OA13081A - Process for making larvicidal evaporation suppressant powder. - Google Patents

Description

NOM DU DEPOSANT: O'Brien, Robert Neville 013081

TITRE: PROCESS FOR MAKING LARVICIDAL EVAPORATION SUPPRESSANTPOWDER

BACKGROUND OF THE INVENTION - TECHNÏCAL FIELD

In general, this invention relates to a specially blended, powdery, larvicidalcomposition suitable for application to open water catchments to control localmosquito populations, and more especially to the hereinafter described water-freepréparation process for making a powderthat possesses utility both for abatement ofuse by mosquitoes of an open water catchment as a successful breeding site, andfor conserving water by suppressing the évaporation of water from the samecatchment. A further use is for spreading on water or soil with suitable larvicides forother target pests. A tried-and-proven method of abating the kind of mosquito breeding which istypically localized at a site consisting of an open water catchment is to drain thecatchment or procure its drying up, thus depriving egg-laying female mosquitoes ofopportunity to use that particular site for breeding. However, whenever conservationof water stored in open catchments is a high priority social objective, a “drying-the-site” method of mosquito control has to be ruled out. In realistic scénarios, therefore,there would be advantage to devising suitable means capable of simultaneouslyconserving water and controlling mosquitoes. The powder to be manufactured inaccordance with the instant invention will constitute such means for rapid spreadingon water and for spreading on moist soil against other pests. 1 013081

BACKGROUND OF THE INVENTION - PRIOR ART

The field of mosquito larvicides encompasses a number of variouslyformulated known toxicological and non-toxicological compositions suitable forapplication to mosquito breeding waters without rapid means of spreading and watersaving properties. Non-toxicological compositions include those known to utilize as alarvicide at least one suitably selected organic compound capable of forming amonomolecularfilm, or ie., monolayer, on the water catchment surface. The film tobe formed in such a case need contain no toxin which kills mosquito larvae, butinstead is designed to cause them to sink and drown by so modifying the surface of acatchment that the denser-than-water larvae which normally hang suspendedtherefrom will be deprived of their usual means of support, viz., surface tension on aring of hairs surrounding trachéal openings atthe upwardly directed, air-snorkeling,rear end of each aquatic mosquito larva.

Concerning the field of water conservation, it is well-known that somealthough not ail organic compounds capable of forming a monolayer on a watersurface can be effective as water évaporation suppressants. Since not every kind ofmonolayer produces a film that is effective for practical water évaporationsuppression, itwould be factually insupportable to infer that, merely by the formationon mosquito breeding waters of any kind of monolayer whatsoever, that thereinherently would resuit effective water évaporation suppression, alwaysaccompanying the intended mosquito control effect. Nor, on the otherhand, would itbe factually supportable to infer that every formed monolayer that does effectivelysuppress évaporation of water must inherently be léthal to mosquito larvae.

In 1968, the June issue of Mosquito News published “A FEASIBILITY STUDYON THE UTILIZATION OF MONOMOLECULAR FILMS FOR MOSQUITO 2 013081 ABATEMENT”, wherein Gerald A. Lorenzen and Wilmon M. Meinke reported, amongotherthings.theirfinding that film-forming cetyl alcohol, ie., n-hexadecanol, which iswell-known in surface chemistry to be a compound effective for évaporationsuppression use, has no larvicidal effect on the Culex quinquefasciatus mosquitospecies common in Texas.

Lorenzen and Meinke also reported that particles of cetyl alcohol floating onthe water surface of test units were observed to be apparentiy fed upon by mosquitolarvae with no ill effect to them. Plausible effect of such feeding behavior upon thesurface area coverage capacity of the amount of finely ground film-forming materialused received no mention, but it may reasonably be supposed that an individual cetylalcohol particle ingested by a mosquito larva does not subsequently participate inusual film-spreading and film-repairing processes associated.with use of powderedfatty alcohol évaporation suppression. A real prospect thus exists that presence of ahigh population of actively feeding mosquito larvae at a water catchment site canhâve a deleterious effect on certain évaporation suppression measures, speciffcallythose wherein a fatty alcohol of high enough carbon number to be solid-phase infinely particulate bulk form is utilized. For an example of a fast fitm-spreadingpowder for suppressing water évaporation which contains fatty alcohol particles uponwhich mosquito larvae may conceivably feed, see United States Patent Number6,303,133 B1(O’Brien).

In 1977, the September issue of Mosquito News published “MOSQUITOCONTROL WITH MONOMOLECULAR ORGANIC SURFACE FILMS: I -SELECTION OF OPTIMUM FILM-FORMING AGENTS”, wherein William D. Garrettand Sheldon A. White cited both the above cited report by Lorenzen and Meinke andA. S. Msangi’s earlier research-based conclusion (1956) that n-hexadecanolproduces no appréciable influence on aquatic larvae of the Anopheles gambiae 3 013081 mosquito species common in Africa.

Thus, aithough a monolayer of cetyi alcohol is known to suppress waterévaporation effectively, deficiency of the same film-forming compound for a Iarvicidairôle is also known.

One traceable trend respecting délinéation of criteria for optimum materialssélection directed to forming monolayers capable of interfering with mosquitobreeding diverges in major respects from another traceable trend respectingdélinéation of criteria for optimum materials sélection directed to forming monolayersthat effectively suppress évaporation.

Preference fora liquid State for film-forming material in its pre-distribution bulkphase, and for a high fluidity of the formed monolayer on water are two of theseveral key criteria listed by Garrett and White in the second of the above citedMosquito News reports which from a physico-chemical standpoint are criteriaconducive to Iarvicidai effectiveness. The same two criteria, unfortunately, tend tobe incompatible with effective suppression of water évaporation from an openréservoir, particularly if the film-forming material selected is a normally solid-phasefatty alcohol.

According to a classic surface chemistry textbook INSOLUBLEMONOLAYERS AT LIQUID-GAS INTERFACES by George L. Gaines, Jr.(Interscience Publishers, 1966), high fluidity as a formed monolayer property runscounter to optimum effectiveness at suppressing évaporation. The kind ofmonolayer that imposes higher résistance (than other kinds) to egress through it ofwater vapor is the so-called “condensed film” kind of monolayer, featuring close side-by-side packing of upright un-branched molecularchains, sometimes referred to as a“compact” monolayer. Extent of vapor passage résistance increases with chainlength, provided the chain is truly linear so that adjacent molécules in a film can be 4 013081 closely packed as in the solid crystal phase.

Fatty alcohols with a carbon number lower than 14 are liquid at standardtempérature, and even if un-branched form a film of high fluidity on water, ratherthan forming the condensed kind of monomolecular film that retards évaporationsignificantly more effectively. Thus, lauryl alcohol, ie, dodecanol, with 12 carbonatoms per molécule, wouid not be recommended for optimization of évaporationsuppression properties, although it wouid be selectable for its ability to causemosquito larvae mortality in the manner reported by Lorenzen and Meinke in thefirstof the above cited Mosquito News reports.

The discussions of larvicidal agencies présent in both above cited MosquitoNews reports are predicated on the concept that mosquito breeding at a given openwater site can feasibly be abated on a non-toxicological basis by suitably modifyingthe water surface to prevent normal larval respiration.

Another relevant factor in the background of the instant invention is the knownuse of biological mosquito larvicides comprising toxin-carrying spores of microbialspecies, eg., Bacillus thuringiensis variety Israelensis, and Bacillus sphaericus,which shall collectively be referred to hereinafter as ‘mosquito-specificentomopathogens’. The toxins are specifically léthal to larvae of mosquitoes whenthe minute Bacillus spores are ingested thereby. There exist also publications listinglarvicides for many other pests in the entomological literature.

It has also been suggested that a so-called “synergistic” mode of treatmentofa mosquito breeding site can be practiced, wherein larvicidal agencies include boththe surface tension réduction by a monolayerthatdrowns mosquito larvae, and theuse of mosquito-specific entomopathogens to poison them. Film-formingcompounds recommended for known compositions for carrying out such a“drowning-plus-poisoning” type of larvicidal treatment are compatible with the 5 013081 optimized materials sélection criteria proposed in the above cited Garrett and WhiteMosquito News report, because these are typicaily branched chain compounds thatprocure the highly fluid --rather than condensed-- kind of monolayerto give morerapid spreading hence more rapid delivery to ail parts of the liquid surface to betreated. For a citable example wherein ethoxylated and branched-chain compoundsare recommended, see the “Insecticide composition for controlling insects whichhâve an aquatic breeding site” by A. I. McMullen, United States Patent Number4,707,359 (Nov. 17,1987). The composition by McMullen is not designed to procureeffective évaporation suppression.

Significantly, concerning préparation of formulations according to theMcMullen insecticidal monolayer-forming invention, problems that would beencountered if attempting to evenly distribute mosquito-specific entomopathogenswithin a main body comprising film-forming constituents were easily avoided by theuse of water as a dispersion medium during product préparation. Contrastingly, thefilm-spreading powder of above cited United States Patent Number 6,303,133 B1(O’Brien) does not lend itself during its préparation process to admixture of itsconstituents with water, because addition of water during processing wouldprematurely activate ionization of the slaked lime, ie., calcium hydroxide, that isincluded to provide a unique, rapid dispersai mechanism that takes effect when thepowder is broadcast upon a body of water intended to be coated by an effectiveevaporation-suppressing monolayer. Without feasibility of using water in theProcessing, a real problem of how to evenly distribute mosquito-specificentomopathogens within a main body comprising dry particulate film-forming andother constituents arises.

It has already been noted above that the O’Brien patented powder, so long asit places finely divided alcohol particles on a water catchment surface, is susceptibleto a number of such particles being ingested by mosquito larvae, if présent, thussuffering a loss of reserve film-forming material that would be expected to be of a 6 013081 magnitude proportionate to the number of feeding larvae. Insofar as is known atthistime of disclosing the instant invention, nobody has previously suggested the spécifiemanner of resolving this problem that is presently proposed.

As a final point closing background discussion, it is acknowledged as havingalready been known in the general art pertaining to insecticides to dispersemosquito-specific entomopathogens in a quantity of liquid-phase lauryl alcohol, ie.,dodecanol, which is not a satisfactory évaporation suppressant material, although asfar back as 1968 (Lorenzen and Meinke) this 12-carbon fatty alcohol was proposedto be suitable for forming a monomolecular film intended specifically for mosquitoabatement use. In US Patent Application Number 09/739,895 (O'Brien), published20 September2001 as US Patent Application Publication No. 2001/0022355 (issued6 May 2003 as US Patent No. 6,558,705), it is stated that when the powder referredto in this application is spread as a powder, then wetted either by rain or irrigation,spreading appears to be rapid on the wet soil.

BRIEF SUMMARY OF THE INVENTION

One important technical object of the invention is to devise a way to reducethe susceptibility of finely divided fatty alcohol particles to being ingested bymosquito larvae, when such particles are located on the surface of a watercatchment infested by the larvae.

Another important technical object of the invention is to devise a water-freemode of processing thatdistributes particulate mosquito-specific entomopathogensevenly within a quantity of film-spreading powder containing, together with otherChemical constituents, finely particulate fatty alcohol, preferably cetyl alcohol, stearylalcohol, or a blend of these two compounds.

The object of the invention is procurementof a spécial powder that possesses 7 013081 utility both for abatement of use by mosquitoes of an open water catchment as asuccessful breeding site, and for conserving water by suppressing the évaporation ofwater from the same catchment. A further object is the spreading of appropriatelarvicides against soil dweliing pests on moist soil.

It bas been found that the foregoing objects can substantially be satisfied bymaking a iarvicidal variant of a known hydrated iime-containing “film-spreadingpowder for suppressing water évaporation” that has previously been described inUnited States Patent Number 6,303,133 B1 (O’Brien). This variant of that hydratedIime-containing powder is rendered Iarvicidal by virtue of stirring or otherwiseintimately blending a suitable proportion of known mosquito-specificentomopathogens, dispersed in lauryl alcohol, into constituent of the originalcomposition made in accordance with the cited O’Brien patent. Further, anyappropriate larvicide for water or soil dweliing pests may also be incorporated andrapidly spread.

It has been found that the foregoing objects can also substantially be satisfiedby making a Iarvicidal variant of an acidified gypsum-containing “composition forreducing évaporation at sites both on land and open water” that is disclosed inUnited States Patent Application Serial No. 09/739,895 (O’ Brien). Equivalent^ aswith the hydrated Iime-containing variant, this acidified gypsum-containing variant isrendered Iarvicidal by virtue of stirring or otherwise intimately blending a suitableproportion of known mosquito-specific entomopathogens, dispersed in laurylalcohol, into constituents of the original composition made in accordance with thecited O’Brien patent application. Extending this logically to include larvicides forother water or soil dweliing pests is now put forward.

Due to pre-dispersal of mosquito-specific entomopathogens or otherpesticides in lauryl alcohol before blending with other constituents, it is surprisingly 8 013081 easyto evenlydistribute the entomopathogensthroughout the volume ofa powderedévaporation suppressing composition, without the use of water in the process.

The resulting product is storable for considérable periods of time in sacks,drums, etc., that can be handled and shipped without a deleterious internai settlingand gravitational séparation of constituents that would likely occur if the laurylalcohol were not used and instead only the dry entomopathogenic material, eg.Bacillus thuringiensis spores were directly combined with the original dry particulateévaporation suppressant materiais.

When the resulting product is broadcast upon the surface of an open watercatchment, for example by a crop-dusting type mode of distribution from an aircraftover-flying a réservoir, ail the highly désirable effects associated with the uniquerapid film spreading ionization-caused particle expulsion achieved in accordancewith the disclosures of the above cited O’Brien patent and patent application areretained. The film-spreading and film-repairing processes are the same as for thecorresponding composition versions without larvicidal constituents. A significant limitation to be observed when making the powder of the instantinvention is to keep the lauryl alcohol content at a minimal level commensurate toeffectively distributing the Bacillus thuringiensis spores or équivalententomopathogenic particulate material with the other normally solid-phasecomposition constituents. Even though lauryl alcohol is itself normally liquid-phaseat standard température, when absorbed by sufficient powder of the balance of otherconstituents it ceases to occur in the end-product as a macroscopic-scale liquid. It isno intention associated with the instant invention to make an oily “sludge" or “slurry”instead ofthe intentionally devised dry powder, but such an oily and non-particulatedresuit would of course be expected if too high a proportion of lauryl alcohol wereused. 9 013081

In another aspect, the invention consists of an insecticidal and évaporationsuppression product for use on water or iand, the product comprising: a) evaporation-suppressant particies comprising: i) an ionizable spreading agent selected from the group consistingof hydrated lime and acidified gypsum; and ii) a fatty alcohol with an un-branched carbon chain of 14 to 24carbon atoms; b) lauryl alcohol; and c) a pesticide dispersed in the lauryl alcohol; wherein the particies and pesticide-containing lauryl alcohol are blended one withthe otherto form a powdery product. The pesticide may be a larvicide. The pesticidemay be a mosquito-specific entomopathogen. The acidified gypsum may beacidified using a di-functional acid. The di-functional acid may be oxalic acid.

In another aspect, the invention consists of a two-component insect controland évaporation suppressant product for use on water or Iand, the productcomprising: a) an évaporation suppressant component comprising particiescomprising: i) an ionizable spreading agent selected from the groupconsisting of hydrated lime and acidified gypsum; and ii) a fatty alcohol with an un-branched carbon chain of 14 to 24carbon atoms; and b) an insect control component comprising i) an ionizable spreading agent selected from the groupconsisting of hydrated lime and acidified gypsum; ii) lauryl alcohol; and iii) a pesticide dispersed in the lauryl alcohol; 10 013081 wherein thetwo components are mixable priorto use, and the relative insect-controland evaporation-suppressant effectiveness of the mixed components is adjustableby adjusting the proportions of the évaporation suppressant component and theinsect control component.

In another aspect, the invention consists of a process for preparing aninsecticidal and evaporation-suppressing powder, comprising the steps of: a) procuring evaporation-supressant particles comprising: i) an ionizable spreading agent selected from the groupconsisting of hydrated lime and acidified gypsum; and ii) a fatty alcohol with an un-branched carbon chain of 14 to 24carbon atoms; b) dispersing a pesticide in lauryl alcohol; b) blending the particles with the pesticide-containing lauryl alcohol,without using water as a blending agent.

The process may further comprise the step of, priorto the step of blending theparticles with the pesticide-containing lauryl alcohol, blending thepesticide-containing lauryl alcohol with an ionizable spreading agent selected fromthe group consisting of hydrated lime and acidified gypsum, without using water as ablending agent, whereby the step of blending the particles with thepesticide-containing lauryl alcohol comprises blending the particles with the blendedionizable spreading agent and pesticide-containing lauryl alcohol.

In another aspect, the invention consists of a method for providing bothévaporation suppression and insecticidal effects on land or water, the methodcomprising: applying to the surface of the land or water a powder comprising:a) evaporation-suppressant particles comprising: 11 013081 i) an ionizable spreading agent selected from the groupconsisting of hydrated lime and acidified gypsum; and ii) a fatty alcohol with an un-branched carbon chain of 14 to 24carbon atoms; b) lauryl alcohol; and c) a pesticide dispersed in the lauryl alcohol; wherein the particles and pesticide-containing lauryl alcohol are blended one withthe other.

Additional details relating to carrying out the invention follow, starting withreview of precursor O’Brien évaporation suppressant powders.

DETAILED DESCRIPTION OF THE INVENTION US Patent No. 6,303,133 taught a powdery hydrated lime-containingévaporation suppressant having particles that repel one another during a water-induced ionization process. Prior art had not taught combination of long-chain solid-phase fatty alcohols with hydrated lime, ie., calcium hydroxide. The compositiontaught in US Patent No. 6,303,133 comprises microparticles of long-chain fattyalcohol and calcium hydroxide, and has been shown upon water induced ionizationto enhance the rate of film-spreading on a water surface due to the phenomenon ofthe particles mutually repelting one another in a manner not apparent in prior art. Asalready indicated in the BRI EF DESCRIPTION section above, the instant inventionby further including a component consisting of mosquito-specific entomopathogensdispersed in lauryl alcohol, contributes a new and previously un-suggested way toreduce the number of solid-phase fatty alcohol particles possibly ingested bymosquito larvae infesting a body of water, while retaining the earlier disclosed 12 phenomenon of mutual particles’ repulsion.

Considered and filed as a continuation-in-partofthe aforesaid lime-containingcomposition disclosure, US Pat. Appl. No. 09/739,895 substituted—in place of thelime of the parent invention—an “acidified gypsum” component consisting of about 5millilitres of sulfuric acid per 300 grams of crushed gypsum. Blending unemulsifieddetergent range fatty alcohois such as cetyl alcohol and/or- stearyl aicohoi with theacidified gypsum produces an effective évaporation suppressant which works onopen bodies of water in the same manner as the lime containing parent. Asindicated in the BRIEF DESCRIPTION section above, the instant invention, byfurther including a composition component consisting of known mosquitoentomopathogens dispersed in lauryl alcohol, promûtes réduction ofthe numberofsolid-phase fatty alcohol particles likely ingested by mosquito larvae, while retaining-in the same manner for the acidified gypsum-containing évaporation suppressant aswith hydrated lime-containing powder for évaporation suppression-the eariierdisclosed phenomenon of mutual particles’ repulsion giving rapid spreading. Afactundisclosed before now is that an équivalent component to the acidified gypsum canbe made using—in substitution for sulfuric acid- oxalic acid or other di-functionalacid with similar magnitude respecting ionization constant and solubility giving evenmore rapid spreading.

The explanation of spreading enhancementforthe self-propelling precursorpowder formulations of O’Brien is that “fast” ions ionized on contact of the powderwith water leave a net positive charge on particles in the case of lime blended withfatty alcohol, and a net négative charge in the case of acidified gypsum similarlyblended. Outdoor pool tests hâve shown the spreading of such precursor powdersacross a water surface to spread against a breeze of about 10 km/h, which is muchfasterthan alcohol films spread from fatty alcohol solid-phase particles unblended 13 013081 with ionizable crushed minerais and thus absent the recently discovered andexploited particles repulsion effect

It is now apparent that enough power is developed to aquatically propel othermaterials blended into a powder, besides the insoluble fatty alcohol component andthe dwindling partly soluble minerai component that “fuels” the propulsion. A varietyof additional types of components appears feasible, including fertilizers, fish food,aquatic herbicides, and toxins that are insecticidal by mechanisms other than thebiological type involved with use of mosquito-specific entomopathogens. In everycase, however, the added substance must be pre-tested for inertness with regard toChemical reaction with the insoluble monolayer former and whichever ionizablecrushed material component is used, inertness being needed during both thepréparation process and when applied in the field for the end-use. A composition that meets the main object of providing both waterconservation by suppressing évaporation and mosquito control by larvicidal effect isreadily manufacturable by a process that basically adds~to the disclosed steps formaking the patented precursor évaporation suppressant formulations of O’Brien-afurther step for blending in a suitable amount of mosquito-specific entomopathogenspre-dispersed in lauryl alcohol and made into a powder with the above mentionedbulking agents used in the évaporation suppressant powder This step should not beincorporated at the melt-processing stage of making either of the precursorévaporation suppressant powders, fortwo reasons: the heat involved would kill themicrobial entomopathogens; and undesired loss by volatilization of some ofthe laurylalcohol would occur with options nextto be described regarding the further blendingstep, the proportion of larvicidal component relative to évaporation suppressingcomponent can be adjusted higherorlowerdepending on extent of mosquito larvaeinfestation and/or need for a pre-determinable amount of évaporation suppression 14 Q 13081 coverage.

One blending option is to absorb into a quantity of one of the precursorévaporation suppressant powders a quantity of pre-mixed dispersion of mosquito-specific entomopathogens in lauryl alcohol. Such a larvicidal dispersion is known tobe sprayable as a liquid provided excessive content of entomopathogen spores isavoided so as to preserve a sprayable consistency. In this case the larvicidalcomponent can be incorporated into the precursor powder by spraying the formeronto the latter in a proportion within ability of the powder to sufficiently absorb laurylalcohol so that in the finished product composition it retains no macroscopically liquidcharacter, even though at a température above its freezing point. This option lendsitself to high volume continuous production of a ready-to-use composition having wellbalanced properties both for water conservation and mosquito control, and which isespecially suitable for marketing to large-scale users expected to treat large publicwater storage réservoirs or for application to agricultural land or other moist soils withappropriate larvicides against other soil dwelling pests.

The alternative blending option lends itself better to batch-type Processingand entails making two powders that may be stockpiled separately until anappropriate need-circumstance is identified that calls for their being blended.Adjustments of the balance between évaporation suppression coverage, on the onehand, and numberof mosquito larvae per hectare of water surface anticipated to bekilled by ingestion of entomopathogens put amidst them, on the other hand, are inthis case left to the product userto make, depending an local circumstances. Forclarity, the property of effectively suppressing évaporation of water is possessedexclusively by one of the two powders, and the larvicidal property is possessedexclusively by the other. A particular pond or rice paddy may for a limited time require some, but 15 013081 comparatively little, use of évaporation suppressant matériel, and may be more inneed of a mosquito larvicide due to being heavily infested. There may be occasionin connection with particular rice cropping practices to allow a paddy to dry out on adefinite schedule. Timed réduction of-and ultimate élimination of-use ofévaporation suppressant would allow this; but the larvicidal property of the otherpowder may remain needed untïl a later date than that at which use of évaporationsuppressant should cease. Thus it is logical to hâve the two blendable powders keptseparately for blending as, when, and if desired, thereby accommodating a greaterrange of use-exigencies. Application to soil will hâve many variations as the growingseason progresses.

It is expected that the relative amount of lauryl alcohol fully absorbable bycrushed minerai particles of hydrated lime or acidified gypsum will be somewhatgreater when the minerai components hâve not been previously intimately pre-combined with cetyl alcohol and/or stearyl alcohol in a melt thereof. This means thata highly effective larvicidal powder lacking in évaporation suppression effectivenessis manufacturable by combining the mosquito-specific pathogens, lauryl alcohol, andcrushed minerai components, sans presence of cetyl alcohol and/or stearyl alcohol.Such a powder has been developed in orderto facilitate end-property adjustments ina preferred composition made by the optional process of blending the two powdersas here suggested viz., the one exclusively possessing the larvicidal property; theother exclusively procuring effective évaporation suppression. To here disclose thetwo blendable powders that can go into a final product capable of usesimultaneously for both mosquito control and water conservation, but easilyadjustable with respect to relative extent of effectiveness towards those twopurposes, cannot help but incidentally also disclose the one of the two blendablepowders that is larvicidal only, and may even be used alone in those cases whereévaporation suppression is not required. Similar reasoning applies to the use on soilof specially made larvicidal mixtures for use against soil dwelling pests. 16 013081

Most generally however, in contemplation especially of iarge-scale continuousproduction in accordance with the first option for enacting the basic process of theinstant invention, it is easy to provide a ready-to-use powderthat without requiringtailored biending of two powders by end users will achieve good balance betweengood évaporation suppression effectiveness and larvicidal effectiveness withouttilting extremely one way or the other, merely by adding lauryl alcohol plus mosquito-specific entomopathogens or others to a main body of powder initially comprisingone or the other of the precursor évaporation suppressant powders by O’Brien.

It should be apparent at this point that competent workers in the art, afterstudying ail the foregoing new subject matter of the présent disclosure, will be armedto carry out the instant invention with no more than routine expérimentation neededand/or desired as may be appropriate to end-use circumstances. 17

Claims (9)

1. 013081 Claims

   1. An insecticidal and évaporation suppression product for use on water or land, theproduct comprising: a) evaporation-suppressant particles comprising: i) an ionizable spreading agent selected from the group consisting ofhydrated lime and acidified gypsum; and ii) a fatty alcohol with an un-branched carbon chain of 14 to 24 carbonatoms; b) lauryl alcohol; and c) a pesticide dispersed in the lauryl alcohol; wherein the particles and pesticide-containing lauryl alcohol are blended one withthe other to form a powdery product.
2. 2. The product of claim 1, wherein the pesticide is a larvicide.
3. 3. The product of claim 1, wherein the pesticide is a mosquito-specificentomopathogen.
4. 4. The product of claim 1, wherein the spreading agent is acidified gypsum and thegypsum is acidified using a di-functional acid.
5. 5. The product of claim 4, wherein the di-functional acid is oxalic acid.
6. 6. A two-component insecticidal and évaporation suppressant product for use on wateror land, the product comprising: a) an évaporation suppressant component comprising particles comprising: i) an ionizable spreading agent selected from the group consisting ofhydratedljme and acidified gypsum; and ii) a fatty alcohol with an un-branched carbon chain of 14 to 24 carbonatoms; and 18 013081 b) an insecticidal component comprising i) an ionizable spreading agent selected from the group consisting ofhydrated lime and acidified gypsum; ii) lauryl alcohol; and iii) a pesticide dispersed in the lauryl alcohol; wherein the two components are mixable prior to use, and the relative insecticidaland evaporation-suppressant effectiveness of the mixed components is adjustableby adjusting the proportions of the évaporation suppressant component and theinsecticidal component.
7. 7. A process for preparing an insecticidal and evaporation-suppressing powder,comprising the steps of: a) procuring evaporation-supressant particles comprising: i) an ionizable spreading agent selected from the group consisting ofhydrated lime and acidified gypsum; and ii) a fatty alcohol with an un-branched carbon chain of 14 to 24 carbonatoms; b) dispersing a pesticide in lauryl alcohol; c) blending the particles with the pesticide-containing lauryl alcohol, withoutusing water as a blending agent.
8. 8. The process of claim 7, further comprising the step of, prior to the step of blendingthe particles with the pesticide-containing lauryl alcohol, blending the pesticide-containing lauryl alcohol with an ionizable spreading agent selected from the groupconsisting of hydrated lime and acidified gypsum, without using water as a blendingagent, whereby the step of blending the particles with the pesticide-containing laurylalcohol comprises blending the particles with the blended ionizable spreading agentand pesticide-containing lauryl alcohol.
9. 9. A method for providing both évaporation suppression and insecticidal effects onland or water, the method comprising: 19 013081 applying to the surface of the land or water a powder comprising: a) evaporation-suppressant parficles comprising: i) an ionizable spreading agent selected from the group consisting ofhydrated lime and acidified gypsum; and ii) a fatty alcohol with an un-branched carbon chain of 14 to 24 carbonatoms; b) lauryl alcohol; and c) a pesticide dispersed in the lauryl alcohol; wherein the particles and pesticide-containing lauryl alcohol are blended one withthe other. 20