HEAVY METAL-FREE CALCIUM HYDROXIDE-BASED ACTIVE SUBSTANCE

Abstract

The invention relates to plant protection agents in the form of a liquid formulation containing a dispersion medium and a particulate composition that comprises a specific mixture of calcium hydroxide, fatty acids and, optionally, additives. The invention also relates to non-aqueous concentrates for providing such plant protection agents, and to the production of such particulate compositions.

Claims

1. A method of treating a plant culture with a pesticide in the form of a liquid formulation, the method comprising the step of applying an effective amount of the pesticide to a plant culture in need thereof; wherein the liquid formulation contains dispersion media at 90-99.9 wt. % and a particulate composition at 0.1-10 wt. %; wherein the particulate composition comprises a mixture consisting of: (a) calcium hydroxide having a heavy metal content of less than 5,000 ppm, (b) fatty acids and/or fatty esters having a chain length of at least a 6 carbon atoms, the reaction products of (a) and (b), and (c) optionally additives; and wherein said particulate composition has a pH of more than 11.0 (measured as 5 wt. % (aq)); has a neutralization capacity for acids b.sub.H+ of at least 5 mol/kg; and contains at least 50 wt % Calcium hydroxide particles that are partially or completely covered by calcium soaps, wherein said calcium soaps are a reaction product of (a) and (b).

2. The method according to claim 1, wherein the plant culture is selected from a. viticultures; b. fruit cultures; c. vegetable cultures; d. hothouse cultures; and e. combinations of one or more cultures thereof.

3. The method according to claim 1, wherein the plant culture is a viticulture.

4. The method according to claim 1 in which said particulate composition has: a neutralization capacity for acids b.sub.H+ of 6 to 26 mol/kg, and/or a primary particle size of 1 to 200 μm, and/or a pH>11.5 (measured as 5 wt. % (aq)).

5. The method according to claim 1, wherein said dispersion medium comprises water, (d) oil, (e) dispersant, (f) emulsifier, and (g) optionally additive.

6. The method of claim 5, wherein the oil (d) is selected from natural oils and fatty acid esters.

7. The method of claim 5, wherein the dispersion medium comprises 90-99.9 wt. % water, (d) 0.1-9 wt. % natural oils and fatty acid esters, (e) 0.1-5 wt. % dispersant, (f) 0.1-5 wt. % emulsifier, and (g) 0-8 wt. % additive.

8. The method according to claim 1, wherein the calcium hydroxide (a) has a heavy metal content of less than 1,000 ppm.

9. The method according to claim 1, wherein the fatty acid (b) is a pure fatty acid selected from the group of C.sub.8-12 fatty acids, or is a mixture of fatty acids in which at least 80 wt. % of the fatty acid molecule contains a chain length of at least eight carbon atoms.

10. The method according to claim 1, wherein the component (b) is obtained from natural sources, and/or at least 50 wt. % of the fatty acids are of a medium chain length selected from the group of C.sub.6-14 carboxylic acids.

11. The method according to claim 1, wherein the pesticide is a bactericide, fungicide or insecticide.

12. The method according to claim 1, wherein the pesticide is a fungicide.

13. A method of treating grapes with a fungicide, the method comprising the step of applying an effective amount of the fungicide to the grapes in need thereof, wherein the fungicide is present as a liquid formulation containing 90-99.9 wt. % dispersion medium and 0.1-10 wt. % particulate composition; wherein the particulate composition comprises a mixture consisting of: (a) calcium hydroxide having a heavy metal content of less than 5,000 ppm, (b) fatty acids and/or fatty esters having a chain length of at least 6 carbon atoms, the reaction products of (a) and (b), and (c) optionally additives; and wherein said particulate composition has a pH of more than 11.0 (measured as 5 wt. % (aq)); has a neutralization capacity for acids b.sub.H+ of at least 5 mol/kg; and contains at least 50 wt % Calcium hydroxide particles that are partially or completely covered by calcium soaps, wherein said calcium soaps are a reaction product of (a) and (b); and wherein the dispersion medium contains 90-99.9 wt % water, 0.1-9 wt % oil, 0.1-5 wt % dispersant, 0.1-5 wt % emulsifier, and 0-8 wt % additives.

Description

EXAMPLE 1: CA(OH).SUB.2./5 WT. % CA(ST).SUB.2

[0103] Calcium hydroxide was mixed with stearic acid in a planetary mill in batches of 100 to 200 g and by means of zirconium oxide grinding balls and heated while processing to at least 60° C. The composition of the material was 95 wt. % calcium hydroxide and 5 wt. % calcium stearate Ca(St).sub.2 that formed during the process by reacting calcium hydroxide and the employed stearic acid. The material is a very fine white powder.

EXAMPLE 2: PURE CA(OH).SUB.2 .(CONTROL TEST WITHOUT FATTY ACID)

[0104] Calcium hydroxide was ground without additional additives by a planetary mill while using the same equipment and same duration of grinding.

EXAMPLE 3: CACO.SUB.3./5 WT. % CA(ST).SUB.2 .(CONTROL TEST WITH CALCIUM CARBONATE INSTEAD OF CALCIUM HYDROXIDE)

[0105] Calcium carbonate (limestone) was mixed with stearic acid in a planetary mill in batches of 200 to 300 g and by means of zirconium oxide grinding balls and heated while processing to at least 60° C. The nominal composition of the material was 95 wt. % calcium carbonate and 5 wt. % calcium stearate that provisionally formed during the process by reacting calcium carbonate and the employed stearic acid. The material is a very fine grayish white powder.

EXAMPLE 4: PURE CA(ST).SUB.2 .(CONTROL TEST WITH FATTY ACID)

[0106] Calcium stearate was ground without additional additives by a planetary mill while using the same equipment and same duration of grinding.

[0107] The composition of the powder was confirmed by means of microanalysis (amount of C, H, N; Cube, Elementar, Germany). All of the above samples were forwarded together to a research institute and tested as the active substance:

[0108] Tests Against Plasmopara Viticola on Grapes

[0109] The above-describe samples were tested in an independent plant research institute. The tests were set up as blind tests parallel to the following controls presented below.

[0110] Study Design:

[0111] Chasselas grapes (stage: 3-5 leaves; height 11-15 cm) were placed in pots (275 mL dirt per pot) as the target plants. During the test, the following conditions were maintained: humidity: 100% relative humidity; temperature of 20-21° C.; 16 of hours light per day. For inoculation, the abaxial side of the fully developed leaves of Plasmopara viticola (50,000 spores/mL) were sprayed, and the entire plant was inoculated.

[0112] Two types of all of the tests were performed: Type 1. Dust application on the dry test plant before inoculation with the pathogen (so-called standard method)

[0113] Type 2. Dust application on a wet test plant before inoculation with the pathogen.

[0114] Evaluation: according to (1) number of leaves with disease symptoms (disease incidence) (2) severity of the disease symptoms (disease severity): Portion of infected leaf surface in percent of the overall leaf surface. The combined “efficacy severity” was then calculated from this in percent.

[0115] Controls: (a) negative without treatment, (b) positive, treatment with a copper preparation, Kocide Opti 0.003%.

[0116] 5 wt. % calcium stearate on calcium hydroxide (example 1) and pure calcium hydroxide (example 2) were checked in a study. 5 wt. % calcium stearate on calcium hydroxide manifested a better effect than the positive control. Pure Ca(OH).sub.2 however manifested only a slight reduction of the infection.

[0117] Results:

[0118] The results are compiled in the following tables; the results are depicted as an average±standard deviation.

TABLE-US-00002 % leaf surface with symptoms of infection % infected leaves Efficacy severity/% Type of application: Type 1 (dry) Type 2 (wet) Type 1 (dry) Type 2 (wet) Type 1 (dry) Type 2 (wet) Example 1: 16 +/− 9 8 +/− 7 65 +/− 15 40 +/− 18 83.2 91.8 Ca(OH).sub.2/5 wt. % Ca(St).sub.2 Example 2:  50 +/− 22 59 +/− 22 89 +/− 17 93 +/− 10 46.8 36.4 Ca(OH).sub.2 100 wt. % Negative control 93 +/− 4 93 +/− 4  100 100 Positive control 17 +/− 6 17 +/− 6  84 +/− 8  84 +/− 8  81.7 81.7

[0119] 5 wt. % Calcium stearate on calcium carbonate (example 3) and pure calcium stearate (example 4) were checked in a study. Both are inactive and do not yield any relevant reduction of the infection.

TABLE-US-00003 % leaf surface with symptoms of infection % infected leaves Efficacy severity/% Type of application: Type 1 (dry) Type 2 (wet) Type 1 (wet) Type 2 (wet) Type 1 (dry) Type 2 (wet) Example 3 42 +/− 7  47 +/− 9  91 +/− 10 86 +/− 11 37.6 30.3 CaCO.sub.3/5 wt. % Ca(St).sub.2 Example 4 62 +/− 20 58 +/− 8  93 +/− 10 91 +/− 10 7.3 13.3 Ca(St).sub.2 100 wt. % Negative control 67 +/− 18 67 +/− 18 92 +/− 20 92 +/− 20 Positive control 6 +/− 3 6 +/− 3 61 +/− 16 61 +/− 16 90.6 90.6

[0120] The results show that the pesticides according to the invention have an effect comparable with that of the positive control and are however free of heavy metals.

[0121] Moreover, it was revealed that the absence of one of the components (a) or (b) yielded ineffective products. Likewise, replacing Ca(OH).sub.2 with CaCO.sub.3 yielded ineffective products.

[0122] II. Liquid Formulations.

[0123] Production of a Concentrate

EXAMPLE 5

[0124] To produce a liquid formulation, the following components were mixed with a Silverson mixer (agitator with large holes) at 4,000 RPM over 20 minutes (all entries in percent by weight):

TABLE-US-00004 Agnique ME 18 RDF (fatty acid ester) 53.8 Ganex V220 (dispersant) 4.0 Attagel 50 (structuring agent) 2.0 AOT (emulsifier) 4.5 Soprophor BSU (emulsifier) 4.5 Brij L 4 (emulsifier) 6.0 nekagard 2 (Ca(OH).sub.2) 25.2

[0125] The mixture was then mixed further with an Eiger ball mill (300 glass spheres with a diameter of 1.0 to 1.3 mm; 4,000 RPM, fill level 80%; 17 minutes). This yielded a gray, freely flowing liquid and a particle size D(50) of 2.2 μm and D(90) of 10.4 μm; measured with a Malvern Mastersizer 2000; before measuring, the samples were diluted with Agnique ME 18 RDF to thereby obtain a concentrate.

EXAMPLE 6

[0126] To produce a liquid formulation, the following components were mixed with a Silverson mixer (agitator with large holes) at 4,000 RPM over 20 minutes (all entries in percent by weight):

TABLE-US-00005 Agnique ME 18 RDF (fatty acid ester) 53.8 Ganex V220 (dispersant) 4.0 Attagel 50 (structuring agent) 2.0 AOT (emulsifier) 4.5 Soprophor BSU (emulsifier) 6.0 Brij L 4 (emulsifier) 4.5 nekafin 2 (CaO) 25.2

[0127] The mixture was then mixed further with an Eiger ball mill (300 glass spheres with a diameter of 1.0 to 1.3 mm; 4,000 RPMs, fill level 80%; 17 minutes). This yielded a light gray, freely flowing liquid with a density of 1.17 g/cm.sup.3 (CIPTAC MT 3) and a particle size D(50) of 1.4 μm and D(90) of 3.7 μm; measured with a Malvern Mastersizer 2000; before measuring, the samples were diluted with Agnique ME 18 RDF to thereby obtain a concentrate.

[0128] Production of a Pesticide

[0129] Field Tests

[0130] The concentrates from examples 5 and 6 were tested in an independent plant research institute.

[0131] Study design: Before being spread, the above concentrates were diluted with water while stirring and tested on grapes as the plants at a dose of 0.5 wt. % to fight downy mildew.

[0132] Results: Pesticides produced by diluting the concentrate from examples 5 and 6 were highly effective against downy mildew when applied on grapes. The tested pesticides manifested a comparable or better effect than the reference treatments based on copper.