PESTICIDAL COMPOSITIONS WITH ENHANCED ACTIVE INGREDIENT
RETENTION IN PEST CONTROL ZONES
PRIORITY CLAIM
This application claims the benefit of U.S. Provisional Patent Application
Serial No. 61/527,561, filed August 25, 201 1.
TECHNICAL FIELD
The present disclosure relates to compositions and methods for the application
of chemicals (for example, pesticides and herbicides) to soil. In some embodiments,
this disclosure relates to compositions and methods that may increase the retention of a
chemical in an area of soil to which the chemical is applied. Particular embodiments
include micronized solid active chemicals that have been coated with polymers, for
example, via a spray-dry process.
BACKGROUND
Particulate chemicals in water can move through soil, either horizontally or
vertically, depending on water movement and the physical/chemical properties of the
particle and soil. Soil is made up of different size particles that do not fit together
tightly; i.e., there is "soil pore space" between the soil particles. Categories of soil pore
spaces include mesopores, which are filled with water at field capacity and function as
water storage pores for plant growth. Mesopores vary in size, typically ranging from
0.3 to 200 micrometers (mih, or microns) and distribution. The size and distribution of
mesopores is dependent on soil type and structure. Other soil pore types include
macropores (typically >200 microns), which are pores that are too large to have any
water capillary action, and micropores (typically <0.3 microns), which are too small for
plants to use. Encyclopedic Dictionary of Hydrogeology, Eds. Poehls and Smith,
2009, Academic Press, New York, pp. 270-1 .
The incorporation of active materials and chemicals in soil is important in a
variety of contexts. For example, controlling pest and weed populations by the
application of pesticide and/or herbicide compositions directly to the soil as a
pre-emergence application prior to weed emergence is essential to modern agriculture.
Unfortunately, many active chemical formulations lose their efficacy relatively soon
after their application for many reasons. Among the factors known to influence the
persistence of pesticides, the chemical stability, volatility, and solubility in plants have
long been thought to be the most important. Edwards (1975) Pure and Applied
Chemistry 42(l/2):39-56. When a pesticide is applied to a crop or soil, it moves from
one part of the system to another, and is ultimately degraded in situ or moved out of the
system. It is important to control these processes, because pesticides that move to other
systems will not satisfy their intended purpose and may damage the environment. One
route for reducing the activity of an active ingredient is movement through the soil
following irrigation or rainfall, removing the active ingredient from the zone of weed
emergence. A pesticide can disappear from soil, for example, by volatilization,
leaching, surface run-off, or uptake by plants. Chemical residues that remain in plants
or soil may be metabolized, but often, for persistent pesticides, these residues represent
only a small proportion of the whole.
DISCLOSURE
Disclosed herein are methods and compositions that take advantage of the
finding that polymer-coating of a particle comprising a solid active chemical
dramatically reduces disappearance of the active chemical from a zone of soil to which
the coated chemical is applied. In particular examples, polymer-coated chemical
particles exhibit increased persistence in a zone of soil (e.g., a target zone to which the
coated particles are applied by spraying). Through increased persistence, a
polymer-coated particle comprising a pesticide may provide increased control of
susceptible pests. Thus, in embodiments, manufacture and/or use of polymer-coated
particles comprising an active chemical increases the amount of the active chemical
that will stay in a target zone (e.g., a weed germination zone), and reduces the
movement of the active chemical out of the target zone, for example, due to leaching or
water movement.
In some embodiments, a polymer-coated particulate composition comprising a
biologically active compound is provided. In particular embodiments, a
polymer-coated particle may be at least about 0.1 m in diameter; at least about .0 mih
in diameter; at least about 20 m in diameter; at least about 30 mh in diameter; at least
about 50 mhi in diameter; at least about 75 mhi in diameter; and at least about 100 m i
in diameter (e.g., approximately 100 m in diameter). In particular embodiments, a
polymer-coated particulate composition may comprise combinations, mixtures, and/or
suspensions of particles having any and/or all of these diameters. For example, a
polymer-coated particulate composition may comprise a plurality of polymer-coated
particles, wherein essentially all of the polymer-coated particles are between 0.1 and
100 mh in diameter (e.g., between 1.0 and 30 mih in diameter). In some embodiments,
the coating of a polymer-coated particulate composition may comprise any oil-based
polymer (e.g., a latex polymer).
In particular embodiments, a polymer-coated particle comprising a biologically
active compound may consist essentially of the biologically active compound, or
consist of the biologically active compound. In further embodiments, a
polymer-coated particle may comprise a biologically active compound as part of a
composition that is capable of maintaining solid form at a particular temperature (e.g.,
30°C, and 50°C). In these and further embodiments, a biologically active compound
may be non-solid (e.g., a liquid and a melted wax) and be comprised in a solid
composite composition that also comprises a carrier (e.g. , a silica carrier).
In some embodiments, a polymer-coated particulate composition comprising a
biologically active compound according to the invention may persist longer in a target
zone to which the composition is applied than a non-coated particulate composition
comprising the same compound. Thus, in particular examples, a polymer-coated
particulate composition may exhibit reduced disappearance (e.g., reduced
volatilization, leaching, surface run-off, or uptake by plants) than a non-coated
particulate composition comprising the same compound.
Thus, also disclosed herein are methods for decreasing the rate at which a
biologically active compound disappears from a target zone, as well as methods for
increasing the persistence of a biologically active compound in a target zone. In some
embodiments, a method may comprise applying a polymer-coated particulate
composition comprising a biologically active compound to the target zone. In
particular embodiments, a polymer-coated particulate composition comprising a
biologically active compound may be applied to a target zone as part of one of many
available formulation types available to those of skill in the art (e.g., as an aqueous
suspension). In particular examples, a polymer-coated composition may be applied by
broadcast spraying.
The foregoing and other features will become more apparent from the
following detailed description of several embodiments, which proceeds with reference
to the accompanying figures.
BRIEF DESCRIPTION OF THE FIGURE
FIG. 1 includes data showing the average control (%) of CAPBP (Capsella
bura-pastoris (Shepherd's purse)) 28 days after application of several polymer-coated
propyzamide formulations (Compositions #8 and #10, respectively, and a control
non-coated propyzamide formulation (Kerb 50WP). Data were collected for three
application rates of each formulation.
MODE(S) FOR CARRYING OUT THE INVENTION
I . Overview of several embodiments
Embodiments of the invention include agricultural compositions that may be
used to increase the retention (or decrease the disappearance) of an active chemical in a
target area of soil to which the composition is applied. In particular examples, a
composition of the invention may be prepared by coating solid particulate (e.g., solid
micronized) ingredients with a polymer, for example and without limitation, via a
spray-dry process. Thus, methods of making compositions of the invention are also
disclosed. Further disclosed are methods of using a composition of the invention, for
example, to increase the persistence of an active chemical in a target zone of soil to
which the composition is applied.
In particular embodiments, a technical grade active chemical that may be a
solid may be micronized. Any solid, soil-applied active chemical, or any solid,
foliar-applied active chemical that has soil activity, may be used in certain
embodiments of the invention, so long as the active chemical can be micronized, for
example and without limitation, to a size of between about 0.1 m and about 100 m .
Examples of classes of active chemicals that may be used in some embodiments
include, without limitation: pesticides; herbicides (e.g., propyzamide); fungicides;
insecticides; biocides; etc. In certain embodiments, an active chemical that may not be
a solid at a particular temperature (e.g., a liquid and a wax) may be incorporated into a
composite composition with a earner (e.g., a silica carrier), such that the composite
composition is a solid.
In some embodiments, a polymer-coated particulate composition comprising a
biologically active compound may be formulated as a suspension, a granule product, a
powder, or any other formulation type that may facilitate the application of the
particulate composition in a commercial formulation.
II. Terms
Pesticide: As used herein, the term "pesticide" refers to a chemical compound
that has a biological activity against an organism. Thus, a pesticide may be any
substance, or mixture of substances, capable of preventing, destroying, repelling or
mitigating any pest. A pesticide may be a chemical substance, biological agent (such
as a virus or bacterium), antimicrobial, disinfectant, or device used against any pest.
Pests include, without limitation, insects, plant pathogens, invasive plants (e.g., weeds),
molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy
property, spread disease, or cause a nuisance.
The biological activity of a pesticide is determined by its active ingredient
(which may also be called the active substance). Generally, pesticide products very
rarely consist of pure technical material. However, in some embodiments of the
invention, a pesticide is provided as a pure technical material. The active ingredient is
usually formulated with other materials, and any material, such as a carrier, that may be
incorporated in a solid particle comprising the active ingredient, may be so
incorporated in some embodiments for polymer coating.
Subclasses of pesticides include, for example and without limitation:
herbicides, insecticides, fungicides, rodenticides, pediculocides, biocides, algicides,
avicides, bactericides, acaricides, molluscicides, nematicides, rodenticides, and
virucides.
Pesticides can be classified by target organism, chemical structure, and physical
state. Pesticides can also be classed as inorganic, synthetic, or biologicals
(biopesticides), although this distinction may not be clear in every case. Biopesticides
include, for example, both microbial pesticides and biochemical pesticides.
Plant-derived pesticides (sometimes referred to as "botanicals") include, for example
and without limitation: the pyrethroids; rotenoids; nicotinoids; and a group that
includes strychnine and scilliroside.
Many pesticides can also be grouped into chemical families. For example,
insecticides include organochlorines, organophosphates, and carbamates.
Organochlorine hydrocarbons may be further separated into dichlorodiphenylethanes,
cyclodiene compounds, and other related compounds that operate by disrupting the
Na+/K+ balance of insect nerve fibers, forcing the nerve to transmit continuously.
Herbicides include phenoxy and benzoic acid herbicides (e.g., 2,4-D), triazines (e.g.,
atrazine), ureas (e.g., diuron), and chloroacetanilides (e.g., alachlor). Phenoxy
compounds tend to selectively kill broadleaved weeds rather than grasses. The
phenoxy and benzoic acid herbicides function similar to plant growth hormones,
leading to cell growth without normal cell division, and thereby crushing the plant's
nutrient transport system. Triazines interfere with photosynthesis.
In view of the foregoing, it will be clear that the term "pesticide," for the
purposes of the present disclosure, encompasses all classes of biologically active
chemicals that are useful to control the population of an organism.
Formulation: As used herein, the term "formulation" refers to a mixture that is
prepared according to a specific procedure (i.e., the "formula"). Formulation may
improve the properties of a pesticide for handling, storage, application, and it may
substantially influence its effectiveness and safety. Formulation terminology follows a
two-letter convention (e.g., GR denotes "granules"), listed by CropLife International in
the Catalogue of Pesticide Formulation Types and International Coding System,
Technical Monograph no. 2, 6th Ed. However, some manufacturers do not follow these
industry standards, which can cause confusion for users.
Pesticide formulations for mixing with water and application as a spray are
common. Water-compatible formulations include: emulsifiable concentrates (EC),
wettable powders (WP), soluble liquid concentrates (SL), and soluble powders (SP).
Non-powdery formulations with reduced use (or no use) of hazardous solvents that
may have improved stability include: suspension concentrates (SC); capsule
suspensions (CS); and water dispersible granules (WG). Other pesticide formulations
include: granules (GR) and dusts (DP), although for improved safety the latter have
generally been replaced by microgranules (MG). Specialist formulations are available
for ultra-low volume spraying, fogging, fumigation, etc. Some pesticides (e.g.,
malathion) may be sold as technical material (TC - which is mostly AI, but also
typically contains small quantities of (usually non-active) by-products of the
manufacturing process). In embodiments of the present invention, a polymer-coated
particulate composition comprising a biologically active compound may be included in
any formulation (including those set forth above) that facilitates the application of the
compound in an effective manner.
Target zone: As used herein, the term "target zone" (for example, a soil target
zone) refers to an area and/or volume. For example, a soil target zone may refer to a
two-dimensional surface area of soil to which a formulation is applied, and also to a
three-dimensional volume, defined by the two-dimensional area and a specified soil
depth. Some embodiments involve a soil target zone to which a formulation or product
is to be applied in order to provide a biological effect mediated by the formulation or
product. In particular embodiments and examples, a soil target zone may be a weed
germination zone that is defined by the surface area to which a formulation is applied,
and a soil depth defined by the soil depth at which a weed may germinate (e.g., 4
inches (10.16 cm), 6 inches (15.24 cm), and 8 inches (20.32 cm)). It is understood that
the soil depth at which a targeted weed species may germinate depends upon the
identity of the targeted weed species.
III. Polymer-coated micronized chemicals
Solid polymer-coated particulate compositions may comprise a biologically
active compound (e.g. , a pesticide). Any chemical composition that may be formulated
in solid particles may be used in some or all embodiments of the invention. For
example, a solid biologically active compound may be coated with a polymer to form a
composition of the invention. Further, a solid biologically active compound may be
incorporated with one or more additional materials in a solid composite composition,
wherein the solid composite composition is coated with a polymer. Still further, a
biologically active compound that is not a solid may be incorporated with one or more
additional materials in a solid composite composition, wherein the solid composite
composition is coated with a polymer.
In particular embodiments, a solid polymer-coated particulate composition
comprising a biologically active compound may reduce the disappearance of the
biologically active compound from soil to which the composition is applied, when
compared to uncoated particles. For example, when the polymer-coated composition is
applied to a target zone, the biologically active compound may persist longer and/or
remain in a greater concentration in the target zone. The biologically active compound
also may move at a reduced rate and/or in smaller amounts to areas adjacent and/or
near to the target zone (e.g., by leaching).
In some embodiments, a biologically active compound in a polymer-coated
particle may be selected from a group of pesticides comprising herbicides, insecticides,
nematocides, fungicides, and other chemicals that may require soil incorporation. For
example, a chemical in a large-diameter particle may be a pesticide selected from a
group comprising the herbicides: cyhalofop-butyl, haloxyfop, penoxsulam,
flumetsulam, cloransulam-methyl, florasulam, pyroxsulam, diclosulam, fluroxypyr,
clopyralid, acetochlor, triclopyr, isoxaben, 2,4-D, MCPA, dicamba, MSMA,
oxyfluorfen, oryzalin, trifluralin, benfluralin, ethalfluralin, aminopyralid, atrazine,
picloram, tebuthiuron, pendimethalin, propanil, propyzamide, glyphosate, and
glufosinate.
In further embodiments, a chemical in a biologically active compound may be a
pesticide selected from a group comprising the insecticides: organophosphate
insecticides (e.g., chlorpyrifos), molt accelerating compounds (e.g., halofenozide,
methoxyfenozide and tebufenozide), pyrethroids (e.g., gamma-cyhalothrin and
deltamethrin), and biopesticides (e.g., spinosad and spinetoram). A chemical in a
biologically active compound may also be a pesticide selected from a group
comprising the fungicides: mancozeb, myclobutanil, fenbuconazole, zoxamide,
propiconazole, quinoxyfen and thifluzamide.
In particular embodiments, the biologically active compound in a solid
polymer-coated particulate composition may be, for example, a solid, a wax, and a
liquid. The biologically active compound may be incorporated into a composite
composition with other materials prior to polymer coating. In embodiments, the
composite composition may be a solid at a temperature of at least about 50°C (for
example and without limitation, 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C,
53°C, 54°C, and 55°C). In particular embodiments, the composite composition may
comprise a wetting agent, a dispersing agent, a carrier, a silica carrier, a lipid-based
colloidal carrier, an inert mineral carrier, a diy carrier, a filler, and/or a clay, etc.
In some embodiments, a particle that is coated with a polymer may be greater
than about 0.1 m in diameter. For example, in particular embodiments, a
large-diameter particle may be at least about 0.1 mih in diameter (e.g., at least about
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, and 9 mh , etc.) in diameter;
at least about 1 mhi in diameter; at least about 0 mhi in diameter; at least about 20 mh
in diameter; at least about 30 mh in diameter; at least about 40 m in diameter; at least
about 50 mhi in diameter; at least about 60 mh in diameter; at least about 70 mh in
diameter; at least about 80 mh in diameter; at least about 90 m in diameter; at least
about 100 mh in diameter; and at least about 110 m i , or more, in diameter.
In some embodiments, a polymer-coated particulate composition comprising a
biologically active compound may be coated with a hydrophobic polymer (e.g., an
essentially water-insoluble polymer, a water-insoluble polymer, a polymer that is not
readily soluble in water, an oil-based polymer, etc.). For example, in particular
embodiments, a polymer-coated particulate composition comprising a biologically
active compound may be coated with a latex polymer. In particular examples, the
polymer may be, for example and without limitation, a binder and/or encapsulating
material, such as those set forth in Table 1.
Table 1: Polymer-coating materials
Binder/encapsulating
UCAR® 379G Vinyl-Acrylic Latex
material
Binder/encapsulating
UCAR® 627 100% Aciylic Latex
material
Binder/encapsulating
UCAR® 4 18 Cationic Latex
material
Binder/encapsulating
NEOCAR® 820 Acrylic Latex
material
Binder/encapsulating
NEOCAR® 2300 Vinyl-Acrylic Latex
material
Binder/encapsulating PolyvinylpyiTolidone/Polyvinylacetate
AGRIMER® VA 3E
material Co-polymer
Binder/encapsulating Polyvinylpyrrolidone/Polyvinylacetate
AGRIMER® VA 6
material Co-polymer
Binder/encapsulating
AGRIMER® 30 Polyvinylpyrrolidone
material
Binder/encapsulating
CELVOL® 205 Polyvinylacetate with 88% Hydrolysis
material
Binder/encapsulating
Methocel™ K4M Hydroxypropyl Methylcellulose
material
Binder/encapsulating
Chitosan Chitosan
material
Binder/encapsulating
Sodium Alginate Sodium Alginate
material
LyckebyCulinar AB Binder/encapsulating
Water-soluble Starch
Starch material
In certain embodiments, a polymer-coated particulate composition may be
produced by a method comprising providing a solid particulate composition (e.g., a
solid biologically active compound, and a composite composition comprising a
biologically active compound), and adhering a polymer to the surface of a solid particle
of the composition. In some embodiments, the polymer may be adhered to the surface
of the solid particle by a spray-dry process. For example, water may be added first to
an appropriately sized container, followed by any wetting and/or dispersing agents, and
then a biologically active compound may be added to the mixture. The mixture may be
processed (e.g., for dispersion, and to improve consistency). The mixture may be
milled until a desired particle size (or sizes) is obtained, for example, in a suspension
concentrate.
In particular embodiments, a spray-dried formulation may be prepared by a
method comprising providing a solid particulate composition (e.g., a solid biologically
active compound, and a composite composition comprising a biologically active
compound) in a container of suitable volume, and optionally adding any wetting
agents, dispersing agents, binders, and encapsulating materials, with an appropriate
amount of water to make a slurry or suspension. The resultant slurry or suspension
may be spray-dried (e.g., with a Btichi B-290 Mini Spray Dryer outfitted with a Orion
SAGE model 365 syringe pump to deliver the slurry or suspension into the spray dryer
at a controlled rate).
A formulation comprising a polymer-coated particulate composition may
include other compounds. For example, in some embodiments, a pesticidal
composition may include between about 1 weight percent and about 20 weight percent
(e.g., from about 1 weight percent to about 7 weight percent) of at least one surfactant.
A surfactant may be anionic, cationic, or nonionic in character. Typical surfactants
include, without limitation: salts of alkyl sulfates (e.g., diethanolammonium lauryl
sulfate), alkylarylsulfonate salts (e.g., calcium dodecylbenzenesulfonate), alkyl and/or
arylalkylphenol-alkylene oxide addition products (e.g., nonylphenol-C18 ethoxylate),
alcohol-alkylene oxide addition products (e.g., tridecyl alcohol-C16 ethoxylate), soaps
(e.g., sodium stearate), alkylnaphthalenesulfonate salts (e.g., sodium
dibutylnaphthalenesulfonate), dialkyl esters of sulfosuccinate salts (e.g., sodium
di(2-ethylhexyl) sulfosuccinate), sorbitol esters (e.g., sorbitol oleate), quaternary
amines (e.g., lauryl trimethylammonium chloride), ethoxylated amines (e.g.,
tallowamine ethoxylated), betaine surfactants (e.g., cocoamidopropyl betaine),
polyethylene glycol esters of fatty acids (e.g., polyethylene glycol stearate), block
copolymers of ethylene oxide and propylene oxide, salts of mono and dialkyl
phosphate esters, and mixtures thereof.
In particular embodiments, a surfactant may be selected from a group
comprising polymers, sulfates of alkoxylated alkanoles, fatty alcohol polyglycol ethers,
and polysorbates. By way of example and not limitation, the surfactant may be a CI2
alcohol ethoxylate, such as an ethoxylated lauryl alcohol surfactant. An example of
such an ethoxylated lauryl alcohol surfactant is AGNIQUE® DMF 112S, which is
commercially available from Cognis Corporation (Cincinnati, OH). A polymeric
surfactant, such as that commercially available from Huntsman International LLC (The
Woodlands, TX) under the trademark TERSPERSE® 2500 series, may also be
employed. An alcohol polyglycol ether, such as ETHYLAN™ NS 500 LQ alcohol
polyglycol ether (Akzo Nobel; Chicago, IL), may also be employed. For example, the
pesticidal composition may include between about 0.05 weight percent and about 2
weight percent (e.g., about 0.3 weight percent) of the AGNIQUE® DMF 112S,
between about 0.5 weight percent and about 4 weight percent of the TERSPERSE®
2500 series, and, e.g. , about 1.9 weight percent and the ETHYLAN™ NS 500 LQ.
A pesticidal composition may also optionally include a thickener. For
example, in some embodiments, a pesticidal composition may include between about
0.05 weight percent and about 0.5 weight percent of a thickener. One example of a
thickener is an organic gum (e.g., xanthan gum, such as KELZAN® S xanthan gum).
For example, in particular embodiments, a pesticidal composition may include about
0.2 weight percent of KELZAN® S xanthan gum.
A pesticidal composition may also optionally include a dispersant. For
example, in some embodiments, a pesticidal composition may include between about
0.5 weight percent and about 6 weight percent of a dispersant. One example of a
dispersant is MORWET® D-425 powder (Akzo Nobel), which includes a blend of an
alkyl naphthalene sulfonate condensate and lignosulfonate. For example, in particular
embodiments, a pesticidal composition may include about 2.9 weight percent of
MORWET® D-425 powder.
A pesticidal composition may also optionally include a preservative. For
example, in some embodiments, a pesticidal composition may include between about
0.5 weight percent and about 6 weight percent of a preservative. One example of a
preservative is PROXEL® GXL preservative (Arch UK Biocides Limited; England).
For example, in particular embodiments, a pesticidal composition may include about
0.1 weight percent of PROXEL® GXL preservative.
A pesticidal composition may also optionally include a rheology stabilizer. For
example, in some embodiments, a pesticidal composition may include between about
0.5 weight percent and about 6 weight percent of a rheology stabilizer. One example
of a rheology stabilizer is a microcrystalline cellulose gel {e.g., AVICEL® CL 6 11
rheology stabilizer; FMC Corporation (Philadelphia, PA)). For example, in particular
embodiments, a pesticidal composition may include about 1.1 weight percent of the
AVICEL® CL 611 rheology stabilizer.
A pesticidal composition may also optionally include between about 0.05
weight percent and about 1 weight percent of a buffer. The buffer may include, for
example, and aqueous solution of a weak acid and its conjugate base of a weak base
and its conjugate acid. The buffer solution may be formulated to maintain a desired pH
of the insecticide formulation.
In particular embodiments, a pesticidal composition may also include between
about 2 weight percent and about 10 weight percent and, more particularly, between
about 3 weight percent and about 6 weight percent of the propylene glycol.
In some embodiments, a base formulation may be combined with a liquid
carrier and a self-emulsifiable ester. Examples of suitable liquid carriers include, but
are not limited to: liquid carriers including benzene, alcohols, acetone, xylene,
methylnaphthalene, dioxane and cyclohexanone. Examples of self-emulsifiable esters
include, but are not limited to, succinate triglyceride oil derived from maleating
triglyceride oil (e.g., VEG-ESTER® additives; Lubrizol, Inc.). For example, a
pesticidal composition may be formed by combining between about 10 weight percent
and about 30 weight percent of the base formulation with between about 30 weight
percent and about 50 weight percent of each of cyclohexanone and VEG-ESTER®
GY-350 additive. Further examples of the use of self-emulsifiable carriers in pesticide
application are provided in U.S. Patent Application 2010/01 13275.
A formulation comprising a polymer-coated particulate composition
comprising a biologically active compound may also optionally comprise one or more
fillers in some embodiments. Fillers which may be incorporated into a large-diameter
chemical particle may include, for example, powdered or granular materials, including
without limitation: diatomites, attapulgites, bentonites, talcs, montmorillonites,
perlites, vermiculites, calcium carbonates, corncob grits, wood flour, lignin sulfonates,
etc.
In addition to the formulations set forth above, a polymer-coated particulate
composition comprising a biologically active compound may also be included in a
formulation in combination with one or more additional compatible ingredients. Other
additional ingredients may include, for example and without limitation: one or more
other biologically active compound(s); dyes; and any other additional ingredients
providing functional utility (e.g., fragrances, viscosity-lowering additives, and
freeze-point depressants).
Kits and suspensions comprising a polymer-coated particulate composition
comprising a biologically active compound are also provided in some embodiments.
In particular examples, a kit may comprise polymer-coated particles comprising a
biologically active compound, and may further comprise other ingredients and/or
materials to be incorporated in a formulation with the coated particles.
While it is possible to utilize the compounds directly as herbicides, it is
preferable to use them in mixtures containing a herbicidally effective amount of the
compound along with at least one agriculturally acceptable adjuvant or carrier.
Suitable adjuvants or carriers should not be phytotoxic to valuable crops,
particularly at the concentrations employed in applying the compositions for
selective weed control in the presence of crops, and should not react chemically with
the compounds of Formula I or other composition ingredients. Such mixtures can be
designed for application directly to weeds or their locus or can be concentrates or
formulations that are normally diluted with additional carriers and adjuvants before
application. They can be solids, such as, for example, dusts, granules, water
dispersible granules, or wettable powders, or liquids, such as, for example,
emulsifiable concentrates, solutions, emulsions or suspensions. They can also be
provided as a pre-mix or tank mixed.
Suitable agricultural adjuvants and carriers that are useful in preparing the
herbicidal mixtures of the invention are well known to those skilled in the art. Some
of these adjuvants include, but are not limited to, crop oil concentrate (mineral oil
(85%) + emulsifiers (15%)); nonylphenol ethoxylate; benzylcocoalkyldimethyl
quaternary ammonium salt; blend of petroleum hydrocarbon, alkyl esters, organic
acid, and anionic surfactant; C9-C1 1 alkylpolyglycoside; phosphated alcohol
ethoxylate; natural primary alcohol (Ci2 -C ) ethoxylate; di-sec-butylphenol EO-PO
block copolymer; polysiloxane-methyl cap; nonylphenol ethoxylate + urea
ammonium nitrrate; emulsified methylated seed oil; tridecyl alcohol (synthetic)
ethoxylate (8EO); tallow amine ethoxylate (15 EO); PEG(400) dioleate-99.
Liquid carriers that can be employed include water and organic solvents. The
organic solvents typically used include, but are not limited to, petroleum fractions or
hydrocarbons such as mineral oil, aromatic solvents, paraffinic oils, and the like;
vegetable oils such as soybean oil, rapeseed oil, olive oil, castor oil, sunflower seed
oil, coconut oil, corn oil, cottonseed oil, linseed oil, palm oil, peanut oil, safflower
oil, sesame oil, tung oil and the like; esters of the above vegetable oils; esters of
monoalcohols or dihydric, trihydric, or other lower polyalcohols (4-6 hydroxy
containing), such as 2-ethyl hexyl stearate, 7-butyl oleate, isopropyl myristate,
propylene glycol dioleate, di-octyl succinate, di-butyl adipate, di-octyl phthalate and
the like; esters of mono, di and polycarboxylic acids and the like. Specific organic
solvents include toluene, xylene, petroleum naphtha, crop oil, acetone, methyl ethyl
ketone, cyclohexanone, trichloroethylene, perchloroethylene, ethyl acetate, amyl
acetate, butyl acetate, propylene glycol monomethyl ether and diethylene glycol
monomethyl ether, methyl alcohol, ethyl alcohol, isopropyl alcohol, amyl alcohol,
ethylene glycol, propylene glycol, glycerine, N-methyl-2-pyrrolidinone,
N N-dimethyl alkylamides, dimethyl sulfoxide, liquid fertilizers and the like. Water
is generally the carrier of choice for the dilution of concentrates.
Suitable solid earners include talc, pyrophyllite clay, silica, attapulgus clay,
kaolin clay, kieselguhr, chalk, diatomaceous earth, lime, calcium carbonate,
bentonite clay, Fuller's earth, cottonseed hulls, wheat flour, soybean flour, pumice,
wood flour, walnut shell flour, lignin, and the like.
It is usually desirable to incorporate one or more surface-active agents into
the compositions of the present invention. Such surface-active agents are
advantageously employed in both solid and liquid compositions, especially those
designed to be diluted with carrier before application. The surface-active agents can
be anionic, cationic or nonionic in character and can be employed as emulsifying
agents, wetting agents, suspending agents, or for other purposes. Surfactants
conventionally used in the art of formulation and which may also be used in the
present formulations are described, inter alia, in "McCutcheon 's Detergents and
Emulsiflers Annual," MC Publishing Corp., Ridgewood, New Jersey, 1998 and in
"Encyclopedia of Surfactants," Vol. I-III, Chemical publishing Co., New York,
1980-81. Typical surface-active agents include salts of alkyl sulfates, such as
diethanolammonium lauryl sulfate; alkylarylsulfonate salts, such as calcium
dodecylbenzenesulfonate; alkylphenol-alkylene oxide addition products, such as
nonylphenol-C] ethoxylate; alcohol-alkylene oxide addition products, such as
tridecyl alcohol-Ci ethoxylate; soaps, such as sodium stearate;
alkylnaphthalene-sulfonate salts, such as sodium dibutylnaphthalenesulfonate;
dialkyl esters of sulfosuccinate salts, such as sodium di(2-ethylhexyl) sulfosuccinate;
sorbitol esters, such as sorbitol oleate; quaternary amines, such as lauryl
trimethylammonium chloride; polyethylene glycol esters of fatty acids, such as
polyethylene glycol stearate; block copolymers of ethylene oxide and propylene
oxide; salts of mono and dialkyl phosphate esters; vegetable or seed oils such as
soybean oil, rapeseed/canola oil, olive oil, castor oil, sunflower seed oil, coconut oil,
corn oil, cottonseed oil, linseed oil, palm oil, peanut oil, safflower oil, sesame oil,
tung oil and the like; and esters of the above vegetable oils, particularly methyl
esters.
Oftentimes, some of these materials, such as vegetable or seed oils and their
esters, can be used interchangeably as an agricultural adjuvant, as a liquid carrier or
as a surface active agent.
Other adjuvants commonly used in agricultural compositions include
compatibilizing agents, antifoam agents, sequestering agents, neutralizing agents
and buffers, corrosion inhibitors, dyes, odorants, spreading agents, penetration aids,
sticking agents, dispersing agents, thickening agents, freezing point depressants,
antimicrobial agents, and the like. The compositions may also contain other
compatible components, for example, other herbicides, plant growth regulants,
fungicides, insecticides, and the like and can be formulated with liquid fertilizers or
solid, particulate fertilizer carriers such as ammonium nitrate, urea and the like.
The compositions of the present invention may be applied in conjunction
with one or more other non-polymer coated pesticide to control a wider variety of
undesirable pests. When used in conjunction with these other non-polymer coated
pesticides, the presently claimed compositions can be formulated with the other
non-polymer coated pesticide or pesticides as premix liquid or solid concentrates,
tank mixed with the other non-polymer coated pesticide or pesticides for spray
application or applied sequentially with the other non-polymer coated pesticide or
pesticides in separate spray applications. The non-polymer coated pesticide or
pesticides may include one or more of an insecticide, an herbicide, a fungicide, an
acaricide, a nematicide, a biocide, etc.
Suitable non-polymer coated herbicides for use in conjunction with the
compositions of the present invention may be selected from, but are not limited to:
4-CPA; 4-CPB; 4-CPP; 2,4-D; 3,4-DA; 2,4-DB; 3,4-DB; 2,4-DEB; 2,4-DEP;
3,4-DP; 2,3,6-TBA; 2,4,5-T; 2,4,5-TB; acetochlor, acifluorfen, aclonifen, acrolein,
alachlor, allidochlor, alloxydim, allyl alcohol, alorac, ametridione, ametryn,
amibuzin, amicarbazone, amidosulfuron, aminocyclopyrachlor, aminopyralid,
amiprofos-methyl, amitrole, ammonium sulfamate, anilofos, anisuron, asulam,
atraton, atrazine, azafenidin, azimsulfuron, aziprotryne, barban, BCPC,
beflubutamid, benazolin, bencarbazone, benfluralin, benfuresate, bensulfuron,
bensulide, bentazone, benzadox, benzfendizone, benzipram, benzobicyclon,
benzofenap, benzofluor, benzoylprop, benzthiazuron, bicyclopyrone, bifenox,
bilanafos, bispyribac, borax, bromacil, bromobonil, bromobutide, bromofenoxim,
bromoxynil, brompyrazon, butachlor, butafenacil, butamifos, butenachlor,
buthidazole, buthiuron, butralin, butroxydim, buturon, butylate, cacodylic acid,
cafenstrole, calcium chlorate, calcium cyanamide, cambendichlor, carbasulam,
carbetamide, carboxazole chlorprocarb, carfentrazone, CDEA, CEPC,
chlomethoxyfen, chloramben, chloranocryl, chlorazifop, chlorazine, chlorbromuron,
chlorbufam, chloreturon, chlorfenac, chlorfenprop, chlorflurazole, chlorflurenol,
chloridazon, chlorimuron, chlornitrofen, chloropon, chlorotoluron, chloroxuron,
chloroxynil, chlorpropham, chlorsulfuron, chlorthal, chlorthiamid, cinidon-ethyl,
cinmethylin, cinosulfuron, cisanilide, clethodim, cliodinate, clodinafop, clofop,
clomazone, clomeprop, cloprop, cloproxydim, clopyralid, cloransulam, CMA,
copper sulfate, CPMF, CPPC, credazine, cresol, cumyluron, cyanatryn, cyanazine,
cycloate, cyclosulfamuron, cycloxydim, cycluron, cyhalofop, cyperquat, cyprazine,
cyprazole, cypromid, daimuron, dalapon, dazomet, delachlor, desmedipham,
desmetryn, di-allate, dicamba, dichlobenil, dichloralurea, dichlormate, dichlorprop,
dichlorprop-P, diclofop, diclosulam, diethamquat, diethatyl, difenopenten,
difenoxuron, difenzoquat, diflufenican, diflufenzopyr, dimefuron, dimepiperate,
dimethachlor, dimethametryn, dimethenamid, dimethenamid-P, dimexano,
dimidazon, dinitramine, dinofenate, dinoprop, dinosam, dinoseb, dinoterb,
diphenamid, dipropetryn, diquat, disul, dithiopyr, diuron, DMPA, DNOC, DSMA,
EBEP, eglinazine, endothal, epronaz, EPTC, erbon, esprocarb, ethalfluralin,
ethametsulfuron, ethidimuron, ethiolate, ethofumesate, ethoxyfen, ethoxysulfuron,
etinofen, etnipromid, etobenzanid, EXD, fenasulam, fenoprop, fenoxaprop,
fenoxaprop-P, fenoxasulfone, fenteracol, fenthiaprop, fentrazamide, fenuron, ferrous
sulfate, flamprop, flamprop-M, flazasulfuron, florasulam, fluazifop, fluazifop-P,
fluazolate, flucarbazone, flucetosulfuron, fluchloralin, flufenacet, flufenican,
flufenpyr, flumetsulam, flumezin, flumiclorac, flumioxazin, flumipropyn,
fluometuron, fluorodifen, fluoroglycofen, fluoromidine, fluoronitrofen, fluothiuron,
flupoxam, flupropacil, flupropanate, flupyrsulfuron, fluridone, flurochloridone,
fluroxypyr, fiurtamone, fluthiacet, fomesafen, foramsulfuron, fosamine, furyloxyfen,
glufosinate, glufosinate-P, glyphosate, halosafen, halosulfuron, haloxydine,
haloxyfop, haloxyfop-P, hexachloroacetone, hexaflurate, hexazinone,
imazamethabenz, imazamox, imazapic, imazapyr, imazaquin, imazethapyr,
imazosulfuron, indanofan, indaziflam, iodobonil, iodomethane, iodosulfuron,
iofensulfuron, ioxynil, ipazine, ipfencarbazone, iprymidam, isocarbamid, isocil,
isomethiozin, isonoruron, isopolinate, isopropalin, isoproturon, isouron, isoxaben,
isoxachlortole, isoxaflutole, isoxapyrifop, karbutilate, ketospiradox, lactofen,
lenacil, linuron, MAA, MAMA, MCPA, MCPA-thioethyl, MCPB, mecoprop,
mecoprop-P, medinoterb, mefenacet, mefiuidide, mesoprazine, mesosulfuron,
mesotrione, metam, metamifop, metamitron, metazachlor, metazosulfuron,
metflurazon, methabenzthiazuron, methalpropalin, methazole, methiobencarb,
methiozolin, methiuron, methometon, methoprotryne, methyl bromide, methyl
isothiocyanate, methyldymron, metobenzuron, metobromuron, metolachlor,
metosulam, metoxuron, metribuzin, metsulfuron, molinate, monalide, monisouron,
monochloroacetic acid, monolinuron, monuron, morfamquat, MSMA, naproanilide,
napropamide, naptalam, neburon, nicosulfuron, nipyraclofen, nitralin, nitrofen,
nitrofluorfen, norflurazon, noruron, OCH, orbencarb, rt/zo-dichlorobenzene,
orthosulfamuron, oryzalin, oxadiargyl, oxadiazon, oxapyrazon, oxasulfuron,
oxaziclomefone, oxyfluorfen, parafluron, paraquat, pebulate, pelargonic acid,
pendimethalin, penoxsulam, pentachlorophenol, pentanochlor, pentoxazone,
perfluidone, pethoxamid, phenisopham, phenmedipham, phenmedipham-ethyl,
phenobenzuron, phenylmercury acetate, picloram, picolinafen, pinoxaden,
piperophos, potassium arsenite, potassium azide, potassium cyanate, pretilachlor,
primisulfuron, procyazine, prodiamine, profluazol, profluralin, profoxydim,
proglinazine, prometon, prometryn, propachlor, propanil, propaquizafop, propazine,
propham, propisochlor, propoxycarbazone, propyrisulfuron, propyzamide,
prosulfalin, prosulfocarb, prosulfuron, proxan, prynachlor, pydanon, pyraclonil,
pyraflufen, pyrasulfotole, pyrazolynate, pyrazosulfuron, pyrazoxyfen, pyribenzoxim,
pyributicarb, pyriclor, pyridafol, pyridate, pyriftalid, pyriminobac, pyrimisulfan,
pyrithiobac, pyroxasulfone, pyroxsulam, quinclorac, quinmerac, quinoclamine,
quinonamid, quizalofop, quizalofop-P, rhodethanil, rimsulfuron, saflufenacil,
S-metolachlor, sebuthylazine, secbumeton, sethoxydim, siduron, simazine, simeton,
simetryn, SMA, sodium arsenite, sodium azide, sodium chlorate, sulcotrione,
sulfallate, sulfentrazone, sulfometuron, sulfosulfuron, sulfuric acid, sulglycapin,
swep, TCA, tebutam, tebuthiuron, tefuryltrione, tembotrione, tepraloxydim, terbacil,
terbucarb, terbuchlor, terbumeton, terbuthylazine, terbutryn, tetrafluron, thenylchlor,
thiazafluron, thiazopyr, thidiazimin, thidiazuron, thiencarbazone-methyl,
thifensulfuron, thiobencarb, tiocarbazil, tioclorim, topramezone, tralkoxydim,
triafamone, tri-allate, triasulfuiOn, triaziflam, tribenuron, tricamba, triclopyr,
tridiphane, trietazine, trifloxysulfuron, trifluralin, triflusulfuron, trifop, trifopsime,
trihydroxytriazine, trimeturon, tripropindan, tritac, tritosulfuron, vemolate and
xylachlor.
IV. Movement of soil-incorporatedpolymer-coated chemicals
Also provided are methods that take advantage of the finding that the
disappearance of an active compound (e.g., a pesticide, and a herbicide) from a zone of
soil can be reduced (or its retention and/or persistence increased) by applying the active
compound in a polymer-coated particulate composition. Some embodiments include
methods for decreasing the rate at which an active compound is leached from a target
zone. These and further embodiments also include methods for increasing the
persistence of an active compound in a target zone. In particular examples, a
polymer-coated particulate composition comprising a biologically active compound
may be suspended in water and applied to a target zone. In particular examples, a
target zone is an area of soil with a horizontal and a vertical dimension. A target zone
may have any size.
Soil consists of three different phases: a solid phase that contains mainly
minerals of varying sizes and organic compounds that accounts for approximately 20%
of the soil space, and liquid and gas phases that are contained within the total pore
space. The total pore space accounts for the remaining approximately 80% of the soil
space. There are three main categories of soil pores (i.e., macropores, mesopores, and
micropores) that all have different characteristics and contribute different attributes to
soils, depending on the number and frequency of each type of pore that occurs in a
particular soil.
Soils are classified according to the proportion of mineral particles of different
sizes present. The porosity of surface soil typically decreases as the particle size of the
soil increases, because of soil aggregate formation in fine-textured surface soils
subjected to soil biological processes. Aggregation typically involves particulate
adhesion and higher resistance to compaction. For the typical bulk density of sandy
soil (approximately between 1.5 and 1.7 g/cm3), the porosity is calculated to be
expected to be between 0.43 and 0.36. Typical bulk density of clay soil is between 1.1
and 1.3 g/cm3, which implies a porosity between 0.58 and 0.51. The porosity of
subsurface soil is lower than the porosity of surface soil due to compaction by gravity.
See, e.g., Brady and Weil, The Nature and Properties of Soils, 12th ed., Upper Saddle
River, NJ., Prentice-Hall, 1999.
With a few exceptions, the smaller the particles a soil is composed of, the
longer active compounds (e.g., pesticides) persist in it. This may be contrary to what
would be expected, since smaller soil particles imply increased porosity (see above).
Soil structure affects the leaching of active compounds (which decreases the
persistence of the compounds) because the pore size and pore size distribution greatly
affect the movement of water through soil. The way in which particle size and
structure influences persistence in soil is complex, because structure is also intimately
linked with such features as hydrogen ion concentration, organic matter and clay
content. For example, an active compound (e.g., a pesticide) may become absorbed on
to soil particles, thereby increasing the persistence of the compound. Mechanisms that
may be responsible for absorption in certain compound-soil combinations include:
physical adsorption; chemical adsorption (i.e., ion exchange or protonation); hydrogen
bonding; and coordination (metal complexes). In any one soil, several mechanisms or
combinations of mechanisms may exist with regard to a particular compound. Bailey
and White (1970) Res. Rev. 32:29.
In general, factors that may influence the amount of adsorption of active
compounds by soil colloids include: the physicochemical configuration of the soil
particles; the physicochemical configuration of the compound; the dissociation
constant of the compound; the water-solubility of the compound; the molecular size of
the compound; the soil acidity; temperature; the electrical potential of the soil clay
surface; the moisture content of the soil; and the compound formulation. Clay and
organic matter are two particular soil constituents that may influence the persistence of
pesticides in soils.
Clay particles are the smallest particles in soil (about 2 mh ), and soils with
more than 40% of clay particles are referred to as clay soils. Such soils have a much
larger internal reactive surface area than other soils, thus providing a greater surface
area for adsoiption of pesticides. There is a strong con-elation between the amount of
clay in a soil and the ability of the soil to bind and retain pesticides.
The amount of organic matter in particular soils may be, for example, from less
than about 1% to more than about 50%. Soil organic matter contributes to the
adsorption of pesticides, and there is a coi elation between the persistence of pesticides
in soils and the amount of organic matter in them. Most of soil organic matter consists
of humic compounds that have not been completely characterized, but do have a very
high cation exchange capacity. Humic compounds may have functional groups, for
example, carboxyl, amino, and phenolic hydroxyl, which may provide sites for
hydrogen bonding with certain pesticide molecules.
In view of the complexity of the aforementioned processes and systems, it is an
unanticipated result that a polymer-coated particulate composition persists longer in a
target zone than an uncoated particulate composition of the same type.
In some embodiments, a polymer-coated particulate composition comprising a
biologically active compound may be applied to a target zone by any method known to
those of skill in the art. For example, in particular embodiments, a polymer-coated
particulate composition may be applied by broadcast spraying, pre-emergent spray
application, post-emergent spray application, controlled droplet application, granule
application, dust application, aerial spraying, ultra-low volume spray application, crop
dusting, or seed treatment. In some embodiments, the polymer-coated particulate
composition may be applied to a target zone in a liquid suspension. In other
embodiments, the polymer-coated particulate composition may be applied in dry form.
Compositions applied in dry form may later be suspended in water, for example, by
rain water or irrigation.
One of the more common forms of chemical application, especially in
conventional agriculture, is spray application, such as, for example, application using
mechanical sprayers. Hydraulic sprayers that may be used to accomplish spray
application may consist of a tank, a pump, a lance (for single nozzles) or boom, and a
nozzle (or multiple nozzles). Sprayers may convert a chemical formulation (e.g., a
suspension of polymer-coated particles comprising an active compound), often
containing a mixture of a liquid carrier (e.g., water and fertilizer) and chemical, into
droplets. This conversion is accomplished by forcing the spray mixture through a
spray nozzle under pressure. The size of droplets produced during spraying may be
altered through the use of different nozzle sizes, by altering the pressure under which it
is forced, or a combination of the foregoing. Large droplets may have an advantage of
being less susceptible to "spray drift," but generally require more water per unit of
target area. Due to static electricity, small droplets may be able to maximize contact
with a target organism in the target area, but small droplets are susceptible to spray drift
(e.g., during application during periods of high wind).
Air-assisted or mist sprayers may be used for post-emergent pesticide
application to tall crops, such as tree fruit, where boom sprayers and aerial application
would be ineffective. Air-assisted sprayers inject a small amount of liquid into a
fast-moving stream of air, which break down large droplets into smaller droplets.
Foggers use a different method to fulfill a similar role to air-assisted sprayers in
producing particles of very small size. Whereas air-assisted sprayers create a
high-speed stream of air which can travel significant distances, foggers use a piston or
bellows to create a stagnant area of pesticide that is often used for enclosed areas, such
as houses and animal shelters.
Seed treatment represents a further category of application methods that may
achieve high effective dose-transfer efficiency in some embodiments. Seed treatment
generally comprises the application of an active compound to a seed prior to planting,
in the form of a seed treatment, or coating, to protect against soil-borne risks to the
plant. Compositions for seed treatment may additionally provide supplemental
chemicals and nutrients that encourage plant growth. A seed coating may include a
nutrient layer (containing, e.g., nitrogen, phosphorus, and potassium), a rhizobial layer
(containing, e.g., symbiotic bacteria and other beneficial microorganisms), and a
pesticide layer to make the seed less vulnerable to pests.
The following examples are provided to illustrate certain particular features
and/or embodiments. The examples should not be construed to limit the disclosure to
the particular features or embodiments exemplified.
EXAMPLES
Example 1: Polymer-coated particulate composition
A suspension concentrate (SC) of polymer-coated particles of the pesticide,
propyzamide, was prepared according to the composition shown in Table 2. The water
was added first to an appropriately sized container, followed by the wetting and
dispersing agents, and lastly the propyzamide technical material. The mixture was
stirred at 2000 rpm with a five-inch (12.7 cm) dispersing blade for 20 minutes using an
overhead mixer. The SC was then homogenized using a Silverson® L4RT-A with a
two-inch (5.08 cm) homogenizer probe for 30 minutes to improve consistency. The
homogenized mixture was then transferred to a 250 mL capacity media mill (Eiger
Machines Mini Motor Mill 250, Eiger Machines Inc.), where it was milled with 1.0
mm zirconium oxide beads at 5000 lpm until the particle size was reduced to 2.0-4.0
m h D(o.5). This SC (or another SC of similar composition) was used to prepare all of
the listed spray-dried wettable powder (WP) formulations.
Each spray-dried formulation was prepared by adding the milled propyzamide
SC to a container of suitable volume, and adding in the wetting agents, dispersing
agents, binders, and an appropriate amount of DI water to make the suspension 25%
solid content by weight. The resultant slurry was mixed with an IKA® EuroStar power
control-vise 6000 with a two-inch (5.08 cm) dispersing blade. After stirring for 10
minutes at 500 rpm, the formulation was homogenized with a Silverson® L4RT-A for
10 minutes at 5000 rpm. Once homogenized, the formulation was spray-dried with a
Biichi™ B-290 Mini Spray Dryer outfitted with an Orion SAGE model 365 syringe
pump to deliver the slurry into the spray dyer at a controlled rate of 200-400 mL/hour.
The inlet temperature was in the range of 135°C to 165°C, and the outlet temperature
was in the range of 80°C to 99°C. The aspirator was set to 100%. After all of the
slurry was run through the spray dryer, the spray dryer was allowed to cool to ambient
temperature, and then the sample was collected typically in a powder form in the
collector container below a cyclone chamber. The sample powder was then assayed
for propyzamide concentration, and stored in glass jars for further evaluation.
Table 2 : Propyzamide Suspension Concentrate
The compositions of polymer-coated propyzamide formulations were provided
Tables 3-10. A description of the co-formulant materials is provided in Table 11.
Table 3 : Compositions containing UCAR® 379G Latex
Table 4: Compositions containing UCAR® 627
Table 5: Compositions containing NEOCAR® 820
Material #14 #15 #16 #17
Propyzamide AI 77.91% 81.09% 8 1.88% 79.38%
Impurities from technical grade
4.10 4.26 4.3 4.17
Propyzamide
GEROPON® SDS 0.90 0.94 0.95 0.92
Borresperse Na 9.40 9.86 9.96 9.65
MORWET® D-425 2.63 2.76 2.79 2.70
NEOCAR® 820 5.06 1.08 0.12 3.1 7
Table 6: Compositions containing NEOCAR® 2300
Table 7: Composition containing UCAR® 418
Table 8: Compositions containing PVP/PVA polymers and co-polymers
Table 9: Composition containing PVOH polymers
Material #26
Propyzamide AI 77.74%
Impurities from technical grade Propyzamide 4.09
GEROPON® SDS 0.90
Borresperse Na 9.45
MORWET® D-425 2.65
CELVOL® 205 5.18
Table 10: Compositions containing starch, biopolymers, or derivatives
Table 11: Description of co-formulant materials used in formulations
Purchased
Material Properties Description
from
GEROPON® SDS Wetting agent Dioctyl Sodium Sulfosuccinate Rhodia
REAX® 88A Dispersing agent Lignosulfonate MeadWestvaco
Borregaard
Borresperse Na Dispersing agent Lignosulfonate
Lignotech
MORWET® D-425 Wetting agent Naphthalene sulfonate Akzo-Nobel
2-[methyl[(9Z)- 1-oxo-9-octadecen-
GEROPON® T-77 Wetting agent 1-yl]amino]- ethanesulfonic acid, Rhodia
Na salt
Block Co-polymer of Polyethylene
PLURONIC® P-105 Wetting agent BASF
Oxide and Polypropylene Oxide
Magnetics
Fe20 3 Carrier/filler Iron (III) Oxide International,
Inc.
PERGOPAK® M Carrier/filler Polyurea Albamarle
Binder/encapsulating
UCAR® 379G Vinyl-Acrylic Latex Dow Chemical
material
Binder/encapsulating
UCAR® 627 100% Acrylic Latex Dow Chemical
material
Binder/encapsulating
UCAR® 4 18 Cationic Latex Dow Chemical
material
Binder/encapsulating
NEOCAR® 820 Acrylic Latex Dow Chemical
material
Binder/encapsulating
NEOCAR® 2300 Vinyl-Acrylic Latex Dow Chemical
material
Binder/encapsulating Polyvinylpyrrolidone/Polyvinyl-
AGRIMER® VA 3E ISP International
material acetate Co-polymer
Binder/encapsulating Polyvinylpyrrolidone/Polyvinyl-
AGRIMER® VA 6 ISP International
material acetate Co-polymer
Binder/encapsulating
AGRIMER® 30 Polyvinylpyrrolidone ISP International
material
Purchased
Material Properties Description
from
Binder/encapsulating Polyvinylacetate with 88%
CELVOL® 205 Celanese
material Hydrolysis
Binder/encapsulating
Methocel™ 4M Hydroxypropyl Methylcellulose Dow Chemical
material
Binder/encapsulating
Chitosan Chitosan Sigma Aldrich
material
Binder/encapsulating
Sodium Alginate Sodium Alginate Sigma Aldrich
material
Lyckeby Culinar AB Binder/encapsulating
Water-soluble Starch Lcykeby Culinar
Starch material
Example 2: Increased retention of active ingredients in a soil zone
Polymer-coated particulate compositions comprising propyzamide as an active
ingredient showed improved retention and residue of propyzamide in the soil zone to
which the polymer-coated particles were applied; i.e., the top layer of soil, which is the
most effective biological control zone. The compositions for the three formulations
that were used in these experiments, composition #8 and composition #10, and Kerb™
50W are listed in Table 12.
Table 12. Compositions used in field trials
Composition
Materials Kerb™ 50W Composition #8
#10
Propyzamide 50.5% 69.44% 77.99%
Calcium Lignosulfonate 5% - -
Tamol 731 SD 1% - -
Triton X-120 AG 0.5% - -
Kaolin P300 Clay 43% - -
- -
Borresperse Na - 8.68% 9.38%
MORWET® D-425 - 2.43% 2.63%
UCAR® 627 - 15.00% 5.00%
GEROPON® SDS - 0.80% 0.90%
Impurities from Technical
- 3.65% 4.10%
Material
Table 13 shows the average concentration of propyzamide in micrograms per
gram of soil in the top 1 inch (2.54 cm) of soil. These data represent the average of
several soil cores taken from a field trial that were analyzed at the specified depths for
propyzamide concentration. These data show that the coated formulations,
composition #10 and composition #8 provided a significantly higher concentration of
propyzamide in the top 1 inch (2.54 cm) of soil compared to the uncoated,
commercially available propyzamide particle product Kerb™ 50W.
Field Trial Protocol
Field trials were conducted in California under bare ground conditions using
standard herbicide small plot research methodology. Plot size was 7 x 20 feet (2.13 x
6.09 m). Prior to applying the treatments, trial area preparation was completed using
normal agricultural procedures to destroy existing vegetation and prepare the soil for
the herbicide applications. All treatments were applied pre-emergence to weed
germination. The trial site was irrigated to activate the treatments and to move the
propyzamide active ingredient into the soil. There were four replicates per treatment.
All treatments in the field trial were applied by calculating the active
ingredient rate applied on an area basis and then mixing each treatment separately in
water and applying at a spray volume of 20 gallons per acre (187 L/ha). Treatments
were applied with a C0 2 backpack sprayer using turbojet spray nozzles at a spray
pressure of 30 psi (2.07 Bar; 2.1 1 kg/cm). Treatments were rated as compared to the
untreated control plots.
The treated plots and control plots were rated blind at various intervals after
application. Ratings were based of percent (%) visual weed control, where 0%
corresponds to no control and 100% corresponds to complete kill. After rating was
completed, plots were sampled with a mechanical tractor powered soil sampler using
standard soil sampling procedures and methodologies using plastic tube inserted into
soil sampling probe. Each soil sample was taken to a depth of 18 inches (45.72 cm).
Immediately upon sampling, soil cores were placed in a freezer and maintained
frozen until processed.
Table 13: Herbicidal Efficacy of Formulations
Table 13 shows data demonstrating the average control (%) of CAPBP
{Capsella bura-pastoris (Shepherd's purse)) 76 days after application of several
polymer-coated propyzamide formulations (Compositions #8 and #10, respectively,
and a control non-coated propyzamide formulation (Kerb 50WP). Data were collected
for three application rates of each formulation as measured for control of Shepherds
purse {Capsella bursa-pastoris), Annual bluegrass (Poa annua), and Chickweed
(Stellaria media).
Analytical Method for the Determination of Propyzamide from soil cores
Preparation of Standard Solutions:
A standard stock solution was prepared by weighing approximately 25.5 mg of
propyzamide analytical standard (TSN1 05825, purity 98.2%) into a 25 ml volumetric
flask and filling to volume with methanol. Concentration was approx. 1000
micrograms/ml. Using the standard stock solution, six working standards were
prepared by serial dilutions in methanol yielding concentrations of 0.25, 0.5, 1, 5, 10
and 20 micrograms/ml.
Sample preparation for propyzamide soil cores. To prepare the soil cores for
analysis they had to be thawed in advance for 45-60 minutes. During this time, 250
mLjars were weighed. Once the core was thawed it was sectioned off and each section
was placed into a 250 mL jar. The jars were then weighed again to determine the
actual weight of the soil segment. Once weighed, 200 mL of methanol was added to
each jar. The jars were then sonicated for 15 minutes and shaken for 45 minutes at 200
rpm. After the shaking was complete, the jars were allowed to settle for 15 minutes
before an aliquot was taken with a plastic syringe. The aliquot was filtered through a
0.45 m nylon filter into an autosampler vial for HPLC analysis.
Chromatographic conditions:
Instrument: HPLC Agilent 100
Column: Phenomenex Luna C18 (150 x 4.6 mm) 3um S/N 302448
Mobile phase: Isocratic: 80% Acetonitrile: 20% Acetic Acid in water 0.4%
v/v.
Flow rate: 1 ml/min.
Detection: 230 nm.
Temperature: 25 C.
Injection volume: 10 m .
Table 14. Propyzamide retention in the top one inch (2.54 cm) of soil
While the invention may be susceptible to various modifications and alternative
forms, specific embodiments have been shown by way of example in the drawings and
have been described in detail herein. However, it should be understood that the
invention is not intended to be limited to the particular forms disclosed. Rather, the
invention is to cover all modifications, equivalents, and alternatives falling within the
scope of the invention as defined by the following appended claims and their legal
equivalents.
CLAIMS
What may be claimed is:
1. A polymer-coated particulate composition comprising a biologically
active compound.
2. The polymer-coated particulate composition of claim 1, wherein the
biologically active compound is a pesticide.
3. The polymer-coated particulate composition of claim 2, wherein the
biologically active compound is propyzamide.
4. The polymer-coated particulate composition of claim 1, comprising
particles of the biologically active compound that are between about 0.1 and about 100
microns in diameter.
5. The polymer-coated particulate composition of claim 4, comprising
particles of the biologically active compound are between about 1 and about 30
microns in diameter.
6. The polymer-coated particulate composition of claim 4, wherein
essentially all of the particles of the biologically active compound are between about
0.1 and about 100 microns in diameter.
7. The polymer-coated particulate composition of claim 4, wherein the
particles of the biologically active compound have a median diameter of about 0.5
microns to about lOOmicrons.
8. The polymer-coated particulate composition of claim 1, wherein the
composition comprises particles that consist of the biologically active compound and a
polymer coating.
9. The polymer-coated particulate composition of claim 1, wherein the
composition comprises particles that comprise the biologically active compound and a
polymer coating.
10. The polymer-coated particulate composition of claim 9, wherein the
composition comprises particles that comprise the biologically active compound, a
polymer coating, and at least one additional material.
11. The polymer-coated particulate composition of claim 1, wherein the
biologically active compound is a technical material.
1 . The polymer-coated particulate composition of claim 1, wherein the
biologically active compound is a solid.
13. The polymer-coated particulate composition of claim 1, wherein the
biologically active compound is not a solid.
14. The polymer-coated particulate composition of claim 13, wherein the
composition comprises composite particles that comprise the biologically active
compound and at least one additional material making the composite particle a solid,
and a polymer coating.
15. The polymer-coated particulate composition of claim 9, wherein the
polymer is a hydrophobic polymer.
16. The polymer-coated particulate composition of claim 15, wherein the
polymer is a latex polymer.
17. The polymer-coated particulate composition of claim 15, wherein the
polymer is a polymer that is not readily soluble in water.
18. The polymer-coated particulate composition of claim 17, wherein the
polymer is an essentially water-insoluble polymer.
19. The polymer-coated particulate composition of claim 18, wherein the
polymer is a water-insoluble polymer.
20. The polymer-coated particulate composition of claim 9, wherein the
polymer is selected from a group comprising the binders/encapsulating agents listed in
Table 1.
21. The polymer-coated particulate composition of claim 10, wherein the at
least one additional material is selected from a group comprising wetting agents,
dispersing agents, carriers, and fillers.
22. The polymer-coated particulate composition of claim 21, wherein the at
least one additional material is selected from a group comprising dioctyl sodium
sulfosuccinate, a lignosulfonate, a naphthalene sulfonate, a
2-[methyl[(9Z)-l-oxo-9-octadecen-l-yl] amino]-ethanesulfonic acid salt, a
polypropylene oxide, a polyethylene oxide, a block co-polymer of polypropylene oxide
and polyethylene oxide, iron (III) oxide, and a polyurea.
23. A formulation comprising the polymer-coated particulate composition
of claim .
24. The formulation of claim 23, wherein the formulation is a liquid
suspension.
25. The formulation of claim 23, wherein the formulation is selected from
the group consisting of a water dispersible granule, a suspension concentrate, and a
wettable powder.
26. The formulation of claim 23, further comprising at least one compatible
ingredient selected from the group consisting of surfactants, thickeners, dispersants,
presei-vatives, stabilizers, buffers, propylene glycol, self-emulsifiable esters, liquid
carriers, fillers, dyes, fragrances, viscosity-lowering additives, freeze-point depressants,
and other biologically active compounds.
27. The formulation of claim 23, wherein the formulation is suitable for soil
application to a target zone.
28. The formulation of claim 27, wherein the biologically active compound
persists longer in the target zone when it is applied than the compound persists when it
is applied in a formulation comprising non-polymer coated particles.
29. The formulation of claim 27, wherein the biologically active compound
moves more slowly from the target zone when it is applied than the compound moves
from the target zone when it is applied in a formulation comprising non-polymer
coated particles.
30. A method for producing the polymer-coated particulate composition of
claim 1, the method comprising:
providing the biologically active compound in a solid particulate composition;
and
adhering a polymer to the solid particulate composition.
31. The method according to claim 30, wherein the biologically active
compound is a solid particulate material.
32. The method according to claim 30, wherein the biologically active
compound is not a solid material, wherein the solid particulate composition is a
composite composition comprising at least one additional material.
33. The method according to claim 30, wherein the solid particulate
composition comprises particles that are milled to a particle size of between about 0.1
microns and about 100 microns.
34. The method according to claim 30, wherein adhering the polymer to the
solid particulate composition is through a spray-dry process.
35. The method according to claim 34, wherein the spray-dry process
comprises mixing the polymer and the solid particulate composition to form a
suspension.
36. The method according to claim 35, wherein the spray-dry process
further comprises passing the suspension through a spray dryer to produce a powder
comprising the biologically active compound and the polymer.
37. The method according to claim 30, wherein the biologically active
compound is a pesticide.
38. A method for decreasing the rate at which a biologically active
compound disappears from a target zone, comprising applying the polymer-coated
particulate composition of claim 1 to the target zone, wherein disappearance of the
biologically active compound from the target zone is reduced compared to
disappearance of the biologically active compound from the target zone when applied
in a non-polymer coated particulate composition.
39. The method according to claim 38, wherein the target zone is a zone of
soil with a vertical dimension and a horizontal dimension.
40. The method according to claim 39, wherein the vertical dimension is
two inches (5.08 cm) of soil.
41. A method for increasing the persistence of a biologically active
compound in a target zone, comprising applying the polymer-coated particulate
composition of claim 1 to the target zone, wherein persistence of the biologically active
compound in the target zone is increased compared to persistence of the biologically
active compound in the target zone when applied in a non-polymer coated particulate
composition.