HK1161954A - Controlling spray drift of pesticides with self-emulsifiable esters - Google Patents

Description

Method for controlling pesticide spray drift by using self-emulsifying ester

This application claims benefit of U.S. provisional application 61/110,060 filed on 31/10/2008.

Technical Field

The present invention relates to a novel method for reducing agrochemical spray drift during application by incorporating self-emulsifying esters into the liquid to be sprayed.

Background

Agricultural spraying processes by economical and efficient techniques use hydraulic nozzles that inherently produce a wide range of spray droplet sizes. It was found that the likelihood of these spray droplets drifting from the earliest desired point of application was a function of droplet size, with smaller droplets having a higher tendency for off-target movement to occur. Significant research efforts, including multiple field trials, wind tunnel trials and subsequent generation of predictive mathematical models, have greatly improved understanding of the relationship between spray droplet size and off-target drift potential. Spray droplet size distribution has been found to be a major factor, although other factors such as meteorological conditions and spray boom height increase the likelihood of drift. Teske et al (Teske M.E., Hewitt A.J., Valcore, D.L.2004.the Role of Small drops in classic Drop sizes distribution Isicas 17^thAnnual Conference: arlington VA), a value of < 156 microns (μ) has been reported as the fraction of spray droplet distribution that is driven to drift. Wolf: (www.bae.ksu.edu/Faculty/wolf/float Htm) Values < 200 μ are referenced as driftable granularity levels. Thus, a good guess for droplet size that might push the drift to occur is below 175 μ granularity.

The negative consequences of off-target motion can be significant. Some herbicides have proven to be very sensitive to phytotoxicity to specific plant species at very low parts per million (ppm) or even parts per billion (ppb) levels, resulting in limited application around sensitive crops, orchards and residential vegetation. For example, the California pesticide administration (California Dept of Pe)Pesticide Regulation) of herbicide containing propanil applied in the air of San Joaquin grain¹/₂-a buffer distance of 2 miles (0.8-3.2 km).

High molecular weight water-soluble polymers are currently added to spray compositions as container mixes (tank mix) to increase droplet size and thereby reduce drift (see, e.g., WO 2008/101818a2 and U.S. patent 6,214,771B 1). However, high molecular weight water-soluble polymers are not entirely satisfactory because they are expensive when used at the concentrations required to considerably increase the droplet size. In addition, studies have shown that commercial drift retardants generally cannot be used with a variety of aerial herbicide container mixtures due to pump shear, wind shear, and other various performance issues, which are more pronounced under high speed aerial application conditions. . See Hewitt, A.J, (2003) Drift Control Adjuvants in Spray Applications: performance and Regulatory aspects, Proc.third Latin American Symposium on Agricultural additives, Sao Paulo, Brazil.

Disclosure of Invention

It has now been found that spray drift during application can be reduced by incorporating self-emulsifying esters into agricultural spray mixtures. The present invention relates to a method of reducing spray drift during pesticide application comprising incorporating 0.01 to 5% v/v self-emulsifying ester or mixture thereof in the pesticide spray. A number of factors lead to a reduction in spray drift, including a reduction in the production of fine spray droplets (< 175 μ in diameter) and an increase in the spray droplet Volume Median Diameter (VMD). For a given spray equipment, application and conditions, and based on the self-emulsifying ester, the median diameter of the majority of spray droplets is increased above the median diameter of the spray composition without the self-emulsifying ester.

Another embodiment of the invention is a premix formulation comprising 1 to 90 wt% pesticide and 0.05 to 30 wt% self-emulsifying ester. The premix formulation is preferably a solution, emulsion, suspension, wettable or soluble powder or water dispersible granule formulation or water soluble granule formulation.

The method of reducing spray drift is applicable to the application of any pesticide or crop protection agent, including herbicides, fungicides and insecticides (insecticides). Particularly preferred herbicides to which the method is applicable include cyhalofop-butyl, fluazifop-butyl, penoxsulam, flumetsulam, cloransulam-methyl, florasulam, pyroxsulam, flumetsulam, fluroxypyr, clopyralid, dichloram, triclopyr, isoxaben, 2, 4-D, 2-methyl-4-chloro (MCPA), dicamba, mearsone, oxyfluorfen (MSMA), oxyfluorfen (oxydefrin), pyrimethanil (oxalanil), pyrimethanil (trifluralin), pyrimethanil (trifloxystrobin), pyrimethanil (pyrimethanil), pyrimethanil (pyri, Glyphosate (glyphosate) and glufosinate (glufosinate). Particularly preferred insecticides for which the method is applicable include organophosphates such as chlorpyrifos (chlorpyrifos), MACs such as halofenozide (halofenozide), methoxyfenozide (methoxyfenozide) and diphenylhydrazide (tebufenozide), pyrethroids such as gamma-cyhalothrin and deltamethrin (deltamethrin) and biopesticides such as spinosad and spinetoram. Particularly preferred fungicides for which the method is suitable include mancozeb (mancozeb), myclobutanil (myclobutanil), fenbuconazole (fenbuconazole), zoxamide (zoxamide), propiconazole (propiconazole), quinoxyfen (quinoxyfen) and thifluzamide (thifluzamide). The invention is particularly useful for the application of herbicides, most particularly herbicides that are subject to limited application around sensitive crops that have been improved in tolerance to the herbicide, such as 2, 4-D, dicamba, glyphosate and glufosinate.

Used in the present inventionEmulsified Esters (SEE) are characterized by the combination of oily (hydrophobic), hydrophilic nonionic and optionally anionic functionalities in a single molecule that can form a homogeneous stable emulsion in the aqueous phase. Unlike conventional emulsions, in which one or more oils are blended with one or more surfactants (emulsifiers), the additives are not necessary for the emulsions disclosed herein. These SEE can be used to form a uniform stable aqueous emulsion with slight to moderate agitation of the mixture of SEE and water without the additional use of emulsifiers or oils. Examples of such SEE include, but are not limited to, the following: (1) self-emulsifying esters based on trimer acids by bringing them to bear C₅₄Oleic and linoleic acids of lipophilic backbone are prepared by polymerization of ester moieties of molecules containing nonionic and anionic surfactant functionalities (see, e.g., U.S. patents 5,688,750 and 5,707,945; products available under the trademark Priolube from Croda Uniqema, Inc); (2) esters prepared by esterifying ethoxylated trimethylolpropane with fatty acids and dicarboxylic acid anhydrides (see, e.g., WO 1990/005714); (3) esters derived from high molecular weight dibasic acids, polyoxyalkylene glycols, and monofunctional aliphatic alcohols (see, e.g., U.S. patent 3,912,642); (4) self-emulsifying ester compounds prepared by reacting ethoxylated trimethylolpropane with carboxylic acids or reactive derivatives thereof, such as anhydrides, as disclosed in U.S. patent 5,219,479; (5) succinic triglyceride oil derived from maleic triglyceride (from plants or land animals) (see, e.g., WO 2005/071050a1), a product purchased from Lubrizol, inc. under the trademark VEG-ESTER; (6) ethoxylated fatty acid esters (see, e.g., WO 1996/022109); (7) alkoxylate esters prepared by reacting an alcohol with ethylene oxide and propylene oxide and/or butylene oxide and capping the resulting alkoxylate with an alkanoic or aromatic acid, as disclosed in U.S. patent 4,559,226, a product purchased under the trademark Hetester from Bernel Chemical Company, inc. (a branch office of azo International, Inc.); and (8) alkoxylated triglyceride products available under the trademarks Aqnique RSO and Agnique SBO from Cognis, inc.

The self-emulsifying ester may be incorporated into a pesticide spray by: mixed together with the diluted pesticide formulation directly in the container or premixed together with the pesticide formulation before dilution to the final spray volume. The self-emulsifying ester was combined at the following concentrations: 0.01 to 5 vol% of the final spray volume, preferably 0.05 to 1.0 vol% of the final spray volume, most preferably 0.05 to 0.2 vol% of the final spray volume.

The method of the invention reduces off-target movement of the pesticide spray in aerial and ground applications.

The optimum droplet size depends on the application for which the composition is to be used. If the droplets are too large, coverage by spraying is less; that is, large droplets may fall on certain areas, while the areas between these areas receive little or no spray composition. The maximum acceptable droplet size may depend on the amount of composition applied per unit area and the uniformity required for spray coverage. Smaller droplets provide more uniform coverage, but are more prone to drift during spraying. Larger droplets are preferred if the wind is particularly strong during spraying, while smaller droplets are preferred on calm days.

The spray droplet size is also dependent on the spray equipment; such as nozzle size and configuration. One skilled in the art can readily adjust the percentage of surfactant and/or polymer in the composition to provide the desired droplet size for a given device, application and condition. In any case, for a given spray equipment, application and conditions, and based on the self-emulsifying ester, the median diameter of the majority of spray droplets is increased above the median diameter of a spray composition without the self-emulsifying ester.

In addition to the above methods, the present invention also encompasses a premix formulation comprising from 1 to 90 wt%, preferably from 5 to 70 wt%, most preferably from 20 to 60 wt% of a pesticide and from 0.05 to 30 wt%, preferably from 1.0 to 20 wt%, and most preferably from 1.0 to 10 wt% of a self-emulsifying ester.

Optionally, the compositions of the present invention may contain a surfactant. The surfactant may be anionic, cationic or nonionic in nature. Typical surfactant packageIncluding alkyl sulfates such as diethanol-ammonium lauryl sulfate; alkyl aryl sulfonates such as calcium dodecylbenzenesulfonate; alkylphenol-alkylene oxide addition products and/or arylalkylphenol-alkylene oxide addition products, e.g. nonylphenol-C₁₈An ethoxylate; alcohol-alkylene oxide addition products, e.g. tridecyl alcohol-C₁₆An ethoxylate; soaps, such as sodium stearate; alkyl naphthalene sulfonates such as sodium dibutylnaphthalene sulfonate; dialkyl esters of sulfosuccinates, such as sodium bis (2-ethylhexyl) sulfosuccinate; sorbitol esters, such as sorbitol oleate; quaternary amines, such as lauryl trimethyl ammonium chloride; ethoxylated amines, such as tallow amine ethoxylate (tallowamine ethoxylated); betaine surfactants, such as cocoamidodipropylbetaine; polyethylene glycol esters of fatty acids, such as polyethylene glycol stearate; block copolymers of ethylene oxide and propylene oxide; and salts of monoalkyl phosphates and salts of dialkyl phosphates; and mixtures thereof. The concentration of the surfactant or mixture of surfactants in the formulation is typically 2 to 20 wt%.

In addition to the formulations described above, the present invention also encompasses formulations in combination with one or more additional compatible ingredients. Other additional ingredients may include, but are not limited to, one or more other pesticides, dyes, and any other additional ingredients that provide functional utility, such as stabilizers, fragrances, viscosity reducers, and freeze-point depressants.

The premix formulation is preferably a solution, emulsion, suspension, wettable or soluble powder or water dispersible granule formulation or water soluble granule formulation.

The following examples illustrate the invention.

Detailed Description

Example 1

To prepare 2, 4-D formulations A through G at each concentration as shown in Table 1, a stainless steel beaker equipped with a mechanical stirrer was first charged with 90 grams of DMA6 SEQUESTERED (68.8% 2, 4-D dimethylammonium salt in aqueous solution). Then a total of 10 grams of different combinations of Priolube products were added according to the composition of table 1. Each liquid mixture was stirred to homogenize the composition and obtain a formulation.

Preparing a spray aqueous solution by: lmL each of the formulations was added to 99mL of deionized water to make a 1% v/v dilution. The spray solution was then sprayed at 40psi (276 kilopascals (kPa)) through a TeeJet 8002 flat fan nozzle, and the droplet size was measured by using a Sympatec Helos particle sizer. Measurements were made with the tip of the nozzle at 6 or 12 inches (15.24 or 30.48 centimeters (cm)) from the measurement zone of the particle sizer. The results are reported in Table 2(6 inches; 15.24cm) and Table 3(12 inches; 30.48 cm). From these results, it can be seen that the driftable fines produced by the spray compositions of the present invention with droplet sizes of less than 175 μm are greatly reduced. The present invention effectively reduces driftable fine droplets by reducing droplet size distribution but not significantly increasing large droplets, thereby having minimal impact on spray coverage and quality.

TABLE 1 composition of the formulation of example 1

DMA6 SEQUESTERED, 6lb (2.72 kg) ae/gal2, 4-D-dimethylammonium, Dow Agrosciences, LLC concentrate for manufacturing use.

TABLE 2 spray performance of the example 1 composition at 6 inches (15.24cm) from the nozzle.

Spray solution	VMD＊，μm	The percentage of < 100 ANGSTROM	The percentage of < 175 ANGSTROM μm
				DMA 6 SEQ 1％	213.00	15.99	38.72
A 1％	223.60	14.21	35.64
				B 1％	287.44	4.36	16.24
C 1％	281.19	4.65	17.55

D 1％	278.43	5.27	18.76
				E 1％	267.02	6.03	21.37
F 1％	255.07	8.52	25.99
				G 1％	238.08	10.86	30.62

VMD-volume median diameter

Percentage of spray volume with droplet size less than 100 μm

Percentage of spray volume with droplet size less than 175 μm

TABLE 3 spray performance of example compositions at 12 inches (30.48cm) from the nozzle

Spray solution	VMD＊，μm	The percentage of < 100 ANGSTROM	The percentage of < 175 ANGSTROM μm
				DMA 6SEQ 1％	164	20.8	53.7
A 1％	204	13.7	40.6
				B 1％	251	7.2	25.9
C 1％	248	7.9	27.6
				D 1％	227	10.3	33.4
E 1％	237	9.0	30.5
				F 1％	231	9.8	32.4
G 1％	190	15.4	44.8

Example 2

Spray solution formulations H to N were prepared at 1% v/v in the same operation as in example 1. An appropriate amount of dimethylammonium glyphosate was then added to each spray solution to achieve a 1: 1 acid equivalent ratio of 2, 4-D to glyphosate. And uniformly stirring the diluent to obtain a spray solution. It was then sprayed according to the same procedure and settings as described in example 1. The results are shown in table 4 (measured at 6 inches (15.24cm) from the nozzle) and table 5 (measured at 12 inches (30.48cm) from the nozzle). From these results, it can be seen that the addition of glyphosate did not significantly affect the spray profile compared to the previous examples, indicating the stability of the invention in controlling the driftable fines.

TABLE 4 spray performance of the composition of example 2 at 6 inches (15.24cm) from the nozzle

TABLE 5 spray performance of the composition of example 2 at 12 inches (30.48cm) from the nozzle

Example 3

To prepare the herbicide formulations O to Q at each concentration as shown in table 4, a stainless steel beaker equipped with a mechanical stirrer was first charged with 95 grams of the herbicide formulation (DMA6SEQ (Garlon 3A) or Milestone) and 5 grams of Hetester PCA (available from azo International inc.). Each liquid mixture was stirred to homogenize the composition and to obtain a formulation for subsequent dilution and spray analysis.

Each aqueous spray solution was prepared by: 2mL of each formulation was added to 98mL of deionized water to make a 2% v/v dilution. The solution was then sprayed in the same operation and setup as described in example 1, with the nozzle 12 inches (30.48cm) from the particle sizer measurement area. The results are shown in table 6 and from these results it can be seen that the present invention does effectively reduce driftable fine droplets by reducing the size distribution without significantly increasing the large droplets, thereby having minimal impact on spray coverage and quality.

Commercial products of Garlon 3A, 3lb (1.36kg) ae/gal triclopyr triethylamine salt, Dow Agrosciences, LLC.

Commercial products of Milestone, 2lb (0.91kg) ae/gal aminopyralid triisopropanolamine Dow Agrosciences, LLC.

TABLE 6 spray performance of the example 3 composition.

Example 4

To prepare each of the herbicide formulations R to T shown in table 7, the sample tank was first charged with 294mL of deionized water, followed by 6mL of a commercial herbicide formulation (DMA6SEQ (Clarity) or accurd XRT II) to prepare a 2% v/v dilution of the formulation. The sample was then shaken until homogeneous. Veg-Ester GY-350(Lubrizol, Inc.) was then added to each solution in an amount equal to 0.1% w/w of the dilute herbicide formulation. The sample was shaken again until homogeneous. The solution was then sprayed in the same operation and settings as described in example 1, with the nozzle being 12 inches (30.48cm) from the particle sizer measurement area. The results are shown in Table 5. From these results, it can be seen that the present invention does effectively reduce driftable fine droplets by changing the size distribution without significantly increasing the large droplets, thereby having minimal impact on spray coverage and quality.

Clarity, 4lb (1.8lkg) ae/gal dicamba diglycolamine salt, a commercial product from BASF.

Accord XRT II, 4lb (1.81kg) ae/gal glyphosate diethylamine salt, Dow Agrosciences, a commercial product of LLC.

TABLE 7 spray Properties of the example 4 composition

Example 5

1.40ml of an aqueous solution of dicamba dimethylammonium salt (dicamba DMA, 46.9% w/wa.e., 560.92g a.e./L) and 0.649g Priolube 3952 were added to 324ml of deionized water and shaken manually to give a solution containing 0.43% v/v dicamba DMA and 0.2% w/w Priolube 3952. In a similar manner, 1.45ml of dicamba dimethylammonium salt solution and 0.70g of Agnique SBO-10 were added to 335ml of deionized water to give a solution containing 0.43% v/v dicamba DMA and 0.2% w/w Agnique SBO-10. As a control, 1.45ml of dicamba DMA concentrate was added to 336ml of deionized water to give a 0.43% v/v solution. Finally, a 0.43% v/v solution of Clarity was prepared for comparison. The resulting solutions were sprayed and their droplet size distribution measured as described in example 1, where the nozzle was 12 inches (30.48cm) from the particle sizer measurement area. The results are summarized in table 8. From these results, it can be seen that the present invention does effectively reduce driftable fine droplets by changing the size distribution without significantly increasing the large droplets, thereby having minimal impact on spray coverage and quality.

TABLE 8 spray performance of the example 5 composition.

Example 6

To 359.07g of deionized water were added in order: 2.75g2, 4-D dimethylethanolamine ammonium salt solution (53.6% a.e.), 0.15g Agnique SBO-10, 0.38g propylene glycol and 3.52g glyphosate dimethylammonium salt solution (42.2% a.e.). As a control, another sample was prepared as just described except that the Agnique SBO-10 was replaced with an additional 0.15g of deionized water. The resulting solutions were shaken briefly by hand and then analyzed for their spray droplet distribution as described in example 1, where the nozzle was 12 inches (30.48cm) from the particle sizer measurement area. The results are shown in table 9.

TABLE 9 spray Properties of the compositions of example 6

Claims (8)

1. A method of reducing spray drift during pesticide application, the method comprising incorporating 0.01 to 5% v/v self-emulsifying ester or mixture thereof in a pesticide spray.

2. The method of claim 1, wherein the pesticide is a herbicide.

3. The method of claim 2, wherein the herbicide is 2, 4-D, glyphosate, triclopyr, aminopyralid, dicamba, or mixtures thereof.

4.The method of claim 1, wherein the pesticide is an insecticide.

5. The method of claim 1, wherein the pesticide is a fungicide.

6. The process of claim 1, wherein the self-emulsifying ester is (1) a trimer acid-based self-emulsifying ester prepared by reacting a compound having C₅₄Oleic and linoleic acids of a lipophilic backbone are prepared by polymerization of the ester moiety of molecules containing nonionic and anionic surfactant functionalities; (2) esters prepared by esterifying ethoxylated trimethylolpropane with fatty acids and dicarboxylic acid anhydrides; (3) esters derived from high molecular weight dibasic acids, polyoxyalkylene glycols, and monofunctional aliphatic alcohols; (4) a self-emulsifying ester compound prepared by reacting an ethoxylated trimethylolpropane with a carboxylic acid or a reactive derivative thereof; (5) succinic triglyceride oil derived from maleic triglyceride from plants or land animals; (6) ethoxylated fatty acid esters; (7) alkoxide esters prepared by reacting an alcohol with ethylene oxide and propylene oxide and/or butylene oxide and capping the resulting alkoxide with an alkanoic or aromatic acid; and (8) alkoxylated triglycerides.

7. A pre-mix formulation comprising from 1 to 90 wt% of a pesticide and from 0.05 to 30 wt% of a self-emulsifying ester.

8. The premix formulation of claim 6 comprising 20 to 60 wt% pesticide and 1.0 to 10 wt% self-emulsifying ester.