PHYTOSANITARY COMPOSITION COMPRISING ESSENTIAL OILS THAT POTENTIATE ANTIFUNGAL ACTIVITY

Abstract

The present invention relates to phytosanitary compositions with fungicidal properties that comprise a mixture of essential oils obtained from plants and agents with known fungicidal properties, such as alkali metal or ammonium bicarbonates, and compounds based on copper or the salts thereof, for use, principally, in contact-protection against fungal infections in cultivated plants and post-harvest, and also in other antifungal applications. In said compositions, the effect of the agents that have known fungicidal properties is potentiated synergistically by the aforementioned essential oils. The present invention also relates to the use of said essential oils as potentiators for agents with known fungicidal properties.

Claims

1. A phytosanitary composition having antifungal activity comprising: (1) one essential oil obtained from plants selected from oregano oil (Origanum vulgare) and thyme oil (Thymus vulgaris) or its active compounds carvacrol at a concentration between 0.1 and 530 ppm or thymol at a concentration between 0.31 and 530 ppm, or a combination thereof; and (2) potassium carbonate at a concentration between 3.5 and 25 mM.

2. A phytosanitary composition according to claim 1, characterised in that the carvacrol is at a concentration between 22 and 310 ppm.

3. A phytosanitary composition according to claim 1, characterised in that the thymol is at a concentration between 22 and 350 ppm.

4. A phytosanitary composition according to claim 1, characterised in that the potassium carbonate is at a concentration between 10 and 25 mM.

5. A phytosanitary composition according to claim 1, characterised in that the composition is in liquid or solid form, such as a suspension, dispersion, emulsion, spray, microencapsulate or other type of mixture which remains stable over time or is incorporated in polymers, or waxes or any other similar support.

6. A phytosanitary composition according to claim 1, characterised in that the phytosanitary composition is formulated together with additives such as surfactants, polymers, alkalinising agents, pH-controlling agents, among others.

7. A phytosanitary composition according to claim 1, which further comprises a fertiliser selected from the group comprising compounds containing nitrogen and/or phosphorus, such as urea, melamine, hexamine, dicyanodiamide, ameline, cyanuric acid, melamine nitrate, triethyl phosphate and the like or mixtures thereof.

8. A phytosanitary composition according to claim 1, which further comprises a compound or product having chemical and/or biological activity used in agriculture, such as herbicides, insecticides, plant growth regulators and the like, or mixtures thereof.

Description

EXAMPLES

Example 1 (Comparative). Inhibition of Growth of the Fungus Botrytis cinerea by KHCO.SUB.3 .Alone

[0025] The fungus Botrytis cinerea was cultured in PDB (potato dextrose broth) medium with different concentrations of KHCO.sub.3 and the % inhibition representing the extent to which growth was impeded in comparison with a control which did not have the compound under test, in this case KHCO.sub.3, was determined. The % inhibition was calculated in the following way:

% inhibition=[(OD.sub.control?OD.sub.x)/OD.sub.control]?100

where OD.sub.control is the optical density of the control culture (without test compound) and OD.sub.x is the optical density of the culture with the test substance. The optical density of the liquid culture was measured 24 hours after the start of culturing.

[0026] The following results were obtained (Table I):

TABLE-US-00001 TABLE I Inhibition of the growth of B. cinerea by KHCO.sub.3 KHCO.sub.3 0 10 15 20 25 30 concentration (mM) Inhibition 0 34.2 ? 37.0 ? 38.8 ? 39.7 ? 0.7 46.9 ? 2.7 (%) ? SD 6.7 11.3 6.8

[0027] As will be seen from the table above, with a KHCO.sub.3 concentration between 10 and 25 mM similar results were obtained as regards inhibition of the B. Cinerea culture. However greater inhibition was obtained at 30 mM.

Example 2. (Comparative). Inhibition of Growth of the Fungus Botrytis cinerea by Carvacrol Alone

[0028] The fungus B. cinerea was cultured in a similar way to Example 1 with the difference that different concentrations of carvacrol, the compound isolated from the essential oil of oregano, were used in the medium. The 24 hour optical density of the culture was measured and the results are shown in Table II.

TABLE-US-00002 TABLE II Inhibition of the growth of B. cinerea by Carvacrol Carvacrol 0.1 0.31 1 3.1 10 31 100 concentration (ppm) Inhibition 0 10.5 ? 7.7 13.7 ? 4.1 22.4 ? 3.4 21.3 ? 5.0 51.4 ? 5.5 74.4 ? 1.1 (%) ? SD

Example 3. Inhibition of Growth of the Fungus Botrytis cinerea by the Composition According to this Invention (Carvacrol+KHCO.SUB.3.)

[0029] The fungus B. cinerea was cultured in a similar way to Example 1 with the difference that different concentrations of carvacrol were used in the medium and that a constant concentration of KHCO.sub.3 (30 mM) was used for all the cultures. The optical density of the culture was measured at 24 hour and the results are shown in Table III.

TABLE-US-00003 TABLE III Inhibition of the growth of B. cinerea by the composition according to this invention (Carvacrol + KHCO.sub.3) KHCO.sub.3 30 30 30 30 30 30 30 concentration (mM) Carvacrol 0.1 0.31 1 3.1 10 31 100 concentration (ppm) Inhibition 86.1 ? 2.2 84.2 ? 3.6 48.9 ? 3.0 52.7 ? 2.6 82.5 ? 3.7 86.5 ? 1.3 91.1 ? 1.1 (%) ? SD

[0030] As will be seen, a carvacrol concentration as low as 0.1 ppm, whose inhibiting effect alone is zero (see Example 2) effectively doubles the inhibiting capacity of the KHCO.sub.3, achieving levels of inhibition which are not even obtained with KHCO.sub.3 concentrations that are toxic to plants.

Example 4. Inhibiting Effect of Copper Oxychloride Alone on the Fungus Alternaria alternata

[0031] Alternaria alternata was cultured in a similar way to Example 1 with the difference that different concentrations of copper oxychloride, a copper-based fungicide extensively used in agriculture, were used in the medium. The 24 hour optical density of the culture was measured and the results are shown in Table IV.

TABLE-US-00004 TABLE IV Inhibition of A. alternata by copper oxychloride Copper 0.1 0.5 1 5 10 15 20 oxychloride concentration (ppm) Inhibition 3.1 ? 6.4 0.0 ? 6.7 9.9 ? 0.9 10.0 ? 8.4 23.1 ? 4.7 37.4 ? 3.6 61.3 ? 6.7 (%) ? SD

Example 5. Inhibition of the Fungus Alternaria alternata by Carvacrol Alone

[0032] Alternaria alternata was cultured in a similar way to Example 2. The 24 hour optical density of the culture was measured and the results are shown in Table V.

TABLE-US-00005 TABLE V Inhibition of A. alternata by Carvacrol. Carvacrol 10 31 100 310 1000 concen- tration (ppm) Inhibition 17.7 ? 11 27.2 ? 14 74.6 ? 8 97.2 ? 7 93.0 ? 6.0 (% ? SD)

Example 6. Inhibition of the Fungus Alternaria alternata by the Composition According to this Invention (Carvacrol+Copper Oxychloride)

[0033] The fungus A. alternata was cultured in a similar way to Example 4 with the difference that different concentrations of carvacrol were used in the medium and that a constant concentration of copper oxychloride (5 ppm) was used throughout. The 24 hour optical density of the culture was measured and the results are shown in Table VI.

TABLE-US-00006 TABLE VI Inhibition of A. alternata by the composition according to this invention (Carvacrol + copper oxychloride) Copper 5 5 5 5 5 oxychloride concen- tration (ppm) Carvacrol 1 3.1 10 31 100 concen- tration (ppm) Inhibition 1.4 ? 13 26.0 ? 12 34.7 ? 14 53.2 ? 12 85.7 ? 3.6 (%) ? SD

[0034] As will be seen, a carvacrol concentration of 35 ppm and 5 ppm of copper oxychloride inhibit the growth of A. alternata by more than 50%, while carvacrol alone in that concentration provides 27% inhibition and copper oxychloride only 10%.

Example 7. Inhibition of the Fungus Penicillium digitatum by KHCO.SUB.3 .Alone

[0035] The fungus Penicillium digitatum was cultured in a similar way to Example 1. The 24 hour optical density of the culture was measured and the results are shown in Table VII.

TABLE-US-00007 TABLE VII Inhibition of P. digitatum by KHCO.sub.3. KHCO.sub.3 10 20 30 40 50 concen- tration (mM) Inhibition 19.4 ? 2.9 19.1 ? 10 19.6 ? 8.9 19.8 ? 2.2 21.9 ? 6.6 (% ? SD)

[0036] As will be seen, the same degree of inhibition is obtained for different KHCO.sub.3 concentrations.

Example 8. Inhibition of the Fungus Penicillium digitatum by Thymol Alone

[0037] The fungus P. digitatum was cultured in a similar way to Example 1 with the difference that different concentrations of thymol, a compound isolated from thyme oil, were used in the medium. The 24 hour optical density of the culture was measured and the results are shown in Table VIII.

TABLE-US-00008 TABLE VIII Inhibition of P. digitatum by Thymol alone Thymol 0.31 1 3.1 10 31 100 310 concentration (ppm) Inhibition (% ? 28.2 ? 3.9 24.2 ? 6.0 36.3 ? 2.3 36.2 ? 2.0 50.7 ? 2.0 78.3 ? 2.2 95.6 ? 0.5 SD)

Example 9. Inhibition of the Fungus Penicillium digitatum by the Composition According to this Invention (KHCO.SUB.3.+Thymol)

[0038] The fungus P. digitatum was cultured in a similar way to Example 7 with the difference that different concentrations of thymol were used in the medium and that a constant concentration of KHCO.sub.3 (30 mM) was used throughout. The 24 hour optical density of the culture was measured and the results are shown in Table IX.

TABLE-US-00009 TABLE IX Inhibition of P. digitatum by the composition according to this invention (KHCO.sub.3 + Thymol) KHCO.sub.3 concentration 30 30 30 30 30 30 (mM) Thymol 0.31 1 3.1 10 31 100 concentration (ppm) Inhibition 58.0 ? 2.1 62.9 ? 8.4 47.1 ? 3.7 56.4 ? 3.7 75.5 ? 1.9 92.6 ? 1.6 (%) ? SD

[0039] It will be seen how the results are improved by adding thymol to KHCO.sub.3. With 31 ppm of thymol only 50% inhibition is achieved, and with 30 mM of KHCO.sub.3 20% inhibition is achieved. However when the two compounds are combined inhibition of growth of the fungus P. digitatum is increased up to some 75%.