GB1568282A

GB1568282A - Organophosphorus-containing insecticidal compositions

Info

Publication number: GB1568282A
Application number: GB692077A
Authority: GB
Original assignee: Airwick AG
Current assignee: Airwick AG
Priority date: 1976-02-20
Filing date: 1977-02-18
Publication date: 1980-05-29
Also published as: LU74397A1; IT1086668B; CA1076476A; CH629083A5; FR2341271B1; BR7701051A; ES456097A1; FR2341271A1; JPS52122626A; DE2707154A1

Abstract

Insecticide composition which is composed of (A) an insecticide which is solid at 20 DEG C and is composed of a phosphoric ester, phosphonic ester or thiophosphoric ester, (B) 0.2 to 10 parts by weight per part by weight of A of a carbon compound of low volatility which is liquid at 25 DEG C, has a vapour pressure of not more than 0.01 torr and in which the insecticide A is sparingly soluble, and (C) a volatile carbon compound which is liquid at 25 DEG C, which has a vapour pressure at 25 DEG C of at least 5 torr and which dissolves the components A and B readily, forming a complete and homogeneous solution with these components, and which represents a liquid solution. This composition can be used for preparing a solid insecticide composition by applying it to the surface of a solid, pulverulent or non-pulverulent carrier and allowing the liquid C to evaporate.

Description

(54) ORGANOPHOSPHORUS-CONTAINING INSECTICIDAL COMPOSITIONS (71) We, AIRWICK AG, a Swiss body corporate, of 4002 Basle, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to the increasing of power of solid insecticidal organophosphorus materials, especially belonging to the category of phosphoric or thiophosphoric esters. In particular the invention relates to compositions either in the form of homogeneous liquid solutions, which contain, in addition to the said insecticidal material, and at least one liquid of low volatility which is a poor solvent for the said material, and at least one volatile liquid which is a good solvent for the said materials, or in the form of solid compositions prepared from these solutions.

The use of solid organophosphorus insecticidal materials has been known for a number of years and various types of compositions containing these active materials have been proposed and/or marketed such as, for example, powders, baits and liquids.

The liquids are very widely accepted because they are very adaptable in use; they can be used in all kinds of apparatus; for example they can be applied by means as diverse as spraying devices, brushes and aerosol containers which contain a compressed or liquefied gas; they make it possible to produce any desired dilutions with perfect distribution of the active material.

Two known liquid forms can be produced from solid organophosphorus insecticides, namely suspensions and solutions.

The suspensions present problems which are well-known to those skilled in the art: their stability is always of short duration, so that they are best prepared at the time of use, which necessitates additional work for the user and entails, for the manufacturer, all the difficulties which always accompany the preparation of wettable powders, such as the need for the material to be very fine and the need to use a pair of surface-active agents suitable for the active material and suitable for the fillers present in the powder.

For these reasons, solutions are generally preferred. However, these also exhibit disadvantages; in particular, the presence of the liquids used as solvents favours the penetration of the active material into the porous materials to which the solution is applied, such as, for example, walls and ceilings; as a result, the efficacy of the composition at the surface of the treated materials decreases rapidly, which is particularly objectionable if it is desired to achieve protection against harmful insects such as flies, mosquitoes, cockroaches, ants, wasps and the like; the tendency is therefore frequently to renew the application. which is rather uneconomical and furthermore results in the treated surfaces having a messy appearance due to the accumulation of the liquid products.

On the other hand, when using only very volatile solvents, the active material will crystallise on the surface of the treated material and can no longer by absorbed by the latter: however, the Applicant has found that, in that case, the efficacy of the active material was greatly reduced.

Another possibility of avoiding at least partly, the above disadvantages consists in employing solutions in solvents of low volatility, containing a high concentration of active material; however, this entails a real danger because of the considerable toxicity of the insecticidal materials in question.

British Patent Specification No. 1382894 describes the liquid insecticidal homogeneous solutions which comprise one or more ortho-substituted phenyl-Nmethyl carbamate; at least one slightly volatile organic compound with low dissolving capacity for the carbamate and at least one volatile organic compound with good dissolving capacity for the carbamate. The solutions can also contain other insecticidally active ingredients including phosphoric esters, phosphonic esters and thio-phosporic esters.

According to the present invention there is provided a liquid insecticidal homogeneous solution, which is free from any insecticidal carbamate compound, comprising: (A) as active ingredient, at least one insecticidal organophosphorus compound which is solid at 20"C; (B) 0.2 to 10 parts by weight, per part by weight of component (A), of at least one carbon compound which is liquid at 250C, has a dissolving capacity for component (A) at 200C of at most 5 parts by weight of component (A) per 100 parts by weight of component (B), and has a vapour pressure at 250C which does not exceed 0.01 mm Hg, and (C) at least one carbon compound which is liquid at 25"C, has a dissolving capacity for component (A) and for component (B) of at least 5 parts by weight of component (A) and at least 5 parts by weight of component (B) per 100 parts by weight of component (C), has a vapour pressure at 25"C of at least 5 mm Hg, component (C) being present in amount sufficient to form a homogeneous solution with the amounts of the components (A) and (B) present.

It has been found that when a solid organophosphorus insecticide precipitates from a liquid which is a poor solvent therefor, then as a result of the evaporation of a volatile co-solvent which, together with the organophosphorus compound and the poor solvent, formed a homogeneous solution before evaporation, the organosphosphorus compound has a very high efficacy and exhibits this for a long period of time even if the solution is applied to an absorbent material.

The insecticidal solution according to the invention can furthermore comprise (D) optionally, an adjuvant which is soluble, is inert towards (A) + (B) + (C) and is chosen from amongst D') liquids which have a dissolving capacity for component (A) at 200C of at most 5 parts by weight of component (A) per 100 parts of component (D') and have a vapour pressure at 250C equal to or greater than 0.01 mm Hg; (D") non-volatile solid diluents; (D"') liquefied gases which can be used as propellants; (D"") insecticidally active materials, different from (A) and other than a carbamate and (D""') dyestuffs, perfumes and stabilisers.

The solid insecticidal materials (A) can, for example, be chosen from amongst the following: O,O-dimethyl 0-(1 ,2-dibromo-2,2-dichloro-ethyl) phosphate (otherwise referred to as NALED), melting point: 25"C; O,O,O,O-tetramethyl O,O-(4,4'-phenyl-thiophenyl) bis-thiophosphate, melting point: 30"C; O,O-dimethyl 0 (2,4,5-trichlorophenyl) thiophosphate (otherwise referred to as TRICHLORMETAFOS), melting point: 41"C; O,O-diethyl O-(3 ,5,6-trichloro- pyrid-2-yl) thiophosphate (otherwise referred to as CHLORPYRIFOS), melting point: 43"C; O,O-dimethyl S-(2-methoxy-ethylcarbamoylmethyl) dithiophosphate (otherwise referred to as AMIDITHION), melting point: 46"C; O,O-dimethyl 0 (3,5,6-trichloro-pyrid-2-yl) thiophosphate (otherwise referred to as CHLORPYRI FOS-METHYL), melting point: 47"C; O,O-dimethyl S-(6-chloro-2oxo-benzoxazol-3-yl)-methyl dithiophosphate (otherwise referred to as PHOSALONE), melting point: 48"C; O,O-dimethyl S-2-(2-methylcarbamoylethyl)-thioethyl thiophosphate (otherwise referred to as VAMIDOTHION), melting point: 48"C; O,O-dimethyl S-(methylcarbamoylmethyl) dithiophosphate (otherwise referred to as DIMETHOATE), melting point: 52"C; O,O-dimethyl 0 (2-chloro-4-nitrophenyl) thiophosphate (otherwise referred to as DICAPTHON), melting point: 52"C; O,O-dimethyl O-( 1 methylcarbamoyl-prop- 1 en-2-yl) phosphate (otherwise referred to as MONOCROTOPHOS), melting point: 54"C; O,O-dimethyl O-(4-bromo-2,5-dichloro-phenyl) thiophosphate (otherwise referred to as BROMOPHOS), melting point; 54"C; O-methyl O-(2-chloro-4-tertiary butylphenyl) N-methylphosphoramidate (otherwise referred to as CRUFOMATE), melting point 60"C; O,O-dimethyl S-(morpholinocarbonylmethyl) dithiophosphate (otherwise referred to as MORPHOTHION), melting point: 64"C; O,O-dimethyl S (ethylcarbamoylmethyl) dithiophosphate (otherwise referred to as METHYLETHOATE), melting point 68"C; O,O-dimethyl S-phthalimidomethyl dithiophosphate (otherwise referred to as PHTHALOPHOS), melting point: 72"C; O,O-dimethyl-S-(4-oxo- 1 ,2,3-benzotriazin-3-yl)-methyl dithiophosphate (otherwise referred to as AZINPHOS-METHYL), melting point: 740 C; O,O-dimethyl 0-(2,5dichloro-4-iodophenyl) thiophosphate (otherwise referred to as IODOFENPHOS), melting point: 76"C; O,O-dimethyl (2,2,2-trichloro- I -hydroxy-ethyl) phosphonate (otherwise referred to as TRICHLORPHON), melting point: 48"C; O,O-dimethyl S-(6-chloro-2-oxo-4-aza-benzoxazol-3-yl)-methyl thiophosphate (otherwise referred to as AZAMETHIPHOS), melting point: 89"C, O,O-diethyl 0-(3,4tetramethylene-coumarin-7-yl) thiophosphate (otherwise referred to as COUMITHOATE), melting point: 89"C; O,O-dimethyl O-(3 ,5 ,6-trichloro-pyrid-2- yl) phosphate (otherwise referred to as FOSPIRATE), melting point: 92"C; 0,0dimethyl S-(5-methoxy-4-oxo-pyran-2-yl) thiophosphate (otherwise referred to as ENDOTHION), melting point: 95"C; O,O-diethyl O-(3-chloro-4-methyl-coumarin7-yl) thiophosphate (otherwise referred to as COUMAPHOS), melting point: 95"C; O,O-dimethyl O-[2-chloro- I -(2,4,5-trichlorophenyl)-vinyl] phosphate (otherwise referred to as TETRACHLORVINPHOS), melting point: 97"C; O,O-diethyl S-(2oxo4-aza-benzoxazole-3-yl)-methyl dithiophosphate, melting point: 99"C; and O,O-dimethyl S-(4,6-diamino- 1, 3,5-triazin-2-yl)-methyl dithiophosphate (otherwise referred to as MENAZON), melting point: 162"C.

The preferred compositions according to the invention are those in which the insecticidal phosphoric ester is chosen from amongst at least one of the following compounds: (I) O,O-dimethyl S-(4-aza-6-chloro-2-oxo-benzoxazol-3-yl)-methyl thiophosphate (otherwise referred to as AZAMETHIPHOS); (2) O,O-diethyl O-(3 ,5 ,6-trichloro-pyrid-2-yl) thiophosphate (otherwise referred to as CHLORPYRIPHOS); (3) O,O-dimethyl O-(2,5-dichloro-4-iodophenyl) thiophosphate otherwise referred to as IODOFENPHOS); (4) O,O-dimethyl O-(2,4,5-trichlorophenyl) thiophosphate (otherwise referred to as TRICHLORMETAPHOS); (5) O,O-dimethyl S-(6-chloro-2-oxo-benzoxazol-3-yl)-methyl dithiophosphate (otherwise referred to as PHOSALONE); and (6) O,O-dimethyl 2,2,2-trichloro- 1 -hydroxyethyl phosphonate (otherwise referred to as TRICHLORPHON).

Preferably, the amount of insecticidal material (A) does not exceed 10% of the total weight of the liquid composition and represents at least 0.2% of the total weight of the components (A)+(B)+(C).

The liquid of low volatility, (B), is used in a proportion of between 0.2 and 10 parts by weight per part by weight of insecticidal material (A); it has in fact been observed that below 0.2 part the effect provided by the liquid of low volatility becomes too slight to be useful; above 10 parts, the effect indeed persists, but after application the composition remains excessively liquid and accordingly the disadvantages, mentioned earlier, which are inherent in compositions which remain in the form of a homogeneous solution after application are again encountered. The preferred proportions are between 1 and 5 parts by weight of the liquid of low volatility per part of insecticidal material (A).

The liquid of low volatility, (B), preferably has a vapour pressure at 250C which is less than 0.005 mm Hg. Its dissolving capacity for the insecticidal material, (A), at 20"C, is at most 5 parts of A per 100 parts of (B), by weight; preferably, this proportion is at most 3 parts of (A). The liquid (B) is thus a diluent for the active material (A). It must be chemically inert towards this active material (A), towards the liquid (C) and towards any other components which may be present in the composition according to the invention.

It will be seen that the part of insecticidal material (A) which remains dissolved in the liquid (B) after evaporation of the liquid (C), will not exceed 50% of the total weight of (A) present in the composition, and in the case of the preferred limits this amount is at most 15% of the weight of (A). This is an important feature of the invention.

The liquid of low volatility, (B), can be virtually non-volatile and can have a vapour pressure at 250C which is ess than 10-a mm Hg.

The liquid of low volatility, (B), is preferably chosen from amongst aliphatic hydrocarbons, halogenated aliphatic hydrocarbons, halogenated aromatic hydrocarbons, esters of aliphatic acids, esters of aromatic acids, heterocyclic compounds, preferably heterocyclic compounds of which the hetero atom is oxygen, high-molecular alcohols, polyols, ether-alcohols and amino-alcohols, aliphatic mercaptans, high-molecular ketones and natural oils.

Amongst these, aliphatic hydrocarbons, halogenated aliphatic hydrocarbons, esters of aliphatic acids, esters of aromatic acids, oxygen-containing heterocyclic compounds, alcohols, polyols and ketones are generally preferred.

In particular, the liquid of low volatility, (B), can for example be chosen from amongst one or more of the following solvents, provided, however, that the dissolving capacity of the resulting liquid for the insecticidal material (A) lies, at 20"C, between the limits indicated above: a vaseline oil (oil consisting of a mixture of hydrocarbons of the paraffin series obtained from petroleum residues Vaseline is a registered Trade Mark), a paraffin oil, hexadecane, l-bromotetradecane, I-chloro-hexadecane, tetrachlorodiphenyl, isopropyl myristate, dioctyl adipate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, bis (tridecyl) phthalate, 5-(3,6,9-trioxa-2-hydroxyundecyl)- 1,3-benzodioxole, 1dodecanol, l-tridecanol, glycerol, dibutyl ether of diethylene glycol (dibutyl carbitol), 2-amino-2-ethyl-propane-1,3-diol, tertiary dodecanethiol and oleone (9,26-pentadiatricontadien- 18-one), octanoic acid, oleic acid, 2-dodecylsuccinic anhydride, olive oil and linseed oil.

The liquid of low volatility, (B), is preferably chosen from amongst the following solvents: vaseline oil, paraffin oil, hexadecane, l-chloro-hexadecane, isopropyl myristate, dioctyl adipate, dioctyl sebacate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, bis-(tridecyl) phthalate, 5-(3,6,9-trioxaundecyloxy-2)1,3-benzodioxole, I-tridecanol, glycerol and oleone.

All these diluents (B) have a vapour pressure, at 250 C, of less than 0.01 mm Hg, and dissolving capacities for the active materials, at 200 C, ranging from 0 to 5 parts by weight of A per 100 parts by weight of B.

The volatile liquid (C) preferably has a vapour pressure, at 250 C, greater than 80 mm Hg; preferably, it is miscible in all proportions with the liquid (B); its dissolving capacity for the insecticidal material (A), at 200 C, is at least five parts by weight of (A) per 100 parts of (C) and preferably greater than ten parts per 100. The amount of liquid (C) required in the composition depends on its solvent power for the insecticidal material (A) and the liquid (B) and on the amount of each of these components; the amount of liquid (C) to be used must always be sufficient to afford a complete and homogeneous solution. Accordingly, the liquid (C) is a solvent for the active material (A). It is chemically inert towards this active material, towards the liquid (B) and towards any other ingredients which may be present in the composition according to the invention The volatile liquid (C) is preferably chosen from amongst aliphatic hydrocarbons, halogenated aliphatic hydrocarbons, aromatic hydrocarbons, aliphatic esters, heterocyclic compounds, preferably oxygen-containing heterocyclic compounds, aliphatic alcohols, aliphatic ethers, aliphatic ketones, nitro-alkanes and nitrilo-alkanes.

In particular, the volatile liquid (C) can be, for example, one of the following solvents, or a mixture of two or more of these solvents, provided however that the dissolving capacity, at 200 C, of this liquid for the insecticidal material (A) lies within the limits indicated above: methylene chloride, chloroform, benzene, methyl acetate, ethyl acetate, isopropyl acetate, propyl acetate, isobutyl acetate and/or butyl acetate, methyl propionate and/or ethyl propionate, methyl butyrate and/or ethyl butyrate, 2-methoxyethyl acetate, tetrahydrofuran, dioxane, ethoxyethane, methanol, ethanol, isopropanol, methoxyethanol, acetone, methyl ethyl ketone, butan-2-one, nitromethane and acetonitrile.

Thus, the liquids C which are more particularly preferred because their vapour pressures at 25"C are between 80 and 500 mm Hg and their solvent powers towards the active materials proposed by the invention vary between a value of 10 parts by weight of (A) per 100 parts by weight of (C) and miscibility in all proportions.

Preferably, the liquids (B) and (C) are miscible in all proportions.

A preferred solution according to the invention comprises: (A) from 0.01 to 10%, calculated relative to the total weight of the composition, of at least one insecticidal organophosphorus compound which is solid at 20"C; (B) from 0.01 to 10%, calculated relative to the total weight of the composition, of a carbon compound which is liquid at 250 C, is chemically inert towards component (A), has a vapour pressure at 25"C of O to 0.01 mm Hg, and has a dissolving capacity for component (A), at 200C, of at most 5 parts by weight of component (A) per 100 parts by weight of component (B); and (C) from 15 to 99.8%, calculated relative to the total weight of the composition, of a carbon compound which is liquid at 25"C, is chemically inert towards components (A) and (B), has a vapour pressure, at 250C, of 5 to 600 mm Hg and has a dissolving capacity for component (A), at 200C, of at least 5 parts by weight of (A) per 100 parts by weight of (C).

The liquids (D') are chosen from amongst the liquids having a vapour pressure, at 25"C, of at least 0.01 mm Hg. Their dissolving capacity for the insecticidal material (A) at 200C is at most 5 parts by weight of (A) per 100 parts by weight of (D'). These liquids (D') are thus more volatile diluents than the diluents (B); they make it possible to reduce the required proportion of liquid (B) and, by evaporating substantially more rapidly than the latter, they impart, after a certain time, a drier appearance to the composition after application and evaporation of the liquid (C).

Preferably the solution according to the invention contains a diluent (D') which is liquid at 25"C, is chemically inert towards the other components of the composition, is soluble in the mixture of (A) + (B) + (C), has a vapour pressure at 25"CD of 0.2 to 100 mm Hg and has a dissolving capacity for component (A) of 0.005 to 5 parts by weight of (A) per 100 parts by weight of (D').

The liquids (D') may be chosen from amongst the liquids having a vapour pressure, at 250C, greater than 10 mm Hg and even greater than 40 mm Hg, and a dissolving capacity for the insecticidal material (A), at 20"C, equal to or preferably less than 5 parts by weight of (A) per 100 parts by weight of(D'). They thus make it possible to dilute the liquid (C) if the latter has a very high solvent power.

The liquids (D') are chosen, for example, from amongst aliphatic hydrocarbons, aromatic hydrocarbons, halogenated aliphatic hydrocarbons, alkoxyalkanes, saturated aliphatic alcohols of more-than two carbon atoms, and heavy ketones.

The liquids (D') which, at 25"C, have a vapour pressure of less than 10 mm Hg are, for example, mixtures of saturated aliphatic hydrocarbons, or aliphatic alcohols having at least five carbon atoms, such as amyl alcohol or 1-octanol, and heavy ketones such as laurone (tricosane-12-one) and/or stearone (pentatriacontan-l 8-one).

The liquids (D') which, at 25"C, have a vapour pressure greater than 10 mm Hg are, for example, mixtures of saturated aliphatic hydrocarbons, pentane, hexane, heptane, butyl chloride, 1,1,1 -trichloroethane, trichloroethylene, benzene and isopropanol.

Amongst these, hexane, isopropanol, octanol, mixtures of saturated hydrocarbons such as "Isopar L" andaurone are very particularly preferred.

The compositions according to the invention can also contain non-volatile solid diluents (D") chosen from amongst natural or synthetic waxes, natural or synthetic resins and solid hydrocarbons; they are used, preferably, in a low proportion which does not exceed 10% by weight of the composition. The waxes are, for example, chosen from amongst beeswax, candelilla wax, carnauba wax, Japan wax, montan wax, synthetic waxes obtained from chlorinated naphthalene, glycol stearates and solid fatty ketones.

The resins are chosen, for example, from amongst colophony, gum lac and synthetic organic resins such as homopolymers and copolymers based on vinyl derivatives (vinyl acetate, vinyl propionate, vinyl butyrate, vinyl ethers or vinylformal), on alkenes (ethylene, propylene, butylene and the like) and/or on styrene and/or vinylpyrrolidones and/or cellulosic derivatives (the methyl, ethyl or benzyl ethers of cellulose, cellulose acetate, propionate, butyrate, phthalate, nitrate and the like) and/or on isoprene and/or on butadiene and/or on acrylic or methacrylic esters and/or on allyl esters (allyl phthalate, isophthalate, maleate, cyanurate and the like); such organic synthetic resins can also arise from the interaction of compounds with reactive groups, as in the case of the so-called "epoxy" resins, resulting from the condensation of an epoxide with a polyphenol, in the case of "polyester" resins, resulting from the action of a polyacid on a polyol, in the case of the polyurethanes, resulting from the condensation of a polyisocyanate with a polyol, and in the case of resins of the coumarone-indene type.

The solid hydrocarbons are chosen, for example, from amongst the microcrystalline and macro-crystalline alkanes having at least 24 carbon atoms, and their mixtures, known under the names of microwax, tank bottomwax, ozokerite, ceresine, paraffin and isoparaffin.

The liquefied gases (D"') which can be used as propellants are, for example. chosen from amongst butane, isobutane, propane, methoxymethane. trichlorofluoromethane, dichlorofluoromethane, 1,2-dichloro-1,1,2,2-tetrafluoro ethane, tetrafluoromethane and octafluorocyclobutane.

The supplementary insecticidal active materials (D"") are preferably nonsolvents or poor solvents for the insecticidal material (A). They are chosen, for example, from amongst liquid organophosphorus compounds, natural pyrethrins. rotenone, synthetic pyrethrinoids, N,N'-dibutyl-para-chlorobenzenesulphonamide, 1 ,4,4a,5,6,7,8,8-octahydro-3a,4,7,7a-tetrahydro-4,7-methano-indane, hexachlorocyclohexane and 1,2,3,4,10,10-endoexohexachloro-6,7-epoxy- 1 ,4,4a,5,6,7,8,8a-octahydro-l ,4,5,8-dimethano-naphthalene.

In general terms, the introduction, into the composition, of liquids which have both a very low volatility and are good solvents for the insecticidal material (A) will be avoided. Preferably, the presence of water, beyond the amount which corresponds to the normal contents of commercial technical product, will also be avoided.

The solutions according to the invention are intended to be applied to any surface frequented by the insects to be destroyed; they can also serve for the preparation of solid products which contain the active material (A) in a superactivated form; these solid products are prepared from carriers such as, for example, cardboard made from cellulose, asbestos or waste paper, wool and/or cotton felts, mineral or organic granules and powders such as talc, kaolin, dried clay, fossil silicas, synthetic silicas, non-fossil natural silicas, vermiculite, magnesium silicate, aluminium silicate, calcium phosphate, calcium carbonate, wood flour, soya flour and nutshell flour. The invention thus also provides a process for the preparation of a solid insecticidal composition which process comprises applying a solution according to the invention to the surface of a pulverulent or non-pulverulent carrier e.g. chosen from amongst cardboards, felts, and mineral or organic granules and powders, and allowing component (C) and any other volatile component present to evaporate.

The value of the compositions according to the invention is demonstrated in the experiments related below.

EXPERIMENT A The following nine compositions A-0 to A-8 were prepared in an aerosol container (values expressed in percentages by weight):

Composition A-0 A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A Azamethiphos (a) 2 2 2 2 2 2 2 2 2 Didecyl phthalate (a') - 4 - - - - - - Isopropyl myristate (a") - - 4 - - - - - 1-Chloro-hexadecane (a"') - - - 4 - - - - T.U.O.B. (a"") - - - - 4 - - - B Vaseline oil (b) - - - - - 4 - - Tridecanol (b') - - - - - - 4 - Oleone (b") - - - - - - - 4 Dibutyl phthalate (b"") - - - - - - - - 4 Tetrahydrofurane (c) 2 2 2 2 2 2 2 2 2 C Methylene chloride (c') 26 26 26 26 26 26 26 26 26 Trichlorofluoromethane 35 33 33 33 33 33 33 33 33 D"' Dichlorodifluoromethane 35 33 33 33 33 33 33 33 33 (a) O,O-Dimethyl S-(6-chloro-2-oxo-4-aza-benzoxazol-3-yl)-methyl thiophosphate or O,O-dimethyl S-[6-chloro-oxazolo(4,5-b)-2(3H)-pyridin-3-one]methyl thiophosphate.

(a') A liquid which has a vapour pressure, at 25 C, of less than 0.0001 mm Hg and a dissolving capacity of 1.6 parts of Azamethiphos in 100 parts at 20 C.

(a") A liquid which has a vapour pressure, at 25 C, of about 0.001 mm Hg and a dissolving capacity of 0.7 part of Azamethiphos in 100 parts at 20 C.

(a"') A liquid which has a vapour pressure, at 25 C, of less than 0.0001 mm Hg and a dissolving capacity of 4.3 parts of Azamethiphos in 100 parts at 20 C.

(a"") Abbreviation for 5-(3,6,9-trioxa-undecyloxy-2)- 1,3-benzodioxole; a liquid which has a vapour pressure, at 25 C, of less than 0.005 mm Hg and a dissolving capacity of 4.6 parts of Azamethiphos in 100 parts at 200 C.

(b) Semi-refined oil having a density of 0.870 at 15 C, a viscosity of 1.7 Engler at 50 C, a vapour pressure, at 25 C, of less than 0.001 mm Hg and virtually zero dissolving capacity for Azamethiphos at 200 C.

(b') A liquid which has a vapour pressure, at 250C, of about 0.005 mm Hg and a dissolving capacity of 0.5 part of Azamethiphos in 100 parts at 200 C.

(b") A liquid which has a vapour pressure, at 250C, of less than 0.000001 mm Hg and a dissolving capacity of about 2.2 parts of Azamethiphos in 100 parts at 200 C.

(b"') A liqu EXPERIMENT B The procedure of Experiment A was employed, using compositions A-0, A-l, A-2, AH, A-7 and A-8 and employing insects of the species Periplaneta americana The table below indicates the results recorded (KD%).

Time in minutes A-0 A-1 A-2 A-4 A-7 A-8 15 0 0 0 2 2 2 30 0 4 4 6 2 10 45 0 25 18 34 8 55 60 .4 61 24 72 30 79 75 8 73 33 86 46 96 90 | 16 73 39 96 5-4 98 105 | 20 77 45 96 66 100 120 26 79 51 97 72 - 135 36 85 53 98 82 180 46 89 63 100 88 EXPERIMENT C The following two compositions C-0 and C-1 were prepared in an aerosol container (values expressed in percentages by weight):

Composition C-0 C-1 A Azamethipho s 1 1 B Didecyl phthalate (a') 2 2 C Methylene chloride (c') 19 17 D"' Trichlorofluoromethane 40 40 Di chlorodifluoromethane 40 40 These compositions were each tested on one hundred insects of the species Musca domestica, 5 to 7 days old and flying freely in a room of size 28 m3. For each test, a weight of 4 grams of composition was vapourised into the atmosphere of the room, and every three minutes the number of insects knocked down was noted. The operation was repeated five times for each composition, making a total of 500150 insects tested per composition.

The cumulative proportions of insects knocked down (KD%) are indicated in the table below:

Time in minutes C - 0 C - 1 12 11 75 15 15 41 18 20 54 21 26 62 24 32 69 27 37 73 30 42 76 EXPERIMENT D A solution D-l having the following constitution (values expressed in percentages by weight) was prepared: Azamethiphos: 8 Dioctyl phthalate (d): 16 Acetone (c"): 76 (c") A liquid having a vapour pressure, at 250 C, of 225 mm Hg and a dissolving capacity, at 200 C, of 44 parts of Azamethiphos in 100 parts.

(d) A liquid which has a vapour pressure, at 250C, of less than 0.0001 mm Hg and a dissolving capacity of 2.4 parts of Azamethiphos in 100 parts at 200 C.

This solution was poured into a malaxator containing very fine talc powder (less than 0.5% retained on a 50 microns screen); after malaxating so as to achieve good distribution of the solution on the powder, the acetone is evaporated by means of a stream of hot air (500 C). The proportions of talc and of solution were chosen so as to give a final powder D-l having the following composition (values expressed as percentages by weight); Azamethiphos: 2.5 Dioctyl phthalate: 5.0 Talc: 92.5 In addition, a conventional formulation D--O was prepared as follows by intimately mixing the constituents (values expressed as percentages by weight): Azamethiphos: 2.5 Talc: 97.5 This mixture was passed through a pin mill so as to give a powder of which less than 0.05% is retained on a 50 microns screen.

Insecticidal efficacy tests were carried out on insects of the species Aphis fabae, which were placed in Petri dishes at the rate of twenty insects (#10%) per dish. Eight dishes were used, of which four had been treated with powder D-0 at the dose of 0.5 milligrams per square centimetre, and four others had been treated with powder D-l at the same dose. Every three minutes, the percentage of insects which appeared dead was noted.

The table below indicates the cumulative percentages noted each time:

Time in minutes D - 0 D - 1 18 4 10 21 4 14 24 6 20 27 13 30 30 23 51 EXPERIMENT E The following two liquid compositions E-O and E-l were prepared (values expressed in percentages by weight):

Composition E - 0 E - 1 A Chlorpyrifos 7 7 B Glycerol (d') - 7 -C Acetone (e) 46.5 43 Methanol (e') 46.5 43 (d') A liquid whichd has a vapour pressure, at 25 C, of less than 0.0001 mm Hg and a dissolving capacity, at 200 C, of 0.3 part of Chlorpyrifos in 100 parts.

(e) A liquid which has a vapour pressure, at 250C, of 225 mm Hg and a dissolving capacity, at 2C)0C, of 650 parts of Chlorpyrifos in 100 parts.

(e') A liquid which has a vapour pressure, at 250C, of 127 mm Hg and a dissolving capacity, at 2C)0C, of 43 parts of Chlorpyrifos in 100 parts.

These solutions were each deposited on one of the faces of glass plates of size 10 x 20 cm at the rate of 0.8 millilitre per plate. After evaporation of the solvent mixture, the plates were placed within contact of insects of the species Blattella germanica under the conditions described in Experiment A.

The results (KD%) are summarised in the table below:

Time in minutes E - 0 E - 1 45 6 9 60 18 33 75 42 59 90 60 85 105 70 92 120 75 95 EXPERIMENT F The following two liquid compositions F4) and F-l were prepared (values expressed in percentages by weight):

Composition F0 F-i A Iodofenphos 2 2 B Hexadecane (s') - 4 C Acetone (v) 49 | 47 Benzene (x) 49 47 (s') A liquid having a vapour pressure, at 250C, of about 0.003 mm Hg and a dissolving capacity, at 200 C, of 2.8 parts of Iodofenphos in 100 parts; (v) A liquid having a vapour pressure, at 250C, of 225 mm Hg and a dissolving capacity, at 200 C, of 48 parts of Iodofenphos in 100 parts; (x) A liquid having vapour pressure, at 250 C, of 95 mm Hg and a dissolving capacity, at 200 C, of 61 parts of Iodofenphos in 100 parts.

These solutions were each deposited on the bottom of a Petri dish of 16 centimetres diameter at the rate of 2 millilitres per dish. After evaporation of the solvent mixture, insects of the species Attagenus piceus were deposited at the rate of 10 insects per disc; 5 repeats were run, representing a total of 50 insects per composition. Every fifteen minutes, the number of dead insects or insects in a state of dorsal decubitus (KD%) was noted.

The table below indicates the mean values (KD%) of the results, recorded.

Time in minutes F -0 F - 1 90 2 6 105 2 12 120 2 14 135 2 20 150 2 22 165 2 25 180 2 29 195 2 34 210 2 40 225 2 58 240 4 70 255 18 90 270 20 98 285 20 98 300 22 100 EXPERIMENT G The following two liquid compositions G-0 and G--l were prepared (values expressed in percentages by weight):

Composition G - 0 G - 1 A Trichlormetafos 4 4 B Hexadecane (s') - 4 C Methylene chloride (f) 96 92 (f) A liquid having a vapour pressure of 420 mm Hg at 25 C and a dissolving capacity, at 2C)0C, of 670 parts of Trichlormetaphos in 100 parts.

These solutions were each deposited on one of the faces of glass plates of size 20 x 20 cm, carrying one gram of sugar powder distributed over their surface, at the rate of 2.4 millilitres per plate. After evaporation of the methylene chloride, each of these plates was placed in a one metre cube cage, each containing one hundred insects of the species Musca domestica. Every 3 minutes, the percentage of dead insects or insects in a state of dorsal decubitus was noted (KD%).

The results are summarised in the table below:

Time in minutes G - G - 1 18 0 3 21 0 6 24 0 9 27 0 12 30 0 21 36 6 36 42 12 48 48 13 54 54 15 61 60 16 67 EXPERIMENT H The following two liquid compositions H-0 and H-I were prepared (values expressed in percentages by weight):

Composition H - 0 H - 1 A Phosalone 0.5 0.5 B Paraffin oil (g) - 2.5 C Methylene chloride (w) 99.5 97 (g) A liquid which can be frozen at -27 C, and has density of 0.851 at 15 C, a vapour pressured, at 25 C, of less than 0.001 mm Hg and a dissolving capacity, at 20 C, of 2.4 parts of Phosalone in 100 parts; (w) A liquid having a vapour pressure, at 25 C, of 420 mm Hg and a dissolving capacity, at 20 C, of 30.4 parts of Phosalone in 100 parts.

These solutions were sprayed onto young bean plants infested with insects of the species Aphis fabae at the rate of 2 millilitres per plant, 6 plants were used for each of the solutions and after two hours the percentage of insects which were dead or appeared dead was recorded for each plant.

The results are summarised in the table below.

H - 0 H - 1 22 79 22 65 42 76 31 71 26 58 35 59 Mean values: 29.7 68 EXPERIMENT I The following two liquid compositions I-0 and I-1 were prepared (values expressed in percentages by weight):

Composition I - 0 I - 1 A Trichlorfon 1 1 B Dioctyl adipate (r') - 3 Chloroform (u) 66 64 C Benzene (x) 33 32 (u) A liquid having a vapour pressure, at 250 C, of 194 mm Hg and a dissolving capacity, at 200 C, of 750 parts of Trichlorfon in 100 parts; (r') A liquid having a vapour pressure, at 25 C, of about 0.006 mm Hg and a dissolving capacity, at 20 C, of 2.1 parts of Trichlorfon in 100 parts; These solutions were each deposited on the bottom of a Petri dish and insects of the species Attagenus piceus were introduced as in Experiment F.

The table below indicates the mean values (KD%) of the results recorded.

Time in minutes I-C) 1-1 90 6 16 120 6 28 150 6 38 180 6 45 210 6 64 240 10 72 270 12 96 300 12 100 The precedings experiments show the value of the compositions according to the invention; in all the cases, the efficacy of the insecticidal material proved to be markedly improved when the solution which contained the material also contained, in accordance with the invention, a non-volatile liquid which is a poor solvent for the said material and a volatile material which is a good solvent for the said material.

EXPERIMENT J The following five aerosol compositions J-0 to J-4 were prepared (values expressed in percentages by weight);

Composition J - 0 J - 1 J - 2 J - 3 J - 4 A D.B.D.P (h) 0.5 0.5 0.5 0.5 0.5 B Dibutyl phthalate (i) - 0.5 - - Isopropyl myristate (i') - - 0.5 - Vaseline oil (i") - - - 0.5 T.U.O.B (i"') - - - - 0.5 C 1,1,1-Trichloroethane (j) 27.8 27.8 27.8 27.8 27.8 D' Isopar "L" (j') 21.7 21.2 21.2 21.2 21.2 D"' Trichlorofluoromethane 20 20 20 20 20 Dichlorodifluoromethane 30 30 30 30 30 (h Abbreviation for O,O-diethyl S-(2-oxo-4-aza-benzoxazol-3-yl)-methyl dithiophosphate; (i) A liquid having a vapour pressure, at 25 C, of about 0.001 mm Hg and a dissolving capacity of 3.6 parts of D.B.D.P in 100 parts at 20 C; (i') A liquid having a vapour pressure, at 25 C, of about 0.001 mm Hg and a dissolving capacity of 1.15 parts of D.B.D.P. in 100 parts at 20 C; (i") Semi-refined oil described in (b) and having virtually zero dissolving capacity for D.B.D.P. at 20 C; (i"') Abbreviation of 5-(3,6,9-trioxa-undecyloxy-2)-1,3-benzodioxole, a liquid having a vapour pressure, at 25 C, of less than 0.005 mm Hg and a dissolving capacity of 5 parts of D.B.D.P. in 100 parts at 200C; (.1) A liquid having a vapour pressure, at 250C, of 121 mm Hg and a dissolving capacity of 18.6 parts of D.B.D.P. in 100 parts at 200C; (j') A distillation cut, between 189 and 205"C, of branched aliphatic hydrocarbons obtained synthetically, which is marketed by Messrs. ESSO STANDARD, contains a mixture of decanes, undecanes and dodecanes, have vapour pressures, at 25"C, of between 0.2 and 2 mm Hg and a dissolving capacity, at 20"C, of about 0.15 part of D.B.D.P. in 100 parts.

The content of each of the containers was sprayed onto one of the faces of a fabric composed of wool fibres and synthetic fibres, at the rate of 400 mg per dm2.

Discs of 70 mm diameter were cut from this fabric and each face, treated face upwards, are placed in the bottom of a Petri dish of the same internal diameter.

One hour later, insects of the species Sitophilus granarius were introduced into the dishes at the rate of 10 insects per dish.

For each aerosol, ten dishes were used. Every six minutes, the cumulative proportion of dead or paralysed insects (KD%) was noted.

The table below indicates the results recorded.

Time in minutes J - J1 J - 1 J - 2 J - 3 J - 4 12 0 5 9 8 9 18 0 27 26 12 16 24 1 40 43 24 35 30 4 56 56 47 -44 36 10 .75 77 65 58 42 15 87 90 75 68 48 19 94 96 8-4 74 54 33 99 99 92 80 60 47 99 100 98 83 N.B. The addition of this experiment makes it possible to eliminate, page 26, the sitophili from amongst the coleoptera.

These experiments were concerned with certain orthoptera, diptera, hemiptera and coleoptera; of course, the compositions according to the invention are equally applicable to the destruction of other species of orthoptera such as, for example, crickets, grasshoppers and mole-crickets, diptera, such as, for example, stable flies, house mosquitoes and yellow-fever mosquitoes, hemiptera such as, for example, bugs and triatomids, and coleoptera such as, for example, varieties of Oryznophilus, Dermestes, Trogodoram, Tribolium, Guathocerus, Tenebrio, Sitophilus and Leptinotarsa, as well as other orders of insects such as, for example, hymenoptera (ants), lepidoptera (Sitotroga and Plodia), isoptera (termites) and heteroptera (house bugs).

The compositions below are given as supplementary examples of the invention (values expressed in parts by weight).

EXAMPLES 1 to 10 Liquid formulations used under atmospheric or superatmospheric pressure

Composition 1 2 3 4 5 6 7 8 9 10 Trichlormetaphos - - - 5 - - - - - Chloropyrifos 10 2 - - - - - - - Azamethiphos - - 3 - - - - - - A Dimethoate - - - - - - - 4 - Iodofenphos - - - - 6 - 1 - - Trichlorphon - - - - - 5 - - - 6 Phosalone - - - - - - - - 10 1-Chloro-hexadecane (s) - - - - - 8 - - - Isopropyl myristate (a") (p) - - - - - - - 20 - Paraffin oil (q) - - - - - - 1 - - B Dioctyl sebacate (p') - - - - - - - - - 24 Hexadecane (s') - - - 5 12 2 - - 10 Glycerol (d') (q') 5 0,6 - - - - - - - Vaseline oil (b) - - 1 - - - - - - EXAMPLES 1 to 10 (Continued)

Composition 1 2 3 4 5 6 7 8 9 10 Acetone (e) (v) - 33 - - - - - 76 - Methyl acetate (v') - - - 79 - - - - - Methyl chloride (c') (w) - - - - 40 - 16 - 75 Ethoxyethane (w') - - - - - 34 - - - C Methanol (e') - 10 - - - - - - - Chloroform (u) - - - - - 50 - - - 40 Butan-2-one (u') - - 91 - - - - - - Benzene (x) - - - - 12 - - - - 30 Ethanol (x') 84 - - - - - - - - Hexane (y) - - - - 10 - - - - Isopropanol (y') - - - - 17 - - - - D' Carnauba wax - - 3 - - - - - - Vinyl acetate - - - 10 - - - - - Paraffin 60/62 C - - - - - - - - 5 RXAMPLES 1 to 10 (Continued)

Composition 1 2 3 4 5 6 7 8 9 10 Butane - 40 - - - - - - - D"' Propane - 10 - - - - - - - Dichlorodifluoromethane - - - - - - 80 - - Diazinon - - - - 2 - - - - D"" Dichlorvos - - 1 - - - - - - Gamma-BHC - 0.4 - - - - - - - Green dyestuff 0.5 - 0.7 - 0.6 - - - - Yellow dyestuff - - - 1 0.2 0.7 - - - Pine essence 0.5 - - - - - - - - D""' Lemon essence - - - - - 0.3 - - - Epoxidised soya oil - - 0.3 - - - - - - Epichlorohydrin - - - - 0.2 - - - - EXAMPLES 11 to 16 Solid formulations produced from liquid compositions

11 12 13 14 15 16 CARRIER USED Talc 70 60 100 - 100 70 Kaolin - 40 - - - 20 Aluminium silicate - - - - - Soya flous - - - - - 10 Calcium carbonate 30 - - - - Sugar - - - 100 - Parts by weight of carrier 96.5 96 94 76 92.5 98.4 LIQUID COMPOSITION USED Chlorpyrifos 10 - - - - Azamethiphos - - - - 4 A Trichlorphon - 10 - 1 - Idofenphos - - 10 - 6 Dimethoate - - - - - 3 EXAMPLES 11 to 16 (Continued)

11 12 13 14 15 16 LIQUID COMPOSITION USED Glycerol (d) (q') 2 - 10 - - Hexadecane (s') - - - - 20 B Dioctyl adipate (r') - - - 10 - Isopropyl myristate (p) - 10 - - - 5 Acetone (c") (v) - - 80 - - 92 Chloroform (u) - 80 - - - C Methylene chloride (c') (w) - - - - 70 Ethoxyethane (w') - - - 88 - Ethanol (x') 86 - - - - D" Dieldrin 2 - - - - Red dyestuff - - - 0.5 - D""' Epoxidised soya oil - - - 0.5 - Parts by weight of liquid 25 20 30 20 25 20 A% after evaporation 2.5 2 3 2 2.5 0.6 (p) A liquid having a vapour pressure, at 250C, of about 0.001 mm Hg and a dissolving capacity, at 20"C, of 2.9 parts of Dimethoate or 1.5 parts of Trichlorphon in 100 parts; (p') A liquid having a vapour pressure, at 25"C, of less than 0.0001 mm Hg and a dissolving capacity, at 20"C, of 1.7 parts of Trichlorphon in 100 parts; (q) A liquid which can be frozen at-270C and having a density of 0.851 at 15"C, a vapour pressure, at 250C, of less than 0.001 mm Hg and a dissolving capacity, at 20"C, of about 5 parts of Iodofenphos in 100 parts; (q') A liquid having a vapour pressure, at 25"C, of less than 0.0001 mm Hg and a dissolving capacity, at 200 C, of 0.5 part of Fospirate or 0.2 part of Iodofenphos in 100 parts; (s) A liquid having a vapour pressure, at 250C, of less than 0.0001 mm Hg and a dissolving capacity, at 200 C, of 2.8 parts of Trichlorphon in 100 parts; (s') A liquid having a vapour pressure, at 250 C, of about 0.003 mm Hg and a dissolving capacity, at 200 C, of 4.2 parts of Trichlormethaphos, or of 2.8 parts of Iodofenphosor of at least 0.1 part of Trichlorphon in 100 parts; (u') A liquid having a vapour pressure, at 250C, of 90 mm Hg and a dissolving capacity, at 200 C, of 46 parts of Azamethiphos in 100 parts; (v) A liquid having a vapour pressure, at 250C, of 225 mm Hg and a dissolving capacity, at 200C, of 13.6 parts of Dimethoate or 48 parts of Iodofenphos in 100 parts; (v') A liquid having a vapour pressure, at 250C, of 216 mm Hg and in which Trichlormetaphos is miscible in all proportions at 200 C; (w) A liquid having a vapour pressure, at 250 C, of 420 mm Hg and a dissolving capacity, at 20"C, of 86 parts of Iodofenphos or 30.4 parts of Phosalone in 100 parts; (w') A liquid having a vapour pressure, at 250C, of 530 mm Hg and a dissolving capacity, at 20"C, of 24 parts of Trichlorphon in 100 parts; (x) A liquid having a vapour pressure, at 250 C, of 95 mm Hg and a dissolving capacity, at 20 C, of 61 parts of Iodofenphos or 17.2 parts of Trichlorphon in 100 parts; (x') A liquid having a vapour pressure, at 250 C, of 59 mm Hg and a dissolving capacity, at 200 C, of 63 parts of Chlorpyrifos or 20 parts of Fospirate in 100 parts; (y) A liquid having a vapour pressure, at 250C, of 151 mm Hg and a dissolving capacity, at 200 C, of 3.3 parts of Iodofenphos in 100 parts; (y') A liquid having a vapour pressure, at 250C, of 44 mm Hg and a dissolving capacity, at 200 C, of 2.3 parts of Iodofenphos in 100 parts.

The words "DICAPTHON" and "ISOPAR" are registered Trade Marks.

Claims

WHAT WE CLAIM IS:-

1. A liquid insecticidal homogeneous solution, which is free from any insecticidal carbamate compound, comprising: (A) as active ingredient, at least one insecticidal organophosphorus compound which is solid at 20"C; (B) 0.2 to 10 parts by weight, per part by weight of component (A), of at least one carbon compound which is liquid at 25"C, has a dissolving capacity for component (A) at 20"C of at most 5 parts by weight of compound (A) per 100 parts by weight of component (B), and has a vapour pressure at 250C which does not exceed 0.01 mm Hg, and (C) at least one carbon compound which is liquid at 250C, has a dissolving capacity for component (A) and for component (B) of at least 5 parts by weight of component (A) and at least 5 parts by weight of component (B) per 100 parts by weight of component (C), has a vapour pressure at 250C of at least 5 mm Hg, component (C) being present in an amount sufficient to form a homogeneous solution with the amounts of the components (A) and (B) present.

2. A solution according to claim 1, comprising: (A) from 0.01 to l00o, calculated relative to the total weight of the composition, of at least one insecticidal organophosphorus compound which is solid at 20"C: (B) from 0.01 to 10 ó, calculated relative to the total weight of the composition, of a carbon compound which is liquid at 25"C, is chemically inert towards component (A), has a vapour pressure at 250C of 0 to 0.01 mm Hg, and has a dissolving capacity for component (A), at 200 C, of at most 5 parts by weight of component (A) per 100 parts by weight of component (B); and (C) from 15 to 99.806, calculated relative to the total weight of the composition, of a carbon compound which is liquid at 250C, is chemically inert towards components (A) and (B), has a vapour pressure, at 250C, of 5 to 600 mm Hg and has a dissolving capacity for component (A), at 200 C, of at least 5 parts by weight of (A) per 100 parts by weight of (C).

3. A solution according to claim 1 or 2, in which component (A) is chosen from O,O-dimethyl S-14-aza-6-chloro-2-oxo-benzoxazol-3-yl]-methyl thiophosphate.

O,O-diethyl O-(3,5,6-trichloro-pyrid-2-yl) thiophosphate, O,O-dimethyl 0-(2,5dichloro-4-iodo-phenyl) thiophosphate, O,O-dimethyl O-(2,4,5-trichloro-phenyl) thiophosphate, O,O-dimethyl S-(6-chloro-2-oxo-benzoxazol-3-yl)-methyl dithiophosphate, O,O-dimethyl (2,2,2-trichloro-1 -hydroxy)-ethyl-phosphonate and O,O-diethyl-S-(2-oxo-4-aza-benzoxazol-3-yl)-methyl dithiophosphate.

4. A solution according to any one of claims 1 to 3, in which component (B) has a vapour pressure at 250C of 0 to 0.005 mm Hg.

5. A solution according to any one of claims 1 to 4, in which component (B) has a dissolving capacity for component (A), at 20"C, of 0 to 3 parts by weight of component (A) per 100 parts by weight of component (B).

6. A solution according to any one of claims I to 5, in which component (B) is chosen from aliphatic hydrocarbons, halogenated aliphatic hydrocarbons, halogenated aromatic hydrocarbons, esters of aliphatic acids, esters of aromatic acids, heterocyclic compounds, alcohols, polyols, etheralcohols, amino-alcohols, aliphatic mercaptans, ketones, aliphatic acids, their anhydrides and natural oils.

7. A solution according to claim 6, in which component (B) is chosen from oil consisting of a mixture of hydrocarbons of the paraffin series obtained from petroleum residues, paraffin oil, hexadecane, I-bromo-tetradecane, I-chlorohexadecane, tetrachlorodiphenyl, isopropyl myristate, dioctyl adipate, di-(2ethylhexyl) adipate, dioctyl sebacate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, bis-(tridecyl)phthalate, 5-(3,6,9-trioxa-undecyloxy-2)- 1 ,3-benzodioxole, l-dodecanol, l-tridecanol, glycerol, the dibutyl ether of diethylene glycol, 2-amino 2-ethyl-propane-I ,3-diol, tertiary dodecanethiol, oleone, octanoic acid, oleic acid, 2-dodecylsuccinic anhydride, olive oil and linseed oil.

8. A solution according to claim 6, in which component (B), is chosen from aliphatic hydrocarbons, halogenated aliphatic hydrocarbons, esters of aliphatic acids, esters of aromatic acids, oxygen-containing heterocyclic compounds, alcohols, polyols and ketones.

9. A solution according to claim 8, in which component (B) is chosen from oil consisting of a mixture of hydrocarbons of the paraffin series obtained from petroleum residues, paraffin oil, hexadecane, I-chloro-hexadecane, isopropyl myristate, dioctyl sebacate, dioctyl adipate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, 5-(3,6,9-trioxa-undecyloxy-2)- 1,3-benzodioxole, 1 -tridecanol, glycerol and oleone.

10. A solution according to any one of claims I to 9, in which component (C) has a vapour pressure, at 250C, of 80 to 500 mm Hg.

11. A solution according to any one of of claims 1 to 10, in which component (C) has a dissolving capacity for component (A), at 20"C, greater than 10 parts by weight of (A) per 100 parts by water of (C).

12. A solution according to any one of claims 1 to 11, in which component (C) is chosen from aliphatic hydrocarbons, halogenated aliphatic hydrocarbons. aromatic hydrocarbons, aliphatic esters, heterocyclic compounds, aliphatic alcohols, aliphatic ethers, aliphatic ketones, nitro-alkanes and nitrilo-alkanes.

13. A solution according to claim 12, in which component (C) is chosen from methylene chloride, chloroform, chloroform, benzene, methyl acetate, ethyl acetate, isopropyl acetate, propyl acetate, isobutyl acetate and/or butyl acetate, methyl propionate and/or ethyl propionate, methyl butyrate and/or ethyl butyrate, 2-methoxy-ethyl acetate, tetrahydrofuran, dioxane, ethoxyethane, methanol, ethanol, isopropanol, methoxyethanol, acetone, methyl ethyl ketone, butan-2-one, nitromethane and acetonitrile.

14. A solution according to claim 12, in which component (C) is chosen from halogenated aliphatic hydrocarbons, aromatic hydrocarbons, aliphatic esters, oxygen-containing heterocyclic compounds, aliphatic alcohols, aliphatic ethers and aliphatic ketones.

15. A solution according to any one of claims I to 14, which contains an adjuvant (D) chosen from: (D') liquids which have a dissolving capacity for component (A) at 20"C of at most 5 parts by weight of component (A) per 100 parts of component (D') and having a vapour pressure, at 250C, equal to or greater than 0.01 mm Hg; (D") non-volatile solid diluents or carriers; (D"') liquefied gases which can be used as propellants; (D"") insecticidally active materials different from (A) and other than a carbamate; and (D""') dyestuffs, perfumes and stabilisers.

16. A solution according to any one of claims 1 to 17 which contains a diluent (D') which is liquid at 25"C, is chemically inert towards the other components of the composition, is soluble in the mixture of (A) + (B) + (C), has a vapour pressure at 25"C of 0.2 to 100 mm Hg and has a dissolving capacity for component (A) of 0.005 to 5 parts by weight of (A) per 100 parts by weight of (D').

17. A solution according to claim 16, in which component (D') is hexane, isopropanol, octanol, laurone or a mixture of aliphatic hydrocarbons.

18. A solution according to claim 1 substantially as described in any one of the foregoing Experiments.

19. A solution according to claim 1 substantially as described in any one of the foregoing Experiments.

20. A method of combating insects at a surface which method comprises applying to the surface a solution as claimed in any one of the preceding claims.

21. A process for preparing a solid insecticidal composition which process comprises applying a solution as claimed in any one of claims 1 to 19 to the surface of a pulverulent or non-pulverulent solid carrier, and allowing component (C) and any other volatile component present to evaporate.

22. A solid insecticidal composition prepared by the process claimed in claim 21.