U.S. patent application number 11/109131 was filed with the patent office on 2005-09-08 for method of controlling the release of agricultural active ingredients from treated plant seeds.
This patent application is currently assigned to Monsanto Technology, L.L.C.. Invention is credited to Asrar, Jawed, Ding, Yiwei.
Application Number | 20050197251 11/109131 |
Document ID | / |
Family ID | 23061159 |
Filed Date | 2005-09-08 |
United States Patent
Application |
20050197251 |
Kind Code |
A1 |
Ding, Yiwei ; et
al. |
September 8, 2005 |
Method of controlling the release of agricultural active
ingredients from treated plant seeds
Abstract
A method of controlling the release rate of an agricultural
active ingredient from a seed that has been treated with that
active includes providing a seed that has been treated with the
active ingredient, applying to the treated seed a film that
includes an emulsion of a polymer in a liquid in which both the
agricultural active ingredient and the polymer have low levels of
solubility, and then curing the film to form a water insoluble
polymer coating on the surface of the treated seed. Seeds that have
been treated by this method are also provided.
Inventors: |
Ding, Yiwei; (Ballwin,
MO) ; Asrar, Jawed; (Chesterfield, MO) |
Correspondence
Address: |
NELSON MULLINS RILEY & SCARBOROUGH, LLP
1320 MAIN STREET-17TH FLOOR
COLUMBIA
SC
29201
US
|
Assignee: |
Monsanto Technology, L.L.C.
St. Louis
MO
|
Family ID: |
23061159 |
Appl. No.: |
11/109131 |
Filed: |
April 19, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11109131 |
Apr 19, 2005 |
|
|
|
10079000 |
Feb 18, 2002 |
|
|
|
60277503 |
Mar 21, 2001 |
|
|
|
Current U.S.
Class: |
504/100 |
Current CPC
Class: |
A01N 43/653 20130101;
A01N 25/26 20130101; A01N 51/00 20130101; A01N 43/653 20130101;
A01N 25/10 20130101; A01N 25/10 20130101; A01N 25/10 20130101; A01N
51/00 20130101; A01N 2300/00 20130101; A01N 25/34 20130101; A01N
25/34 20130101; A01N 2300/00 20130101; A01N 51/00 20130101; A01C
1/06 20130101; A01N 25/26 20130101; A01N 51/00 20130101; A01N
43/653 20130101; A01N 51/00 20130101; A01N 25/34 20130101; A01N
25/10 20130101 |
Class at
Publication: |
504/100 |
International
Class: |
A01N 025/26; A01N
035/00 |
Claims
1. A method of controlling the release rate of an agricultural
active ingredient from a seed treated with the active ingredient,
the method comprising the steps of: providing a seed that has been
treated with an agricultural active ingredient; applying to the
treated seed a film comprising an emulsion of a polymer in a liquid
in which both the agricultural active ingredient and the polymer
have low levels of solubility; and curing the film to form a water
insoluble polymer coating on the surface of the treated seed.
2. The method according to claim 1, wherein the liquid is
water.
3. The method according to claim 2, wherein the ratio of the weight
of the film to the weight of the treated seed is from about 1:10 to
about 1:50, and the weight percent of the polymer in the film at
the time the film is applied to the seed is from about 0.5 percent
to about 25 percent.
4. The method according to claim 3, wherein the ratio of the weight
of the film to the weight of the treated seed is from about 1:16 to
about 1:22, and the weight percent of the polymer in the film at
the time the film is applied to the seed is from about 4 percent to
about 15 percent.
5. The method according to claim 4, wherein the ratio of the weight
of the film to the weight of the treated seed is from about 1:18 to
about 1:21, and the weight percent of the polymer in the film at
the time the film is applied to the seed is from about 5 percent to
about 11 percent.
6. The method according to claim 2, wherein the film additionally
comprises a non-migrating surfactant.
7. The method according to claim 6, wherein the water insoluble
polymer and the non-migrating surfactant and the relative amounts
of each are selected so that the polymer coating that is formed
from the water insoluble polymer and the non-migrating surfactant
has a glass transition temperature within a pre-selected range,
thereby providing a coating which retards the release rate of the
agricultural active ingredient from the seed by a desired
amount.
8. The method according to claim 7, wherein the glass transition
temperature of the polymer coating is within the range of from
about -5.degree. C. to about 75.degree. C.
9. The method according to claim 8, wherein the glass transition
temperature of the polymer coating is within the range of from
about 10.degree. C. to about 50.degree. C.
10. The method according to claim 9, wherein the glass transition
temperature of the polymer coating is within the range of from
about 15.degree. C. to about 40.degree. C.
11. The method according to claim 10, wherein the glass transition
temperature of the polymer coating is within the range of from
about 15.degree. C. to about 25.degree. C.
12. The method according to claim 3, wherein the agricultural
active ingredient is a pesticide.
13. The method according to claim 12, wherein the pesticide is
selected from the group consisting of herbicides, insecticides,
acaracides, fungicides, nematocides, and bactericides.
14. The method according to claim 13, wherein the agricultural
active ingredient is an insecticide.
15. The method according to claim 14, wherein the agricultural
active ingredient is selected from the group consisting of
pyrethrins including,
2-allyl-4-hydroxy-3-methyl-2-cyclopenten-1-one ester of
2,2-dimethyl-3-(2methyl propenyl)-cyclopropane carboxylic acid,
and/or (2-methyl-1-propenyl)-2-methoxy-4-oxo-3-(2
propenyl)-2-cyclopenten-1-yl ester and mixtures of cis and trans
isomers thereof; synthetic pyrethroids including
(s)-cyano(3-phenoxyphenyl)methyl-4-chloro-alpha-(1--
methylethyl)benzeneacetate (fenvalerate), (S)-cyano
(3-phenoxyphenyl)methyl
(S)-4-chloro-alpha-(1-methylethyl)benzeneacetate (esfenvalerate),
(3-phenoxyphenyl)-methyl(+)cis-trans-3-(2,2-dichoroethen-
yl)-2,2-dimethylcyclopropanecarboxylate (permethrin), (.+-.)
alpha-cyano-(3-phenoxyphenyl)methyl(+)-cis,trans-3-(2,2-dichloroethenyl)--
2,2-dimethyl-cyclopropanecarboxylate (cypermethrin),
beta-cypermethrin, theta cypermethrin, S-cyano
(3-phenoxyphenyl)methyl (.+-.) cis/trans
3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate
(zeta-cypermethrin), (s)-alpha-cyano-3-phenoxybenzyl
(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate
(deltamethrin), alpha-cyano-3-phenoxybenzyl-2,2,3,3,-tetramethyl
cyclopropoanecarboxylate (fenpropathrin),
(RS)-alpha-cyano-3-phenoxybenzy-
l(R)-2-[2-chloro-4-(trifluoromethyl)anilino]-3-methylbutanoate
(tau-fluvalinate),
(2,3,5,6-tetrafluoro-4-methylphenyl)-methyl-(1-alpha,
3-alpha)-(Z)-(.+-.)-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylc-
yclopropanecarboxylate (tefluthrin), (.+-.)-cyano-(3-phenoxyphenyl)
methyl
(.+-.)-4-(difluoromethoxy)-alpha-(1-methylethyl)benzeneacetate
(flucythrinate), cyano(4-fluoro-3-phenoxyphenyl)methyl
3-[2-chloro-2-(4-chlorophenyl)ethenyl]-2,2-dimethylcyclopropanecarboxylat-
e (flumethrin), cyano(4-fluoro-3-phenoxyphenyl)methyl
3-(2,2-dichloroethenyl)-2,2-dimethyl-cyclopropanedarboxylate
(cyfluthrin), beta cyfluthrin, transfluthrin,
(S)-alpha-cyano-3-phenoxybe-
nzyl(Z)-(1R-cis)-2,2-dimethyl-3-[2-(2,2,2-trifluoro-trifluoromethyl-ethoxy-
carbonyl)vinyl]cyclopropane carboxylate (acrinathrin), (1R cis) S
and (1S cis) R enantiomer isomer pair of
alpha-cyano-3-phenoxybenzyl-3-(2,2-dichl-
orovinyl)-2,2-dimethylcyclopropanecarboxylate (alpha-cypermethrin),
[1R,3S)3(1'RS)(1',2',2',2'-tetrabromoethyl)]-2,2-dimethyl
cyclopropanecarboxylic acid (s)-alpha-cyano-3-phenoxybenzyl ester
(tralomethrin),
cyano-(3-phenoxyphenyl)methyl-2,2-dichloro-1-(4-ethoxyphe-
nyl)cyclopropanecarboxylate (cycloprothrin), [1.alpha.,
3.alpha.(Z)]-(.+-.)-cyano-(3-phenoxyphenyl)methyl-3-(2-chloro-3,3,3-trifl-
uoro-1-propenyl)-2,2-cimethylcyclopropanecarboxylate (cyhalothrin),
[1-alpha (s),
3-alpha(z)]-cyano(3-phenoxyphenyl)methyl-3-(2-chloro-3,3,3--
trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate (lambda
cyhalothrin), (2-methyl
[1,1'-biphenyl]-3-yl)methyl-3-(2-chloro-3,3,3-tri-
fluoro-1-propenyl)-2,2-dimethyl-cyclopropanecarboxylate
(bifenthrin), 5-1-benzyl-3-furylmethyl-d-cis(1R,3S,
E)2,2-dimethyl-3-(2-oxo,-2,2,4,5-te-
trahydrothiophenylidenemethyl)cyclopropane carboxylate (kadethrin),
[5-(phenylmethyl)-3-furanyl]-3-furanyl
2,2-dimethyl-3-(2-methyl-1-propeny- l)cyclopropanecarboxylate
(resmethrin). (1R-trans)-[5-(phenylmethyl)-3-fur- anyl]methyl
2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate
(bioresmethrin),
3,4,5,6-tetrahydro-phthalimidomethyl-(1RS)-cis-trans-chr-
ysanthemate (tetramethrin), 3-phenoxybenzyl-d,1-cis,trans
2,2-dimethyl-3-(2-methylpropenyl)cyclopropanecarboxylate
(phenothrin), empenthrin, cyphenothrin, prallethrin, imiprothrin,
(RS)-3-allyl-2-methyl-4-oxcyclopent-2-enyl-(1S,3R;
1R,3S)-2,2-dimethyl-3-(2-methylprop-1-enyl) cyclopropane
carboxylate (allethrin), bioallethrin, and ZXI8901; oxadiazine
derivatives including
5-(2-chloropyrid-5-ylmethyl)-3-methyl-4-nitroiminoperhydro-1,3,5-oxadiazi-
ne,
5-(2-chlorothiazol-5-ylmethyl)-3-methyl-4-nitroiminoperhydro-1,3,5-oxa-
diazine,
3-methyl-4-nitroimino-5-(1-oxido-3-pyridinomethyl)perhydro-1,3,5--
oxadiazine,
5-(2-chloro-1-oxido-5-pyridiniomethyl)-3-methyl-4-nitroiminope-
rhydro-1,3,5-oxidiazine,
3-methyl-5-(2-methylpyrid-5-ylmethyl)-4-nitroimin-
operhydro-1,3,5-oxadiazine, and thiamethoxam; chloronicotinyl
insecticides including acetamiprid
((E)-N-[(6-chloro-3-pyridinyl)methyl]-N'-cyano-N-me-
thyleneimidamide), imidacloprid
(1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-- 2-imidazolidinimime),
and nitenpyram (N-[(6-chloro-3-pyridinyl)methyl]-N-e-
thyl-N'-methyl-2-nitro-1,1-ethenediamine); nitroguanidine,
including TI-435; pyrroles; pyrazoles chlorfenapyr
(4-bromo-2-(4-chlorophenyl)-1-et-
hoxymethyl-5-trifluoromethylpyrrole-3-carbonitrile), fenpyroximate
((E)-1,1-dimethylethyl-4[[[[(1,3-dimethyl-5-phenoxy-1H-pyrazole-4-yl)meth-
ylene]amino]oxy]methyl]benzoate), and tebufenpyrad
(4-chloro-N[[4-1,1-dime-
thylethyl)phenyl]methyl]-3-ethyl-1-methyl-1H-pyrazole-5-carboxamide);
phenyl pyrazoles including fipronil
(5-amino-[2,6-dichloro-4-(trifluorome-
thyl)phenyl]-4-[(1R,S)-(trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitri-
le); diacylhydrazines including halofenozide
(4-chlorobenzoate-2-benzoyl-2- -(1,1-dimethylethyl)-hydrazide),
methoxyfenozide (RH-2485,
N-tert-butyl-N'-(3-methoxy-o-toluoyl)-3,5-xylohydrazide), and
tebufenozide (3,5-dimethylbenzoic acid
1-(1,1-dimethylethyl)-2,(4-ethylbe- nzoyl)hydrazide); triazoles
including amitrole and triazamate; biological/fermentation products
including avermectin (abamectin) and spinosad (XDE-105);
organophosphate insecticides including acephate, chlorpyrifos,
chlorpyrifos-methyl, diazinon, fenamiphos, and malathion; and
carbamate insecticides including aldicarb, carbaryl, carbofuran,
oxamyl, and thiodicarb.
16. The method according to claim 15, wherein the agricultural
active ingredient is imidacloprid.
17. The method according to claim 13, wherein the agricultural
active is a fungicide selected from the group consisting of
tebuconazole, simeconazole, fludioxonil, fluquinconazole,
difenoconazole,
4,5-dimethyl-N-(2-propenyl)-2-(trimethylsilyl)-3-thiophenecarboxamide
(silthiopham), hexaconazole, etaconazole, propiconazole,
triticonazole, flutriafol, epoxiconazole, fenbuconazole,
bromuconazole, penconazole, imazalil, tetraconazole, flusilazole,
metconazole, diniconazole, myclobutanil, triadimenol, bitertanol,
pyremethanil, cyprodinil, tridemorph, fenpropimorph,
kresoxim-methyl, azoxystrobin, ZEN90160, fenpiclonil, benalaxyl,
furalaxyl, metalaxyl, R-metalaxyl, orfurace, oxadixyl, carboxin,
prochloraz, trifulmizole, pyrifenox, acibenzolar-5-methyl,
chlorothalonil, cymoaxnil, dimethomorph, famoxadone, quinoxyfen,
fenpropidine, spiroxamine, triazoxide, BAS50001F, hymexazole,
pencycuron, fenamidone, guazatine, and cyproconazole.
18. The method according to claim 6, wherein the film substantially
covers the surface of the seed.
19. The method according to claim 15, wherein the step of providing
a seed that has been treated with an agricultural active ingredient
comprises treating the seed with the agricultural active
ingredient.
20. The method according to claim 19, wherein the step of treating
the seed with the agricultural active ingredient comprises
contacting the seed with the active prior to applying the film
comprising an emulsion of a polymer in water.
21. The method according to claim 20, wherein the amount of active
that is applied to the seed is between about 0.5 gm of active
ingredient/100 kg of seed and 1000 gm/100 kg of seed.
22. The method according to claim 20, wherein the amount of active
that is applied to the seed is between about 25 gm of active/100 kg
of seed and 600 gm/100 kg of seed.
23. The method according to claim 22, wherein the amount of active
that is applied to the seed is between 50 gm/100 kg of seed and 400
gm/100 kg of seed.
24. The method according to claim 21, wherein the active is applied
to the seed in the form of a liquid suspension.
25. The method according to claim 24, wherein the active is present
in the liquid suspension in the form of particles having an average
size of less than about 10 microns.
26. The method according to claim 25, wherein the active is present
in the liquid suspension in the form of particles having an average
size of less than about 2 microns.
27. The method according to claim 25, wherein the active is present
in the liquid suspension in a concentration of between about 0.1%
and about 50%, by weight.
28. The method according to claim 27, wherein the active is present
in the liquid suspension in a concentration of between about 0.5%
and 15%, by weight.
29. The method according to claim 28, wherein the active is present
in the liquid suspension in a concentration of between about 1% and
3%, by weight.
30. The method according to claim 1, wherein the liquid is
non-aqueous.
31. The method according to claim 1, wherein the liquid is an
aqueous/non-aqueous mixture.
32. The method according to claim 2, wherein the seed is the seed
of a plant selected from the group consisting of corn, peanut,
canola/rapeseed, soybean, curcubits, cotton, rice, sorghum, sugar
beet, wheat, barley, rye, sunflower, tomato, sugarcane, tobacco,
oats, vegetables, and leaf crops.
33. The method according to claim 32, wherein the seed has a
transgenic event.
34. The method according to claim 2, wherein the polymer is
selected from the group consisting of polyesters, polycarbonates,
co-polymers of styrene, and mixtures thereof.
35. The method according to claim 2, wherein the polymer is
selected from the group consisting of
acrylonitrile-butadiene-styrene terpolymer (ABS); ABS modified
polyvinylchloride; ABS-polycarbonate blends; acrylic resins and
co-polymers: poly(methacrylate), poly(ethylmethacrylate),
poly(methylmethacrylate), methylmethacrylate or ethylmethacrylate
copolymers with other unsaturated monomers; casein; cellulosic
polymers: ethyl cellulose, cellulose acetate, cellulose
acetatebutyrate; ethylene vinyl acetate polymers and copolymers;
poly(ethylene glycol); poly(vinylpyrrolidone); acetylated mono-,
di-, and tri-glycerides; poly(phosphazene); chlorinated natural
rubber; polybutadiene; polyurethane; vinylidene chloride polymers
and copolymers; styrene-butadiene copolymers; styrene-acrylic
copolymers; alkylvinylether polymers and copolymers; cellulose
acetate phthalates; epoxies; ethylene copolymers: ethylene-vinyl
acetate-methacrylic acid, ethylene-acrylic acid copolymers;
methylpentene polymers; modified phenylene oxides; polyamides;
melamine formaldehydes; phenolformaldehydes; phenolic resins;
poly(orthoesters); poly(cyanoacrylates); polydioxanone;
polycarbonates; polyesters; polystyrene; polystyrene copolymers:
poly(styrene-co maleic anhydride); urea-formaldehyde; urethanes;
vinyl resins: vinyl chloride-vinyl acetate copolymers, polyvinyl
chloride and mixtures of two or more of these.
36. The method according to claim 2, wherein the polymer is
biodegradable and is selected from the group consisting of
biodegradable polyesters; starch-polyester alloys; starch;
starch-PCL blends; polylactic acid (PLA)-starch blends; polylactic
acid; poly(lactic acid-glycolic acid) copolymers; PCL; cellulose
esters; cellulose acetate butyrate; starch esters; starch
ester-aliphatic polyester blends; modified corn starch;
polycaprolactone; poly(n-amylmethacrylate); ethyl cellulose; wood
rosin; polyanhydrides; polyvinylalcohol (PVOH);
polyhydroxybutyrate-valerate (PHBV); biodegradable aliphatic
polyesters; polyhydroxybutyrate (PHB), and biodegradable aliphatic
polyester (BIONOLLE).
37. The method according to claim 6, wherein the non-migrating
surfactant is selected from the group consisting of diallyl amine
pluronics, linoleic alcohol derivatives, allyl alkyl phenol
derivatives, acrylate derivatives, allyl alcohol alkenyl succinic
anhydride derivatives, maleic derivatives, and Trem LF-40 allyl
sulfosuccinate derivatives.
38. A treated seed that is coated by the method of claim 1.
39. The seed of claim 38, wherein the seed is a cotton seed or a
corn seed.
40. A method of protection of a seed comprising treating the seed
by the method of claim 1.
Description
[0001] The present application claims the benefit of U.S.
Provisional Application Ser. No. 60/277,503 filed Mar. 21, 2001,
which is incorporated herein by reference thereto.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to methods for controlling the
release of agricultural active ingredients from treated plant
seeds, and more particularly to methods for controlling the release
of agricultural active ingredients from treated plant seeds by the
use of seed coatings.
[0004] 2. Description of Related Art
[0005] The development and use of pesticides has increased the
yield of most agronomically important plants. Pesticides, including
herbicides, insecticides, nematocides, acaracides, fungicides,
bactericides, and the like, are now widely applied to soils prior
to, during, or after seed planting, or are applied directly or
indirectly to growing plants at various times during the growing
season.
[0006] Widespread use of pesticides has not been without problems,
however, due to the wide spectrum of activity and high toxicity of
some pesticides. Such negative results have been exacerbated by the
widespread distribution of pesticides in the environment through
such vectors as runoff, wind-drift, leaching, animal activity and
the like. This type of movement of pesticides away their point of
application and target of activity also requires that higher levels
of the pesticide be used in order to insure that the application
provides the desired pesticidal activity for the desired period of
time that it is required.
[0007] One method that has been found to be promising in some
applications is the treatment of plant seeds with pesticides.
General information on this subject is provided in, for example,
Chemtech, 8.284-287 (May 1978). In situations where seed treatment
is effective, it can reduce the amount of pesticide that is
required to obtain a desired level of activity. Other advantages of
direct, pre-planting seed treatment include reducing the number of
separate field passes that a farmer must make to prepare for,
plant, and raise a crop, and limiting at least the initial zone of
pesticidal activity to the seed and its immediate environment.
Further information about seed coatings has been published by Barke
et al., who describe seed coating compositions comprising a
stabilizing polyol in U.S. Pat. No. 4,272,417. Seed coatings
containing polyelectrolyte complexes are disclosed by Dannelly in
U.S. Pat. No. 4,245,432. Kouno has described a method of applying
gel coating to seeds in U.S. Pat. No. 4,808,430. In U.S. Pat. No.
4,735,015, Schmolka has described enveloping a seed in a coating
containing certain polyoxyethylene-polyoxybutylene block
copolymers.
[0008] Early seed treatment applications were often carried out by
simply applying a pesticide--a fungicide, for example--directly to
a seed, followed by drying the treated seed for storage and use. It
was soon apparent, however, that this technique also had drawbacks,
such as toxicity of the pesticide to the seed, high rates of loss
of the pesticide during storage and the exposure of workers
handling and planting the seed to high levels of the pesticide. In
cases where the pesticide was water soluble or easily leached from
the seed, the loss of pesticide from the zone of the seed could be
rapid. Not only could this reduce the efficacy of the treatment,
but could also cause unwanted release of the pesticide into the
environment.
[0009] In many cases, it is desirable to retard or control the
release of the active from the seed because of safety
considerations and to increase the efficiency of use of the active.
For example, if release of a pesticide can be controlled so that
the concentration of the pesticide in the zone of the seed reaches
and remains at an effective level during the time the target pest
is active, the efficiency of use of the pesticide is increased over
what would ordinarily be expected if the pesticide was merely
applied to the soil at planting. Examples of methods to control the
release of actives by the use of seed coatings have been described
by, among others, Turnblad et al. in U.S. Pat. Nos. 5,849,320 and
5,876,739, who disclosed insecticidal coatings comprising a polymer
binder, an insecticide and a filler, where the binder formed a
matrix for the insecticide and the filler. Application of such a
coating to a seed and the optional subsequent application of a
protective polymer overcoating were also described.
[0010] One of the considerations of including a pesticide, such as
an insecticide, in the seed coating itself is that the active agent
is present throughout the coating and even on the outer surface of
the coated seed. This permits anyone handling the seed to contact
the active ingredient directly. In order to minimize this contact,
it is necessary to add a second, additional, coating to the seed.
This requires additional materials and results in higher cost of
seed preparation.
[0011] Another problem that has hindered the development of seed
coatings that control the release of pesticides has been the
requirement for coatings that are carefully tailored to provide a
certain chemical relationship with the pesticide. For example, the
combination of the pesticide and the coating must meet certain
criteria of release rate, protection of the active, protection of
the seed, and the like, while not binding the pesticide so tightly
that release is prevented entirely. The development of coating
formulations that meet these criteria has routinely taken
significant time and effort, and the formulations are most often
limited to use with one type of pesticide.
[0012] Accordingly, it would be useful to devise a method for
controlling the release of agricultural actives from a seed that
has been treated with such actives where the methods are easy, fast
and economical to administer, and are effective in controlling the
release of the active from the treated seed. Moreover, it would be
useful if such methods could be used with a wide range of
agricultural actives and if they could be practiced without the
inconvenience and expense of having to develop a polymer coating
having certain chemical compatibility between a particular active
and the polymer.
SUMMARY OF THE INVENTION
[0013] Briefly, therefore, the present invention is directed to a
novel method of controlling the release rate of an agricultural
active ingredient from a seed treated with the active ingredient,
the method comprising the steps of: providing a seed that has been
treated with an agricultural active ingredient; applying to the
treated seed a film comprising an emulsion of a polymer in a liquid
in which both the agricultural active ingredient and the polymer
have low levels of solubility; and curing the film to form a water
insoluble polymer coating on the surface of the treated seed.
[0014] The present invention is also directed to a novel treated
seed that is coated by the method described above.
[0015] The present invention is also direct to a novel method of
protection of a seed comprising treating the seed by the method
described above.
[0016] Among the several advantages found to be achieved by the
present invention, therefore, may be noted the provision of a
method of controlling the release rate of an agricultural active
ingredient from a seed treated with the active ingredient, where
the method is easy, fast and economical to administer; the
provision of such a method that is effective in controlling the
release of the active from the treated seed; the provision of such
a method that can be used with a wide range of agricultural
actives; and the provision of such a method that can be practiced
without the inconvenience and expense of having to develop a
polymer coating having certain chemical compatibility between a
particular active and the polymer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows the release of imidacloprid as a function of
time from corn seed that had been treated with imidacloprid
followed by no overcoating, or overcoating according to an
embodiment of the subject method with an emulsion containing
Aquacoat ECD, Surelease Polymer, Stepan NMS Latex with
T.sub.g=25.degree. C., or Stepan NMS Latex with T.sub.g=15.degree.
C.;
[0018] FIG. 2 shows the release of imidacloprid as a function of
time from cotton seed that had been treated with imidacloprid
followed by no overcoating, or overcoating according to an
embodiment of the subject method with an emulsion containing Stepan
NMS Latex; and
[0019] FIG. 3 shows the release of tebuconazole as a function of
time from corn seed that had been treated with tebuconazole
followed by no overcoating, or overcoating according to an
embodiment of the subject method with an emulsion containing Stepan
NMS Latex with T.sub.g=15.degree. C., or Stepan NMS Latex with
T.sub.g=25.degree. C.
DETAILED DESCRIPTION OF THE INVENTION
[0020] In accordance with the present invention, it has been
discovered that the release rate of an agricultural active
ingredient from a seed that has been treated with such active can
be controlled by applying to the treated seed a film of an emulsion
of a polymer in a liquid in which both the agricultural active
ingredient and the polymer have low levels of solubility, and then
curing the film to form a water insoluble polymer coating on the
surface of the treated seed.
[0021] This method has been found to be an effective way to provide
seeds that have been treated with, for example, a pesticide, that
have a controlled release rate of the pesticide into the
environment around the planted seed, thereby increasing the
efficiency of the pesticide. Moreover, the polymer coating is easy
and economical to apply to the seeds, and the application can be
done in the same equipment in which the seeds are treated with
pesticide. Unlike conventional methods of forming controlled
release compositions, the novel method provides the unexpected
advantage that the polymer that is used to form the coating does
not necessarily have to have any particular chemical compatibility
with the active ingredient. Therefore, the method is believed to be
especially useful for seeds that have been treated with two or more
active ingredients that have chemical characteristics that are
significantly different from each other. Such a combination of
actives would normally make it difficult, if not impossible, to
design a typical controlled-release formulation having desirable
release characteristics for both active ingredients.
[0022] It is believed that another surprising property of the novel
method is that it results in treated seed having a single coating
that has very low levels of the active ingredient at the outer
surface of the coating. This is thought to remove the need for the
application of a separate overcoating of the seed, while providing
a treated seed that is safer to handle and provides greater control
of the active than an uncoated seed.
[0023] Polymers that can be used to form the present coating are
those that are capable of forming a water insoluble coating upon
curing. When it is said that the coating is a water insoluble, it
is meant is that the coating has a water solubility of less than
about 1%, and preferably less than about 0.1%, by weight, at
25.degree. C. Among the advantages that a coating having low water
solubility provides is that the loss of the coating due to water
solubilization in the environment is reduced. It is also preferred
that the polymer is one that is non-toxic to the seed to which it
is to be applied, i.e., that it is non-phytotoxic.
[0024] Polymers that are suitable for use in the present method can
be polyesters, polycarbonates, co-polymers of styrene, and mixtures
thereof. Examples of preferred polymers are
acrylonitrile-butadiene-styrene terpolymer (ABS); ABS modified
polyvinylchloride; ABS-polycarbonate blends; acrylic resins and
co-polymers: poly(methacrylate), poly(ethylmethacrylate),
poly(methylmethacrylate), methylmethacrylate or ethylmethacrylate
copolymers with other unsaturated monomers; casein; cellulosic
polymers: ethyl cellulose, cellulose acetate, cellulose
acetatebutyrate; ethylene vinyl acetate polymers and copolymers;
poly(ethylene glycol); poly(vinylpyrrolidone); acetylated mono-,
di-, and triglycerides; poly(phosphazene); chlorinated natural
rubber; polybutadiene; polyurethane; vinylidene chloride polymers
and copolymers; styrene-butadiene copolymers; styrene-acrylic
copolymers; alkylvinylether polymers and copolymers; cellulose
acetate phthalates; epoxies; ethylene copolymers: ethylene-vinyl
acetate-methacrylic acid, ethylene-acrylic acid copolymers;
methylpentene polymers; modified phenylene oxides; polyamides;
melamine formaldehydes; phenolformaldehydes; phenolic resins;
poly(orthoesters); poly(cyanoacrylates); polydioxanone;
polycarbonates; polyesters; polystyrene; polystyrene copolymers:
poly(styrene-co maleic anhydride); urea-formaldehyde; urethanes;
vinyl resins: vinyl chloride-vinyl acetate copolymers, polyvinyl
chloride and mixtures of two or more of these.
[0025] The polymers derived from unsaturated amine salts that are
described in WO 98/32726, WO 98/32773, WO 00/05950, WO 00/06612,
and WO 00/06611, to the Stepan Company, are preferred. More
preferred are the polymers that are known commercially as NMS Latex
polymers (Stepan Company).
[0026] Polymers that are biodegradable are also useful in the
present invention. As used herein, a polymer is biodegradable if is
not water soluble, but is degraded over a period of several weeks
when placed in an application environment. Examples of
biodegradable polymers that are useful in the present method
include biodegradable polyesters; starch-polyester alloys; starch;
starch-PCL blends; polylactic acid (PLA)-starch blends; polylactic
acid; poly(lactic acid-glycolic acid) copolymers; PCL; cellulose
esters; cellulose acetate butyrate; starch esters; starch
ester-aliphatic polyester blends; modified corn starch;
polycaprolactone; poly(n-amylmethacrylate); ethyl cellulose; wood
rosin; polyanhydrides; polyvinylalcohol (PVOH);
polyhydroxybutyrate-valerate (PHBV); biodegradable aliphatic
polyesters; and polyhydroxybutyrate (PHB). A biodegradable
aliphatic polyester such as BIONOLLE, from Showa High Polymer,
Tokyo, Japan, is preferred.
[0027] The polymer emulsion of the present method can also include
a non-migrating surfactant. When it is said that the surfactant is
"non-migrating", it is meant that the surfactant is substantially
insoluble in water and, if the liquid used to form the polymer
emulsion is other than water, then the surfactant is also
substantially insoluble in that liquid. When it is said that the
surfactant is "substantially insoluble", it is meant that it has a
solubility in a particular liquid at 25.degree. C. of less than
about 1% by weight, preferably of less than about 0.1% by weight,
and more preferably of less than about 0.01% by weight.
[0028] The non-migrating surfactant can also be a molecule that is
bound to the polymer that is described above, rather than being a
separate entity. Such binding can be in the nature of a chemical
bond, or it can be in the nature of an ionic attraction.
[0029] Non-migrating surfactants that are useful in the present
method are disclosed by Guyot, A., in Current Opinions in Colloid
and Surface Science, pp. 580-585 (1996); Guyot, A. et al., in
Advances in Polymer Science, 11, 43-65, Springer-Verlag, Berlin
(1994); and by Holmberg, K., in Progress in Organic Coatings,
20.325-337 (1992). Preferred non-migrating surfactants are
described in WO 00/05950, and include diallyl amine pluronics
(available from BASF), linoleic alcohol derivatives (available from
ICI), allyl alkyl phenol derivatives (available from DKS, Japan),
acrylate derivatives (available from PPG), allyl alcohol alkenyl
succinic anhydride derivatives (available from KAO, Japan),
Polystep RA series (maleic derivatives, available from Stepan Co.),
maleic derivatives (available from Rhone Poulenc), and Trem LF-40
allyl slufosuccinate derivatives (available from Henkel).
[0030] It is believed that the use of a surfactant having the
characteristics described above provides the benefits of (1)
permitting control of permeability of the coating, which modulates
the release rate of the active through the coating and also
controls the rate of water permeation from the soil into the seed;
and (2) remaining with the polymer while in liquid emulsion form;
and (3) the surfactant is not lost from the coating by contact with
water after planting. The coating permeability is related to the
glass transition temperature of the polymer/surfactant mix
(T.sub.g,), and this parameter can be used as an indicator of the
degree of permeability of the coating.
[0031] In a preferred embodiment of the invention, the water
insoluble polymer and the non-migrating surfactant and the relative
amounts of each are selected so that the polymer coating that is
formed from the water insoluble polymer and the non-migrating
surfactant has a glass transition temperature within a pre-selected
range, thereby providing a coating which retards the release rate
of the agricultural active ingredient from the seed by a desired
amount. The glass transition temperature of the polymer coating can
be within the range of from about -5.degree. C. to about 75.degree.
C. It is preferred, however that the glass transition temperature
of the polymer coating is within the range of from about 10.degree.
C. to about 50.degree. C., more preferred that the glass transition
temperature of the polymer coating is within the range of from
about 15.degree. C. to about 40.degree. C., and even more preferred
that the glass transition temperature of the polymer coating is
within the range of from about 15.degree. C. to about 25.degree.
C.
[0032] It is believed that the subject method can be used on the
seed of any plant. However, it is preferably used on seeds of plant
species that are agronomically important. In particular, the seeds
can be of corn, peanut, canola/rapeseed, soybean, curcubits,
cotton, rice, sorghum, sugar beet, wheat, barley, rye, sunflower,
tomato, sugarcane, tobacco, oats, was well as other vegetable and
leaf crops. It is preferred that the seed be corn, soybeans, or
cotton seed, and more preferred that the seed be corn.
[0033] Seeds on which the present invention can be used can be
seeds that do not have a transgenic event, or can be transgenic
seeds.
[0034] Although the present method can be applied to a seed at any
state of development, it is preferred that the method is applied
after the seed has been harvested and before the seed has been
planted. It is also preferred that the subject method be applied to
a seed that has been dried to a moisture level that is suitable for
stable storage.
[0035] The subject method can be used to control the release of
almost any type of agricultural active ingredient that has been
applied to a seed. For example, the active can be a growth factor,
a growth regulator, a pesticide, or the like. If the active is a
pesticide, such pesticide can be selected from herbicides,
molluscicides, insecticides, nematocides, acaricides, fungicides,
bactericides, and the like. Although the subject method can be used
for seeds that have been treated with only one active, it is also
useful for seeds that have been treated by two or more active
ingredients.
[0036] Pesticides suitable for use in the invention include
pyrethrins and synthetic pyrethroids; azoles, oxadizine
derivatives; chloronicotinyls; nitroguanidine derivatives;
triazoles; organophosphates; pyrrols; pyrazoles; phenyl pyrazoles;
diacylhydrazines; biological/fermentation products; and carbamates.
Known pesticides within these categories are listed in The
Pesticide Manual, 11th Ed., C. D. S. Tomlin, Ed., British Crop
Protection Council, Farnham, Surry, UK (1997).
[0037] Pyrethroids that are useful in the present composition
include pyrethrins and synthetic pyrethroids. The pyrethrins that
are preferred for use in the present method include, without
limitation, 2-allyl-4-hydroxy-3-methyl-2-cyclopenten-1-one ester of
2,2-dimethyl-3-(2-methylpropenyl)-cyclopropane carboxylic acid,
and/or
(2-methyl-1-propenyl)-2-methoxy-4-oxo-3-(2-propenyl)-2-cyclopenten-1-yl
ester and mixtures of cis and trans isomers thereof (Chemical
Abstracts Service Registry Number ("CAS RN") 8003-34-7).
[0038] Synthetic pyrethroids that are preferred for use in the
present invention include (s)-cyano(3-phenoxyphenyl)methyl-4-chloro
alpha (1-methylethyl)benzeneacetate (fenvalerate, CAS RN
51630-58-1), (S)-cyano-(3-phenoxyphenyl)methyl
(S)-4-chloro-alpha-(1-methylethyl)benze- neacetate (esfenvalerate,
CAS RN 66230-04-4), (3-phenoxyphenyl)-methyl(+)c-
is-trans-3-(2,2-dichoroethenyl)-2,2-dimethylcyclopropanecarboxylate
(permethrin, CAS RN 52645-53-1), (.+-.)
alpha-cyano-(3-phenoxyphenyl)meth-
yl(+)-cis,trans-3-(2,2-dichloroethenyl)-2,2-dimethyl-cyclopropane
carboxylate (cypermethrin, CAS RN 52315-07-8), (beta-cypermethrin,
CAS RN 65731-84-2), (theta cypermethrin, CAS RN 71697-59-1),
S-cyano (3-phenoxyphenyl)methyl (.+-.) cis/trans
3-(2,2-dichloroethenyl) 2,2 dimethylcyclopropane carboxylate
(zeta-cypermethrin, CAS RN 52315-07-8),
(s)-alpha-cyano-3-phenoxybenzyl (1R,3R)-3-(2,2
-dibromovinyl)-2,2-dimethy- lcyclopropanecarboxylate (deltamethrin,
CAS RN 52918-63-5), alpha-cyano-3-phenoxybenzyl
2,2,3,3,-tetramethyl cyclopropoanecarboxylate (fenpropathrin, CAS
RN 64257-84-7), (RS)-alpha-cyano-3-phenoxybenzyl(R)-2-
-[2-chloro-4-(trifluoromethyl)anilino]-3-methylbutanoate
(tau-fluvalinate, CAS RN 102851-06-9),
(2,3,5,6-tetrafluoro-4-methylphenyl)methyl-(1-alpha,
3-alpha)-(Z)-(.+-.)-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylc-
yclopropanecarboxylate (tefluthrin, CAS RN 79538-32-2),
(.+-.)-cyano (3-phenoxyphenyl)methyl
(.+-.)-4-(difluoromethoxy)-alpha-(1-methyl ethyl)benzeneacetate
(flucythrinate, CAS RN 70124-77-5),
cyano(4-fluoro-3-phenoxyphenyl)methyl
3-[2-chloro-2-(4-chlorophenyl)ethen-
yl]-2,2-dimethylcyclopropanecarboxylate (flumethrin, CAS RN
69770-45-2), cyano(4-fluoro-3-phenoxyphenyl) methyl
3-(2,2-dichloroethenyl)-2,2-dimeth- yl-cyclopropanedarboxylate
(cyfluthrin, CAS RN 68359-37-5), (beta cyfluthrin, CAS RN
68359-37-5), (transfluthrin, CAS RN 118712-89-3),
(S)-alpha-cyano-3-phenoxybenzyl(Z)-(1R-cis)-2,2-dimethyl-3-[2-(2,2,2-trif-
luoro-trifluoromethyl-ethoxycarbonyl)vinyl]cyclopropane carboxylate
(acrinathrin, CAS RN 101007-06-1), (1R cis) S and (1S cis) R
enantiomer isomer pair of
alpha-cyano-3-phenoxybenzyl-3-(2,2-dichlorovinyl)-2,2-dime-
thylcyclopropane carboxylate (alpha-cypermethrin, CAS RN
67375-30-8),
[1R,3S)3(1'RS)(1',2',2',2',2'-tetrabromoethyl)]-2,2-dimethylcyclopropanec-
arboxylic acid (s)-alpha-cyano-3-phenoxybenzyl ester (tralomethrin,
CAS RN 66841-25-6), cyano-(3-phenoxyphenyl)methyl
2,2-dichloro-1-(4-ethoxyphenyl- )cyclopropane carboxylate
(cycloprothrin, CAS RN 63935-38-6), [1.alpha.,
3.alpha.(Z)]-(.+-.)-cyano-(3-phenoxyphenyl)methyl
3-(2-chloro-3,3,3-trifl-
uoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate (cyhalothrin,
CAS RN 68085-85-8), [1-alpha (s),
3-alpha(z)]-cyano(3-phenoxyphenyl)methyl-3-(2--
chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate
(lambda cyhalothrin, CAS RN 91465-08-6),
(2-methyl-[1,1'-biphenyl]-3-yl)m-
ethyl-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl-cyclopropanecar-
boxylate (bifenthrin, CAS RN 82657-04-3),
5-1-benzyl-3-furylmethyl-d-cis(1- R,3S, E)2,2-dimethyl-3-(2
-oxo,-2,2,4,5 tetrahydro thiophenylidenemethyl)c-
yclopropanecarboxylate (kadethrin, RU15525, CAS RN 58769-20-3),
[5-(phenylmethyl)-3-furanyl]-3-furanyl-2,2-dimethyl-3-(2-methyl-1-propeny-
l)cyclopropane carboxylate (resmethrin, CAS RN 10453-86-8),
(1R-trans)-[5-(phenylmethyl)-3-furanyl]methyl
2,2-dimethyl-3-(2-methyl-1-- propenyl)cyclopropanecarboxylate
(bioresmethrin, CAS RN 28434-01-7),
3,4,5,6-tetrahydro-phthalimidomethyl-(1RS)-cis-trans-chrysanthemate
(tetramethrin, CAS RN 7696-12-0), 3-phenoxybenzyl-d,I-cis,trans
2,2-dimethyl-3-(2-methylpropenyl)cyclopropane carboxylate
(phenothrin, CAS RN 26002-80-2); (empenthrin, CAS RN 54406-48-3);
(cyphenothrin; CAS RN 39515-40-7), (prallethrin, CAS RN
23031-36-9), (imiprothrin, CAS RN 72963-72-5),
(RS)-3-allyl-2-methyl-4-oxcyclopent-2-enyl-(1S,3R;
1R,3S)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylate
(allethrin, CAS RN 584-79-2), (bioallethrin, CAS RN 584-79-2), and
(ZXI8901, CAS RN 160791-64-0). It is believed that mixtures of one
or more of the aforementioned synthetic pyrethroids can also be
used in the present invention. Particularly preferred synthetic
pyrethroids are tefluthrin, lambda cyhalothrin, bifenthrin,
permethrin and cyfluthrin. Even more preferred synthetic
pyrethroids are tefluthrin and lambda cyhalothrin, and yet more
preferred is tefluthrin.
[0039] Insecticides that are oxadiazine derivatives are useful in
the subject method. The oxadizine derivatives that are preferred
for use in the present invention are those that are identified in
U.S. Pat. No. 5,852,012. More preferred oxadiazine derivatives are
5-(2-chloropyrid-5-ylmethyl)-3-methyl-4-nitroiminoperhydro-1,3,5-oxadiazi-
ne,
5-(2-chlorothiazol-5-ylmethyl)-3-methyl-4-nitroiminoperhydro-1,3,5-oxa-
diazine,
3-methyl-4-nitroimino-5-(1-oxido-3-pyridinomethyl)perhydro-1,3,5--
oxadiazine,
5-(2-chloro-1-oxido-5-pyridiniomethyl)-3-methyl-4-nitroiminope-
rhydro-1,3,5-oxidiazine; and
3-methyl-5-(2-methylpyrid-5-ylmethyl)-4-nitro-
iminoperhydro-1,3,5-oxadiazine. Even more preferred is thiamethoxam
(CAS RN 153719-23-4).
[0040] Chloronicotinyl insecticides are also useful in the subject
method. Chloronicotinyls that are preferred for use in the subject
composition are described in U.S. Pat. No. 5,952,358, and include
acetamiprid
((E)-N-[(6-chloro-3-pyridinyl)methyl]-N'-cyano-N-methyleneimidamide,
CAS RN 135410-20-7), imidacloprid
(1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2- -imidazolidinimime,
CAS RN 138261-41-3), and nitenpyram
(N-[(6-chloro-3-pyridinyl)methyl]-N-ethyl-N'-methyl-2-nitro-1,1-ethenedia-
mine, CAS RN 120738-89-8).
[0041] Nitroguanidine insecticides are useful in the present
method. Such nitroguanidines include those described in U.S. Pat.
Nos. 5,633,375, 5,034,404 and 5,245,040, and, in particular, TI-435
(N-[(2-chloro-5-thiazoyl)methyl]-N'-methyl-N"-nitro,
[C(E)]-(9CI)-guanidine, (having a common name of clothianidin) CAS
RN 210880-92-5).
[0042] Pyrrols, pyrazoles and phenyl pyrazoles that are useful in
the present method include those that are described in U.S. Pat.
No. 5,952,358. Preferred pyrazoles include chlorfenapyr
(4-bromo-2-(4-chlorophenyl)-1-ethoxymethyl-5-trifluoromethylpyrrole-3-car-
bonitrile, CAS RN 122453-73-0), fenpyroximate
((E)-1,1-dimethylethyl-4[[[[-
(1,3-dimethyl-5-phenoxy-1H-pyrazole-4-yl)methylene]amino]oxy]methyl]benzoa-
te, CAS RN 111812-58-9), and tebufenpyrad
(4-chloro-N[[4-1,1-dimethylethyl-
)phenyl]methyl]-3-ethyl-1-methyl-1H-pyrazole-5-carboxamide, CAS RN
119168-77-3). A preferred phenyl pyrazole is fipronil
(5-amino-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(1R,S)-(trifluoromet-
hyl)sulfinyl]-1H-pyrazole-3-carbonitrile, CAS RN 120068-37-3).
[0043] Diacylhydrazines that are useful in the present invention
include halofenozide
(4-chlorobenzoate-2-benzoyl-2-(1,1-dimethylethyl)-hydrazide, CAS RN
112226-61-6), methoxyfenozide (RH-2485; N-tert-butyl-N'-(3-methoxy-
-o-toluoyl)-3,5-xylohydrazide, CAS RN 161050-58-4), and
tebufenozide (3,5-dimethylbenzoic acid
1-(1,1-dimethylethyl)-2-(4-ethylbenzoyl)hydrazi- de, CAS RN
112410-23-8).
[0044] Triazoles, such as amitrole (CAS RN 61-82-5) and triazamate
are useful in the method of the present invention. A preferred
triazole is triazamate
(ethyl-[[1-[(dimethylamino)carbonyl]-3-(1,1-dimethylethyl)-1H--
1,2,4-triazol-5-yl]thio]acetate, CAS RN 112143-82-5).
[0045] Biological/fermentation products, such as avermectin
(abamectin, CAS RN 71751-41-2) and spinosad (XDE-105, CAS RN
131929-60-7) are useful in the present method.
[0046] Organophosphate insecticides are also useful as one of the
components of the present method. Preferred organophophate
insecticides include acephate (CAS RN 30560-19-1), chlorpyrifos
(CAS RN 2921-88-2), chlorpyrifos-methyl (CAS RN 5598-13-0),
diazinon (CAS RN 333-41-5), fenamiphos (CAS RN 22224-92-6), and
malathion (CAS RN 121-75-5).
[0047] In addition, carbamate insecticides are useful in the
subject method. Preferred carbamate insecticides are aldicarb (CAS
RN 116-06-3), carbaryl (CAS RN 63-25-2), carbofuran (CAS RN
1563-66-2), oxamyl (CAS RN 23135-22-0) and thiodicarb (CAS RN
59669-26-0).
[0048] Fungicides that are useful in the present invention include
tebuconazole, simeconazole, fludioxonil, fluquinconazole,
difenoconazole,
4,5-dimethyl-N-(2-propenyl)-2-(trimethylsilyl)-3-thiophenecarboxamide
(silthiopham), hexaconazole, etaconazole, propiconazole,
triticonazole, flutriafol, epoxiconazole, fenbuconazole,
bromuconazole, penconazole, imazalil, tetraconazole, flusilazole,
metconazole, diniconazole, myclobutanil, triadimenol, bitertanol,
pyremethanil, cyprodinil, tridemorph, fenpropimorph,
kresoxim-methyl, azoxystrobin, ZEN90160, fenpiclonil, benalaxyl,
furalaxyl, metalaxyl, R-metalaxyl, orfurace, oxadixyl, carboxin,
prochloraz, trifulmizole, pyrifenox, acibenzolar-5-methyl,
chlorothalonil, cymoaxnil, dimethomorph, famoxadone, quinoxyfen,
fenpropidine, spiroxamine, triazoxide, BAS50001F, hymexazole,
pencycuron, fenamidone, guazatine, and cyproconazole.
[0049] When a pesticide is described herein, it is to be understood
that the description is intended to include salt forms of the
pesticide as well as any isomeric and/or tautomeric form of the
pesticide that exhibits the same activity as the form of the
pesticide that is described.
[0050] The pesticides that are useful in the present method can be
of any grade or purity that pass in the trade as such pesticide.
Other materials that accompany the pesticides in commercial
preparations as impurities can be tolerated in the subject methods
and compositions, as long as such other materials do not
destabilize the composition or significantly reduce or destroy the
activity of any of the pesticide components against a target
pest(s). One of ordinary skill in the art of the production of
pesticides can readily identify those impurities that can be
tolerated and those that cannot.
[0051] The agricultural actives that are useful in the present
invention can be provided in solid or liquid form, and can be
provided as emulsions, dispersions, solutions, or in particulate
form. The actives can be alone or can be in combination with other
materials, as long as such other materials do not destabilize, or
significantly reduce or destroy the activity of the active.
[0052] The present method can be applied to seeds that have already
been treated by others, such as commercially available treated
seeds, but the novel method can also include the step of treating
seeds with an active. When treatment of a seed with an active is
included in the present method, it is preferred that the treatment
is carried out so that an evenly distributed coating of the
pesticide is applied to the outer surface of the seed without loss
of pesticide due to excess liquid falling off of the seed during or
after the treatment. After addition of the active, the seeds must
not be dried and agitated so long that the active is abraded off
the seed due to dusting and scuffing.
[0053] The amount of active that is applied to the seed can be any
amount, but is preferably between about 0.5 gm of active
ingredient/100 kg of seed and about 1,000 gm/100 kg of seed; more
preferably between about 25 gm and about 600 gm/100 kg of seed, and
even more preferably between about 50 gm and about 400 gm/100 kg of
seed.
[0054] The active can be applied to the seed in any form and such
forms as capsule suspensions (CS), emulsifiable concentrates (EC),
emulsions in oil or water (EO and EW), granules (GR), suspension
concentrates (SC), soluble granules (SG), soluble concentrates
(SL), soluble powders (SP), and water dispersible granules (WG) are
suitable. It is preferred to apply the active to the seed in the
form of a flowable liquid. The active can be in a true solution in
the liquid, or it can be present as small droplets or particles to
form a suspension, dispersion or emulsion. Since many pesticides
have low water solubility, it is preferred that when water is the
liquid, an aqueous dispersion, suspension, or emulsion of the
pesticide be used, and that the pesticide be present in the
dispersion, suspension, or emulsion in the form of small particles
or droplets. As used herein, the term "suspension" will be
considered to include any form of liquid containing small
particles, and to include the terms dispersion and emulsion.
[0055] The particles of pesticide in the liquid suspension can be
of any size that permits the suspension to be applied to the seed
by any means, such as, for example, by spraying. It is preferred
that the particles of pesticide in the suspension have a number
average nominal size of less than about 10 microns, more preferably
of less than about 5 microns, even more preferably of less than
about 2 microns, and even more preferably of less than about 1
micron (be "sub-micron" in size). It is believed that the use of
such small particles causes the pesticide to form a more stable and
homogenous suspension--thereby allowing a more even distribution of
the pesticide over the surface of the seed, and that the small
particles are less subject to abrasion from the treated seed after
the pesticide treatment has been applied.
[0056] The active can be applied to the seed in any type of
conventional seed treatment or coating equipment. Application in a
seed treating machine having the characteristics of a CMS seed
coating machine (Vector Corporation, Marion, Iowa), for example,
has been found to be suitable. One method that has been found to be
successful for applying a pesticide, such as imidacloprid, to seed,
is to mill the imidacloprid to 1-2 micron, or to sub-micron, size
and then to add the small particles of imidacloprid to water to
form an aqueous suspension. A mill that is capable of reducing
solids to fine particles, such as a Mirco-Jet Pulverizer air mill,
available from Fluid Energy Processing and Equipment Company,
Hatfield, Pa., can be used for the size reduction.
[0057] The concentration of the pesticide in the suspension should
be low enough to permit easy handling and application of the
suspension to the seed--such as by spraying--and thorough
distribution of the pesticide among the seeds so that the outer
surface of each seed is substantially covered. However, the
concentration should be high enough that, when used in combination
with the other parameters of seed treatment, to avoid the loss of
pesticide from the seeds by dripping or pooling of the treating
liquid suspension. Pesticide concentrations of between about 0.1%
and about 50%, by weight, are useful for such suspensions,
preferred are concentrations between about 0.5% and 15%, by weight,
even more preferred are concentrations between about 0.6% and about
5%, and yet more preferred are concentrations of the pesticide
between about 1% and 3%, by weight of the suspension. Sticking
agents and dyes can also be added to the pesticide suspension to
promote the adherence of the suspension to the seeds and to
identify the seeds as having been treated.
[0058] A desired amount of the suspension of the pesticide is
sprayed onto the seed in, for example, a CMS seed treater, over a
period of time that is long enough to permit thorough distribution
of the suspension over the seed, but short enough so that the
treated seed do not completely dry. It is believed that if the
treated seed are allowed to remain in a heated seed treater until
the suspension is completely dry, the danger of loss of the
pesticide by abrasion increases. When the exit temperature of the
heated air circulating through the CMS machine is held to about
95.degree. F., and the aqueous suspension contains about 1.6% by
weight imidacloprid and 8% by weight of a sticking agent, an
application time of between about 3 minutes and about 20 minutes is
suitable, and an application time of between about 5 and about 15
minutes is preferred.
[0059] After an agricultural active has been applied to the seed,
the novel coating can be applied. It is preferred that the polymer
of the subject coating be applied to the seed in the form of a film
of a liquid suspension, dispersion or emulsion. As used herein,
when describing the coating the term "emulsion" will be understood
to include all suspensions, dispersions and emulsions. When the
liquid in which the active is distributed is water, the emulsion
can be termed a latex. It will be understood that when the term
"film" is used in this specification, it generally applies to the
film of the polymer emulsion in liquid form after application to
the seed, unless the context suggests otherwise. Likewise, the term
"coating" applies to the coating on the seed that is formed from
the curing of the film. When a film containing the active is
applied to the seed, it is preferred that the film substantially
covers the surface of the seed. However, while preferable, such
substantial coverage is not required in order to obtain the
advantages of the invention.
[0060] The liquid in which the active is suspended is one in which
both the active and the polymer have low solubility. When it is
said that the active has low solubility in the liquid, it is meant
that the solubility of the active in the liquid at 20.degree. C. is
less than about 10 g/l. It is preferred that the solubility of the
active in the liquid at 20.degree. C. is less than about 1,000
mg/l, a solubility of less than about 200 mg/l is more preferred,
less than about 100 mg/l is even more preferred, and less than
about 50 mg/l is even more preferred.
[0061] When it is said that the polymer has low solubility in the
liquid, it is meant that the solubility of the polymer in the
liquid at 25.degree. C. is less than about 5%, by weight. It is
preferred that the solubility of the polymer is less than about 2%,
by weight, less than about 1%, by weight is more preferred, and
less than about 0.1%, by weight, is even more preferred.
[0062] It is believed that the use of a liquid in which both the
polymer and the agricultural active have low solubility provides an
advantage to the novel method. By way of example, when the liquid
is water, the polymer forms a latex when distributed in the water.
A film of the latex is applied to the treated seed, and the latex
film has both hydrophobic and hydrophilic character. Without
wishing to be bound to this or any other theory, it is believed
that this characteristic advantageously modulates the distribution
of the active ingredient throughout the coating during drying and
formation of the polymer coating. Because the active ingredient has
low solubility in the liquid of the film, it is believed that the
latex permits the transfer of only a small fraction of the active
ingredient into the polymer portion of the latex coating while it
is still in the emulsion, but prevents the loss of the active into
the liquid. This is believed to prevent the loss of active from the
surface of the seed and to retain the major portion of the active
on the seed's surface and away from the interface of the coating
with the surrounding environment. It is believed that these
properties provide the desirable retardation of release rate of the
active from the coated, treated seed after the coating has formed,
while providing a coating with a low level of active on the outside
surface.
[0063] Although a water-based emulsion is preferred, emulsions or
dispersions of the polymers of the present method in non-aqueous
solvents, or in aqueous/non-aqueous solvent mixtures are also
within the scope of the invention.
[0064] The polymer is added to the liquid under conditions that an
emulsion is formed. This can be done by the addition of finely
milled particles of the active to the liquid, or a liquid/active
mixture can be subjected to high shear to form the emulsion. Such
emulsion-forming techniques are well-known in the art.
[0065] The polymer can be added to the liquid in any amount, but
the concentration of the polymer in the emulsion that is used to
form the film should be low enough to permit easy handling and
application of the emulsion to the seed--such as by spraying--and
thorough distribution of the film among the seeds so that the outer
surface of each seed is substantially covered. However, the
concentration should be high enough, when used in combination with
the other parameters of seed treatment, to avoid the loss of
polymer from the seeds by dripping or pooling of the emulsion. It
is preferred that the concentration of polymer in the emulsion at
the time that a film of the emulsion is applied to the seeds is
about 0.5% to about 50%, by weight, more preferred is a
concentration of about 0.5% to about 20%, by weight, even more
preferred is a concentration of about 2% to about 20%, yet more
preferred is a concentration of about 4% to about 15%, by weight,
and even more preferred is a concentration of about 5% to about
11%, by weight.
[0066] If it is desirable, materials other than the polymer can be
added to the liquid in order to serve as plasticizers, emulsifiers,
stabilizers, anti-oxidants, fillers, dyes, safeners, and the like.
Such materials are well known in the art.
[0067] The polymer emulsion can be applied to the seeds in the same
type of seed treatment equipment as used for the application of the
active ingredient to the seeds. In fact, it is preferred that the
emulsion be added to the seeds immediately after the addition of
the active ingredient and without removing the seeds from the
treater. It is preferred that a short amount of time--on the order
of 30 sec. to 3 minutes--elapse between the end of the application
of the active and the beginning of the application of the emulsion
film. This permits some degree of liquid removal from the treated
seeds, but is not long enough to allow the treated seeds to become
completely dry.
[0068] The amount of the polymer emulsion that is added to the
seeds is an amount that is sufficient to provide a coating of the
desired thickness. The ratio of the weight of the film of the
emulsion that is present on each seed after the emulsion has been
added relative to the weight of the treated seed is preferably
within a range of from about 1:10 to about 1:50, more preferred is
a ratio of about 1:15 to about 1:25, even more preferred is a ratio
within a range of about 1:16 to about 1:22, and yet more preferred
that the ratio be within a range of about 1:18 to about 1:21.
[0069] Without being bound by this or any other theory, it is
believed that the combination of the amount of the polymer film
that is added to the seed, the concentration of the polymer in the
emulsion, and the time required for the addition of the emulsion to
the seed is important to provide an overcoat that retains
substantially all of the active ingredient on the seed and provides
an exterior surface that has a very low concentration of the active
ingredient.
[0070] After the film of the polymer emulsion has been applied to
the seed, it is cured to form the polymer coating. When it is said
that the film is "cured", or when "curing the film" is referred to,
what is meant is that a solid coating of the polymer is formed from
the polymer in the film. Curing is often the result of drying of
the liquid from the film, but can also be carried out by chemical
reaction, adsorption, sequestration, or other forms of polymer
curing that are known in the art.
[0071] The subject coating is insoluble in water, as described
above, and is present on at least some part of the outer surface of
each seed. It is preferred that the coating completely cover the
outer surface of each seed. Although the ratio of the weight of the
coating relative to the weight of the treated seed can vary over a
wide range, it is preferred that the ratio be within a range of
from about 1:1 to about 1:1,000, more preferably within a range of
about 1:10 to about 1:600, and even more preferably within a range
of about 1:20 to about 1:400.
[0072] It is believed that the present coating contains some of the
active ingredient distributed throughout its thickness. However,
because the preferred method of applying the coating is to apply a
film of a controlled amount of the particular emulsion to the
surface of each seed (rather than to immerse the seed in a large
amount of polymer) it is believed that only a small portion of the
active on the seed diffuses from the surface of the seed into the
coating during the time the film dries and forms a solid coating.
It is believed that the concentration of the active in the coating
is highest at or near the surface of the seed and decreases to a
low level at the interface of the coating with the surrounding
environment (the outer surface of the coating).
[0073] Although the coating is substantially water insoluble, it
must not totally prevent the seed from imbibing water in order to
germinate. Therefore, the coating must be sufficiently permeable to
water so that the seed can imbibe moisture for germination, but
still must retard the release of the active. Moreover, the coating
must be sufficiently permeable to oxygen and carbon dioxide so that
the normal respiration of the seed is not significantly
impaired.
[0074] Seeds that have been treated by the subject method can be
stored, handled and planted like any other seeds. Similar methods
and conditions can be used as are used with any other treated, or
non-treated seeds and the same handling and planting equipment can
be used that is used for conventional seeds.
[0075] Athough the subject coating reduces the exposure of persons
handling the treated and coated seed to the active, suitable
precautions to protect such personnel should be taken.
[0076] The following examples describe preferred embodiments within
the scope of the invention. Other embodiments within the scope of
the claims herein will be apparent to one skilled in the art from
consideration of the specification or practice of the invention as
disclosed herein. It is intended that the specification, together
with the examples, be considered exemplary only, with the scope and
spirit of the invention being indicated by the claims which follow
the examples. In the examples all percentages are given on a weight
basis unless otherwise indicated.
EXAMPLE 1
[0077] This illustrates the treatment of corn seed with
imidacloprid.
[0078] A coating suspension was prepared by mixing water (133.6 g)
at room temperature, with Vinamul 18132 (8.4 g, available from
Vinamul Limited Inc.), Seedkare Luster Kote Plus Red (7.03 g,
available from Sub-Sahara Co.), and imidacloprid (2.47 g, available
from the Gustafson Company). Prior to preparing the suspension, the
size of the imidacloprid particles was reduced from over 100
microns to a nominal average size of approximately 1-2 microns. The
size reduction can be carried out by milling for a time sufficient
to produce imidacloprid particles having a nominal size of below
about 1-2 microns.
[0079] The ingredients were then mixed together and the mixture was
stirred with a mechanical stirrer at medium speed at room
temperature for 20 minutes. At this time the coating suspension was
ready for application to the seed.
[0080] Corn seed (908.21 g, Asgrow RX601, Lot LF OZ34982, available
from Asgrow Seed Company, L.L.C.) was preheated with agitation in
the drum of a CMS seed treatment machine (model PSC-0.5; available
from Vector Corporation, Marion, Iowa) for three minutes at
one-half rotation of the drum every minute. The inlet and exhaust
temperatures of the air flowing into and out of the CMS machine
were set to be controlled at 101.degree. F. and 90.degree. F.
respectively. The actual exhaust temperature was 99.degree. F. The
drum speed was set at 20 rpm and the drum position angle was down.
Atomizing air flow rate for spray application of the coating
suspension was 50 cfh and the tube size on the pump was 16. The
pump speed was set at 5.5. Over a period of 14.5 minutes, the
coating suspension was sprayed directly on the seed through a
nozzle. A pulse spray mode was used. The weight of the seed after
application of the coating suspension was 921.94 g.
EXAMPLE 2
[0081] This illustrates the treatment of corn seed with
imidacloprid and subsequent coating with a polymer latex having a
glass transition temperature of 15.degree. C.
[0082] Corn seed (908.13 g) was treated with a coating suspension
that contained water (133.6 g), imidacloprid (2.48 g; milled as
described in Example 1), Vinamul 18132 (8.39 g), and Seedkare
Lusterkote Plus Red (7.03 g). The coating suspension was prepared
and applied to corn seed as described in Comparative Example 1,
except that the time to apply the suspension was about 8
minutes.
[0083] After the coating suspension had been applied to the corn
seed, and while the treated seed was still in the drum of the CMS
machine, an aqueous emulsion of a polymer latex was applied to the
seed. The polymer latex emulsion was prepared by mixing water (38.1
g) at room temperature, with polymer latex (11.7 g, NMS-7 polymer
latex having a solids content of 45.8% by weight; and having a
glass transition temperature (T.sub.g) of 15.degree. C., available
from the Stepan Company, Northfield, Ill.). The conditions for the
CMS Treater during the overcoating process were as follows: the
inlet temperature was set for 106.degree. F.; exhaust temperature
(set) 90.degree. F.; exhaust temperature (actual) 99.degree. F.;
seed temperature during overcoating was 34.2.degree. F.; drum speed
20 rpm, drum angle was down, atomizing air pressure was 50 psi;
tube size on the pump was 16; pump speed was 5; and time to apply
the overcoating emulsion was 2 min. 45 sec. The weight of the seed
after treating and overcoating was 929.49 g.
EXAMPLE 3
[0084] This illustrates the treatment of corn seed with
imidacloprid and subsequent coating with a polymer latex having a
glass transition temperature of 25.degree. C.
[0085] Corn seed (908.24 g) was treated with a coating suspension
that contained water (133.6 g), imidacloprid (2.47 g), Vinamul
18132 (8.39 g), and Seedkare Lusterkote Plus Red (7.02 g). The
coating suspension was prepared and applied to corn seed as
described in Example 2.
[0086] After the coating suspension had been applied to the corn
seed, an aqueous emulsion of a polymer latex was applied to the
seed as described in Example 2. The polymer latex emulsion was
prepared by mixing water (33.1 g) at room temperature, with polymer
latex (12.7 g, NMS-7 polymer latex having a solids content of 39.6%
by weight; and having a glass transition temperature (T.sub.g) of
25.degree. C., available from the Stepan Company, Northfield,
Ill.). The conditions for the CMS Treater during the overcoating
process were the same as in Example 2, and the time to apply the
overcoating emulsion was 3 min. 10 sec. The weight of the seed
after treating and overcoating was 929.31 g.
EXAMPLE 4
[0087] This illustrates the treatment of corn seed with
imidacloprid and subsequent coating with an aqueous dispersion of
ethylcellulose.
[0088] Corn seed (908.14 g) was treated with a coating suspension
that contained water (133.6 g), imidacloprid (2.47 g), Vinamul
18132 (8.38 g), and Seedkare Lusterkote Plus Red (7.02 g). The
coating suspension was prepared and applied to corn seed as
described in Example 2.
[0089] After the coating suspension had been applied to the corn
seed, an aqueous dispersion of ethylcellulose was applied to the
seed as described in Example 2. The ethylcellulose dispersion was
prepared by mixing water (30 g) at room temperature, with
ethylcellulose (20.16 g, Surelease polymer, Lot E-7-19010; an
off-white, turbid, liquid dispersion having a solids content of
24%-26% of ethylcellulose 20 cP, and also containing ammonium
hydroxide, medium chain triglycerides and oleic acid in small
amounts; available from Colorcon Company). The conditions for the
CMS Treater during the overcoating process were the same as in
Example 2, and the time to apply the overcoating emulsion was 3
min. 30 sec. The weight of the seed after treating and overcoating
was 929.07 g.
EXAMPLE 5
[0090] This illustrates the treatment of corn seed with
imidacloprid and subsequent coating Aquacoat Type ECD formulation
of ethylcellulose.
[0091] Corn seed (908.48 g) was treated with a coating suspension
that contained water (133.6 g), imidacloprid (2.47 g), Vinamul
18132 (8.38 g), and Seedkare Lusterkote Plus Red (7.05 g). The
coating suspension was prepared and applied to corn seed as
described in Example 2.
[0092] After the coating suspension had been applied to the corn
seed, Aquacoat Type ECD-30 aqueous dispersion of ethylcellulose
(ECD) was applied to the seed as described in Example 2. The ECD
dispersion was prepared by mixing water (33.2 g) at room
temperature, with Aquacoat Type ECD-30 (16.8 g of a while liquid
dispersion having 27% by weight of ethylcellulose; the dispersion
having a total solids content of 30%, and containing cetyl alcohol
and sodium lauryl sulfate. Available from FMC Corporation). The
conditions for the CMS Treater during the overcoating process were
the same as in Example 2, and the time to apply the overcoating
emulsion was 3 min. 40 sec. The weight of the seed after treating
and overcoating was 927.7 g.
EXAMPLE 6
[0093] This illustrates the treatment of corn seed with
imidacloprid and subsequent coating with a vinyl acetate-ethylene
copolymer.
[0094] Corn seed (908.14 g) was treated with a coating suspension
that contained water (133.6 g), imidacloprid (2.47 g), Vinamul
18132 (8.37 g), and Seedkare Lusterkote Plus Red (7.03 g). The
coating suspension was prepared and applied to corn seed as
described in Example 2.
[0095] After the coating suspension had been applied to the corn
seed, an aqueous dispersion of Airflex 500 was applied to the seed
as described in Example 2. The Airflex 500 dispersion was prepared
by mixing water (45.38 g) at room temperature, with Airflex 500
(4.62 g; Airflex 500 is a fine-particle-size aqueous dispersion of
a vinyl acetate-ethylene copolymer; the emulsion is used as a base
for interior and exterior paints and other flexible coatings. The
solids content of the emulsion is 55% by weight and the average
particle size is 0.17 microns. Available from Air Products
Company). The conditions for the CMS Treater during the overcoating
process were the same as in Example 2, and the time to apply the
overcoating emulsion was 5 min. 10 sec. The weight of the seed
after treating and overcoating was 924.23 g.
EXAMPLE 7
[0096] This illustrates the release profiles of imidacloprid into
water from treated corn seeds with and without polymer overcoating
and shows the release-retarding effect of certain polymer
overcoats.
[0097] The treated corn seed from Examples 1 through 5 was tested
for the release rate of imidacloprid into excess water. Treated
seeds were placed in an amount of water sufficient that at 100%
release of the active from the treated seeds, the total active
present in the water is less than approximately one-third the water
solubility level of the active. The water containing the seeds is
then agitated by shaking. At intervals, an aliquot is taken and
filtered to separate the active that is dissolved in the water from
the active that remains on the seed, or remains in the form of a
controlled release matrix. The filtered aliquot is then assayed for
active present. Release curves show the percent of the total active
that was originally present on the seeds that has been released
into the water as a function of the time of immersion.
[0098] In a typical sample, treated seeds containing approximately
45 mg of imidacloprid were placed in a 16 ounce bottle along with
450 ml of water. The total amount of imidacloprid in the bottle was
calculated to be about 100 ppm, which is less than one-third of the
water solubility limit of imidacloprid at room temperature (about
510 ppm). The bottle containing the water and the seeds was then
inverted approximately 100 times and an aliquot of liquid was
removed and the time of removal was noted. The bottle was then
placed on a platform shaker and agitated until time for the next
sample withdrawal. The aliquot was filtered with a 0.45 micron PTFE
filter and the filtered aliquot was assayed for imidacloprid
content by HPLC. An Alltech Alltime C18 reverse phase column (5
micron particle size with column dimensions of 250.times.4.5 mm)
was used with a flow rate of 1.2 ml/min and an injection volume of
20 microliters. The mobile phase contained 30% of acetonitrile and
70% of water. The UV detector (Varian 9050) was set at 220 nm and
the retention time for imidacloprid was between 6 and 7 min. For
subsequent time points of the release curve, the procedure
described above was used to determine the concentration of active
in the water.
[0099] When seeds were treated with, for example, tebuconazole, the
same procedure was used to determine the release rate, except that
the relative amounts of treated seeds and water were adjusted to
maintain the maximum level of the active at less than one-third of
its solubility level.
[0100] The results of the release rate test are shown in FIG. 1,
where the percent release of the total imidacloprid on the seed is
shown as a function of time for each of the treated and coated
seeds and for the treated and uncoated seed. It can be seen that
imidacloprid was lost from the uncoated seed more rapidly that for
any of the seeds having a polymer coating. However, the release
rate varied significantly according to the type of polymer and the
glass transition temperature of the polymer. Seeds treated with the
two Stepan NMS-7 latex polymers provided the highest reduction in
release rate, and showed that the release rate could be varied by
varying the glass transition temperature of the polymer coating. In
this instance, it was seen that the polymer having the lower
T.sub.g provided the lower release rate. However, it is believed
that the effect of T.sub.g upon release rate may be reversed for
polymers having different structures. It is believed that this
shows that with a given polymer, the release rate of the active can
be controlled by selecting a polymer having a T.sub.g that will
provide the desired rate.
EXAMPLE 8
[0101] This illustrates the treatment of cotton seed with
imidacloprid and shows the effect on imidacloprid release rate of
overcoating the treated cotton seed with a polymer coating derived
from an aqueous latex.
[0102] Cotton seed (908 g, which had been received from Deltapine
Company (Boligard cotton seed with Roundup Ready.RTM. technology;
Lot# 458 BR-S-9299-2, treatment code 2) was treated with a coating
suspension that contained water (133.6 g), Vinamul 18132 (8.46 g),
Seedkare Lusterkote Plus Red (7.04 g) and imidacloprid (2.47 g).
The coating suspension was prepared and applied to the seed in the
manner described in Example 2, except that cotton seed was
substituted for corn seed.
[0103] After the seed was treated with the imidacloprid suspension,
a portion of the treated seed were removed from the CMS machine and
the remainder of the seed were left in the machine. An aqueous
emulsion of a polymer latex (12.7 g of NMS-7, polymer latex, having
a T.sub.g of 25.degree. C., available from Stepan Company, diluted
with 38.1 g of water) was applied to the seed as described in
Example 2.
[0104] Samples of the treated cotton seed with and without the
polymer overcoating were tested by the same technique as described
in Example 7 to determine the release profiles of imidacloprid into
excess water.
[0105] The release profiles of imidacloprid from treated cotton
seed with and without the novel coating are shown in FIG. 2. It can
be seen that the uncoated seeds lost over 90%, by weight, of the
imidacloprid that had been deposited on the treated seeds within 5
hours. However, cotton seeds having the coating lost only 30% or
less in the same time. This showed that the novel coating could be
applied to treated cotton seed as well as to corn seed, and that
the coating provided the same advantageous retardation of release
rate of the imidacloprid as shown for coatings applied to corn.
EXAMPLE 9
[0106] This illustrates the effect of overcoating corn seed treated
with tebuconazole with polymers having different glass transition
temperatures.
[0107] Three separate batches of corn seed (908 g) were treated in
a CMS seed treater with tebuconazole (supplied as RAXIL.RTM. in a
liquid mixture containing 6% by weight tebuconazole, RAXIL.RTM. is
available from Bayer Corporation). A suspension of RAXIL.RTM. (15.2
ml) was prepared by mixing it with Vinamul 18132 (8.32 g) and
Seedkare Lusterkote Plus Red (7.0 g) in water (133.6 g). The
suspension was applied to corn seed by the methods described in
Example 2.
[0108] One batch of the corn seed treated with tebuconazole was
left without further treatment.
[0109] For the other two batches of treated corn seed, after the
tebuconazole coating suspension had been applied to the seed, a
polymer latex emulsion was applied by the methods described in
Example 2. One batch was coated with a latex emulsion prepared by
mixing water (38.1 g) at room temperature with polymer latex (11.1
g of Stepan NMS-7 polymer latex having a solids content of 45.8% by
weight, and having a T.sub.g=15.degree. C., available from Stepan
Co., Northfield, Ill.). The emulsion was applied to the seeds
within a period of 4 min. 20 sec. The weight of the treated and
overcoated seeds was 933.1 g.
[0110] The final batch of tebuconazole treated corn seed was
overcoated as described above, except with a latex emulsion
prepared by mixing water (33.1 g) at room temperature with polymer
latex (12.7 g of Stepan NMS-7 polymer latex having a solids content
of 39.6% by weight, and having a T.sub.g=25.degree. C., available
from Stepan Co., Northfield, Ill.). The emulsion was applied to the
seeds within a period of 4 min. 50 sec. The weight of the treated
and overcoated seeds was 931.58 g.
[0111] The release rate of tebuconazole from the three batches of
treated corn seed was determined as described in Example 7, except
that the assay was for tebuconazole rather than imidacloprid. The
release rate profiles for tebuconazole into water are shown in FIG.
3 and indicate that coating with either polymer provides a
controlled rate of release of the tebuconazole relative to the
seeds having no overcoating. Little difference in the release rate
was noticed as a function of the T.sub.g of the polymers in this
test.
[0112] All references cited in this specification, including
without limitation all papers, publications, presentations, texts,
reports, manuscripts, brochures, internet postings, journal
articles, periodicals, and the like, are hereby incorporated by
reference. The citation and/or discussion of the references herein
is intended merely to summarize the assertions made by their
authors and no admission is made that any reference constitutes
prior art. Applicants reserve the right to challenge the accuracy
and pertinency of the cited references.
[0113] In view of the above, it will be seen that the several
advantages of the invention are achieved and other advantageous
results attained.
[0114] As various changes could be made in the above methods and
compositions without departing from the scope of the invention, it
is intended that all matter contained in the above description and
shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
* * * * *