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IMPROVEMENTS IN OR RELATING TO SULFUR BASED PESTICIDES

20220125047 · 2022-04-28

    Inventors

    Cpc classification

    International classification

    Abstract

    Optimised sulfur based pesticides using sulfosuccinates alone and in combination with an anionic surfactant to improve the retention and distribution of sulfur on plant vegetation from aqueous spray solutions.

    Claims

    1. A treatment of vegetation comprising spraying the vegetation with an aqueous dispersion of a formulation comprising a sulfosuccinate and sulfur, wherein the sulfosuccinate improves retention of the aqueous spray solution on vegetation and distribution of the aqueous spray solution on vegetation when the spray solution is sprayed onto the vegetation.

    2.-4. (canceled)

    5. The treatment according to claim 1 for prevention or reduction of powdery mildew on plant vegetation.

    6. (canceled)

    7. The treatment according to claim 1, in which the vegetation comprises grapevines.

    8. The treatment according to claim 1 for prevention or reduction of Septoria diseases on plant vegetation.

    9. (canceled)

    10. The treatment according to claim 1, in which the vegetation comprises wheat.

    11.-13. (canceled)

    14. The treatment according to claim 1, in which the sulfosuccinate is dioctyl sulfosuccinate (docusate sodium).

    15. The treatment according to claim 1, in which the sulfur and the sulfosuccinates are present in the aqueous spray solution at a ratio of from 1 to 0.33 by weight to 1 to 0.005 by weight.

    16. The treatment according to claim 1, in which the formulation contains a further surfactant.

    17. The treatment according to claim 16, in which the further surfactant is sodium lauryl sulfate.

    18. (canceled)

    19. A pesticide formulation containing a sulphosuccinate sulfur and at least one further surfactant.

    20. (canceled)

    21. The pesticide formulation according to claim 19, in which the further surfactant is an anionic surfactant selected from phosphate esters, substituted and non-substituted sulphonic acids, and their salts, monosulphate esters, naphthalene sulphonic acid derivatives, sulphonated vegetable oils, sulphonated esters of natural fatty acids, carboxylic acid derivatives, alkyl substituted succinic acid, polycarboxylic acid salts.

    22. (canceled)

    23. The pesticide formulation according to claim 21, in which the anionic surfactant is sodium lauryl sulfate.

    24. (canceled)

    25. The pesticide formulation according to claim 19, in which a ratio of the surfactants is in a range of from 1:2 to 2:1.

    26. The pesticide formulation according to claim 19, which does not contain an amphoteric surfactant.

    27. An aqueous spray solution that contains from 0.01% to 10%, preferably 0.02% to 5%, more preferably 0.05% to 1.0% sulfur derived from a formulation according to claim 19.

    28. (canceled)

    29. A formulation according to claim 27, containing: i) from 25 wt % to 85 wt % sulfur; ii) from 0.125 wt % to 30 wt % sodium dioctyl sulfosuccinate; and iii) from 0.125 wt % to 30 wt % sodium lauryl sulfate.

    30.-36. (canceled)

    Description

    EXAMPLE 1

    [0039] The solid formulations set out in Table 1 were prepared from sulfur milled to an average particle size of 20 microns as measured by a Beckman Coulter LS particle size analyser, sodium dioctylsulfosuccinate (docusate sodium) and sodium lauryl sulfate.

    TABLE-US-00001 TABLE 1 Sulphur Docusate sodium Sodium lauryl Code (grams) (grams) sulfate (grams) A 800 125 0 B 800 41.7 83.3 C 800 62.5 62.5 D 800 83.3 41.7

    [0040] The formulations as above were incorporated into water to produce a spray solution containing 0.32% by weight of sulfur. The formulations were sprayed onto grapevines in the field at 8-10 day intervals at a treatment rate of 4 kg formulated product/hectare and the development of powdery mildew after was assessed before each successive spray application and compared to the development with no treatment and to the development with the commercial product Tiowetting DF a product containing 80 wt % sulfur applied at 4 kg formulated product/hectare and 8 kg formulated product/hectare.

    [0041] Disease incidence on leaves and bunches eight days after the third application is shown below:

    TABLE-US-00002 Powdery Mildew Powdery Mildew on leaf on bunch Product (frequency %) (frequency %) A (4 KG) 34.5 c 52.0 b B (4 KG) 29.5 c 37.8 b C (4 KG) 41.3 c 53.0 b D (4 KG) 58.0 bc 63.3 b Tiowetting DF (4 KG) 78.0 ab 96.3 a Tiowetting DF (8 KG) 62.3 bc 73.9 b No treatment 97.5 a 99.8 a

    [0042] The letters referring to statistically different data groups.

    [0043] Statistical analysis confirmed no significant differences between Products A, B, C and D applied at 4 kg/hectare and Tiowetting DF applied at 8 kg/ha on leaves and bunches.

    EXAMPLE 2

    [0044] In a glasshouse trial sodium dioctylsulfosuccinate and sodium lauryl sulphate in the ratio used in Product D from Example 1 was used in combination with Microthiol WG 80% which is a 800 g/kg (80%) sulfur wettable granule commercial formulation.

    [0045] The Microthiol was mixed with the surfactant combination at different concentrations and applied to grapevine seedlings in the glasshouse. The plants were infected artificially with powdery mildew 24 hours later.

    [0046] The materials used and the amounts used are set out in Table 2 below and 10 plants were used in each experiment.

    TABLE-US-00003 TABLE 2 No Product Rate 1 Check = only water 2 Microthiol WG 80%  50 ppm 3 Microthiol, WG 80% 100 ppm 4 Microthiol WG 80% 200 ppm 5 Microthiol WG 80% 400 ppm 6 Surfactant combination D alone  50 ppm 7 Surfactant combination D alone 100 ppm 8 Surfactant combination D alone 400 ppm 9 Microthiol + surfactant combination D  50 + 100 ppm 10 Microthiol + surfactant combination D  50 + 400 ppm 11 Microthiol + surfactant combination D 100 + 50 ppm 12 Microthiol + surfactant combination D 100 + 100 ppm 13 Microthiol + surfactant combination D 100 + 400 ppm 14 Microthiol + surfactant combination D 200 + 50 ppm 15 Microthiol + surfactant combination D 200 + 100 ppm 16 Microthiol + surfactant combination D 200 + 400 ppm 17 Microthiol + surfactant combination D 400 + 50 ppm 18 Microthiol + surfactant combination D 400 + 100 ppm 19 Microthiol + surfactant combination D 400 + 400 ppm

    [0047] Surfactant combination D as used in Product D of Example 1.

    [0048] The results are set out in Table 3 below.

    TABLE-US-00004 TABLE 3 Powdery mildew disease severity and protection Protection Severity Efficiency Thesis (%) (%) Water Check 74.6 Microthiol 50 ppm 53.8 28.0 Microthiol 100 ppm 30.8 58.8 Microthiol 200 ppm 23.2 69.0 Microthiol 400 ppm 17.8 76.1 Surfactant combination D 50 ppm 65.3 12.5 Surfactant combination D 100 ppm 62.9 15.8 Surfactant combination D 400 ppm 56.4 24.5 Microthiol 50 ppm + surfactant combination 43.8 41.4 D 100 ppm Microthiol 50 ppm + surfactant combination 36.4 51.2 D 400 ppm Microthiol 100 ppm + surfactant combination 41.6 44.,3 D 50 ppm Microthiol 100 ppm + surfactant combination 20.5 72.6 D 100 ppm Microthiol 100 ppm + surfactant combination 26.1 65.1 D 400 ppm Microthiol 200 ppm + surfactant combination 17.9 76.0 D 50 ppm Microthiol 200 ppm + surfactant combination 16.8 77.4 D 100 ppm Microthiol 200 ppm + surfactant combination 12.3 83.6 D 400 ppm Microthiol 400 ppm + surfactant combination 9.4 87.5 D 50 ppm Microthiol 400 ppm + surfactant combination 5.0 93.3 D 100 ppm Microthiol 400 ppm + surfactant combination 4.3 94.2 D 400 ppm

    [0049] Untreated checks exhibit a percentage of disease severity of 75% (Table 3). This severity is moderate to high and validates the trial. [0050] At 50 ppm of Microthiol, disease severity is statistically lower than the one obtained on the untreated check. From 50 ppm to 400 ppm, disease severity is reduced from 54 to 18% indicating a clear dose effect.

    [0051] The results in Table 3 show that the addition of the surfactant combination to Microthiol significantly improves the protection efficiency at all rates of Microthiol tested. It was also observed that the variations between replicates in the trial were significantly reduced in the treatments where the surfactant combination was mixed with Microthiol. Analysis was carried out to determine if the improvements in protection efficiency were additive or synergistic.

    [0052] Compatibility Analyses

    [0053] Calculation of synergistic, antagonistic or additive responses was performed using the well known Colby formula (1967, 2015): E=X+Y−(X*Y)/100. Whereas, E is the expected value of protection efficiency (disease protection expressed in percentage) of a mixture of 2 products X and Y; X and Y are respectively the % of disease protection of product X or Y when applied individually, and XY the % of disease protection obtained when products X and Y are applied in combination.

    [0054] Whereas, if E=observed value, the combination is additive; If E<observed value, the combination is synergistic; and if E is > to the observed value, the combination is antagonistic.

    [0055] The results of this analysis are shown in Table 4 and indicate that a synergistic effect is observed at each concentration of Microthiol and consistently with the higher Microthiol rate of 400 ppm (difference between assessed value and expected value).

    [0056] Table 4: Expected disease protection values calculated using the Colby formula in comparison with the observed scored values

    TABLE-US-00005 TABLE 4 Expected value of Assessed Microthiol and disease protection value Surfactant (%) calculated of disease Combination D using Colby protection Concentrations (ppm) formula (%) Effect Microthiol 50 + D 100 39.4 41.4 no effect Microthiol 50 + D 400 45.6 51.2 synergistic Microthiol 100 + D 50 63.9 44.3 antagonistic Microthiol 100 + D 100 65.3 72.6 synergistic Microthiol 100 + D 400 68.9 65.1 no effect Microthiol 200 + D 50 72.8 76.0 no effect Microthiol 200 + D 100 81.8 77.4 no effect Microthiol 200 + D 400 76.6 83.6 synergistic Microthiol 400 + D 50 79.1 87.5 synergistic Microthiol 400 + D 100 79.9 93.3 synergistic Microthiol 400 + D 400 82.0 94.2 synergistic D = surfactant combination D

    EXAMPLE 3

    [0057] A field trial was conducted to investigate mixtures of the surfactant combination D employed in Example 2 with Tiowetting DF a commercial product containing 800 g/kg sulfur. Tiowetting DF at a dose rate of 4 kg/ha was mixed with the surfactant combination D at 250 g/ha, 500 g/ha and 750 g/ha and the performance on grapevines against powdery mildew was compared to Tiowetting DF alone at 4 kg/ha and 8 kg/ha. Applications were made at 7 day intervals in a spray volume of 1000 I water/hectare. Disease severity was assessed on leaves and on bunches seven days after the ninth application. Disease severity in the untreated control was 78.8% on leaves and on 84.0% bunches and the amount by which the presence of the powdery mildew was reduced compared to the control are shown in Table 5.

    TABLE-US-00006 TABLE 5 Reduction of Reduction of Powdery Powdery Mildew on Mildew on Leaves Bunches Treatment (% control) (% control) 4 kg/ha Tiowetting DF + 250 94.8 b 70.1 b g/ha surfactant combination D 4 kg/ha Tiowetting DF + 500 96.8 b 84.9 ab g/ha surfactant combination D 4 kg/ha Tiowetting DF + 750 99.8 a 96.9 a g/ha surfactant combination D 4 kg/ha Tiowetting DF 85.7 c 44.8 c 8 kg/ha Tiowetting DF 96.8 b 79.4 ab

    [0058] The letters refer to statistically different data groups.

    [0059] Powdery mildew disease control on leaves and bunches with 4 kg/ha Tiowetting DF+surfactant combination D at 250 g/ha, 500 g/ha and 750 g/ha was equal to or better than 8 kg/ha Tiowetting DF alone.

    EXAMPLE 4

    [0060] In another field trial on grapevines Tiowetting DF was applied at 2 kg/ha, 4 kg/ha and 8 kg/ha alone or in mixture with the surfactant combination D used in Example 2 at 750 g/ha. Applications were made at 7 day intervals in a spray volume of 1000 I water/hectare. Disease severity was assessed on leaves and on bunches seven days after the ninth application. Disease severity in the untreated control was 76.0% on leaves and on 77.0% bunches and the amount by which the presence of the powdery mildew was reduced compared to the control are shown in Table 6.

    TABLE-US-00007 TABLE 6 Reduction of Reduction of Powdery Powdery Mildew on Mildew on Leaves Bunches Treatment (% control) (% control) 2 kg/ha Tiowetting DF + 750 91.4 ab 79.6 ab g/ha surfactant combination D 4 kg/ha Tiowetting DF + 750 97.0 a 90.3 a g/ha surfactant combination D 8 kg/ha Tiowetting DF + 750 99.9 a 99.2 a g/ha surfactant combination D 2 kg/ha Tiowetting DF 62.1 c 40.9 c 4 kg/ha Tiowetting DF 82.0 b 71.9 b 8 kg/ha Tiowetting DF 99.0 a 93.8 a

    [0061] The letters refer to statistically different data groups.

    [0062] Powdery mildew disease control on leaves and bunches with 2 kg/ha, 4 kg/ha and 8 kg/ha Tiowetting DF+the surfactant combination D at 750 g/ha was always equal to 8 kg/ha Tiowetting DF alone.

    [0063] Accordingly the use of the surfactant combination according to this invention increases the efficacy of sulfur by up to 4-fold and reduces the required amount of sulfur for a desired degree of treatment at least by half.

    EXAMPLE 5

    [0064] In another field trial on courgettes grown in a glasshouse, the Products from Example 1 were tested at 4 kg/ha in comparison to Tiowetting DF applied at 4 kg/ha and 8 kg/ha. Powdery mildew disease incidence and severity were assessed 14 days after seven applications of the fungicides at 7 day intervals. The results are shown in Table 7 below.

    TABLE-US-00008 TABLE 7 Powdery Mildew Powdery Mildew on leaves on leaves Product (% incidence) (% severity) A (4 KG)  4.5 c  0.2 c B (4 KG)  3.5 c  0.16 c C (4 KG)  4.0 c  0.08 c D (4 KG)  3.0 c  0.04 c Tiowetting DF (4 KG)  11.5 b  5.65 b Tiowetting DF (8 KG)  7.5 c  1.07 c No treatment 100.0 a 100.0 a

    [0065] The letters referring to statistically different data groups.

    [0066] Each of the four Products applied at 4 kg/ha were in the same statistical group as 8 kg/ha Tiowetting DF, and numerically the disease control was better with all four Products than with the higher rate of the sulphur standard.

    EXAMPLE 6

    [0067] In a controlled environment trial, sodium dioctylsulfosuccinate and sodium lauryl sulphate in the ratio used in Product C from Example 1 was used in combination with Microthiol WG 80%, applied to wheat seedlings at the two leaf stage in a growth chamber. The plants were inoculated artificially with Zymoseptoria tritici 24 hours later.

    [0068] The materials used and the amounts used are set out in Table 8 below; there were 30 seeds in each pot and 3 pots were used for each treatment. Comparisons were made to treatments with two reference fungicides, Aviator Xpro applied 24 hours before infection and Heliosoufre S applied 5 days and 24 hours before infection, and with Microthiol applied alone at treatment rates of up to 5000 ppm as well as the untreated control which was sprayed with water.

    TABLE-US-00009 TABLE 8 No Product Rate 1 Untreated (water) control 2 Aviator Xpro 3 Heliosoufre S 4 Microthiol WG 80%  200 ppm 5 Microthiol WG 80%  500 ppm 6 Microthiol WG 80% 1000 ppm 7 Microthiol WG 80% 2000 ppm 8 Microthiol WG 80% 5000 ppm 9 Microthiol + surfactant combination C  200 ppm + 31.25 ppm 10 Microthiol + surfactant combination C  500 ppm + 78.125 ppm 11 Microthiol + surfactant combination C 1000 ppm + 156.25 ppm 12 Microthiol + surfactant combination C 2000 ppm + 312.5 ppm 13 Microthiol + surfactant combination C 5000 ppm + 781.25 ppm

    [0069] Aviator Xpro is available from Bayer and is an emulisifiable concentrate containing bixafen and prothioconazole.

    [0070] The results are shown in FIG. 4 which shows the percentage of septoria leaf blotch disease severity on wheat treated with different concentrations of Microthiol applied alone or in mixture with surfactant combination C (ANL-AD002). Letters correspond to statistically different data groups (Kruskal-Wallis test, 5% threshold). Error bars correspond to 95% confidence limits. FIG. 4 shows that septoria leaf blotch was well controlled by the reference fungicide Aviator Xpro and the internal control fungicide Heliosoufre S, but no disease control was observed with Microthiol applied alone up to the highest rate, 5000 ppm. Addition of surfactant combination C to Microthiol at concentrations of 1000 ppm and above resulted in reduction of septoria disease; at 2000 ppm and 5000 ppm Microthiol mixed with respectively 312.5 ppm and 781.25 ppm of surfactant combination C, there was no significant difference to the control achieved with the reference fungicides.

    [0071] Photographs of infected leaves in FIGS. 5a, b and c show the severe damage caused by septoria leaf blotch on leaves treated with Microthiol alone at 1000, 2000 and 5000 ppm respectively and the good control achieved by the mixture of the same concentration of Microthiol and the surfactant combination C.

    EXAMPLE 7

    [0072] This is not an Example of the invention as the formulations do not contain sulfur however the Example assesses the surface wetting properties of the preferred surfactants used in this invention. The wetting properties of the individual surfactants and in combination were evaluated by dissolving the surfactants at various concentrations in deionised water. Surface tension and equilibrium contact angle were measured in triplicate using a drop shape analyser with results given in Table 9 below.

    TABLE-US-00010 TABLE 9 Concentration surface tension contact angle (% w/w) (mN/m) (°) Water 74.5 108.6 sodium lauryl sulfate (SLS) 0.005 70.6 107.1 0.025 56.8 72.8 0.050 46.1 63.9 0.100 37.2 55.3 0.200 34.2 51.5 0.250 33.4 50.6 sodium dioctylsulfosuccinate (SDS) 0.005 44.3 54.1 0.010 43.6 38.2 0.025 34.7 35.4 0.050 32.2 31.5 0.100 28.3 28.7 0.200 26.8 24.4 0.250 26.1 22.8 0.500 25.3 21.4 SLS + SDS SLS @ 0.025 + SDS @ 0.025 34.3 45.5 SLS @ 0.050 + SDS @ 0.050 32.5 38.6 SLS @ 0.100 + SDS @ 0.100 30.4 36.9

    [0073] Table 9 shows that there are clear differences between the surface tension values of the surfactants. SDS is very effective at reducing surface tension of water with little dependence on concentration. SLS on the other hand lowers the surface tension but to a far lesser extent and demonstrates a greater dependence on concentration (there is roughly a factor of 10 difference between the two surfactants). Values for the combination are clearly governed by the level of SDS with little effect imparted by the SLS component.

    [0074] In terms of contact angle there is a similar trend with SDS giving small equilibrium values and SLS providing intermediate values between SDS and water. Here however the combination gives values midway between the individual components at circa 45°. Generally, a contact angle between 40-60° is considered ideal wetting for aqueous pesticide spray solutions on plant surfaces and this Example shows that use of the combination of the surfactants enables this to be achieved.

    EXAMPLE 8

    [0075] Product A and Product C from Example 1 and Tiowetting DF (all 800 g/kg Sulfur formulations) were diluted to an equivalent field rate of 4 kg formulated product/1000 L in CIPAC D water. Dilutions were inverted 10 times and a 200 μl droplet was deposited onto a microscope slide. Slides were allowed to dry undisturbed for 4 hours and imaged at 100× magnification. Blank samples of Product A and Product C were prepared without sulfur to provide a baseline for background appearance. No blank formulation of Tiowetting DF was available.

    [0076] Replicate photographs (r1 and r2) were taken at the centre of the slide and at the outer edge and the images obtained are FIGS. 1a, 1b and 1c (Product A), 2a, 2b and 2c (Product C) and 3a and 3b (Tiowetting DF) attached hereto.

    [0077] The figures show some clear differences between formulations. In the case of Product A there is a uniform distribution of sulfur particles throughout the centre and outer region of the droplet. The overall coverage appears light compared to Product C, where there is a higher concentration of sulphur particles in the centre of the droplet. These differences are likely to be linked to surface tension which is lower for Product A (sodium dioctylsulfosuccinate alone) than for Product C (sodium dioctylsulfosuccinate/sodium lauryl sulfate combination) resulting in more wetting of the surface and a thinner deposit.

    [0078] Dispersion is poorer in the case of Tiowetting alone where there are several larger sulphur particles concentrated in the centre of the droplet in amongst a continuous deposition of very fine material. The fine material in this figure is likely to be clay employed as a carrier in the Tiowetting granule formulation whilst the larger particles are sulfur agglomerates. All three formulations contain equal amounts of sulfur, and the overall coverage obtained using the surfactants of this invention is clearly improved.