural formula of flavan-3-ols,

[0032] FIG. 2 the known structural formula of procyanidin B2,

[0033] FIG. 3 the known structural formula of procyanidin B5,

[0034] FIG. 4 the known structural formula of procyanidin A1,

[0035] FIG. 5 the known basic structural formula of stilbenes as trans-isomer and as cis-isomer,

[0036] FIG. 6 examples of known stilbene derivatives,

[0037] FIG. 7 a graphical representation of fungicidal efficacy of a mixture of rhaponticin and procyanidin B2,

[0038] FIG. 8 a graphical representation of the fungicidal efficacy of a mixture of epigallocatechingallate and resveratrol,

[0039] FIG. 9 a graphical representation of the fungicidal efficacy of a mixture of epigallocatechingallate and trihydroxy-stilbenglucoside, and

[0040] FIG. 10 a graphical representation of the fungicidal efficacy of a mixture of gallocatechin and epigallocatechin gallate.

[0041] Flavan-3-ols are compounds with the known basic structure shown in FIG. 1. Examples of important representatives of these compounds are listed below with the corresponding association R.sup.1 and R.sup.2 of the structural formula:

[0042] R.sup.1═H; R.sup.2═H: afzelechin

[0043] R.sup.1═H; R.sup.2═H: epiafzelechin

[0044] R.sup.1═OH; R.sup.2═H: catechin

[0045] R.sup.1═OH; R.sup.2═H: epicatechin

[0046] R.sup.1═OH; R.sup.2═OH: gallocatechin

[0047] R.sup.1═OH; R.sup.2═OH: epigallocatechin

[0048] Proanthocyanidins are compounds composed of linked flavan-3-ol moieties. Various types of links are shown below. A representative of the proanthocyanidins epicatechin-(4β.fwdarw.8)-epicatechin referred to as procyanidin B2, shown in FIG. 2. Other proanthocyanidins are the compound epicatechin (4β.fwdarw.6)-epicatechin referred to as procyanidin B5 having the structural formula shown in FIG. 3, and epicatechin (4β.fwdarw.8,2β.fwdarw.7) catechin referred to as procyanidin A1 with the structural formula shown in FIG. 4.

[0049] FIG. 5 shows the basic structural formula of stilbenes as trans-isomer and a cis-isomer. Table 1 lists the corresponding radicals R1 to R6 for different stilbenes.

TABLE-US-00001 TABLE 1 Stilbene R1 R2 R 3 R4 R5 R6 Resveratrol OH H OH H OH H Piceid = 3,5,4′-trihydroxy- glucose H OH H OH H stilbene-3-O-β-D-glucoside Astringine (3′-OH-piceide) glucose H OH OH OH H Piceatannol = 3,3′,4′,5- OH OH H OH H OH tetrahydroxystilbene Pterostilbene OCH.sub.3 H OCH.sub.3 H OH H Resveratroloside OH H OH H glucose H

[0050] Table 2 lists the radicals R1, R2 and R3 for various stilbene derivatives.

TABLE-US-00002 TABLE 2 R1 R2 R3 Name of the compound at C-3 at C-4′ at C-3′ 3,5,4′-trihydroxy stilbene-4′- H glucose H O-β-D-glucoside 3,5,4′-trihydroxy stilbene-4′- H 6-O- H O-β-D-(6″-O-galloyl) glucoside galloylglucose Rhapontigenin-3′-O-β-D- H CH.sub.3 O- glucopyranoside glucose Rhaponticin-6″-O-gallate 6-O- CH.sub.3 OH galloyl- glucose Rhaponticin-2″-O-gallate 2-O- CH.sub.3 OH galloyl- glucose Rhaponticin-2″-O-coumarate 2-O- CH.sub.3 OH coumaroyl glucose Piceatannol-3-O-β-D- glucose H OH glucopyranoside Piceatannol-3′-O-.β.-D- H H O- glucopyranoside glucose Piceatannol-3′-O-.β.-D- H H O-xylose xylopyranoside Piceatannol-3′-O-.β.-D-(6″-O- H H O-(6- galloyl) glucopyranoside galloyl)- glucose Deoxyrhaponticin-6″-O-gallate 6-O- CH.sub.3 H galloyl- glucose 3,4′,5-trihydroxy-stilbene-4′- H 6- H O-β-D-(6″-O-galloyl) glucoside galloylglucose

[0051] Table 3 shows the corresponding radicals R1, R2 and R3 for the stilbene rhaponticin and for rhaponticin derivatives.

TABLE-US-00003 TABLE 3 R1 R2 Name of the compound at C-3 at C-4′ Rhaponticin glucose CH.sub.3 Rhapontigenin H CH.sub.3 Deoxyrhaponticin glucose CH.sub.3 Deoxyrhapontigenin H CH.sub.3 Dioxyrhaponticin glucose OH

[0052] FIG. 6 shows the structural formulas of the resveratrol dimers e-Viniferin and d-Viniferin as examples of stilbene derivatives.

[0053] Material and Methods

[0054] Barley plants (3 plants/container) were cultivated for three weeks in Frustrorf soil. The inoculation of the leaves with mildew took place 2 hours after application of the test preparations (protective application). Fresh conidia of Blumeria graminis f. sp. hordei were used for the inoculation, species A6, and carried onto the leaves in the mildew tower by way of wind distribution. For a leaf segment test, 10 cm long leaf segments, starting from the stalk base, were cut off and 15 leaves of the youngest as well as the second youngest leaf were laid out on benzimidazole agar. The benzimidazole agar consists of 0.5% agar and an admixture of 40 ppm benzimidazole in one liter of water.

[0055] The concentration of the standard substances for the leaf application was adjusted to 125, 62.5, 32, 16 and 8 ppm. An adjuvant was added to the standard substances with BT S240 (50 ml/ha) in order to ensure a uniform distribution of the application solution on the leaf. The mildew effect was evaluated by counting the mildew blisters per leaf on a 7 cm long leaf.

[0056] The beneficial fungicidal action of the active ingredient combination according to the invention is evident from the following examples. While the individual active ingredients in the fungicidal action show weaknesses, the combinations of two active ingredients exhibit an efficacy that exceed the efficacy attained by simply adding the individual efficacy.

[0057] A synergistic effect is always present in fungicides/antifungal compounds when the fungicidal action of the active ingredient combination is greater than the sum of the individual efficacies.

[0058] The expected efficacy for a given combination of two or three active ingredients can be calculated according to S. R. Colby (“Calculating Synergistic and Antagonistic Responses of Herbicide Combinations”, Weeds 1967, 15, 20-22) as follows:

[00001]$E_1=X+Y-\frac{X-Y}{100},$

[0059] or when using three active ingredients

[00002]$E_2=X+Y+Z-\frac{X-Y-Z}{100},$

Note that it wrongly says E1 in the PCT and DE text.

[0060] wherein

[0061] X represents the efficacy when using the active compound A in an application rate of mg/ha,

[0062] Y represents the efficacy when using the active compound B in an application rate of mg/ha,

[0063] Z represents the efficacy when using the active compound C in an application rate of mg/ha,

[0064] E1 represents the efficacy when using the active ingredients A and B in application rates of m and n g/ha, and

[0065] E2 represents the efficacy when using the active ingredients A and B and C in application rates of m, n and r g/ha.

[0066] The results of the efficacy against barley powdery mildew (Blumeria graminis f. sp. Hordei) show a synergistic effect at certain mixing ratios, as seen in the following tables. In Table 1, the efficacies calculated for mixtures of the stilbene glucoside rhaponticin (RHAP) as a stilbene derivative and procyanidin B2 (PROCY) based on the known efficacy of the individual substances are compared with the observed efficacies. The concentration-dependent efficacies for the individual substances and the mixtures are shown graphically in FIG. 7. In this example and in the following examples, the reference quantity 100 for the efficacy is the efficacy achieved with a concentration of 125 ppm of the respective pure substance. Table 4 and FIG. 7 demonstrate that a synergistic effect, as described above, could be observed at all the used mixture ratios. This means that when using the mixtures, the calculated efficacies of the individual substances are exceeded.

TABLE-US-00004 TABLE 4 Observed Calculated Example Mixture according to the invention efficacy efficacy 1 Control (untreated) (100% 0 infection) 2 RHAP + PROCY (16 + 16 ppm) 100 96 3 RHAP + PROCY (8 + 8 ppm) 72 45 4 RHAP + PROCY (32 + 16 ppm) 100 98 5 RHAP + PROCY (16 + 8 ppm) 98 90 6 RHAP + PROCY (16 + 32 ppm) 100 97 7 RHAP + PROCY (8 + 16 ppm) 86 91 8 RHAP + PROCY (62.5 + 16 ppm) 100 98 9 RHAP + PROCY (16 + 62.5 ppm) 100 97 10 RHAP + PROCY (8 + 32 ppm) 100 92

[0067] In Table 5, the efficacies calculated for mixtures of epigallocatechin gallate (EPIC-G) as flavan-3-ol and resveratrol (RESV) as stilbene with the systematic designation trans-3,5,4′-trihydroxystilbene are compared with the observed efficacies. The concentration-dependent efficacies for the used individual substances and for the mixtures are shown graphically in FIG. 8. Table 5 and FIG. 8 show that a synergistic effect, as described above, could be observed at all the used mixture ratios. This means that the calculated efficacies are always exceeded when the mixtures are used.

TABLE-US-00005 TABLE 5 Observed Calculated Example Mixture according to the invention efficacy efficacy 1 Control (untreated) (100% 0 infection) 2 EPIC-G + RESV (16 + 16 ppm) 100 91 3 EPIC-G + RESV (8 + 8 ppm) 100 71 4 EPIC-G + RESV (32 + 16 ppm) 100 97 5 EPIC-G + RESV (16 + 8 ppm) 100 87 6 EPIC-G + RESV (16 + 32 ppm) 100 94 7 EPIC-G + RESV (8 + 16 ppm) 93 80 8 EPIC-G + RESV (62.5 + 16 ppm) 100 98 9 EPIC-G + RESV (16 + 62.5 ppm) 100 92 10 EPIC-G + RESV (8 + 32 ppm) 100 87

[0068] In Table 6, the efficacies calculated for mixtures of epigallocatechin gallate (EPIC-G) as flavan-3-ol and trihydroxystilbenglucoside (TH-STIB-GI) as stilbene are compared with the observed efficacies. The concentration-dependent efficacies for the used individual substances and for the mixtures are shown graphically in FIG. 9. Table 6 and FIG. 9 show that that a synergistic effect, as described above, could be observed at all the used mixture ratios.

TABLE-US-00006 TABLE 6 Observed Calculated Example Mixture according to the invention efficacy efficacy 1 Control (untreated) (100%  0 infection) 2 TH-STIB-GI + EPIC-G (16 + 16 ppm) 73 56 3 TH-STIB-GI + EPIC-G (8 + 8 ppm) 65 45 4 TH-STIB-GI + EPIC-G (32 + 16 ppm) 92 77 5 TH-STIB-GI + EPIC-G (16 + 8 ppm) 83 67 6 TH-STIB-GI + EPIC-G (16 + 32 ppm) 83 60 7 TH-STIB-GI + EPIC-G (8 + 16 ppm) 66 54 8 TH-STIB-GI + EPIC-G (62.5 + 16 ppm) 96 80 9 TH-STIB-GI + EPIC-G (16 + 62.5 ppm) 92 69 10 TH-STIB-GI + EPIC-G (8 + 32 ppm) 81 74

[0069] In Table 7, the efficacies calculated for mixtures of gallocatechin (GAL-C) as flavan-3-ol and epigallocatechin gallate (EPIC-G) as additional flavan-3-ol are compared with the observed efficacies. The concentration-dependent efficacies for the used individual substances and for the mixtures are shown graphically in FIG. 10. Table 7 and FIG. 10 show that a synergistic effect, as described above, could be observed at ail the used mixture ratios.

TABLE-US-00007 TABLE 7 Observed Calculated Example Mixture according to the invention efficacy efficacy 1 Control (untreated) (100%  0 infection) 2 GAL-C + EPIC-G (16 + 16 ppm) 95 76 3 GAL-C + EPIC-G (8 + 8 ppm) 97 62 4 GAL-C + EPIC-G (32 + 16 ppm) 99 88 5 GAL-C + EPIC-G (16 + 8 ppm) 100 69 6 GAL-C + EPIC-G + (16 + 32 ppm) 94 78 7 GAL-C + EPIC-G + (8 + 16 ppm) 90 70 8 GAL-C + EPIC-G + (62.5 + 16 ppm) 100 93 9 GAL-C + EPIC-G + (16 + 62.5 ppm) 95 88 10 GAL-C + EPIC-G + (8 + 32 ppm) 90 72

[0070] The excellent fungicidal efficacy of the active ingredient combination of the invention against oat crown rust (Puccinia coronata) is evident from the following examples. While the individual active ingredients have weaknesses in their fungicidal efficacy, the respective combinations show an efficacy that exceeds that of a simple addition of the individual efficacies. The results of the efficacy against oat crown rust (Puccinia coronata) show a synergistic effect at certain mixing ratios, as shown in the following tables.

[0071] Rhaponticin (=RHAP) and procyanidin B2 (=PROCY) and epigallocatechin gallate (=EPIC-G) and resveratrol (=RESV) were also tested against oat crown rust (Puccinia coronata) in different concentrations, see Table 8 and Table 9. Oats were cultivated for three weeks in Frustrorfer soil. An adjuvant of BT S240 was added to the standard substances (50 ml/ha) to ensure a uniform distribution of the application solution on the leaf. The leaves were inoculated with oat crown rust 8 hours after application of the standard substances (protective application). For the application, uredo spores of oat crown rust (Puccinia coronata) were taken up by a medium which consisted of a mixture of methyl nonafluoroisobutyl ether and methyl nonafluorobutyl ether. With this mixture, the medium evaporates very quickly after application to the leaves, and the rust spores previously distributed with the medium remain on the leaf surface. After this medium was applied, the plants were incubated in the dark for 24 h and then laid out in the leaf segment test. For a leaf segment test, 10 cm long leaf segments, starting from the stalk base, were cut off and 15 leaves of the youngest as well as the second youngest leaf were laid out on benzimidazol agar (0.5% agar, admixture of 40 ppm benzimidazole after autoclaving). The efficacy against oat crown rust was evaluated by counting the rust blisters per leaf on a 7 cm long leaf. The classification took place after 20 DAT (days after treatment). The synergistic effect was again calculated according to the Colby formula.

[0072] Oat crown rust (Puccinia coronata) was chosen as a model for examining the synergistic effect against rust diseases to show that the compounds of the invention are capable of synergistically attacking also rust diseases in addition to mildew diseases. Major rust diseases include, among others, major rust diseases in cereal such as yellow rust (Puccinia striiformis), brown rust (Puccinia recondita), leaf rust (Puccinia hordei) or black rust (Puccinia graminis). Important other rust diseases are found in soy (Phakopsora pachyrhizi) or in roses, pears, turf grasses.

TABLE-US-00008 TABLE 8 Mixture according Observed Calculated Example to the invention efficacy efficacy 1 Control (untreated) (100%  0 infection) 2 RHAP + PROCY 86 74 (62.5 + 62.5 ppm) 3 RHAP + PROCY 75 62 (32 + 32 ppm) 4 RHAP + PROCY 64 45 (16 + 16 ppm) 5 RHAP + PROCY 84 70 (62.5 + 32 ppm) 6 RHAP + PROCY 73 52 (32 + 16 ppm) 7 RHAP + PROCY 81 68 (32 + 62.5 ppm) 8 RHAP + PROCY 73 58 (16 + 32 ppm) 9 RHAP + PROCY 90 77 (125 + 32 ppm) 10 RHAP + PROCY 87 73 (32 + 125 ppm) 11 RHAP + PROCY 77 63 (16 + 62.5 ppm)

TABLE-US-00009 TABLE 9 Mixture according Observed Calculated Example to the invention efficacy efficacy 1 Control (untreated) (100%  0 infection) 2 EPIC-G + RESV 96 86 (62.5 + 62.5 ppm) 3 EPIC-G + RESV 92 78 (32 + 32 ppm) 4 EPIC-G + RESV 72 54 (16 + 16 ppm) 5 EPIC-G + RESV 92 84 (62.5 + 32 ppm) 6 EPIC-G + RESV 83 71 (32 + 16 ppm) 7 EPIC-G + RESV 93 81 (32 + 62.5 ppm) 8 EPIC-G + RESV 84 72 (62.5 + 16 ppm) 9 EPIC-G + RESV 83 69 (16 + 62.5 ppm)

LIST OF ABBREVIATIONS

[0073] EPIC-G Epigallocatechin gallate [0074] GAL-C Gallocatechin [0075] PROCY Procyanidine [0076] RESV Resveratrol (trans-3,5 4′-trihydroxystilbene) [0077] RHAP Rhaponticin [0078] TH-STIB-GI Trihydroxystilbenglucoside: 3,4′,5-trihydroxystilbene-3-O-beta-D-glucopyranoside