Note: Descriptions are shown in the official language in which they were submitted.
WO 94123579 ~ ~ PCT/EP94/01087
- 1 -
SOLID CROP PROTECTION FORMULATION
The present invention relates to crop protection
formulations which are in solid form, for example powder,
granules or tablets.
Crop protection agents are formulated in solid or
liquid compositions, usually in the form of a concentrate
for ease of handling and transportation, which is diluted
with water by the user before application. Often a surface
active agent is required to facilitate dilution and is
incorporated into the formulation.
Liquid formulations in the form of emulsifiable
concentrates contain a very high proportion of organic
solvent (often up to 80 percent) which are increasingly
coming under scrutiny for their effect on the environment;
emulsion concentrates have a higher water content but
still contain organic solvents. Suspension concentrates,
another water-based liquid form, are often viscous giving
rise to handling problems and loss of active ingredient
through retention in the packaging.
Solid formulations can also have disadvantages; the
more common granules and powders in particular can be
difficult to measure but more importantly can be dusty and
pose inhalation hazards for the formulator and the user.
Tablets have not been used extensively because they are
often slow to dissolve. In addition, solid formulations
have been found generally to possess a lower biological
~ activity than liquid formulations. Also, with
unsophisticated mixing techniques at the site of use,
usually in a farmer's field, the tendency of solid forms
not to disperse immediately can cause not only clogging of
~~~fl~~~
WO 94/23579 PCT/EP94/01087
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spray equipment with undispersed formulation, but also an
inadequate application of active ingredient to the crop to
be treated.
Thus, there is a need for a fast-dispersing solid
crop protection formulation which has better handling
characteristics and enhanced biological activity over
conventional forms, to satisfy both environmental concerns
and provide an effective product for the farmer to use in
an unsophisticated manner in the field.
European Patent Application No. 90202212.8
(Publication No. 0413402) (Shell) refers to a solid
pesticidal formulation including as active ingredient, an
organotin compound and the use of such a formulation in
combating pests. Comparative Example 12 refers to the
preparation, by a solvent evaporation process, of a solid
concentrate formulation of polyvinylpyrrolidone and the
commercially available pyrethroid insecticide alpha
cypermethrin. The acaricidal activity of the
polyvinylpyrrolidone/alpha cypermethrin formulation is
compared with that of a standard suspension concentrate
formulation of alpha cypermethrin. The results indicate
that a solid concentrate formulation of pyrethroid
insecticide alpha cypermethrin exhibits only an equivalent
acaricidal activity in comparison with the standard
suspension concentrate.
This invention is based upon the discovery of
enhanced aphicidal activity of a solid concentrate
formulation of polyvinylpyrrolidone and pyrethroid
insecticides.
According to a first aspect of the present invention,
there is provided a method of combating aphid pests at a
WO 94/23579 '') ~ PCT/EP94/01087
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locus, the method comprising applying to the locus an
0
aqueous dispersion prepared by dispersing a solid
concentrate which comprises polyvinylpyrrolidone and a
pyrethroid insecticide in water.
It was expected that the dispersion of the solid
concentrate of polyvinylpyrrolidone and a pyrethroid
insecticide in water would have aphicidal activity of a
similar level to that of a suspension concentrate of the
l0 pyrethroid insecticide. Surprisingly this has been found
not to be the case - the aqueous dispersion of the
invention has an activity which is of a similar level to
that found for an emulsion concentrate of the pyrethroid
insecticide. Thus, the invention may provide an
advantageous method of combating aphid pests, using a
pyrethroid, which obviates the need to deliver the
pyrethroid insecticide in a liquid formulation having a
very high proportion of an organic solvent.
A broad range of pyrethroid insecticides for use in
the present invention are disclosed in the following
publications: U.K. Patent Application No. 1 413 491
(NRDC), European Patent Application No. 22382 (FMC),
European Patent Application No. 107296 (ICI), U.K. Patent
Application No. 1 565 932 (Bayer), U.K. Patent Application
No. 1 439 615 (Sumitomo), U.K. Patent Application No. 1
560 303 (Sumitomo), U.K. Patent Application No. 2 013 206
(Sumitomo), and U.K. Patent Application No. 2 064 528
(Shell) .
Examples of commercial pyrethroid insecticides for
use in the present invention include: 5-benzyl-3-
furylmethyl(E)-(1R)-cis-2,2-dimethyl-3-(2-oxothiolan-3-
ylidenemethyl)cyclopropanecarboxylate; permethrin (3-
phenoxybenzyl(1RS)-cis-trans-3-(2,2-dichlorovinyl)-2,2-
WO 94/23579 PCTIEP94101087
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dimethylcyclopropanecarboxylate); fenpropathrin ((RS)-a-
4
c y a n o - 3 - p h a n o x y b a n z y 1 2 , 2 , 3 , 3 -
tetramethylcyclopropanecarboxylate);esfenvalerate((S)-a
cyano-3-phenoxybenzyl(S)-2(4-chlorophenyl)-3
methylbutyrate); fenvalerate ((RS)-cyano-3
phenoxybenzyl(RS)-2-(4-chlorophenyl)-3-methylbutyrate);
cyfluthrin ((RS)-a-cyano-4-fluoro-3-phenoxybenzyl(1RS)-
c i s - t r a n s - 3 - ( 2 , 2 - d i c h 1 o r o v i n y 1 ) - 2 , 2 -
dimethylcyclopropanecarboxylate); beta-cyfluthin (a
reaction mixture comprising two enantiomeric pairs in
approximate ratio 1:2, i.e. (S)-a-cyano-4-fluoro-3-
phenoxybenzyl(1R)-cis-3-(2,2-dichlorovinyl)-2,2-
dimethylcyclopropanecarboxylate and (R)-a-cyano-4-fluoro-
3-phenoxybenzyl(iS)-cis-3-(2,2-dichlorovinyl)-2,2-
dimethylcyclopropanecarboxylate with(S)-a-cyano-4-fluoro-
3-phenoxybenzyl (1R)-traps-3-(2,2-dichlorovinyl)-2,2-
dimethylcyclopropanecarboxylate and (R)-a-cyano-4-fluoro-
3-phenoxybenzyl(1S)-traps-3-(2,2-dichlorovinyl)-2,2-
dimethylcyclopropanecarboxylate); lambda-cyhalothrin (a
reaction product comprising equal quantities of (S)-a-
cyano-3-phenoxybenzyl(Z)-(1R)-cis-3-(2-chloro-3,3,3-
trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylate and
(R)-a-cyano-3-phenoxybenzyl(Z)-(1S)-cis-3-(2-chloro-3,3,3-
trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylate);
cyhalothrin ((RS)-a-cyano-3-phenoxybenzyl(Z)-(1RS)-cis-3-
(2-chloro-3,3,3-trifluoropropenyl)-2,2-
dimethylcyclopropanecarboxylate); deltamethrin ((S)-a-
cyano-3-phenoxybenzyl(1R)-cis-3-(2,2-dibromovinyl)-2,2-
dimethylcyclopropanecarboxylate); cypermethrin ((RS)-a-
cyano-3-phenoxybenzyl(1RS)-cis-traps-3-(2,2-
dichlorovinyl)-1,1-dimethylcyclopropanecarboxylate); and
alpha-cypermethrin (a racemate comprising (S)-a-cyano-3- '
phenoxybenzyl(1R)-cis-3-(2,2-dichlorovinyl)-2,2-
dimethylcyclopropanecarboxylate and (R)-a-cyano-3-
WO 94123579 ~ ~ ~ ~ PCT/EP94/01087
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phenoxybenzyl(1S)-cis-3-(2,2-dichlorovinyl)-2,2-
dimethylcyclopropanecarboxylate).
r
Preferably, said pyrethroid insecticide for use in
the method of the invention is of general formula:
CN
0
RICO- O- CH
(B)m (I)
(A)n
where A and B independently represent a halogen atom or a
methyl group; n is 0, 1 or 2; m is 0, 1 or 2; and R'
represents a group of general formula:
Rz
H CH=C~ (II)
2 0 Rs
CH3
CH3 H
where RZ and R3 independently represent a hydrogen or
halogen atom, or an optionally substituted C,~ alkyl group;
or R' represents a group of general formula:
R° CH -
I
CH (III)
HOC CH3
where R' represents a phenyl group optionally substituted
by one or more substituents independently selected from
~~~
WO 94/23579 PCT/EP94/01087
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halogen atoms, or C,~ alkyl, C,~, alkylthio, C,~ alkoxy,
nitro and methylenedioxy groups.
Preferably, A represents a halogen atom. A preferred
halogen atom is a fluorine or chlorine atom, with a
fluorine atom being especially preferred.
Preferably, B represents a halogen atom. A preferred
halogen atom is a fluorine or chlorine atom.
Preferably, n is 0 or 1. Where n is 1, preferably
said atom or group A is substituted in the 4-position
relative to the cyanomethyl group in the compound of
general formula I.
Preferably, m is 0.
Where R' represents a group of general formula II, RZ
and R3 may independently represent a halogen atom or an
optionally substituted C,_2 alkyl group. Preferably, RZ and
R~ independently represent a bromine or chlorine atom or a
trifluoromethyl group. Where RZ and R; each represent a
halogen atom, RZ and R3 preferably represent the same
halogen atom. Where RZ represents a trifluoromethyl group,
R3 preferably represents a chlorine atom.
Where R' represents a group of general formula III , R4
preferably represents a phenyl group optionally
substituted by one or more halogen atoms. Preferred
halogen atoms include fluorine and chlorine atoms. R4
preferably represents a 4-substituted phenyl group and,
more preferably, represents a phenyl group substituted by
a chlorine atom. Most preferably, R4 represents a 4-
chlorophenyl group.
WO 94/23579 PCT/EP94/01087
Preferably, said pyrethroid insecticide for use in
' the method of the present invention is selected from alpha
cypermethrin, deltamethrin, cyfluthrin and esfenvalerate.
Most preferably, said pyrethroid insecticide is alpha
cypermethrin.
The pyrethroid insecticide may be prepared using
known processes, for example, as described in the
aforementioned patent publications.
The solid concentrate may be prepared by dissolving
polyvinylpyrrolidone and at least one pyrethroid
insecticide in a solvent, followed by removal of the
solvent from the resulting solution to yield the solid
concentrate.
The solvent selected for use in the process for the
preparation of the concentrate must be one in which both
the pyrethroid insecticide and polyvinylpyrrolidone are
sufficiently soluble. Such solvents are readily
identifiable by routine experimentation. Examples of
suitable solvents include haloalkanes, preferably having
from one to eight carbon atoms, more preferably from one
to four carbon atoms, ketones, preferably acetone and
alcohols, preferably the lower alcohols having from one to
eight carbon atoms, more preferably one to four carbon
atoms. Preferred solvents are chloroalkanes having from
one to four carbon atoms, with dichloromethane and
trichloromethane being especially preferred.
Removal of the solvent may be effected by methods
well known to a person skilled in the art, for example by
allowing the solution of the pyrethroid and
polyvinylpyrrolidone to stand and allowing the solvent to
evaporate. Preferably, the solvent is removed from the
WO 94123579 PCT/EP94/01087
_ g _
solution by evaporation at a pressure below atmospheric
pressure. Evaporation of the solvent at a pressure below
atmospheric pressure may be effected using conventional
vacuum drying techniques and apparatus at a pressure down
to the minimum operating pressure of the apparatus.
Solvent removal is preferably effected at a pressure below
400 mbar (4x10° Nm2) . Alternatively, solvent removal may be
effected by conventional spray drying techniques. As a
further alternative, the solvent may be removed by
treating the solution with a further solvent to cause the
pyrethroid and polyvinylpyrrolidone to precipitate. Such
further solvents are readily identified by routine
experiment. One example of such a solvent is hexane.
Once the solvent has been removed, the resulting
solid concentrate may be pressed (without heating) into
tablet form or aggromerated into granules. Alternatively,
the solid concentrate may be crushed or ground to reduce
the particle size and so aid dispersion.
Preferably, the solid concentrate is prepared by co-
extruding a pyrethroid insecticide with
polyvinylpyrrolidone, subsequently cooling the extrudate
until brittle, and then milling.
Milling is a process of, primarily, crushing,
grinding and pulverising, which produces minute granules
of extrudate. If desired, the milled extrudate can be
pressed (without heating) into tablet form or agglomerated
into granules without loss of the rapid dispersal
characteristics.
The cooling of the extrudate should be carried out
straight after the extrusion process and may be effected
in any suitable, conventional manner. It has been found
WO 94123579 PCTIEP94/01087
_ g _
useful to run the extrudate onto a roller assembly which
is cooled, for example by using chilled water or
optionally a chilled water-antifreeze mixture. The
r
extrudate is preferably cooled rapidly to a temperature in
the range of from 5 to 25°C, especially 10 to 15°C. The
extrudate can then be run off or, if necessary, scraped or
chipped off, the roller and conveyed direct to suitable
milling equipment, for example a hammer mill or preferably
a roll mill. Using a combined chill roller and roll mill
assembly, it may be possible to perform both the cooling
and milling operations in one piece of equipment.
Following milling, it is preferable to classify or
screen the particulate extrudate, to obtain a particle
size which is optimal for use or subsequent processing.
Undersized particles could be recycled to the extrusion
stage; oversized particles could be recycled to the
milling stage.
The milling equipment is suitably such as to achieve
particles of a granular consistency, having for example a
diameter in the region of 250 micrometers. A solid
formulation prepared in this manner has little associated
dust once sieve-cut to cause particular handling or
product loss problems.
For the extrusion itself, any suitable extrusion
equipment may be utilised. Extruders consist, generally,
of a cylindrical barrel in which materials are heated and
moved through the barrel by means of at least one rotating
screw. Thus, the action in the barrel is one of shearing,
rubbing and kneading at elevated temperature. In this way,
the pyrethroid and the polyvinylpyrrolidone become mixed
on a molecular scale and under the combination of
externally applied heat and the internal shear force,
WO 94/23579 PCT/EP94/01087
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which creates more internal heat within the mixture, a l,
solid solution of pyrethroid in the polyvinylpyrrolidone
i
is formed.
Suitable extrusion equipment is a twin screw, co-
rotating extruder, such as is used in the food processing,
pharmaceutical and polymer processing industries.
Typically, extrusion is carried out in a twin screw
extruder having a barrel with a cooled feed zone and with
at least one melt zone. For two or more melt zones, each
melt zone is of a different temperature in accordance with
a graduated temperature profile. The melt temperature or
temperature profile is suitably such that the extrudate on
leaving the extruder barrel has a temperature in the range
of from 50 to 200°C for example from 150 to 200°C, but
preferably from 80 to 200°C. There may be several zones in
the extruder barrel, for example from 4 to 9, each having
a defined temperature usually obtained by the combination
of external electrical heating of the barrel, internal
shear forces and, if necessary, water cooling. The
temperature of the mixed materials within the barrel is
often significantly higher than the applied temperature in
view of the heat generated by the internal shear force; to
maintain a defined temperature for each zone, external
cooling, e.g. by water, as well as heating may be
required. The extruder may incorporate a die plate to aid
subsequent extrudate processing, but in fact there is no
need to have a die plate and if, for example, a chill
roller or chill roller/mill assembly is also used, it is ,
preferable that there should be no die plate on the
machine. The extruder may also incorporate a separate ,
preliminary mixing section, if needed.
Any pyrethroid can be formulated using the co-
extrusion process described above, provided that it
WO 94123579 ~ PCT/EP94/01087
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dissolves in polyvinylpyrrolidone to form a solid solution
and does not chemically decompose during extrusion. The
temperature profile of the extrusion process will need to
be adapted to operate at temperatures compatible with the
fusion points of the pyrethroid and the
polyvinylpyrrolidone. Preferably extrusion is carried out
at or especially above the fusion point of the
pyrethroid/polyvinylpyrrolidone mixture. Furthermore, the
amount of pyrethroid used will depend on the degree to
l0 which it is soluble in the polyvinylpyrrolidone. Exceeding
the solubility limit of pyrethroid in polyvinylpyrrolidone
it is still possible to prepare a solid formulation by the
process of the invention but the dispersion and biological
characteristics may be impaired. Naturally for each
pyrethroid, such optimisation of operation temperature and
ingredient proportions for the process can be carried out
by routine experimentation. Suitably, a pyrethroid having
a melting temperature in the range of from 60~ to 200°Cis
used.
Polyvinylpyrrolidone is a well known commercial
product available in various forms from, for example, the
companies BASF and ISP; the water-soluble polymer and its
preparation is described in, inter alia, The Merck Index,
11th Edition, Monograph 7700. Suitable
polyvinylpyrrolidone polymers for use in the present
invention are any of the available forms, without
restriction. Desirably they have a Fikentscher K value,
see US-A-2,706,701 or Cellulose-Chemie 13 (1932), pages 58
to 64 and 71 to 74, of in the range of from 10 to 100
reflecting a molecular weight of from 5,000 to 700,000.
Preferred polyvinylpyrrolidone polymers have a K value of
20 to 40, especially 25 to 35. The polymer is desirably a
homopolymer of vinylpyrrolidone monomers, but may be used
WO 94!23579 PCTIEP94/01087
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as a copolymer provided that at least 50% or more of the
polymer units are vinyl pyrrolidone monomers.
The polyvinylpyrrolidone may be made in any
conventional manner, for example by polymerisation
initiated by hydrogen peroxide or an organic peroxide in
a suitable solvent such as water or a suitable organic
solvent.
Naturally, where the solid concentrate is made by
co-extrusion, the polyvinylpyrrolidone must fuse at the
operating temperature of the extruder, and it may be
necessary to select a compatible polyvinylpyrrolidone
based on the melting point of the active ingredient and
the consequent extrusion temperature required. For
extrusion with alpha-cypermethrin, "Agrimer 30" a
polyvinylpyrrolidone polymer available from ISP has been
found to be very suitable. Agrimer 30 has a K value of 30.
This polyvinylpyrrolidone has a glass transition
temperature of 156 to 157°C; when mixed with alpha-
cypermethrin, which has a melting point of 77°C, a typical
glass transition temperature of the mixture is of the
order of 146°C. A suitable operating extrusion temperature
or temperature profile for such mixtures is such that the
extrudate is a melt having a temperature of above 77°C and
desirably above 110°C (as determined by routine
experimentation); such mixtures have been satisfactorily
extruded up to 185°C.
Polyvinylpyrrolidone prepared by polymerisation in
water may often have a higher water content (of the order
of 5% by weight); polyvinylpyrrolidone prepared by other
means can also imbibe water from the atmosphere because of
its hygroscopic nature. Where the solid concentrate is
made by co-extrusion, the water content of the
WO 94!23579 PCT/EP94/01087
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= polyvinylpyrrolidone prior to extrusion is not critical.
Should polyvinylpyrrolidone having a water content of
a greater than say 3.5% by weight be used, and it is desired
to have a low residual water content in the extrudate,
preferably water vapour is drawn off under vacuum, for
example by means of a vacuum pump, during extrusion. Thus,
preferably, an extruder is used which has one or more vent
ports, to vent moisture, associated with a vent port
stuffer, to prevent loss of solid material through the
vent port, and a vacuum pump to remove water vapour.
The minimum quantity of polyvinylpyrrolidone in the
solid concentrate is dependent upon the desired extent and
rate of dispersion of the concentrate in water. The
quantity of polyvinylpyrrolidone present in the solid
concentrate is preferably greater than 50% w/w, more
preferably in the range of from 50% w/w to 90% w/w, the
most preferred range being from 60% w/w to 70% w/w.
In addition to polyvinylpyrrolidone and a pyrethroid
insecticide, the solid concentrate may comprise other
components common to the art of aphicidal formulations,
for example surface active agents, corrosion inhibitors
and stabilisers. In addition, the solid concentrate may
comprise one or more inert fillers. However, if the
aforementioned other components or fillers are present in
the solid concentrate, the ratio of pyrethroid compound to
polyvinylpyrrolidone is preferably in the range of from
1:1 to 1:5, most preferably from about 1:2 to 1:3.
Inclusion of a surface active agent in the solid
concentrate is not necessary to ensure a ready and rapid
dispersion of the pyrethroid compound in water. However,
examples of suit able surface active agents that may be
included in the concentrate are the sodium salts of xylene
WO 94/23579 . PCTlEP94/01087
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sulphonates, the sodium salts of alkylbenzenesulphonates,
the sodium or calcium salts of polyacrylic acids and
lignin sulphonic acids and sodium or calcium salts of
carboxylic acids. A group of the most suitable surface
active agents is the sodium lignosulfonates, for example
the commercial product °°VANISPERSE°° (Trade
Mark).
Suitable inert fillers for inclusion in the
concentrate include natural and synthetic clays and
l0 silicates, for example natural silicas such as
diatomaceous earths; magnesium silicates, for example
talcs; magnesium aluminium silicates, for example
kaolinites, montmorillonites and micas; calcium carbonate,
calcium sulphate; ammonium sulphate; synthetic calcium or
aluminium silicates; elements, for example carbon and
sulphur; natural and synthetic resins, for example
coumarone resins, polyvinyl chloride, and styrene polymers
and copolymers; solid polychlorophenols and solid
fertilisers, for example superphosphates.
Where the solid concentrate includes other
ingredients common to the art, these may, when the
concentrate is made by using the solvent removal process
described above, conveniently be dissolved in or suspended
in the solution of pyrethroid and polyvinylpyrrolidone
prior to solvent removal.
Where the solid concentrate is made by co-extrusion
of pyrethroid and polyvinylpyrrolidone, said other
ingredients may be co-extruded with the pyrethroid and
polyvinylpyrrolidone. Additional active ingredients or ,
processing auxiliaries, for example conventional
plasticisers, may be used.
WO 94/23579
PCT/EP94/01087
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Any additional ingredients utilised in a co-extrusion
process will depend on the end use of the formulation
a and/or the main extrusion ingredients. Thus, for example,
for extrusion of alpha-cypermethrin technical material,
which is a racemic mixture of two cis-2-isomers as
described above, the extrusion material must be rendered
slightly acidic to prevent epimerisation or inversion of
the cis-2-isomers to the cis-1-isomers. Suitably in the
range of from 0.5 to 0.9 ~ m/m of an organic acid for
example benzoic acid or, preferably, toluene sulphonic
acid, is included in the ingredients for extrusion; useful
results are also expected from the incorporation of water
soluble salts such as potassium hydrogen sulphate or
sodium sulphate; potassium hydrogen sulphate is especially
preferred. Preferably, however, no processing auxiliaries
are included in the extrusion stage.
In a second aspect of the present invention, there is
provided a method of combating aphid pests at a locus, the
method comprising applying to the locus an aqueous
dispersion of polyvinylpyrrolidone and a pyrethroid
insecticide.
In a third aspect, the invention extends to the use
of a solid concentrate which comprises
polyvinylpyrrolidone and a pyrethroid insecticide for the
preparation of an aqueous solution for combating aphid
pests.
In a fourth aspect, the invention extends to the use
of an aqueous dispersion prepared by dispersing a solid
concentrate which comprises polyvinylpyrrolidone and a
pyrethroid insecticide in water for combating aphid pests.
WO 94/23579 PCTlEP94/01087
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The solid concentrate and/or the pyrethroid
insecticide of said second and/or third and/or fourth
aspects may be as described above with reference to the
first aspect of the invention.
The following examples illustrate the invention.
Certain terms used in the examples are explained
below.
FASTAC is a trade name for alpha-cypermethrin and is
particularly a racemate comprising (S)« cyano-3-
phenoxybenzyl(1R)-cis-3-(2,2-dichloro-vinyl)-2,2
dimethylcyclopropanecarboxylate and (R)- a-cyano-3-
phenoxybenzyl(1S)-cis-3-(2,2-dichlorovinyl)-2,2-
dimethylcyclo-propanecarboxylate.
DECIS is a Trade name for deltamethrin which is (S)-
a-cyano-3-phenoxybenzyl(1R)-cis-3-(2,2-dibromovinyl)-2,2-
dimethylcyclopropanecarboxylate.
BAYTHROID is a Trade name for cyfluthrin which is
(RS)-a-cyano-4-fluoro-3-phenoxybenzyl(1RS)-cis-trans-3-
(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate.
Esfenvalerate is (S)-a-cyano-3-phenoxybenzyl(S)-2(4-
chlorophenyl)-3-methylbutyrate.
"m/m" means "mass/mass"; "ai" means "active ,
ingredient" ; "wg" means "Water dispersible granules°' ; "TB"
means "tablet form"; "SC" means "suspension concentrate";
"EC" means "emulsion concentrate".
WO 94123579 ~ PCT/EP94/01087
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~Xample 1
Preparation of FASTAC/~olyvinylpyrrolidone solid
concentrate ~333c~/Kq ai).
A blend of the following powdered materials was mixed
using a core blender:
% m/m
to
FASTAC (technical material, from
Shell International Chemical Company) 333
polyvinylpyrrolidone, (Agrimer 30 from
ISP (Europe) Ltd) 662
benzoic acid 5
A sample of 5 kg of blended material was fed into an
APV MP2030 twin screw co-rotating extruder, 25:1 L/D
(length over diameter). A K-tron T20 volumetric feeder
with agitated hopper was used to feed the extruder. The
extruder barrel which was electrically heated and water
cooled was fitted with a vacuum pump via a vent port for
use when a melt seal had formed. The barrel melt zone
temperatures (nine in all) were set between 25 and 75
degrees centigrade (beginning to end of barrel) to 25 to
175 degrees centigrade (beginning to end of barrel).
A vacuum was drawn once a melt seal had formed in
order to remove the water vapour that formed in the barrel
from the residual moisture content of the
polyvinylpyrrolidone. The extruder screws were constructed
to give at least one conveyor section followed by a paddle
shearing/mixing section. The extrudate was finally
conveyed to the end of the barrel and extruded without a
die-plate directly onto a chill roller (chilled with water
WO 94/23579 PCTlEP94101087
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at 4 degrees centigrade). The extrudate was rapidly cooled ,
to a brittle glassy material on the rollers and removed as
chips by pegs rotating near the surface of the larger of
the two chill rollers. The chipped material was hammer
milled and sieve cut to approximately 250 micrometers. It
was then mixed with typical tabletting inerts and
compressed to a tablet using a tabletting machine.
The extrudate showed no detectable crystalline FASTAC
using differential scanning calorimetry (Perkin-Elmer DSC
7 machine) when heated through the normal melting
temperature of FASTAC.
~;xamule 2
Preparation of Deltamethrin/polyvinvlpvrrolidone
so~i~ concentrate lWG)
A 90g/kg solid concentrate of deltamethrin and
2o polyvinylpyrrolidone was prepared by a solvent evaporation
technique, as follows:
Deltamethrin and polyvinylpyrrolidone were dissolved
in a solvent blend 90:10 acetone . methanol. The solution
was evaporated to dryness using a rotary evaporator. The
solid residue was then crushed.
Examples 3 to 6
By processes analogous to the processes described in
E x a m p 1 a s 1 a n d 2 , t h a a c t i v a ,
ingredient/polyvinylpyrrolidone formulations noted in
Table 1 were prepared. Table 1 also includes data for
Examples 1 and 2, for ease of reference.
WO 94123579 PCT/EP94/01087
_ 19
TABLE 1
EXAMPLE PREPARED ACTIVE INGREDIENT CONCENTRATI WG
NO. BY ON ai m/m or
PROCESS TB
OF
EXAMPLE:
1 1 FASTAC 333g/kg WG
2 2 Deltamethrin 90g/kg WG
3 2 Cyfluthrin 90g/kg WG
4 2 Esfenvalerate 77g/kg WG
5 1 FASTAC 350g/kg WG
6 1 FASTAC 150g/kg TB
Comparative Example C1
Preparation of FASTAC emulsion concentrate (EC)
formulation.
A 100g/1 emulsion concentrate of FASTAC was prepared
as follows:
FASTAC was dissolved to homogeneity in the solvents
SHELLSOL A (Trade Mark) (an aromatic solvent blend) and
cylcohexanone, together with a pair of commercial
emulsifiers .
WO 94/23579 ~ PCT/EP94/01087
Comparative Example C2
r
Preparation of FASTAC suspension concentrate (SC)
;Formulation
5
A 250g/1 suspension concentrate of FASTAC was
prepared as follows:
FASTAC was slurried in water in which a commercial
10 dispersant (ORTAN 731 (Trade Mark) (Rohm & Haas)) was
dissolved. The slurry was milled to a volume median
diameter in the range 2 to 2.5 micrometers. Afterwards,
xanthan gum (ex. Kelco International Limited) was added to
a concentration of 3g/kg in the total formulation, to
15 prevent particle settling.
Comparative Examples C3 to C6.
By processes analogous to the processes described in
20 Comparative Examples C1 and C2, the formulations noted in
Table 2 were prepared. Table 2 also includes data for
Comparative Examples C1 and C2, for ease of reference.
WO 94/23579 ~ PCT/EP94/01087
- 21 -
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WO 94/?3579 . ; ~ PCT/EP94I01087
- 22 -
assessment of Aphicidal activity against pea aphids
(Acvrthosiphum uisum).
damp le 7
T h a a p h i c i d a 1 a c t i v i t y o f t h a
FASTAC/polyvinylpyrrolidone formulation of Example 1 was
compared with that of the FASTAC 100g/1 emulsion
concentrate formulation of Comparative Example C1 and of
the FASTAC 250 g/1 suspension concentrate formulation of
Comparative Example C2 as follows:
(i) Each formulation was diluted with tap water to
provide a series of spray concentrations spanning the
expected LCD (the dosage of active ingredient required to
kill 99% of the test species) to LCso (the dosage of active
ingredient required to kill 50% of the test species)
range. The top spray concentration applied, 0.0025%, was
estimated to be equivalent to 10 g active
ingredient/hectare (ai/ha), the rate of FASTAC currently
recommended for control of pea aphids. Lower
concentrations were applied where necessary.
(ii) 6 cm tall pea seedlings were placed on their sides in
9 cm diameter petri dishes lined with filter paper. Ten
adult pea aphids (Acyrthosiphum pisum) were introduced
into each petri dish and the aphids allowed to settle
before spraying with the formulations described above.
Assessments of knockdown activity and mortality were made ,
1 hour and 24 hours after treatment.
WO 94/23579 PCT/EP94101087
- 23 -
Results
The activity of the FASTAC formulations against pea
aphids (P~cyrthosiphum pisum) as assessed 24 hours after
treatment is shown in Table 3.
Additionally, it was observed that the knockdown was
extremely rapid for each of the FASTAC formulations
referred to in Table 3. Each formulation achieved complete
knockdown within half-an-hour.
WO 94/23579 PCT/EP94/01087
- 24 -
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WO 94123579 PCT/EP94/01087
- 25 -
Example s
The aphicidal activity of the polyvinpyrrolidone
formulations of Examples 2 to 6 was compared with that of
the formulations of Comparative Examples C1 to C6, as
follows:
The formulations were diluted with tap water to a
concentration of 0.001% active ingredient (ai) from which
a further four half dilutions were prepared. The
individual solutions were applied to a petri dish
containing a pea seedling infested with ten adult pea
aphids (Acvrthosiphum pisum). Treatments were applied at
a volume rate of approximately 400 1/ha (i.e. 0.001% ai
equates to a dose rate of -4g ai/ha). Depending on the
activity/inactivity of individual formulations in a first
test, adjustments to the dose range applied were made for
some formulations in repeat tests.
Speed of action was assessed by recording % knockdown
(KD) after 1 hour whilst mortality was assessed after 24
hours. The dose/KD and dose/mortality data were analysed
to estimate the concentrations achieving 50% KD after 1
hour and 50% mortality (LC50) after 24 hours. Each
formulation was tested twice and the data averaged.
In addition to LC50 values, toxicity indices (TI's)
relative to a standard were calculated. By taking the
commercial FASTAC EC formulation of Comparative Example C1
as the "standard" in this case, it is ascribed a TI of
100. Consequently any formulation less active than the
FASTAC EC will have a TI of <100 or if more active it will
have a TI >100.
WO 94123579 PCT/EP94/01087
- 26 -
r
Results
The results for Example 8 are summarised in Table 4.
TABLE 4
Formulation 1 hour KD 24 hour mortality
of Example
No.
LC50 TI LC50 TI
2 0.000053 210 0.00016 210
C3 >0.001 <10 0.00053 65
C4 0.000095 130 0.00012 290
3 0.00039 29 0.00052 68
C5 0.00029 39 0.00053 65
0.000040 230 0.00010 290
C7 0.000058 170 0.000094 310
6 0.00011 100 0.00034 100
7 0.00012 92 0.00031 110
C1 0.00010 100 0.00031 100
