CA1307201C - Flowable insecticidal delivery compositions and methods for controlling insect populations in an aquatic environment - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Superabsorbent solid organic polymers which absorb over 100 times their weight in water are used in flowable aquatic environment insect population control compositions of varying viscosities. Methods for using the superabsorbent polymer insecticidal delivery agents for the control of aquatic environment insect populations, including mosquito population control methods, in an area needing aquatic environment insect population control treatment or in a dry area that is expected to need aquatic environment insect population control, are described.

Description

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 .

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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.

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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.
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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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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 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 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:

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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 ~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 .

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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-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.

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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 . . .
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~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.

~ 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 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 ~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, 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 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 ~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 -~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 ~ 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 ~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 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.

; ' ~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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Claims (11)

1. A controlled release variable-viscosity, flowable, insecticidal delivery composition for controlling a population of aquatic environment insects in preflood or flood conditions comprising:
(a) at least one superabsorbent solid organic polymer comprising hydrophilic acrylamide or acrylate polymers, co-polymers or ter-polymers which absorb over 100 times their weight in water, (b) at least one insecticidal agent, and (c) water or oil, said polymer, agent and water or oil being present as a flowable formulation wherein the agent is present in a total amount effective to control the population of aquatic environment insects and wherein said composition is an admixture formed by mixing the superabsorbent polymer, the insecticidal agent, and the water or oil.

2. The composition of claim 1, wherein the variable-viscosity, flowable formulation is formed by vigorous or high shear mixing, and the superabsorbent polymer is substantially water-insoluble.

3. The composition of claim 2, wherein said superabsorbent polymer comprises a starch graft polymer, co-polymer or ter-polymer.

4. The composition of claim 1, wherein said superabsorbent polymer is selected from the group consisting of: an acrylamide sodium acrylate copolymer; a hydrolyzed starch-polyacrylonitrile; 2-propenenitrile, homo-polymer, hydrolyzed, sodium salt; poly (acrylamide-co-sodium acrylate); poly (2-propenamide-co-2-propenoic acid, sodium salt); starch-g-poly (acrylonitrile); starch-g-poly (acrylamide-co-sodium acrylate); a starch, acrylonitrile co-polymer; poly-2-propenoic acid, sodium salt; poly(2-propenamide-co-2-propenoic acid, sodium salt); starch-g-poly(2-propenamide-co-2-propenoic acid, potassium salt);
starch-g-poly(2-propenamide-co-2-propenoic acid); starch-g-poly(2-propenamide-co-2-propenoic acid, sodium salt);
starch-g-poly(2-propenamide-co-2-propenoic acid sodium/
aluminum mixed salts); starch grafted sodium polyacrylates;
copolymer acrylamide acrylate; acrylic acid polymers, sodium salt; cellulosic laminates of poly-2-propenoic acid, sodium salt; crosslinked polyacrylamide copolymer; crosslinked modified polyacrylamide; crosslinked acrylics; and mixtures thereof; and metal salts thereof.

5. The composition of claim 1, wherein the variable-viscosity, flowable formulation is formed by an additive amount of an electrolyte/salt, in the absence of vigorous or high-shear mixing.

6. The composition of claim 1, wherein said agent comprises at least one compound selected from the group consisting of: ovicides, larvicides, pupicides;
insecticides; pesticides; toxicants; biological control agents; microbial control agents; pathogens; parasites;
chemosterilants; film-forming or surface active agents; and insect growth regulators.

7. The composition of claim 1, wherein the ratio of superabsorbent polymer to water is from about 0.001:100 to 1:1.

8. A controlled release variable-viscosity, flowable mosquitocidal delivery composition for controlling a population of aquatic environment mosquitoes comprising:
at least one superabsorbent solid organic polymer selected from 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 comprising a film-forming agent, and at least one additional compound selected from the group consisting of ovicides; larvicides; pupicides; insecticides;
pesticides; toxicants; chemosterilants; biological control agents; microbial control agents; pathogens; insect growth regulators; herbicides; 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 mosquitoes and wherein said composition is an admixture formed by mixing the superabsorbent polymer, the insecticidal agent, the additional agent and water or oil.

9. The composition of claim 8, wherein the ratio of superabsorbent polymer to water is from about 0.01:100 to about 0.5:1.

10. The composition of claim 9, wherein said superabsorbent polymer is selected from the group consisting of: an acrylamide sodium acrylate co-polymer; a hydrolyzed starch-polyacrylonitrile; 2-propenenitrile, homo-polymer, hydrolyzed, sodium salt; poly(acrylamide-co-sodium acrylate); poly(2-propenamide-co-2-propenoic acid, sodium salt); starch-g-poly(acrylonitrile); starch-g-poly(acryl-amide-co-sodium acrylate); a starch, acrylonitrile co-polymer; poly-2-propenoic acid, sodium salt; poly(2-propenamide-co-2-propenoic acid, sodium salt); starch-g-poly(2-propenamide-co-2-propenoic acid, potassium salt);
starch-g-poly(2-propenamide-co-2-propenoic acid); starch-g-poly(2-propenamide-co-2-propenoic acid, sodium salt);
starch-g-poly(2-propenamide-co-2-propenoic acid, sodium/aluminum mixed salt); starch grafted sodium polyacrylates; copolymer acrylamide acrylate; acrylic acid polymers, sodium salt; cellulosic laminates of poly-2-propenoic acid, sodium salt; crosslinked polyacrylamide copolymers; crosslinked modified polyacrylamide; crosslinked acrylics; mixtures thereof and metal salts thereof.

11. The composition of claim 6, wherein said agent further comprises at least one of the group selected from herbicides; attractants; repellents: pheromones;
alcohols: solvents; and surfactants.