Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUN~ AND SU~MARY OF THE INVENTION
_ eld of the Inventlon
The present invention relates tG a variable-viscosity,
insecticidal delivery formulation composed of a li~uid carrier,
e.g., water or oil, and one or more solid superabsorbent polymers
with one or more liquid or solid insecticidal or noninsecticidal
film-forming or surface-active agents, ovicides, larvicides,
pupicides, insecticides, biological control agents, pathogens,
parasites, microbial control ayents, insect growth regulators,
conventional toxicants, pesticides, or chemosterilants, with or
without herbicides or attractants, repellents, pheromones,
alcohols, diluents, or other additives. The present invention
also relates to a method of applying the insecticidal delivery
composition with one or more active insecticidal ingredients,
with or without one or more herbicides or other additives, as
variable-viscositv sprays or sols to an aquatic environment
having a natural population of aquatic environment insects, for
the purpose of controlling that population of insects. The
present invention also relates to the use of the insecticidal
delivery composition for a pretreatment application to an aquatic
insect dry habitat in order to control that ~opulation of aquatic
insects that will breed when the insect habitat becomes flooded
by rain or tides. This invention further relates to a facile
'~ "` '2' 2
cæ~
method of comhining t~o or more active ~nsecticidal ingredients
in a liquid carrler, e.g., water or oil, with one or more film-
forming agents, and one or more ~up~rabsorbent polymers, with or
without one or more herbicides or other additives, to formulate
variable-viscosity insecticidal delivery compositions tha-t are
flowable (i.e., sprayable, pump~ble, or injectable) for ground or
aerial application. The application of superabsorbent polymers
makes possible the mixing of active insecticidal and herhicidal
ingredients that would otherwise be di~icult or substantially
impossible to mix homogeneously in a liq~id carrier, e.g., watPr
or oil, as joint- or multiple-action ~ormulations for spray
application. Furthermore, this invenkion relates to the use of
one or more superabsorbent polymers in the formulation of a
variety of sprayable/flowable insecticide compositions to
synergize, enhance, activate, carry, disperse, release,
stabilize, bind, couple, encapsulate, agglomerate, regulate,
thicken, uspend, preserve, protect, ~tc., one or more of the
active and~or inactive ~ormulation components in the flowable
formulation and/or in the target aquatic, semi-aquatic, or
pretreatment environment(s) in which the formulation is applied,
in a manner hat will provide improved flowable formulations,
more efficient formulating ~mixing) procPdures, more efficient
application, and~or generally improve the insecticidal e~icacy
(performance) of the resultant formulation against the target
organism(s).
General Backqround
In particular, the present invention is directed
against mosquitoes that hreed in permanent or semipermanent,
natural or arti~icial, aquatic habitats. Mosquitoes of major
~3~ 3.~
importance to be controlled by the present invention are
species of the genera o-f Aedes, Ano~heles, Culex, Culiseta,
Coquillettidia, Deinocerites, Mansonia, Orthopodomyia,
Psorophora, Uranotaenia and Wyeomyia. It is the main
objective of this invention to direct the use of the flowable
insecticidal delivery composition(s) for the control of the
immature aquatic states of various species of mosquitoes
before they become biting adults capable of being a nuisance
and/or transmitting a disease. This technique is cost-
effec-tive and reduces the environmental and heal-th hazards
that can result when insecticides are extensively broadcast
over large areas for the control of the adult stages.
In addition to mosquitoes, other species of aquatic
environment insects such as biting and nonbiting midges,
black flies, moth flies, crane flies1 horse flies, deer
flies, hover or flower flies can constitute a nuisance and
often a health threat to humans and livestock. Thus, their
growth as a population, if unchecked, can be detrimental.
The medical and veterinary importance of various species of
mosquitoes and other important aquatic environment insects
are discussed in detail by Robert F. Harwood and Maurice T.
James in, Entomoloqy in Human and Animal Health, Seventh
Edition, 1979, Mac~illan Publishing Co., Inc., New York, N.Y.
Therefore, the scope of the present invention also relates to
the use of the flowable insecticidal delivery composition
with one or more active insecticidal ingredients, with or
without one or more herbicides or other additives, for
controlling various species of aquatic environment insects
other than mosquitoes.
Various compositions and methods for
controlling and killing insects are well known. A number
of patents discuss the
use o~ pesticides or insecticides. U.S. Patent No. 3,535,423
discloses a w~tabl~ powder pesticide concentrate that may be
dispersed in water. This is described as allowing the otherwise
insoluble pesticide to b~come soluble ln water. U.S. Patent No.
4,267,280 discloses controlled release pesticides and their
preparation. These pesticides are described as polymers with a
macro-molecular backbone and pendant groups having pesticidal
groups chemically linked thereto and prepared by reacting a
pesticide having a replaceable hydrogen with a multi~unctional
isocyanate to ~orm an adduct which is then reacted with a polyol
polymer substrate. U.S. Patents Nos. 4,400,391 and 4,401,456
disclose the use o~ alginate gel beads to encapsulate bioactive
materials to provide for their controlled release. The patents
describe beads being made to either float or sink and they may
contain insecticides. These beads are also described as acting
as carriers to place the bioactive material near the target
species, for example, a floatlng bead containing a herbicide
releasing the herbicide in close proximity to floating aquatic
weeds or the bead~ ~alling through foliage to release a herbicide
into the soil. U.S. Patent No. 4,344~857 contains a disclosure
that is similar to those imm~diately above; however it involves
encapsulation by xanthate derivatives and does not disclose the
ability to be used in conjunction with an aqueous environment.
A number of patents describe the use o~ substances
other than peF~ticides to control the growth of insects. U.S.
Patent No. 4,053,627 discloses a controlled release system for
juvenile hormones in aqueous environments. This is described as
being accomplished with alginata gel discs comprising alginatP, a
solubilizing agent, and a salt which yields cations, and
containing the juvenile hormone. U.S. Patent No. 4,160,033
~3~;P7~3~ .
discloses a method ~or the control of mosquitoe~ by the use of
film-formlng materials~ The method ls disclosed as invulving the
US8 of a film of organlc material which reduce~ the sur~ace
tension o~ the body o~ water, and subsequently causes the
mosquito larvae and pupae to drown.
At the present tlme, ground and aerial application of
non-petroleum film-forming agents such as ArosurfR MSF for
mosquito control is perPormed malnly of spraying the technical
liq~lid or vigorously agitated suspensions of the film-~orming
agent and water. However, technical film-forming agent(s) such
as Arosur ~ MSF applied as conventlonal liquid sprays are usually
adversely effected by wind drift and cannot penetrate dense
vegetation at the low recommended application rates. There~ore,
most of the costly insecticidal ~ilm-forming agent impinges on
the vegetation and does not reach the water where the mosquitoes
are breeding and/or i~ translocated by the wind to areas not
intended ~or application. In addition, the use of water as a
diluent for applicatlon of large volumes ~or easier vegetative
penetration wi~hout overdosing requires frequen~ high-speed/high-
shear agitation or the use o~ high-pressure/high-shaar, water-
injection systems to adequately suspend the ~ilm-forming agent in
the water for accurate applicatlon rates. Mosquitocidal film-
forming agents such as Arosur ~ MSF are virtually insoluble in
water, and there~ore require continuous or frequently repeated
high-shear agitatlon to ef~ectively suspend or resuspend the
Arosur ~ MSF in the water carrier.
~ he aqueous absorbency mechanlsm of acrylic-based
superabsorbent polymers has been described by the Ch~mdal
Corporation (Arlington Helghts, Illinois 60004) in their
~3~
Technical Data 5heets on Aridall~ Superabsorbent Polymers. The
absorbency of acrylic-based superabsorbent polymers is due to
carboxylic groups located on the backbone of the superabsorbent
polymer. When water contacts the suparabsorbent polymer, these
groups solvate rapidly and develop mutually repul6ive negative
charges. This causes the superabsorbent polymer to uncoil and
absorb many times its weight in water. Crosslinking preven~s
solution of the superabsorbent polymer. The aqueous medium
rapidly becomes orientPd on the surface of the superabsorbent
polymer by virtue of hydrogen bonding. The resulting gel has
remarkable ability to hold the aqueous medium even under
pressure. Superabsorbent polymers hold fluids by a physio-
chemical mechanism.
None of the prior art methods or compositions for
controlling insect populations are without disadvantagesO One
major problem associated with many of the aforementioned
compositions and methods of the prior art is their inability to
simultaneously apply immisc~ble, or otherwise incompatible
substances to the area to be treated. It has ~een found that
while film-forming materials, when combined with water and
ovicides, larYicides, pupicides, insecticides, pesticides,
conventional toxicants, biological control agents, microbial
control agents, pathogen~, parasites, chemosterilants, or insect
growth regulators, with or without herbicides or diluents such as
attractantq, repellents, pheromones, alcohols, etc., may produce
improved insect controlling eficacy over single active component
formulations, problems with mixing the ingredients homogeneously
often result. For example, blends of Arosur ~ MSF (a film-
forming agen~) and water or technical and/or water-base blends
~3~'7;~`g~
or Arosurf~ MSF and various formulations of Bacillus
thurinqiensis var. israelensis (B.t.i.), or Bacillus sphaericus
or Abat ~ ~-~ do not form homogeneous and stable suspensions when
casually mixed, and therefore require frequent and vigorous
agitation. When allowed -to stand, the components would separa-te
in-to distinct layers because of the differences in their
respective specific gravities, and/or the presence of
incompatible active and/or inert formulation ingredients, and
therefore these joint- or multiple-action formulations would
require continuous agitation and/or reagitation -to efEectively
remix the components just prior to their application. (See Levy
et al. 198~, Mosquito News 4:537-543; Levy et al. 19~6. ~ournal
of the American Mosquito Control Association 2:233-236.) These
mixing and remixing requirements make it very difficult to apply
these liquid (aqueous) formulations by conventional means.
While it may be possible to incorporate some known
insecticidal components, singly, jointly or multiply as aqueous-
or oil-base sprays, these formulations cannot regulate (retard)
the release rate of active insecticidal components, and lack the
ability to control both mosquito larvae and pupae simultaneously
while effectively and spontaneously spreading the active
ingredients over the target aquatic habitat.
Since other flowable insecticidal compositions do not
have rapid self-spreading characteristics, they require even
applications to assure tha-t there is eEEective control oE the target
aquatic insects that may be widely dispersed in the
aquatic habitat. In addi-tion, the other flowable insecticidal
components usually affect only one immature developmental stage.
However, the use of insec-ticidal delivery compositions made with
one or more superabsorbent polymers of the present invention
.
~ 3~t~
with, for example, a pupicidal film-formlng agent (e.g., Arosur
~SF), a larvici~al agent such at B.t.l or Bacill-~s sPhaericu~,
and water, have self~spreading potential and can kill mosquito
larvae, pupae, or emerglng adults rapidly in areas far removed
Erom the initial points of application, signi~icantly ~etter than
either of the active ~ormulation components. These formulations
can also kill floating eggs and egg rafts of certain species of
mosquitoes and also entrap and drown females that oviposit on the
surface of the water. Although Arosur ~ MSF can kill mosquito
larvae and pupae, its impact on larval populations is usually
very slow and requires higher application rates than for pupal
control.
No single-, ~oint-, or multiple-action flowable, water-
compatible formulations are available that claim rapid larvicidal
and pupicidal action with some degree of ovicidal and adulticidal
action, self-spreadin~ charactexistics, and field persistenceO
For example, commercial mosguitocidal preparations of sacillus
thurinqiensis var. israelensi~ formulated for water-base spray
applications (e.gO, Vectoba ~ -AS, Vectobac~ 2AS; Tekna ~,
Tekna ~ HP-D, Tekna ~ WDC; Bactimo ~ ~ettable Po~dr;
Skeetal~ ), Bacillus s~haericus (BSP-l), Abat ~ 4-E, Dursba ~,
Bayte ~ 4 and Bayte ~ LC, Furada ~, Baygo ~ 70% we~table powder,
Dimili ~ wettable powder, Altosi ~ Li~uid Larvicide are
available that have slow or quick immature stage kill potential;
however, these do not have rapid multi-developmental stage
control potential, do not have self-spreading characteristics,
are typically composed of only one active insecticidal ingredient
that cannot be simply and rapidly detected or monitored under
field conditions by insecticide applicators, and are not
formulated with superabsorbent polymers.
~C; '7~
Attempts have been made to incorporate film-forming
agents such as those described in U.S. Patent No. 4,160,033 with
a variety of conventional insecticides in water (See LeYy et al.
1984, Mosq~ito News: 44 pp. 537-543, pp. 592 595; Levy et al.
19~6. Journal American Mosq~lto Control Association 2:233-236).
However, these attempts have been unsuccessful because the film-
forming agent (i.e., Arosur ~ MSF) would readily separate into
layers even after vigorous agitation due to incompatibilities of
the film-forming agent with water or other insecticides and/or
inert ingredients in the formulation. Therefore, the resultant
formulations could not be homogeneously mixed to assure that
accurate application rates of the active components would be
applied in the Pield against the target aquatic pest.
;
Speciflc Objec~
It is therefore an object of the present invention to
provide flowable, aqueous- or oil-base superabsorbent polymer
compositions and methods for the pretreated dry habitat control
and aquatic control of a population of aquatic environment
insect~, particularly mo~qultoes, which overcome the problems and
de~iciencies o~ the prior art.
It is also an object of the present invention to
provide flowable, aqueous- or oil-base superabsorbent polymer
compositions and methods which are easy to prepare (formulate)
and use (apply), and which are erodible (biodegradable) and safe
to the environment, but which is effective for use in controlling
one, but preferably more than one immature stage of a natural
population of aquatic environment insect , particularly
mosquitoes.
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f:~ 3a~7~
It is further an object of the present invention
to provide superabsorbent polymer compositions and methods
which can incorporate a wide variety of ingredients into a
single flowable, aqueous- or oil-base insecticidal delivery
formulation to control a broad spectrum of aquatic
environmen-t insect populations, particularly mosquitoes, and
to provide for the variable time release of those
ingredients.
These and other objects are accomplished by the
compositions and methods of the present invention.
Specific Aspects
In accordance with one aspect of the present
invention, there is provided a controlled release variable-
viscosity, flowable, aqueous- or oil-basP insecticidal
delivery compositions for controlling a population of
aquatic environment insects, the flowable delivery
compositions being applied as a pretreatment before the
target habitat is flooded or as a direct treatment to the
aquatic habitat. The composition includes at least one
superabsorbent solid organic polymer comprising hydrophilic
acrylamide or acrylate polymers which absorb over 100 times
their weight in water, at least one insecticidal agent, and
water or oil, said polymer, agent and water or oil be:ing
present as a flowable Eormulation wherein the agent is
present in a total amount e~fective to control the
population of aquatic environment insects and wherein said
composition is an admixture formed by mixing the
superabsorbent polymer, the insecticidal agen-t, and the
water or oil.
In accordance with another aspect of the present
invention, there is provided flowable, aqueous- or oil-base
11
insecticidal delivery compositions for controlling a
population of a~uatic environment insects which includes at
least one superabsorbent polymer, and at least one different
insecticidal agent which is a film-forming agent, the
superabsorbent polymer and a~ent being present in a total
amount effective to control the population of aquatic
environment insects, the delivery compositions being applied
as a variable-viscosity pretreatment application before the
target habitat is flooded or as a direct treatment to the
aquatic habitat.
In accordance with yet another aspect of the
present invention, there is provided a controlled release
variable-viscosity, flowable, aqueous- or oil-base
insecticidal del.ivery compositions for controlling a
population of a~uatic environment insec-ts which includes at
least one superabsorbent solid organic polymer selected ~rom
the group consisting of hydrophilic acrylamide and acrylate
polymers, co-polymers and ter-polymers which absorb over 100
times their weight in water, at least one insecticidal agent
which is a film-forming agent, and at least one additional
compound selected from the group consisting of larvicides;
pupicides; avicides; insecticides; toxicants; pesticides;
biological control agents; microbial control agents;
pathogens; parasites; insect grow-th regulators;
chemosterilants; herbicldes; attractants; repellents;
pheromones; alcohols; and solvents; said composition being
in the form of a flowable, aqueous- or oil-base formulation,
wherein said polymer, agent and additional compound are
present in a total amount effective to control the
population of aquatic environment mos~uitoes an~ wherein
said composition is an admixture formed by mixing the
12
7~
superabsorbent polymer, the insecticidal agent, the
additional agent and water or oil. The additives are
selected from the group consisting of herbicides;
attractants; pheromones; repellents; diluents; alcohols,
surface-active agents; etc. The flowable variable-viscosity
aqueous- or oil-base delivery compositions are applied as a
pretreatment before the target habitat is flooded or as a
direct treatment to the aquatic habitat.
In accordance with another aspect of the present
invention, there is provided a method for controlling a
population of aquatic environment insects which includes the
steps of:
12a
2~
preparing flowable, variable-viscosity agu00us- or oil-
base insecticidal delivery composit10ns wh.ich includes at least
one superabsorbent polymer and at le.ast one insecticidal agent
which includes a film-forming agent, by a ~eri~s of variable
time/speed blending, and/or salt/electrolyts conditioning
treatments;
applying said flowable, a~ueous- or oil-base
insecticidal delivery compositions in an amount effective to
control the population o~ aguatic environment insects, to an
aquatic area needing aquatic insect control treatment, the
flowable aqueous- or oil-base delivery compositions being applied
as a pretreatment before the target habitat i5 flooded or as a
direct treatment to the aquatic habitat.
. In accordanca with still another aspect o~ the present
invention, there is provided a method for controlling a
population o~ aquatic insects. The method includes the steps of:
preparing flowable, variable-viscosity aqueous- or
oil-base insecticidal delivery compositions which includes at
least one superabsorbent polymer and a least one ins cticidal
agent which includes a film-forming agent and at least one
additional compound. The additional compound is selected from
ovicides; larvicides; pupicides; insecticides; conventional
toxicants, pesticides; biological control agents; microbial
control agents; pathogens; parasites; insect growth regulators;
chemosterilant~; and mixtures thereof, with or without
herblcides; attractants; repellents; pheromones; diluen~s;
alcohols; surface-active agents; etc.; and
applying said flowable, aqueous- or oil-base
insecticidal delivery compositions in an amount effective to
control the population of aquatic environment insects, to an
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~3~72~
aqua-tic environment needing aquatic insect con-trol treatment
before the target h~bitat is flooded or as a direct treatment to
the aquatic habitat.
The superabsorbent polymers of the present invention
are synthetic organic polymers which are solid and hydrophilic
absorbing over 100 times their weight in water. Generally, these
superabsorbent polymers are chosen from acrylamide and acrylate
polymers, co-polymers and ter-polymers. These polymers can be
suitably crosslinked and/or modified. These superabsorbent
polymers are typically in apowaer, flake, or granular form,
adapted to optimize khe compatibility and/or release rates of
insecticidal components in water or oil and, thereby, enhance the
activity of flowable insecticidal formulations against the target
aquatic insect.
The acrylamide and acrylate superabsorbent polymers may
be, for example, acrylamide alXali metal or alkali metal/aluminum
acrylate co-polymers; propenenitrile homopolymers, hydroloyzed,
alkali metal or alkali metal/aluminum salts; polymers of
propenamide and propenoic acid, alkali metal salts; hydroly~ed
acrylonitrile co polymers, and starch gra~t co~polymers and ter-
polymers thereof. All of these are designed to be hydrophilic,
absorbing over 100 times their weight in water.
The present invention has been found to be particularly
effective in controlling natural populations of mosquito species
such as Aedes taeniorhYnchusl Aedes sollicitans, AnoPheles
atropos, and Culex ni~ripal~us that can breed in brackish/salt
water habitats. The use of the invention to control species of
fresh or polluted water mosquitoes such as Aedes ae~Y~ Aedes
albopictus, Aedes triseriatus, AnoPheles auadrimaculatus,
nopheles crucians, Culex quinque~asciatus, Psorophora columbiae,
,v
:' t~.,'l .'
2~:~
Psorophora ciliata, Wyeomyia itchellli, Wyeomia vanduzeei, etc.,
in semipermanent or permanent aquatic environment areas needing
mosquito control treatment is also proposed.
Specific Advanta~es
The present invention provides numerous advantages over
prior compositions and methods to control the population of
aquatic environment insects such as mosquitoes. For example, the
flowable aqueous- or oil-base superabsorbent polymer formulations
of the present invention may be composed of one or more of a wide
choice of either nontoxic or toxic biological or microbial
control agents, pathogens, parasites, insect growth regulators,
monomolecular surface films, larvicides, ovicides, pupicides,
insecticides; chemosterilants; pesticides, and/or toxicants, with
or without herbicides or attractants, repellents, pheromones,
diluents, alcohols, etc., depending on the type or nature of the
habitat to be controlled, the environmental impact, and/or the
type of aquatic devalopmental stage or insec-t species to be
controlled. The superabsorbent polymer formulations of the
present invention are flowable (i.e., sprayable, pumpable or
injectable~ and are mainly based on water; however, these
~ormulations can al50 be based on oil. The flowable aqueous- or
oil-base superabsorbent polymer formulations of the present
invention are biodegradable. They are also storage stable,
basically as stable as the individual components; however,
increased stability may occur from encapsulation of the active
components within the aqueous- or oil-base formula-tion. Aqueous-
or oil-base formulations of the present invention can be of
varying viscosities which may be required for a particular
application. The flowable formulations of the present invention
-15-
.
~3~ 3~
can have some variable time release, either ~uick, or gradual,
depending on ~he concentration and typ~s o~ superabsorbent
polymers in the aqueous- or oil-base formulation. The present
invention provides a suspending/compatlbility agent to a~sure
homog~neous delivery of joint- or multiple-active, aqueous- or
oil-base ~ormulations of otherwise incompakible ~oluble or
insoluble liquid or powdered insecticidal and~or non-insecticidal
agents without the necessity o~ continuous or repetitive high-
speed/high-shear agitation for ef~ective spray application of the
active components. Flowable, variable-viscosity aqueous~ or oil-
base ~ormulations of the present invention can be u~ed as a
pretreatment application to areas that are dry but are known to
breed when flooded, there~y assuring that the ~irst broods will
be controlled. Also, encapsulation of the active insecticidal
agents within the variable viscosity flowable superabsorbent
polymer Pormulation can protect the active components from
degradation or deaomposition from ultra-violet radiation,
microbial ackion, temperature effects, run-off, etc., when the
formulation is applied as a pretreatmPnt applicakion. The
present invenkion is al50 nok restricted to applications to any
one type of aquatic en~ironment.
Other objects, aspects and advantages o~ the present
invention will be apparent to one of ordinary skill in the art
from the following:
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
Surprisingly it has been found that certain
superabsorbent polymers constitute a novel class of chemicals
useful in flowable aqueous- or oil-base insecticidal delivery
compositions ~or controlling the population of insects in an
aquatic environment area needing aquatic environment insect
control treatment.
A flowahle insecticidal delivery composition is any
composition which can carry, or be adapted to carry, insecticidal
agent(s), biologically active or biologically inactive agent(s),
etc., to the target habitat, natural or artificial, aquatic or
dry. In a preferred embodiment, the flowable insecticidal
delivery agent is a mixture of one or more superabsorbent
polymers and water or oil. Superabsorbent polymers, including
starch graft co-polymers, are well known in the art. See, for
example, those described in United States Patent Nos. ~,375,535
and 4,497,~30 which have had uses as adhesives, flocculants,
sizes, water-retaining materials for agricul-ture and water-
absorbing materials for sanitary materials. However, the
advantages attendant the use of superabsorbent polymers in a
flowable aqueous- or oil-base insecticidal delivery composition
and more speci~ically for mosquito control in an aquatic
environment, have gone completely unrecognized.
The superabsorbent polymers o~ the present invention
are synthetic organic polymers which are solid and hydrophilic,
absorbing over 100 times their weight in water. These
superabsorbent polymers are substantially water-insoluble, and
are typically in a powder, flake, or granular form, adapted to
optimize the compatibility or release rates of insecticidal
~3g~
components in water and thereby, enhanc~ the acti~ity or eficacy
of the aqueous- or oil-basa ~nsecticidal formulations again t the
target aquatic insect.
Generally, these sup0rabsorbent polymers are chosen
from acrylamide and acrylate polymers, co-polymers and ter-
polymers, which may optionally be modifled by cross-linking or
grafting with, e.g., starch.
The acrylamide and acrylate superabsorbent polymers may
be, for example, acrylamide alkali metal or alkali metal/aluminum
acrylate co polymers; propenenitrile homo-pol~mers, hydrolyzed,
alkali metal or alkali metal/aluminum salts; hydrolyzed
acrylonitrile co-polymers, and starch graft co-polymers and ter-
polymsrs thereof. All of these are designed to be hydrophilic,
absorbing over 100 times their weight in water. The resulting
hydrophilic polymers can absorb from over one hundred to greater
than about 5,000, more typically around 500 to about 1,000, times
their own weight in water (measured using distilled water, pH
7.5, 25C, 760 mm Hg. 3 absorption within about 30 seconds).
However, the water absorption or swelling capacity and ra~s
typically vary with each specific superabsorbent polymer.
One clas~ of superabsorbent polymers include
combinations of a ~tarch and organic monomers, oligomers,
polymers, co-polymers, or ter-polymers. They may be manufactured
in a variety of ways, for example, the methods described in
Vnited States Patents Nos. 4,375,535 and 4,497,930, and can be,
~or example, the product of gra~ting corn starch (amylopectin)
with acryloni~-rile (an acrylic monomer or oligomer).
The superabsorbent polymer~ can also be acrylics,
propenoic or acrylonitrile/acrylamide-base polymers or co-
polymers or ter-polymers that also show superabsorbency
~3~ 0~
properties such as cross-linked or cross-linked modified
polymers.
It has also been observed that superabsorbent polymers
alone, or mixed in water with one or more insecticidal agent(s),
have the ability to further swell in water, thereby altering the
rates of release of the substance(s) in the formulation.
Superabsorbent polymers also have the ability under certain
conditions to reform or contract to a crystal or congealed-like
consistency similar to th~ir original form when evaporation has
caused the water to be removed from the sol or gel-like
formulation and then swell or re-gel when additional water is
added. This ability to be functional after repetitive periods of
wetting and drying is advantageous for pretreatment applications,
applications to habitats that experience rapid flooding and
drying cycles, and/or for prolonging the release of active
components. In addition, insecticides encapsulated in the
variable-viscosity sol, gel-like, or crystal or congealed-like
formulations can be protected from climatological and biological
degradation in pretreatment and/or in semipermanent habitats;
thereby prolonging their Eield activity. Storage or shelf life
may also be prolonged in several of these formulations.
Non-limiting specific examples of superabsorbent
polymers with differential swelling properties, and which are
particularly useful as insecticidal delivery agents include:
1) a co-polymer of acrylamide sodium acrylate (Terra-
Sorb GB):
2) hydrolyzed starch-polyacrylonitrile (Terra-Sorb);
3) 2-propenenitrile, homo~polymer, hydrolyzed, sodium
salt or poly (acrylamide-co-sodium acrylate) or poly (2-
--19--
a1~
propenamide-co-2-propenoic acid, sodium salt), (Water Lock3
Superabsorbent Polymer G-lO0),
4) starch-g-poly (2-propenamide-co-2-propenoic
acid, sodium salt), (Water Lock~ Superabsorbent Polymer A-
100);
5) starch-g-poly (2-propenamide-co-2-propenoic
acid), (Water Lock~ Superabsorbent Polymer A-200);
6) starch-g-poly (2-propenamide-co-2-propenoic
acid pokassium salt), (Water Lock~ Superabsorbent Polymer B-
204);
7) starch-g-poly (2-propenamide-co-2-propenoic
acid, mixed sodium and aluminum salt), (Water Lock~
Superabsorbent Polymer A-222);
8) poly (2-propenamide-co-2-propenoic acid,
sodium salt), (Water Lock~ Superabsorbent Polymer G-400);
9) poly-2-propenoic acid, sodium salt (Water
Lock~ Superabsorbent Polymer J-500 or Aqua Keep~ J-500);
10) sodium polyacryla-te superabsorbent polymers
(Aqua Keep~ J-400 and J-550);
11~ starch-g-poly (acrylonitrile) or starch-g-
poly ~acrylamide-co-sodium acrylate), (General Mills SGP~
502S);
12) starch acrylonitrile co-polymer (Super
Sorb/AG Sorbent);
13) cross-linked modiEied polyacrylamides
(Aquastore~ and Aquastore~ F);
14) cross-linked acrylics (Aridall~ 1078, 10~0,
1091, 1092, 1098 or 1125).
Superabsorbent polymers are generally nontoxic
biodegradable, and relatively inexpensive to buy or produce.
' ~ 20
~3~
See, for example, U.S Patents 3,6~1,815 and ~,159,260.
~ n insecticidal a~ent of the present invention is a
compound which is eff~ctive in an aqueous- or oil-base
superabsorben-t polymer formulation in controlling a population of
aquatic environment insects in an aquatic area needing a~uatic
insect control treatment. In a preferred embodiment,
insecticidal agents include film-forming agents, ovicides,
larvici~es, pupicides, pesticides, insecticides, toxicants,
chemosterilants, biological control agents, pathogens, parasites,
microbial control agents, and insect growth regulators. These
insecticidal agents can be used alone or in a combination;
however, in a more preferred embodiment, the insecticidal agent
contains at least one ~ilm-forming agent. Insecticidal agents
can also be formulated with herbicides, attractants, repellents,
pheromones, or other diluents that enhance the action of the
formulations but show insufficient insecticidal activityO
Electrolytes/salts interfere somewhat with the hydrogen
bonding. Crosslinked acrylic-based superabsorbent polymers
always absorb less aqueous medium when electrolytes/salts are
present. Normally, the addition of water or water-based
insecticidal formulations to various concentrations of
superabsorbent polymers, or visa versa, can form sols or gels of
various consistencies (viscosities) or stiffnesses that may or
may not be Elowable. However, high-shear mixing or the addition
of various electrolytes/salts can break or interfere with the gel
structure or the hydrogen bonding, thereby producing flowable
(sprayable) superabsorbent polymer/insecticide a~ueous
formulations that have the ~esired viscosity. Viscosity
modification will mainly be a function of the active and/or
inactive formulation components, the water absorption
characteristics of the superabsorbent polymer (i.e., the type and
amount of superabsorbent polymers), shear time and stren~th used
t 21
. . .
, ~
~3~7~
t~ mix the formula~ion and/or the concentra~ion and type o~
electrolytes/~alts used to modify the sol or gel consistency of
the formulation. Therefore, the viscosity o~ the aqueous
formulation containing one or more superabsorbent polymers can be
altered to achieve optimum flowability, droplet size and
quantity, and thereby improve the general ground or aerial
application characteristics o-f the formulation for maximum
control of the target aquatic insect. Furthermore, active
insecticidal ingredients encapsulated in the viscous/semi-viscous
but flowable aqueous (or oil base) superabsorbent polymer
formulation can be protected from degradation from the effects of
ultra violet radiation, volatilization, temperature, microbial
activity, evaporation, run-off, etc., particularly when used in
pretreatment habitats. Furthermore, evaporation of water from
the flowable, aqueous superabsorbent/pesticide formulation can
result in a solid congealed-like pesticide encapsulated matrix
(as described in U.S. Patent No. 4,818,534) thereby protecting
the active components for prolonged periods until release of the
insecticidal ingredient is triggered when the preaquatic
(pretreatmen~) habitat is flooded with water.
Film-forming agents that are mosquitocidal are
generall~ water-immiscible organic chemicals which form a
monomolecular or duplex films on water. The chemicals are
generally nonionic, nonvolatile and water immiscible liquids.
They may have a low freezing point, a boiling point above the
maximum air temperature of the environment into which they are
3~
)laced, and are capable oE rapid and spontaneous spreading
with high respreading potentials.
~ xamples of llquid, semisolid, or solid ~ilm-
forming or surface-active agents useful in conjunction with
the present invention for insecticidal and/or
noninsecticidal purposes are: the organic chemicals
described in U.S. Patent No. 4,160,033, and organic
chemicals that reduce the water surface tension to greater
than 31 dynes/cm and/or have an HLB No. greater than 10.
Film-forming agents such as 1-propanol, tridecyl alcohol, 2-
ethyl butanol, 2-ethyl hexanol, l-hexanol, acetone, xylene,
decyl alcohol, polyoxyethylene (20) sorbitan trioleate,
polyoxyethylene alkyl aryl ether, polyoxyethylene (5)
sorbitan monooleate, isostearyl alcohol con taining 20
oxyethylene groups, sorbitan monooleate, isostearyl alcohol
containing 10 oxyethylene groups, Morwet~ surfactants, cetyl
alcohol, steary] alcohol, etc. may be useful.
HLB stands ~or "Hydrophile-Lipophile Balance," as
defined in THE ATLAS HLB SYSTEM, Atlas Chemical Industries,
Inc. (4th Printing), 1963. The HLB number is an indication
of the percentage of the hydrophilic portion of the nonionic
emulsifier molecule, as defined on pages 3 and 18 of this
reference.
A pupicide is any material that can kill
that specific developmental stage of certain a~uatic
insects called a pupa. Pupicides are usually chemicals that
kill pupae directly by forming petroleum or nonpetroleum
films on the surface of water that cause the pupae to drown.
This stage is nonfeeding and directly precedes the adult
stage. Examples of pupicides useful in accordance with the
present invention are Arosurf~ MSF or other film-forming
agents described in U.S. Patent No. 4,160,033.
Biological/microbial pupae control agents such as bacteria,
~3~'~JZ~
Eungi, protozoa, viruses, rickettsiae and nematodes may also be
used.
Formulations of at least one Eilm-forming agent such as
Arosur ~ MSF with superabsorbent polymer(s) and water of the
present invention into a variable-viscosity flowable formulation
allows a significantly more homogeneous and stable (persistent)
suspension of Arosur ~ MSF and water to form after an initial
high shear mixing, as well as larger droplets of the aqueous
formulation to penetrate through the vegetative canopy ~or
release of the active film-forming agent into the target aquatic
habitat with significantly less wind drift-related problems. In
this manner, the need for repeated high-shear mixing/remixing is
virtually eliminated. Also, premixed formulations of
superabsorbent polymer(s), Arosur ~ MSF, and water can be stored
as aqueous formulations for direct use for ground or aerial
application with little or no additional mixing. In addition,
flowable variable-viscosity formulations of superabsorbent
polymer(s), a film-forming agent(s) such as Arosur ~ MSF and
water of the present invention can effect a mechanism for slowing
down the rate of release of active ingredients, thereby extending
the field life or persistence of the mosquito-controlling surface
film for a greater period of time than would be expected with
conventional technical or agitated non-superabsorbent polymer
aqueous formulations of Arosur ~ MSF.
The rate of release and/or re-release of the
mosquitocidal film-forming agent from the variable-viscosity,
flowable superabsorbent polymer formulation will be mainly
dependent on the viscosity of the formulation, that is, the ratio
of superabsorbent polymer to water (or oil), the water absorbing
(swelling) characteristics of the superabsorbent polymer(s), the.
-2~-
~,j .
~7'~
water quality of the natural or artificial habitat and/or
formula-tion diluent, and on the climatological moisture/water
conditions to which the formulation is exposed. High-shear
mixing/agi-tation techniques, the addition oE various
concentrations of salts/electrolytes (e.g., NaCl, KCl, etc.) to
the superabsorbent polymer/pesticide mixture, and/or the use of
invert oil techniques are proposed for regulating the viscosity
of the flowable superabsorhent polymer formulations.
The proposed variable-viscosity, film-formlng
agent/superabsorbent polymerts), flowable, aqueous formulations
will resist wind drift (i.e., have greater drift retardant
characteristics than simple aqueous spray formulations having no
superabsorbent polymer(s)), and initially show a differential
ability to float and/or sinX depending on the specific gravity of
the superabsorbent polymer(s). The aiddition of various
concen-trations of one or more superabsorbent polymer(s) can also
enhance the mixing capability and stability (i.e., reduce or
eliminate product(s) separation or stratification~ of one or more
active and/or inactive formulation components (e.g., formulations
of Arosur ~ MSF and Bacillus thurinqiensis var. israelensis
(~.t.i.) or Bacillus sphaericus (B. s~haericus) in a water base;
see Levy et al. 198~, Mosquito New_, A~:537-5~3 and Levy
e-t al. 1986, Journal of the American Mos~uito Control
Association, 2:233-236) in water by ac-ting as a compa-tibility
or suspending agen-t.
A larvicide is any material that can kill -that specific
developmental stage of certain aquatic insects called a larva.
Larvicides can kill larvae after ingestion of a toxic material,
kill on or after contact with the integument, or kill by physical
(nontoxic) and/or toxic means by causing -the larvae to drown.
i~! .i . j
The larval stage is a feeding ~tage that usually has several
molting or growth phases called instars. For e~ample, in
mosquitoes there are ~our larval inst2rs~ The larval stage
directly precedes the pupal stage. Examples o~ larvicides useful
in accordance with the present invention include biological
control agents or microbial control agents ~uch as Bacillus
thurinqiensis ~ar. israelensis ( g., V~ctoba ~, Bactimo ~,
Tekna ~, Skeeta ~, ~osquito Attac ~ or BaciLlus sphaPricus
(e.g., BSP-1~; conventional toxicants such as Abate~, Bayte ~,
Dursbar~, Prento ~, Pyrenon ~, resmethrin, ~alathion, pyrethrins,
allethrin, Baygo ~, Furada ~, methoxychlor, etc; and nonpetroleum
film-forming oils such as Arosur ~ MSF. Fungi (such as
Lo~ u~ 'D4V~`~ Y I mycelia and oospores), protozoa, viruses,
rickettsiae and nematodes may also be used.
Insect growth regulators (IGRs) are chemicals such as
juvenils hormone or anti-juvenile ho~none analogues that kill the
target aquatic environment insect in one or more immature stages
by adversely affecting the molting or developmental cycle. IGRs
are not cons~dered to be direct larvicides or pupicides. For the
most part, larvae that are exposed to the chemical continue to
develop normally until they reach the pupal stage where they die.
Examples o~ IGRs are Altosi ~, Dimili ~, and fenoxycarb
(Pictyl~ .
Insecticides (i.e., pupicidesl larvicides, insect
growth regulators, pathogens, etc., use~ul in the present
invention are discussed in W.T. Thomas, 1985, Aqricultural
Chemicals, Book 1 Insecticid~s, 1985-86 Revision, Thomas
Publications, Fresno, Cali~ornia, pp. 1-255, and in George 0.
Poinar, Jr. and Gerald M. Thomas, 1978, Dia~nostic Manual for the
~'7~
Identification of l~s~ a~ , Plenum Press, New York, pp.
1-218.
The use of one or more herbicidal in~redients in the
flowable superabsorbent polymer insecticidal compositions is
propos~d for selected ground or aerial appllcations. It has been
shown that certain aquatic weeds (plants) can provide excellent
breeding grounds for di~ease carrying mosquitoes, and programs
aimed at the control of al~ae and submer~ed, floating, or
emergent plants and/or marginal aquatic plants have been shown to
reduce the incidence of various mosquito-transmitted diseases
(Dr. Edward 0. Gangstad, 1986, Freshwa~ Veqetation Manaaement,
Thomas Publications, Fresno, California, 377 pp.). For example,
aquatic weeds such as coontail, widgeon grass, waterweed,
pondweed, stonewort, bladderwort and filamentous green algae
~particularly ~ 9gyL~ have been shown to enhance the
development of several species o~ no~h~les mosquitoes that can
be vectors o~ malaria in the United S~ates and overseas. In
addition, ~ tarsalis, a ~ector of St. Louis and Western
encephalitis in tha midwestern and western Unitsd States/ breed
in aquatic plant (weed~-choaked irrigation and drainage ditches,
seeps, and roadside impoundments. A1SQ~ larvae and pupae of
mosquitoes of the genera Mansonia and Coq~illettidia (potential
vectors of Eastern encephalitis) derive their oxygen by puncture
from air trapped in hollow aquatic plant stems. In addition,
Aedes 3~gy~, a vector of dengue and yellow fever can breed
inside certain water plants. Therefore, the use of herbicides to
complement the insecticidal action of the superabsorbent polymers
formulati~ns of the present invention is proposed to enhance
general mosquito control operations in areas containing
significant densities of aquatic plants.
-27-
~ 3 ~'~t~
Herbicidal materials proposed for use in the present
invention can include one or more materials from the groups,
phenoxy compounds; benzoic, acetic acids and phthalic compound;
dinitro anilines, nitrites, amides, acPtamides and anilides;
carbamates; heterocyclic nitrogen derivatives; urea compounds;
metal organics and inorganics; petroleum derivatives; phosphates;
carbothiolates; cyclic compounds; halogenated hydrocarbons;
dinitros; aliphatic acids; and others. Various herbicidal
~ormulations in these groups are discussed in detail in W.T.
Thomson, 1986, Aqricultural Chemicals~ Book II. Herbicides. 1986-
87 Revision, Thomson Publications, Fresno, California, 301 pp.
and in Dr. Edward 0. Gangstad, 1986, Freshwater Veqet_tion
Manaqement, Thomas Publlcations, Fresno, California, 377 pp.
Herbicides and mixtures th~reof of specific interest in these
groups used ~or controlling floating weeds, immersed broadleaf
weeds, submersed weeds, algae, irrigation and drainage ditch bank
weeds, and irrigation and drainage canal weeds, include Acrolei
ammonium sulfamate, Aquazine~, Banve ~, Casoro ~, copper, copper
sul~ate, Cutrin ~, Dalapo ~, Dichlon ~, Diqua ~, Endothal~,
Fena ~, Karme ~, Monuro ~, petroleum solvents, Rode ~, Roundu~
Sima~in ~, Sona ~, Spik ~, 2,4-D, Velpa ~, and xylene.
Insect population is used here to refer to one or more
group(s~ or species of aquatic environment insects that breed in
any type of aquatic environment or habitat r~quiring control
treatment. The population as used herein denotes a natural or
artificial breeding area and the like or the aquatic insects,
pupae, larvae and eggs contained within any geographical area
needing a~uatic environment insect control treatment. For
example, a field, yard, pasture, pot hole, salt marsh, ditch,
tire, woods, lake, stream, river, bay, pond, etc., may be
-28-
treated. Of course, the area needing aquatic environment insect
control treatment can be any size and the present invention i5
only limited by the amount of time, equipment~ and material
available.
One or more superabsorbent polymers can be usPd t~ ~orm
flowable~ variablP-viscosity single-, joint-, or multi-purpose,
aqueous- or oil-base formulations composed of one or more
insecticides, etcO, with or without herbicides or other dtluents,
solvents, surfactants, attractants, etc., for spray applications
by conventional ground or aerial techniques, to control a variety
of aquatic insects in a variety of aquatic or preaquatic
(pretreatment) habitat~. The superabsorbent polyme.rs are used in
a variety of flowable aqueou~- or oil base insecticide
formulations to synergize, enhance, act~vate, carry, release,
stabilize, bind, agglomerate, regulate, thicken, suspend,
neutralize, preserve, etc., one or more of the active and/or
inactive Por~ulation components ln the flowable formulation
and/or in the target aquatic environment(s) in which the
Pormulation is applied, in a manner that will provide improved
formulations, and mor~ efficient formulation application.
Variable viscosity, aqueous- or oil-base formulations
are flowable and have the ability to release one or more active
agents when applied to aquatic environments. The rate of release
is dependent on the concentration of fo~mulation components
(e.g., superabsorbent polymers, water or oil~, the swelling
characteristics of thQ superabsorbent polymer(s), and on the
habitat of climatological condition to which the formulation is
exposed or released (e.g., dry or wet, pretreatment or aquatic).
Variable-viscosity superabsorbent polymer-based
formulatlons can be formulat~d by admixing an active agent with
-29-
~3~72~
one or mor~ superabsorbent polymer(s) and water or oil in any
suitable order and then treating said ~o~mulation with vigorous
or high-shear mixing and/or electrolytes~salts. The ratlo o~
superabsorbent polymer(s~ to water or oil depends on the desired
viscosity, the nature o~ the superabsorbent polymer(s) and the
method used to render it flowable. Ths ratio of superabsorbent
polymer(s) to water is suitably 0.001:100 to l lo The amount o~
active agent in the flowable formulation is qener~lly 0.00001 to
50 weight percent, preferably 0.0001 to 25 weight percent.
One technique used to render a viscous/semi-viscous
aqueous superabsorbent polymer composition 10wable is suitably
vigorous or high-shear mixing/agitation. Any suitable equipment
or technique used to incorporate insecticid~s into an aqueous
emulsion can be suitably used to render a non-flowable
superabsorbent-base formulation flowable. Invert oil techniques
are also appropriate for mixing and dispensing a highly viscous
aqueous superabsorbent polymer formulation composed of an
insacticlde and ~urface active agent, with or without herbicides
or other additive~.
Normally, unmixed ~ormulations o~ superabsorbent
polymers and water have a tendency to ~orm gels of such a high
viscosity that they are not flowableO An additional technique
used to render a viscous superab~orbent polymer composition of
the present invention flowable, is the additional of varying
concentrations o~ one or more salt(s)/electrolyte(s) such as
sodium chloride. However any suitable salt/electrolyte such as
pota~sium chloride, magnesium chloride, calcium chloride, sodium
sulfite, etc., can be employed. These salts/electrolytes have a
tendency to inter~ere with the hydrogen bonding or reduce the
hydrophilic bonding o~ the water to the gel. Also,
-30-
superabsorbent polymers (e.g., crosslinked acrylics) absorb l~ss
water when electrolytes are present. This technique can be used
by itself or in conjunction with vigorous or high-sh ar m~xing to
produce a flowable (i.e., sprayable, pumpable or injec~able)
aqueous superabsorbent polymer formulation having an active
ingredient such as an insecticide, pesticide or other suitable
agents. The technique and degree of viscosity variation are
dependent upon the active and inactive ingredients in the
superabsorbent polymer ~ormulation. Relevant factors in the
degree of viscosity of the fo~nulations are the water swelling
characteristics of the superabsorbent polymer (i.e., the type and
amount of polymer), water concentration and quality used in the
formulation, the shear time and strength used to mix or agitate
the ~ormulation and/or the type and csncentration of
salts/electrolytes used to modigy the gel consistency. Using a
suitable combination of viscosity varying techniquesl the aqueous
~ormulation can be altered to obtain optimum characteristics such
as flowability (sprayability), encapsulation o active
ingredients, droplet 5iZ~ variations, substrate adherence, slower
release rates of active components, and wind drift retardation.
It is contemplated that aqueous insecticidal delivery
formulations made flowable by vigorous or high-shear agitation
and/or the addition of salts/electrolytes can be uced to control
immature stages of mosquitoes. The superabsorbent polymer(s)
used in the flowable aqueous formulation effectively suspends or
assists in the mixing of the various active and inactive
ingredients, regardle~s of their compatibility with each other
and/or the aqueous medium, to form a homogeneous formulation.
For example, Super Sorb, Arosur ~ MSF and Water, or Super Sorb,
Arosur ~ MSF, water and B.t.i. or B. sphaericus, can be
~3~2~
effectively blended together to form a flowable composition with
suf~icient high-shear agi-tation and/or salt/electrolyte addition
such that the ingredients will no-t separa-te or partition for an
extended period of -time. In contrast, under normal circumstances
such ingredients would rapidly separate requiring repetitive high
shear agitation to render the composition suitably homogeneous
for application purposes. As such, large quantities of the
formulation can be prepared sufficiently ahead of time and
suitably stored until needed, when -they can then be applied by
con~entional spray techniques, without the cumbersome need for
repetitive vigorous or high-shear reagitation.
The flowable aqueous compositions also are advantageous
when used in aerial applications in their ability -to resist wind
drift. By altering viscosity significantly, droplet density,
size, shape and surface characteristics can be altered to
significantly affect the droplet wind resistance, flow, and
deposition characteristics when applied with an aerial delivery
syst~m. Additionally, aquatic buoyancy characteristics can be
suitably altered in the flowable formulation such as by varying
the type and concentration of superabsorbent polymers having
different specific gravities, incorporating micro bubbles in the
shearing technique, or usiny high molecular weight additives for
the sinkiny formula-tions. The variable-viscosity composition
also can be sultably modified to effect its surface
characteristics with oils, wetting agents, surface-active agents,
and the like. Varying concentrations of superabsorbent polymers
replaced with surface active agents can be incorporated such as to
effect the adhesiveness of the water-base spray formulation
causing it to cling or adhere to desired strata or plan-ts when
delivered to the target pretreatment environment. Other
~3~'7~
formulation additives can include the above sur~actants as we31
as suitable polymeric agents such as plasticizers, water-sslu~le
polymers, film-~orming polymers, stc.
The concQntration o~ superabsorbent polymer(s) in the
aqueous or oil ~ase formulations o~ the present invention has
been shown to effect the release rates o~ the active insecticidal
ingredients. In addition, varying the ratio of di~rent types
of these superabsorbent polymers of the present invention that
have differential water uptake characteristics (e.g., Water Loc
and Aridall~ products) in a single formulation may effect a
mechanism to furth~r enhance slow-release characteristics of
certain active insecticidal ingredients. In addition, the
varying specific gravities (i,e., les~ than or greater than one)
of the superabsorbent polymers and active insecticidal
ingredients oP the present invention can be used to devalop
flowable ~ormulations that initially float and/or sink for use in
a variety of habitats to optimize the kill o~ a variety of
aquatic insect species.
It should b~ noted that certain electrolytes/salts
~e.g., alkali metal halides such as NaCl) have been shown to
interfere wlth hydrogen bonding o~ the superabsorbent polymers in
an aqueous medium. Also, crosslinked acrylic superabsorbent
polymers have been shown to absorb less water when electrolytes
are present. This can have an impact on the swelling and
population control ability of the flowable insecticidal delivery
composition (e.g., the release rate of certain insecticidal
agents that are ~ormulated there within). Therefore, it is
possible to utilize certain eleatrolytes/salts in superabsorbent
polymer-base formulations as another mechanism to alter (enhance
in this case) or ad~ust the release rate o~ various active
13B~Z~
ingredients incorporated in the~e formulations. The
salt/electrolyt~ content of the aquatic habitat may also have an
effect on kill of the target species such as mosquitoes by
affecting the superabsorbent polymer swelling,
breakdown~decomposition of viscous formulations, and/or relPase
of active insecticidal ingredients encapsulat~d ~ithin the
flowable aqueous superabsorbPnt polymer ~ormulations.
The following are examples of comparative bioassays
that demonstrate effective control of larvae, p~pae, and/or
emsrging adults of a variety o~ mos~uito species with single and
joint action flowable aqueous formulations of a superabsorbent
polymer and one or more insect control agents. Examples
demonstrating Pormulation viscosity modification with high
mixinq and/or electrolyte/salt condltioning and slow release are
also presented. All parts, percentages and ratios are by weight
unless otherwi~e noted.
EXAMPLES I - VII
Data wa~ collected from the use of aqueous insecticidal
delivery formulations composed of Super Sorb, Water Loc ~, Aqua
Keep ~, and/or Aridal ~ superabsorbent polymers and film-forming
agent isostearyl alcohol containing two oxyethylene groups
(Arosur ~ MSF); and a superabsorbent polymer, Arosur ~ MSF and
~.t.i , or B. sphae~icus; with or without high-shear and
salt/electrolyte conditioning. Arosur ~ MSF is the only film-
forming agent (so-called monomolecular surface film) that is
presently registered by the Environmental Protec~ion Agency
(E.P.A.) for use as a mosquito larvicide and pupicide and
licensed under U.S. Patent No. 4,160,033. ~ products have
-34-
Q~
E.P.A. registration while B. s~haericus (BSP-l) has an E.P.A.
experimental use permit pending E.P.A. registration.
Mixing compatibility/viscosity modification evaluations
were conducted with high-shear mixing or salt/electrolyte
conditioning with formulations of Water Lock ~, Aqua Kee ~, Super
Sorb, Aridall~, and/or Aquastore~ F Superabsorbent polymers,
Arosur ~ MSF, and water; and a superabsorbent polymer, Arosur
MSF, B.t.l. or B. sphaericus, and water or oil; or a
superabsorbent polymer, Arosur ~ MSF, 2,4-D, and water; as well
as with 50/50 superabsorbent polymer blends. Although similar
mixing compatibilities were obtained, the results indicated that
salt/electrolyte type and the concentration, and the shear
time/strength would vary depending on the superabsorbency of the
polymer~s) and the type of insecticide and/or herbicide in the
aqueous formulationO Mosquito bioassays indicated that the
larvicidal and pupicidal efficacy were generally equivalent.
Film-fo~ning agents such as sorbitan monooleate, oleyl
alcohol, 75% sorbitan monooleate and 25% 2-ethyl butanol or 2-
propanol, oleyl alcohol containing 2 oxyethylene groups, and
lauryl ether containing 4 oxyethylene groups were also evaluated
as substitutes for Arosur ~ MSF. These materials wera formulated
in water with Super Sorb or Water Loc ~ G-100 to determine mixing
compatibility and viscosity modification only. Although these
materials were not evaluated against larvae and pupae, mixing
studies indicated that homogeneous formulations were obtained,
thereby suggesting that comparable mosquito-controlling efficacy
would result. In addition, the insect growth regulators Altosi
Liquid Larvicide and fenoxycarb were also formulated with water,
Arosur ~ MSF and Super Sorb or Water Loc ~ G-100, to determine
~'7~
formulation compatibilities. Results indicate that joint-action
formulations of these materials can also be utilized.
Various concentrations of salts/elQctrolytes such as
sodium chloride, potassium chloride, magn~sium chlorid~, calcium
chloride, or sodium sul~ite were used in combination with mild
mixing (not high-speed/high-shear) to determine the optimum
conditions for viscosity modification and component compatibility
of aqueous formulations of Arosur ~ MSF, a Super Sorb, Water
Loc ~, Aqua Kee ~, or Aridall~ superabsorbent polymer, with or
without B.t i. or ~ . spa~risus . Results indicated that sever~l
types of variable-viscosity superabsorbent pol~mer compositions
of one or mor~ insecticides and water were homogeneous, stable,
and flowable could be formulated by varying the
electrolyte~s~/salt(s) concentration and type.
In general, the data indicates that liquid film-forming
or surface-active agents can b~ initially mixed with a
superabsorbent polymer, alone, or in combination with water or
oil, or one or more liquid or solid mosquito larvicides,
ovicides, pupicldes, insecticides, pesticides, biological control
agents, microbial control agents, pathogens, para~ites,
conventional toxicants, and insect growth regulators, by high-
speed or high~shear agltation, or salt/electrolyte conditioning
procedures with mild agitation, to produce flowable, homogeneous
and stable, single-, ~oint- or multiple-action, variable-
viscosity aqueo~s- or oil-base formulation~ for single- and
multi-stage mosquito control in the aquatic environment.
Flowabls formulations produced in this manner with one or more
superabsorbent polymers can be premixsd and stored for prolonged
periods and will not require constant vi~orous spray system
-36-
~3C~
agitation for ef~ective ~ield application of the aqueous- or oil-
base suspensions~high-shear compositions.
Surprisingly, the data indicates that aqueous
formulations of Super Sorb and Arosur ~ MSF generally produced
faster control of larvae of Aedes taeniorh~nchus than Arosurf
MSF alone. The data suggests that the flowable aqueous
superabsorbent polymer formulation rsmained homogeneous and
stable after initial mixing and may produce an activation or
larvicidal enhancement mechanism for Arosur ~ MSF against this
mosquito species in the water qualities tested. It should be
noted that the superabsorbent polymer alone showed no significant
larvicidal activity. In general, some larvicidal enhancem~nt was
observed in tests against Cul~ quinquefasciatus with aqueous
formulations of Super Sorb and Arosur ~ MSF. Tests against this
species in fresh water showed initial larvicidal enhancement or
comparable larvicidal eff1cacy over the test period when the
superabsorbent polymer/Arosur ~ MSF formulations were evaluated
against Arosur ~ MSF alone (i.e., without palymer). It should be
noted that la~vae of the ~ taeniorh~nchus are significantly
more sensitiv~ to Arosur ~ MSF than Çxt, quinouefasciatus.
However, it should be noted that the salt marsh mosquito
Ae. taeniorhynchus is the main pest mosquito in Lee County as
well as in other coastal counties of Florida and other parts of
the U.S.A.
EXAMPLE I
A flo~able formulation was prepared in this example.
Water, Arosur ~ MSF, and Super Sorb were mixed together in a
glass beaker with a laboratory blender containing a shearing
blade to produce an aqueous formulation that could b~ used to
-37-
-~3~7ZO:~
control mosqui-to larvae and pupae at application rates
recommended for the con-trol of immature mosquitoes. For example,
0.~ g of Super Sorb were added to 94.4 g of water purified by
reverse osmosis filtration (RO) while mixing at 1800 rpm Eor 30
sec. Mixing speed was increased to 2400 rpm while adding 5.2g of
Arosur ~ MSF. Mixing was continued for lO min. Observations
indicated that the Arosur ~ MSF was homogeneously suspended in
the water with the addition of 0.4~ Super Sorb superabsorbent
polymer to form a milky semi-viscous flowable formulation. This
formulation was easily sprayable from a plastic hand-pump
sprayer. No visible strati~ication or separation of the
formulation components was observed one hour after preparation.
However, aqueous Arosur ~ MSF formulations containing no Super
Sorb and mixed in a similar manner began to separate into an
Arosur ~ MSF and a water phase within several minutes after
blending. The non-superabsorbent polymer formulation had
separated into 2 distinct phases 1 hour ater mixing, and
required reagitation/remixing to effectively resuspend the 2
components in-to a uniform mixture. The Super Sorb-base milky
formulation appeared stable, i.e., the Arosurf~ MSF and water did
not appear to have separated, when observed at one, two, three
and four week post-mixing intervals. Distinct separation of the
Arosur ~ MSF and water in the non-Super Sorb formulation was
observed at each of these intervals, even though this formulation
was resuspended (remixed) after each weekly observation.
EXAMPLE II
Flowable formulations composed of O.5-0.8%
Super Sorb Arosurf~ MSF, B.-t.i. (Bac-timos~ Primarv Powder,
Vectobac~ -AS, or Tekna ~ ) and reverse osmosis (RO~ water or
-38-
~ 3 ~t~
well water, as well as Super Sorb (0.5-0.~), ArosurfR MSF,
B. sphaericus (BSP-l), and RO or well water were prepared for
application of active ingredients at rates recommended on the
labels for control of larvae or pupae by blending techniques
similar to those described in Example 1. The order of addition
of the components, mixing speed (1200 - ~200 rpm), mixing
intervals (star-t/stop), and mixing duration (15 sec - 30 min)
were dependent on the concentration of Super Sorb, concentration
of Arosur ~ MSF, water quality, and on the type, concentration
and/or formulation of bacillus used in the aqueous composition.
Results were similar to Example I, that is, observations
indicated that homogeneous and persistent (non-separating)
suspensions of the B.t.i. or B. _phaericus and Arosur ~ MSF
and wa-ter resulted at one, two, three, and four week pos-t-mixing
observation periods while non-superabsorbent polymer formulations
of B.t.i. or B. sphaericus mixed with Arosur ~ MSE and water
separated into two or khree distinct layers within 1 hr post-
mixing. In fact, component partitioning began almost immediately
aftar mixing. The duration and speed of mixing did not improve
the compatibility or suspendability of one or more active
ingredients in the non-superabsorbent polymer formulations.
EXAMPLE III
For ~n illustration of a flowable oil-base formulation
of the present invention, 310g of Arosurf~ MSF non-petroleum oil,
3~0g of Aquastor ~ F polymer, and lOg of B.t.l. (Vectobac~
Technical Powder) were mixed in a beaker with a small
electrically-powered mixer for ca. lO min. When a drop o this
semi-viscous non-aqueous (i.e., oil base) flowable formula-tion
was added to water with an eye dropper, a bead of gel
-39-
~3~'7~
formulation (specific gravity > 1) instantly formed upon contact
with the water and slowly expanded as the polymer absorbed water,
thereby releasing both active agents (i.e., B.t.i. and Arosur
MSF).
EXAMPLE IV
The comparative mosquito-controlling efficacy of the
flowable, hiyh-shear, aqueous formulation of Arosur ~ MSF and
Super Sorb superabsorbent polymer was determined in a series of
bioassays against larvae and pupae of Ae. taeniorhynchus and
Cx. ~uincluefasciatus in a variety of water quallties. ~queous
formulations were prepared in a manner similar to that described
in Example I.
Bioassays were conducted in 400 ml glass beakers
containing 250 ml of test water and 2nd to 4th instar laryae, or
combinations, of 5 larvae and 5 pupae (3 replications/
formulation). Aqueous formulations containing Super Sorb were
allowed to sit unmixed for one hour post-blending and were not
remixed, while aqueous formulations containing no Super Sorb were
vigorously hand shaken for 1 minute prior to application.
Flowable formulations were applied to tha water surface wi-th a
glass pipette or microsyringe at application rates recommended
for the control of mosquito larvae and pupae. Bioassays were
conducted in a room maintained at 80~ F (ambien-t) and 80% ~-1.
Results of bioassays against larvae and pupae of
Ae. taeniorhynchus and Cx. quinquefasciatus are presented in
Table I. In general, the data indicated that the Arosur ~ MSF
aqueous formulations, containing varying amounts of Super Sorb
killed 2nd-~th instar larvae of Ae. taeniorhvnchus as quick or
faster than technical Arosurf~ MSF and/or aqueous Arosurf~ MSF
--~0--
:, .
~.
~ 7~3~
containing no Super Sorb. Similar findings w~re recorded in
bioassays against 2nd-4th instar larvae of Ç~l ~u n5~f~ ai~b~;
however, these were not as dramatic a~ the results obtained with
larvae of A~. taeniorhvnchus.
Water quality of the formulatlon diluent and/or
mosquito habitat, ~uperabsorbent polymer concsntration, and
larval instar were shown to afPect the rate oP larvicidal action.
Also, preliminary high-shear mixing results with Super Sorb,
Aridall~ 1092, Wat~r Loc ~ G-lO0, or Aqua Kee ~ J-500
superabsorbent polymers and Arosur ~ MSF, bacilli and water
indicated that the type of polymer (i.e , the water absorbing
characteristics) will affect the optimum percent concentration of
superabsorbent polymer required for ef~ective aq~leous suspension
of the formulation ingredients.
~L~
As an altsrnative, or an addition to, vigorous or
high-speed/high-shear mixing, to reduce viscosity and enhance the
suspendabillty and/or mixing compatibility of one or mors
insectloidal or non-insecticidal components in an aqueous
superabsorbent pol~mer-ba e formulation, additional
viscosity/suspendability modification tests were conductad in 100
ml glass medicine bottles to determine if electrolytes/salts
(e.g., 0.1 ~ 0.5%) such as sodium ~hloride, potassium chloride,
magnesium chloride, calcium chloride or sodium sulfite could b~
used in combination with mild agitatlon (i.e., not high-shear) .to
decrease ths viscosity (i.e., increase the flowability or
fluidity) of variable-viscosity formulations (lO0 g total
prepared) composed of reverse osmosis water, 5% Arosur ~ MSF, and
0.5% of a superabsorbent pol~mer ~uch as Aqua Keep~ J-500, ~uper
-41-
Sorb, or Aridal ~ 1092, with or without 5~ B.-t i (Vectobac~-AS)
or 5% B. _phaericus (BSP-l), withou-t adversely affec-ting -the
suspendability or mixing compatibility of the formulation
componen-ts. Insecticidal ingredients were formulated for aqueous
application to the water surface at 5.0 gal/acre a-t rates that
were recommended on the labels for the control of mosquito larvae
and pupae.
Results indicated that the salt/electrolyte
concentration and type used in the aqueous formulation was
dependent on the type (and concentration) of superabsorbent
pol~ner and the type and concentration of insecticidal
ingredients in the formulation. Also, the tests indicated that
tha order of adding the formulation components in water, as well
as the type of salt/electrolyte used, could affect the ease of
mixing, suspendability, or stability of the ingredients. In
general, results suggested that stable, homogeneous formulations
of water, Arosur ~ MSF, a superabsorbent polymer, with or
without a larvicidal bacillus, and an electrolyte/salt could be
formed with mild agitation (i.e., hand-shaking). It should be
noted that no separation, partitioning, or clumping of the
components was observed at 24 hr post-mixing.
Comparative bioassays to determine the mosquito-
controlling efficacy of hand-shaken (30 sec) aqueous ~ormulations
composed of 5.0~ Vectoba ~ -AS or BSP-l and 5.0% Arosurf~ MSF and
0.5% Super Sorb or Aqua ~ee ~ J-500 with 0.1% sodium chloride or
sodium sulfite against 3rd-4th instar larvae and pupae of Cx.
quinquefasciatus resulted in 100% mortallty within 24-48 hr post-
treatment. One hundred percent control of mixed larvae (3rd-4th
instar) and p~lpae of Ae. t_eniorhynchus was also observed in
-~2-
~3~7~
similar tests with tha B.t.i. (Vectobac~-AS) formulation within
24 hr post-treatment. The same results were also recorded with
the above compositions that were formulated with high shear
mixing but without a salt/electrolyte.
EXAMPLE VI
Additional mixing compatibility tests were
conducted in 100 ml glass medicine bottles with compositions of
0.5 g Aqua Kee ~ J-500, Water Loc ~ A-100, or Aquastor ~ , and
5 g Arosur ~ MSF, 9.5 g 2,4-D, and 85 g R.O. water indicated that
flowable variable-viscosity superabsorbent polymer formulations
composed of a mosquito larvicide/pupicide and a herbicide could
be made with mild agitation (i.e., vigorous hand-shaking for 30
sec). No separate salts/electrolytes were added to the flowable
formulation since the active ingredient in the E.P.A. registered
herbicide formulation is 65.6% dimethylamine salt of 2,4-
Dichlorophenoxyacetic acid. Flowable formulations were prepared
for application of the active ingredients at label recommended
rates, i.e., ca. 0.25 gal/acre Arosurf~ MSF and 0.5 gal/acre 2,~-
D, at 5.0 gal/acre total formulation. No clumping,
stratification, or separation of the components in the flowable
superabsorbent polymer formulations were noted at 2~ hr post-
mixing, even though vigorous or high-shear agitation was not
employed. Surface spreading activity of Arosur ~ MSF was
verified by the use of talc (see Example VII). Formulation
viscosity varied with the type of superabsorbent polymer;
however, all formulations were very flowable.
-43-
; '
~3~
EXAMPLE VII
Tha slow release potential of an insecticidal
ingredient from a variable-viscosity formulation of superabsorbent
polymer was determined by laboratory spreading rate evaluations
according to procedures established by Levy et al. 1984 Mosquito
News 44:419-422. Super Sorb (2 g) and an RØ water-10%
Arosurf~3 MSF mix-ture (10 g) were blended with a high-shear dyna
mixer. This aqueous formulation was applied to the water surface
at one end of a stainless steel pan containing 7,570 ml of
RØ water that had been avenly dusted with 0.15 g baby powder-
type talc at a formulation rate of ca. 0.53 g/pan or ca. 0.26
gal/acre Arosur ~ MSF (3 replications). The spreadiny rates of
Arosur ~ MSF from the a~ueous superabsorbent polymer formulation
were compared to the spreading rates for technical Arosur ~ MSF
applied at 0.26 gal/acre. The comparative slow release potential
of the formulation was determined by the average time in seconds
needed for -the formulation to move or translocate the powder to
the opposite perimeter of the test pan. Results indicated that
the floating aqueous Super Sorb/Arosur ~ MSF formulation
translocated the powder to the perimeter of the pan in an average
of 33.3 sec, while technical Arosur ~ MSF translocated the powder
in 5.3 sec; thereby indicating the slow release potential of
Arosur ~ from an aqueous superabsorbent polymer formulation.
The principles preferred embodiments and modes of
operation of the present invention have been described in the
foregoing specification. The invention which is intended to be
protected herein however is not to be construed as limited to
the particular forms disclosed, since these are to be regarded as
illustrative rather than restrictive. Variations and changes may
-4~-
:~3~
be made by those skilled in the art without departing from khe
spirit o~ the invsntion.
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