Combatting pests with O-ethyl-S-n-propyl-O-(substituted phenyl)-phosphorothiolates

Abstract

Combating insects, acarids and nematodes with O-ethyl-S-n-propyl-O-(substituted phenyl)-phosphorothiolates of the general formula ##STR1## wherein X is halogen, lower alkyl, nitro, cyano, lower alkylmercapto, lower alkylsulfinyl, lower alkoxycarbonyl or lower alkyl carbonyl, andm is 1, 2 or 3.

Description

The present invention relates to and has for its objects the provision of particular new O-ethyl-S-n-propyl-O-(substituted phenyl)-phosphorothiolates, i.e. those wherein the phenyl group carries 1, 2 or 3 halogen, lower alkyl, nitro, cyano, lower alkylmercapto, lower alkylsulfinyl, lower alkoxycarbonyl or lower alkylcarbonyl groups, which possess insecticidal, acaricidal and nematocidal properties, active compositions in the form of mixtures of such compounds with solid and liquid dispersible carrier vehicles, and methods for producing such compounds and for using such compounds in a new way especially for combating pests, e.g. insects, acarids, and nematodes, with other and further objects becoming apparent from a study of the within specification and accompanying examples.

It is known that O,S-dialkyl-O-phenylphosphorothiolates exhibit insecticidal activity. However, this activity is so low that they have not been used in spite of being less toxic to warm-blooded animals than the corresponding O,O-dialkyl-O-phenylphosphorothioates.

For example, O,O-dimethyl-O-4-nitrophenylphosphorothioate (Compound A; common name, methylparathion) of the following formula: ##STR2## has strong insecticidal activity and exhibits excellent effects, while the corresponding O,S-dimethyl-4-nitrophenyl phosphorothiolate (Compound B) of the formula: ##STR3## which has only one-third of the toxicity to warm-blooded animals has unfortunately only one-fiftieth of the insecticidal activity.

As methylparathion is very toxic to warm-blooded animals, much research has been conducted with a view to developing a novel effective insecticide with low toxicity to warm-blooded animals and has resulted in the provision of O,O-dimethyl-O-(3-methyl-4-nitrophenyl)phosphorothioate (Compound C; commercial name, Sumithion) and O,O-dimethyl-O-(3-methyl-4-methylthiophenyl)-phosphorothioate (Compound D; commercial name, Lebaycid).

These phosphorothioates have been widely used as insecticides, but difficulty has been found in controlling harmful insects which have acquired resistance to these insecticides. In such circumstances, there is a strong demand for a novel insecticide effective against resistant harmful insects.

The present invention provides compounds which have great insecticidal activity, only slight toxicity for warm-blooded animals and practically no phytotoxicity, so that they can be used for controlling a great variety of harmful insects, such as harmful sucking insects, biting insects, plant parasites, hygiene pest insects and stored-grain insects.

The present invention is based on the surprising discovery that those O-alkyl-S-alkyl-O-phenylphosphorothiolates in which the alkyl groups are different and in which the alkyl attached to the S atom is n-propyl and the O-alkyl is ethyl have excellent insecticidal activity, very much greater for example than if the two alkyls have the same number of carbon atoms or if the alkyl attached to the S atom is alkyl other than n-propyl.

The present invention accordingly provides particular O-ethyl-S-n-propyl-O-phenyl phosphorothiolates of the following general formula: ##STR4## wherein X is halogen, lower alkyl, nitro, cyano, lower alkylmercapto, lower alkylsulfinyl, lower alkoxycarbonyl or lower alkyl carbonyl, and

m is 1, 2 or 3.

The invention also provides a process for the production of a compound according to the invention in which

(a) a thiol phosphoric acid diester halide of the general formula: ##STR5## is reacted with a phenol of the general formula: ##STR6##

(b) a compound of the general formula: ##STR7## is reacted with an oxidizing agent, or

(c) a salt of a thiophosphoric acid of the general formula: ##STR8## is reacted with a halide of the formula:

Hal-C.sub.3 H.sub.7 -n (V) in which formulae Hal is halogen, M.sup.1 is hydrogen or a metal or ammonium, M.sup.2 is metal or ammonium, R is lower alkyl, and X and m have the meanings stated with respect to formula (I).

Process variant (a) is illustrated by the following formula scheme: ##STR9##

Examples of X are lower alkyl groups such as methyl, ethyl, n-(or iso-) propyl, n-(or iso-, sec.- or tert.-) butyl; halogen atoms such as fluorine, chlorine, bromine or iodine; nitro, cyano, lower alkylmercapto or lower alkylsulfinyl groups; lower alkoxycarbonyl or lower alkylcarbonyl groups.

Hal is preferably chlorine. M.sup.1 may be ammonium, hydrogen, sodium, potassium or lithium.

Examples of the compounds of formula (III) include:

2-(or 3- or 4-)chloro (or bromo)phenol, 2,4-(or 2,5- or 2,6-)dichlorophenol, 2,4-dibromophenol, 2,4,5-(or 2,4,6-)trichlorophenol, 2,5-dichloro-4-bromophenol, 2-(or 3- or 4-)methylphenol, 4-ethylphenol, 2-iso-propylphenol, 4-tert.-butylphenol, 2-sec.-butylphenol, 2,4-(or 3,4- or 3,5-)dimethylphenol, 2-iso-propyl-5-methylphenol, 2-chloro-4-(or 5- or 6-)methylphenol, 4-chloro-2-(or 3-)methylphenol, 2-chloro-4-tert.-butylphenol, 4-chloro-3,5-dimethylphenol, 2,4-dichloro-6-methylphenol, 2-(or 3- or 4-)nitrophenol, 2-(or 3-)chloro-4-nitrophenol, 3-methyl-4-nitrophenol, 3-nitro-4-(or 6-)methylphenol, 2-nitro-4-chlorophenol, 2-nitro-4-methylphenol, 2,6-dichloro-4-nitrophenol, 3-nitro-4-chlorophenol, 2-(or 4-)cyanophenol, 2-chloro-4-cyanophenol, 2-cyano-4-chlorophenol, 2-cyano-4,6-dichlorophenol, 2-(or 4-)ethoxycarbonylphenol, 2-chloro-4-ethoxycarbonylphenol, 2,6-dichloro-4-ethoxycarbonylphenol, 2-methoxycarbonylphenol, 2-ethoxycarbonyl-4-chlorophenol, 2-ethoxycarbonyl-4,6-dichlorophenol, 2-(or 4-)methylcarbonylphenol, 2,6-dichloro-4-methylcarbonylphenol, 2-chloro-4-methylmercaptophenol, 4-methylmercaptophenol, 4-ethylmercaptophenol, 2-methyl-4-methylmercaptophenol, 3-methyl-4-methylmercaptophenol, 3,5-dimethyl-4-methylmercaptophenol, 4-methylsulfinylphenol, 2-methyl-4-methylsulfinylphenol, 3,5-dimethyl-4-methylsulfinylphenol.

Sodium or potassium salts of the corresponding phenols may be used.

In the production of the compounds of this invention according to the above method, the reaction is preferably conducted in a solvent or diluent. For this purpose any inert solvent or diluent may be used.

As the solvent or diluent there may be cited water; aliphatic, alicyclic and aromatic hydrocarbons which may be chlorinated such as hexane, cyclohexane, petroleum ether, ligroin, benzene, toluene, xylene, methylene chloride, chloroform, carbon tetrachloride, mono-, di-, and tri-chloroethylenes, and chlorobenzene; ethers such as diethyl ether, methyl ethyl ether, di-iso-propyl ether, dibutyl ether, ethylene oxide, dioxane and tetrahydrofurane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; nitriles such as acetonitrile propionitrile and acrylonitrile; alcohols such as methanol, ethanol, isopropanol, butanol and ethylene glycol; esters such as ethyl acetate and amyl acetate; amides such as dimethyl formamide and dimethyl acetamide; and sulfoxides and sulfones such as dimethyl sulfoxide and sulfolane.

This process variant may be carried out in the presence of an acid binder according to need. As the acid binder there may be cited hydroxides, carbonates, bicarbonates and alcoholates of alkali metals and tertiary amines such as triethylamine, diethylaniline and pyridine.

In this process variant, the reaction may be effected at temperatures over a broad range, but generally the reaction is carried out at temperatures ranging from about -20.degree. C. to the boiling point of the reaction mixture, preferred temperatures being in the range from about 10.degree. to 100.degree. C.

Process variant (c) is illustrated by the following formula scheme: ##STR10##

Examples of the salts of O-ethyl-O-substituted phenyl thiophosphoric acid of the formula (IV) used as starting material include:

O-ethyl-O-[2- (or 3- or 4-)chlorophenyl]-, O-ethyl-O-[2- (or 4-)bromophenyl]-, O-ethyl-O-[2- (or 3- or 4-)methylphenyl]-, O-ethyl-O-(4-ethylphenyl)-, O-ethyl-O-(2-iso-propylphenyl)-, O-ethyl-O-(4-tert.-butylphenyl)-, O-ethyl-O-(2-sec.-butylphenyl)-, O-ethyl-O-(4-methylmercaptophenyl)-, O-ethyl-O-(4-ethylmercaptophenyl)-, O-ethyl-O-(4-methylsulfinylphenyl)-, O-ethyl-O-[2-(3- or 4-)nitrophenyl]-, O-ethyl-O-[2-(2-(or 4-)cyanophenyl]-, O-ethyl-O-(2-methoxycarbonylphenyl)-, O-ethyl-O-[2-(or 4-)methylcarbonylphenyl]-, O-ethyl-O-[2-(or 4-)ethoxycarbonylphenyl]-, O-ethyl-O-[2,4-(or 2,5- or 2,6-)dichlorophenyl]-, O-ethyl-O-(2,4-dibromophenyl)-, O-ethyl-O-[2,4-(3,4- or 3,5-)dimethylphenyl]-, O-ethyl-O-(2-iso-propyl-5-methylphenyl)-, O-ethyl-O-(2-chloro-4-methylphenyl)-, O-ethyl-O-(2-chloro-6-methylphenyl)-, O-ethyl-O-(2-chloro-5-methylphenyl)-, O-ethyl-O-(2-methyl-4-chlorophenyl)-, O-ethyl-O-(3-methyl-4-chlorophenyl)-, O-ethyl-O-(2-chloro-4-tert.-butylphenyl)-, O-ethyl-O-(3-methyl-4-methylmercaptophenyl)-, O-ethyl-O-(2-chloro-4-nitrophenyl)-, O-ethyl-O-(3-chloro-4-nitrophenyl)-, O-ethyl-O-(3-methyl-4-nitrophenyl)-, O-ethyl-O-(3-nitro-4-methylphenyl)-, O-ethyl-O-(2-methyl-5-nitrophenyl)-, O-ethyl-O-(2-nitro-4-chlorophenyl)-, O-ethyl-O-(2-nitro-4-methylphenyl)-, O-ethyl-O-(3-nitro-4-chlorophenyl)-, O-ethyl-O-(2-chloro-4-cyanophenyl)-, O-ethyl-O-(2-cyano-4-chlorophenyl)-, O-ethyl-O-(2-chloro-4-ethoxycarbonylphenyl)-, O-ethyl-O-(2-ethoxycarbonyl-4-chlorophenyl)-, O-ethyl-O-(2,6-dichloro-4-methylcarbonylphenyl)-, O-ethyl-O-(2-chloro-4-methylmercaptophenyl)-, O-ethyl-O-(2-methyl-4-methylmercaptophenyl)-, O-ethyl-O-(2-methyl-4-methylsulfinylphenyl)-, O-ethyl-O-(2,4,5-trichlorophenyl)-, O-ethyl-O-(2,5-dichloro-4-bromophenyl)-, O-ethyl-O-(2,4,6-trichlorophenyl)-, O-ethyl-O-(3,5-dimethyl-4-chlorophenyl)-, O-ethyl-O-(2,4-dichloro-6-methylphenyl)-, O-ethyl-O-(2,6-dichloro-4-nitrophenyl)-, O-ethyl-O-(2-cyano-4,6-dichlorophenyl)-, O-ethyl-O-(2,6-dichloro-4-ethoxycarbonylphenyl)-, O-ethyl-O-(2-ethoxycarbonyl-4,6-dichlorophenyl)-, O-ethyl-O-(3,5-dimethyl-4-methylmercaptophenyl)-, or O-ethyl-O-(3,5-dimethyl-4-methylsulfinylphenyl)- thiophosphoric acid potassium salt and the corresponding sodium and ammonium salts.

Examples of the n-propylhalide of the formula (V) used as starting material include n-propylbromide and the corresponding chlorides.

This process variant may be carried out in the same manner as process variant (a), and the compound of the present invention can be obtained with high purity and in high yield.

As mentioned above, the compounds of the present invention can be used for controlling harmful insects of a broad range such as those belonging to

______________________________________Coleopterasuch as Rice weevil Sitophilus oryzae Rust-red beetle Tribolium castaneum 28-spotted lady beetle Epilachana vigintiocto- punctata Barley wireworm Agriotes fuscicollis Soy bean beetle Anomala rufocupreaLepidopterasuch as Gypsy moth Lymantria dispar Tent caterpillar Malacosoma neustria testacea Common cabbageworm Pieris rapae crucivo ra Tobacco cutworm Prodenia litura Rice-stem borer Chilo suppressalis Smaller tea tortrix Adoxophyes orana Almond moth Ephestia cautellaHemipterasuch as Green rice leafhopper Nephotettix cincticeps Brown planthopper Nilaparvata lugens Comstock mealybug Pseudococcus comstocki Arrowhead scale Unaspis yanonensis Green peach aphid Myzus persicae Apple aphid Aphis pomi Cabbage aphid Brevicoryne brassicaeOrthopterasuch as German cockroach Blatella germanica American cockroach Periplaneta americana African mole cricket Gryllotalpa africanaIsopterasuch as Japanese termite Leucotermes speratusDipterasuch as House fly Musca domestica vicina Yellow fever mosquito Aedes aegypti Seed-corn maggot Hylemya platura Common mosquito Culex pipiens Malaria mosquito Anopheles simensis Japanese encephalistis Culex tritaeniorhynchusAcarinasuch as Carmine mite Tetranychus telarius Citrus red mite Panonychus citri Japanese citrus red mite Aculus pelekassiNematodesuch as Southern root-knot Meloidogyne incognita nematode Rice white-tip nematode Aphelenchoides besseyi Soy bean cyst nematode Heterodera glycines______________________________________

The active compounds according to the instant invention can be utilized, if desired, in the form of the usual formulations or compositions with conventional inert (i.e. plant compatible or herbicidally inert) pesticide diluents or extenders, i.e. diluents, carriers or extenders of the type usable in conventional pesticide formulations or compositions, e.g. conventional pesticide dispersible carrier vehicles such as gases, solutions, emulsions, suspensions, emulsifiable concentrates, spray powders, pastes, soluble powders, dusting agents, granules, etc. These are prepared in known manner, for instance by extending the active compounds with conventional pesticide dispersible liquid diluent carriers and/or dispersible solid carriers optionally with the use of carrier vehicle assistants, e.g. conventional pesticide surface-active agents, including emulsifying agents and/or dispersing agents, whereby, for example, in the case where water is used as diluent, organic solvents may be added as auxiliary solvents. The following may be chiefly considered for use as conventional carrier vehicles for this purpose: aerosol propellants which are gaseous at normal temperatures and pressures, such as freon; inert dispersible liquid diluent carriers, including inert organic solvents, such as aromatic hydrocarbon (e.g. benzene, toluene, xylene, alkyl naphthalenes, etc.), halogenated, especially chlorinated, aromatic hydrocarbons (e.g. chlorobenzenes, etc.), cycloalkanes (e.g. cyclohexane, etc.), paraffins (e.g. petroleum or mineral oil fractions), chlorinated aliphatic hydrocarbons (e.g. methylene chloride, chloroethylenes, etc.), alcohols (e.g. methanol, ethanol, propanol, butanol, glycol, etc.) as well as ethers and esters thereof (e.g. glycol monomethyl ether, etc.), amines (e.g. ethanolamine, etc.), amides (e.g. dimethyl formamide, etc.), sulfoxides (e.g. dimethyl sulfoxide, etc.), ketones (e.g. acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), and/or water; as well as inert dispersible finely divided solid carriers, such as ground natural minerals (e.g. kaolins, clays, alumina, silica, chalk, i.e. calcium carbonate, talc, attapulgite, montmorillonite, kieselguhr, etc.) and ground synthetic minerals (e.g. highly dispersed silicic acid, silicates, e.g. alkali silicates, etc.); whereas the following may be chiefly considered for use as conventional carrier vehicle assistants, e.g. surface-active agents, for this purpose: emulsifying agents, such as non-ionic and/or anionic emulsifying agents (e.g. polyethylene oxide esters of fatty acids, polyethylene oxide ethers of fatty alcohols, alkyl sulfates, alkyl sulfonates, aryl sulfonates, etc., and especially alkyl arylpolyglycol ethers, magnesium stearate, sodium oleate, etc.); and/or dispersing agents, such as lignin, sulfite waste liquors, methyl cellulose, etc.

Such active compounds may be employed alone or in the form of mixtures with one another and/or with such solid and/or liquid dispersible carrier vehicles and/or with other known compatible active agents, especially plant protection agents, such as other insecticides, acaricides, and nematocides, or rodenticides, fungicides, bactericides, herbicides, fertilizers, growth-regulating agents, antibiotics, antiviral agents, or attractants, e.g. organic phosphorous acid esters, carbamates, dithio- or (thiol) carbamates, chlorinated compounds, dinitro compounds, organic sulfur or metal compounds, substituted diphenyl ethers, anilides, urea, triazines, etc., if desired, or in the form of particular dosage preparations for specific application made therefrom, such as solutions, emulsions, suspensions, powders, pastes, and granules which are thus ready for use.

As concerns commercially marketed preparations, these generally contemplate carrier composition mixtures in which the active compound is present in an amount substantially between about 0.1-95% by weight, and preferably 0.5-90% by weight, of the mixture, whereas carrier composition mixtures suitable for direct application or field application generally contemplate those in which the active compound is present in an amount substantially between about 0.0001-20%, preferably 0.005-10%, by weight of the mixture. Thus, the present invention contemplates over-all compositions which comprise mixtures of a conventional dispersible carrier vehicle such as (1) a dispersible inert finely divided carrier solid, and/or (2) a dispersible carrier liquid such as an inert organic solvent and/or water preferably including a surface-active effective amount of a carrier vehicle assistant, e.g. a surface-active agent, such as an emulsifying agent and/or a dispersing agent, and an amount of the active compound which is effective for the purpose in question and which is generally between about 0.0001-95%, and preferably 0.005-95%, by weight of the mixture.

The active compounds can also be used in accordance with the well known ultra-low-volume process with good success, i.e. by applying such compound if normally a liquid, or by applying a liquid composition containing the same, via very effective atomizing equipment, in finely divided form, e.g. average particle diameter of from 50-100 microns, or even less, i.e. mist form, for example by airplane crop spraying techniques. Only up to at most about a few liters/hectare are needed, and often amounts only up to about 15 to 1000 g/hectare, preferably 40 to 600 g/hectare, are sufficient. In this process it is possible to use highly concentrated liquid compositions with said liquid carrier vehicles containing from about 20 to about 95% by weight of the active compound or even the 100% active substance alone, e.g. about 20-100% by weight of the active compound.

Furthermore, the present invention contemplates methods of selectively killing, combating or controlling pests, e.g. insects, acarids, fungi, bacteria and yeasts, and more particularly methods of combating at least one of insects and acarids, which comprises applying to at least one of correspondingly (a) such insects, (b) such acarids, (c) such nematodes and (d) the corresponding habitat thereof, i.e. the locus to be protected, a correspondingly combative or toxic amount, i.e. an insecticidally, acaricidally or nematocidally effective amount of the particular active compound of the invention alone or together with a carrier vehicle as noted above.

The formulations and ready-to-use preparations may be applied in the usual manner, for instance by spraying (such as liquid spraying), misting, atomizing, dusting, scattering, watering, pouring, fumigating, soil application (such as mixing, sprinkling, vaporizing, irrigating), by surface application (such as painting, banding, dressing), by dipping or in the form of baits.

It will be realized, of course, that the concentration of the particular active compound utilized in admixture with the carrier vehicle will depend upon the intended application. Therefore, in special cases it is possible to go above or below the aforementioned concentration ranges.

The invention is illustrated by the following Examples, comprising preparative Examples 1 to 6, formulation Examples 7 to 12 and test Examples 13 to 19. In the formulation and test Examples, individual compounds according to the invention are identified by numbers corresponding to those in Table 1 following Example 6.

EXAMPLE 1

Synthesis of S-n-propyl-O-ethylchloride phosphorothiolate ##STR11##

19.3 of S-n-propyldichloride phosphorothiolate were dissolved in 100 ml of benzene, into which a mixture consisting of 4.6 g of ethanol, 10.1 g of triethylamine and 20 ml of benzene was dropped while stirring at a temperature no higher than 0.degree. C. Upon completion of the addition, the reaction mixture was stirred at room temperature for 2 hours to complete the reaction. Then the reaction mixture was separated by filtration and the filtrate was concentrated by distillation. The residue thus obtained was distilled under reduced pressure, whereby 15 g of S-n-propyl-O-ethylchloride phosphorothiolate was obtained. Boiling point: 70.degree.-74.degree. C./0.4 mm Hg. Refractive index n.sub.D.sup.20 = 1.4901. ##STR12##

15 g of 4-tert.-butyl phenol were dissolved in 150 ml of benzene, to which 10.1 g of triethylamine were added. 20.3 g of S-n-propyl-O-ethylchloride phosphorothiolate were added dropwise into the mixture while stirring at a temperature no higher than 10.degree. C. Upon completion of the addition, the mixture was stirred for a while at room temperature and was then heated at 65.degree. C. for 3 hours with stirring. Upon completion of the reaction, the mixture was washed with water, 1% hydrochloric acid, 1% sodium carbonate and water in the order mentioned and dried over anhydrous sodium sulfate. After removal of benzene by distillation, the residue was distilled under reduced pressure, whereby O-ethyl-O-(4-tert.-butylphenyl)-S-n-propyl phosphorothiolate was obtained in an amount of 25 g. Boiling point: 155.degree.-156.degree. C./0.07 mm Hg.

Refractive index n.sub.D.sup.20 = 1.5111.

EXAMPLE 2 ##STR13##

13.9 g of 4-nitrophenol were dissolved in 150 ml of benzene, to which 10.1 g of triethylamine were added. 20.3 g of S-n-propyl O-ethylchloride phosphorothiolate were dropped into the mixture while stirring at a temperature no higher than 10.degree. C. Upon completion of the addition, the mixture was stirred for a while at room temperature and was then heated at 65.degree. C. for 3 hours with stirring. Upon completion of the reaction, the mixture was washed with water, 1% hydrochloric acid, 1% sodium carbonate and water in the order mentioned and dried over anhydrous sodium sulfate. After removal of benzene by distillation, the residue was distilled under reduced pressure, whereby O-ethyl-O-(4-nitrophenyl)-S-n-propyl phosphorothiolate was obtained in an amount of 24 g. Boiling point: 159.degree.-161.degree. C./0.025 mm Hg.

Refractive index n.sub.D.sup.20 = 1.5424.

EXAMPLE 3

Synthesis of the potassium salt of O-ethyl-O-(4-methylthiophenyl)thiophosphoric acid ##STR14##

41 g of potassium hydroxide were dissolved in 200 ml of water, to which 250 ml of dioxane were added. While stirring vigorously, 102 g of O-ethyl-O-(4-methylthiophenyl)thionophosphoryl chloride were dropped in at 30.degree.-40.degree. C. Upon completion of the adding, the mixture was further stirred continuously for 1 hour at 60.degree. C. to complete the reaction.

The dioxane and water were distilled off under reduced pressure and the residue was dissolved in water again. Benzene was then added to the solution. The mixture was shaken. The aqueous part was concentrated under reduced pressure and the residue was dissolved in acetone and the inorganic salt was separated by filtration. After the acetone had been distilled off, toluene was added to the residue and the precipitate formed was separated by filtration, whereby 85 g of crude potassium O-ethyl-O-(4-methylthiophenyl)-S-n-propyl phosphorothiolate were obtained.

EXAMPLE 3 ##STR15##

30.2 g of the potassium salt of O-ethyl-O-(4-methylthiophenyl) thiophosphoric acid were dissolved in 80 ml of alcohol, to which 13 g of n-propylbromide were added. The mixture was stirred for 4 hours at 60.degree. C. and the inorganic salt formed was separated by filtration. After the alcohol had been distilled off the residue was dissolved in benzene and washed with water, 1% sodium carbonate and water in the order mentioned. After drying with Na.sub.2 SO.sub.4, the benzene was distilled off and the residue was distilled under reduced pressure, whereby 25 g of O-ethyl-O-(4-methylthiophenyl)-S-n-propyl phosphorothiolate were obtained.

Boiling point: 145.degree.-152.degree. C./0.05 mm Hg. Refractive index n.sub.D.sup.20 = 1.5515.

EXAMPLE 4

Synthesis of potassium O-ethyl-O-(2,4-dichlorophenyl)-thiophosphate ##STR16##

34 g of potassium hydroxide were dissolved in 200 ml of water, to which 200 ml of dioxane were added. While the mixture was being vigorously stirred, 92 g of O-ethyl-O-(2,4-dichlorophenyl)thiophosphoryl chloride were dropped in at 30.degree.-40.degree. C. Upon completion of the addition, the temperature was gradually raised and the mixture was further stirred continuously for 1 hour at 60.degree.-70.degree. C. to complete the reaction.

The dioxane and water were distilled off under reduced pressure and the residue was dissolved in acetone and the inorganic salt was separated by filtration. After distilling acetone off, toluene and n-hexane were added to the residue and the precipitate formed was separated by filtration, whereby 75 g of crude potassium O-ethyl-O-(2,4-dichlorophenyl) thiophosphate were obtained. ##STR17##

32.5 g of potassium salt of O-ethyl-O-(2,4-dichlorophenyl) thiophosphoric acid were dissolved in 70 ml of alcohol, to which 13 g of n-propyl bromide were added. The mixture was stirred for 3 hours at 70.degree. C. and the inorganic salt formed was separated by filtration. After the alcohol had been distilled off, the residue was dissolved in benzene and washed with water and 1% sodium carbonate. After drying with Na.sub.2 SO.sub.4, the benzene was distilled off and the residue was distilled under reduced pressure whereby 27 g of O-ethyl-O-(2,4-dichlorophenyl)-S-n-propyl phosphorothiolate were obtained.

Boiling point: 155.degree.-165.degree. C./0.25 mm Hg. Refractive index n.sub.D.sup.20 = 1.5362.

EXAMPLE 5 ##STR18##

15.3 g of O-ethyl-O-(4-methylthiophenyl)-S-n-propyl-phosphorothiolate, produced in Example 3 (b), were dissolved in 60 ml of glacial acetic acid. 6 g of 30% hydrogen peroxide solution were added dropwise while the reaction temperature was maintained at 20.degree.-30.degree. C. with external cooling. After the completion of the addition, the reaction mixture was stirred for 1 hour and then heated at 40.degree. C. for 30 minutes to complete the reaction. The reaction mixture was diluted with water and benzene and then it was shaken. The benzene layer was washed sequentially with water, 1% sodium carbonate solution and water, and then dried over anhydrous sodium sulfate. After the benzene had been distilled off, 14 g of light yellowish oily O-ethyl-O-(4-methylsulfinylphenyl)-S-n-propyl-phosphorothiolate, n.sub.D.sup.20 = 1.5496, were obtained.

EXAMPLE 6

The following Table 1 contains a list of compounds according to the invention. These compounds can be prepared by methods analogous to those described in Example 1-5.

Table 1______________________________________ ##STR19##______________________________________Com-pound X.sub.m Physical Properties______________________________________1 2-Cl b.p. 132 - 143.degree. C./0.2mmHg n.sub.D.sup.20 1.52762 3-Cl b.p. 130 - 136.degree. C./0.1mmHg n.sub.D.sup.20 1.52433 4-Cl n.sub.D.sup.20 1.52624 2-Br b.p. 140 - 147.degree. C./0.1mmHg n.sub.D.sup.20 1.54675 4-Br b.p. 136 - 140.degree. C./0.15mmHg n.sub.D.sup.20 1.55036 2-CH.sub.3 b.p. 116 - 119.degree. C./0.08mmHg n.sub.D.sup.20 1.51927 3-CH.sub.3 b.p. 132 - 139.degree. C./0.08mmHg n.sub.D.sup.20 1.52098 4-CH.sub.3 b.p. 125 - 133.degree. C./0.1mmHg n.sub.D.sup.20 1.51919 4-C.sub.2 H.sub.5 b.p. 133 - 137.degree. C./0.1mmHg n.sub.D.sup.20 1.518310 2-iso-C.sub.3 H.sub.7 b.p. 119 - 121.degree.C./0.08mmHg n.sub.D.sup.20 1.512011 4-tert-C.sub.4 H.sub.9 b.p. 155 - 156.degree. C./0.07mmHg n.sub.D.sup.20 1.511112 2-sec-C.sub.4 H.sub.9 b.p. 145 - 149.degree. C./0.1mmHg n.sub.D.sup.20 1.510313 4-CH.sub.3 S b.p. 145 - 152.degree. C./0.05mmHg n.sub.D.sup.20 1.551514 4-C.sub.2 H.sub.5 S b.p. 148 - 153.degree. C./0.1mmHg n.sub.D.sup.20 1.548315 n.sub.D.sup.20 1.549616 4-NO.sub.2 b.p. 159 - 161.degree. C./0.25mmHg n.sub.D.sup.20 1.542417 3-NO.sub.2 b.p. 153 - 158.degree. C./0.2mmHg n.sub.D.sup.20 1.542118 2-NO.sub.2 b.p. 151 - 155.degree. C./0.9mmHg n.sub.D.sup.20 1.535119 4-CN b.p. 145 - 149.degree. C./0.15mmHg n.sub.D.sup.20 1.529320 2-CN b.p. 143 - 147.degree. C./0.15mmHg n.sub.D.sup.20 1.529021 b.p. 160 - 162.degree. C./0.25mmHg n.sub.D.sup.20 1.515222 b.p. 153 - 156.degree. C./0.25mmHg n.sub.D.sup.20 1.519323 b.p. 156 - 159.degree. C./0.2mmHg n.sub.D.sup.20 1.513724 b.p. 166 - 169.degree. C./0.15mmHg n.sub.D.sup.20 1.536525 b.p. 155 - 157.degree. C./0.1mmHg n.sub.D.sup.20 1.538826 2,4-Cl.sub.2 b.p. 155 - 165.degree. C./0.25mmHg n.sub.D.sup.20 1.536227 2,5-Cl.sub.2 b.p. 141 - 146.degree. C./0.1mmHg n.sub.D.sup.20 1.541928 2,6-Cl.sub.2 b.p. 141 - 145.degree. C./0.15mmHg n.sub.D.sup.20 1.547729 2,4-Br.sub.2 b.p. 154 - 159.degree. C./0.06mmHg n.sub.D.sup.20 1.568830 2,4-(CH.sub.3).sub.2 b.p. 128 - 131.degree. C./0.1mmHg n.sub.D.sup.20 1.516031 3,4-(CH.sub.3).sub.2 b.p. 130 - 132.degree. C./0.08mmHg n.sub.D.sup.20 1.527032 3,5-(CH.sub.3).sub.2 b.p. 121 - 123.degree. C./0.05mmHg n.sub.D.sup.20 1.517833 2-iso-C.sub.3 H.sub.7, b.p. 125 - 128.degree. C./0.07mmHg n.sub.D.sup.20 1.5103 5-CH.sub.334 2-Cl, 4-CH.sub.3 b.p. 144 - 151.degree. C./0.1mmHg n.sub.D.sup.20 1.529135 2-Cl, 6-CH.sub.3 b.p. 133 - 140.degree. C./0.15mmHg n.sub.D.sup.20 1.530236 2-Cl, 5-CH.sub.3 b.p. 130 - 134.degree. C./0.15mmHg n.sub.D.sup.20 1.531237 4-Cl, 2-CH.sub.3 b.p. 132 - 136.degree. C./0.1mmHg n.sub.D.sup.20 1.532838 4-Cl, 3-CH.sub.3 b.p. 145 - 151.degree. C./0.2mmHg n.sub.D.sup.20 1.528139 2-Cl, b.p. 144 - 146.degree. C./0.1mmHg n.sub.D.sup.20 1.5230 4-tert-C.sub.4 H.sub.940 3-CH.sub.3, b.p. 158 - 160.degree. C./0.1mmHg n.sub.D.sup.20 1.5609 4-CH.sub.3 S41 2-Cl, 4-NO.sub.2 b.p. 160 - 162.degree. C./0.1mmHg n.sub.D.sup.20 1.545542 3-Cl, 4-NO.sub.2 b.p. 170 - 175.degree. C./0.25mmHg n.sub.D.sup.20 1.545043 3-CH.sub.3, 4-NO.sub.2 b.p. 164 - 168.degree. C./0.07mmHg n.sub.D.sup.20 1.540044 3-NO.sub.2, 4-CH.sub.3 b.p. 147 - 152.degree. C./0.1mmHg n.sub.D.sup.20 1.530845 2-CH.sub.3, 5-NO.sub.2 b.p. 160 - 164.degree. C./0.06mmHg n.sub.D.sup.20 1.537346 2-NO.sub.2, 4-Cl b.p. 155 - 157.degree. C./0.08mmHg n.sub.D.sup.20 1.547947 2-NO.sub.2, 4-CH.sub.3 b.p. 156 - 157.degree. C./0.15mmHg n.sub.D.sup.20 1.531848 3-NO.sub.2, 4-Cl b.p. 160 - 164.degree. C./0.1mmHg n.sub.D.sup.20 1.547149 2-Cl, 4-CN b.p. 157 - 161.degree. C./0.1mmHg n.sub.D.sup.20 1.554450 2-Cn, 4-Cl b.p. 145 - 147.degree. C./0.06mmHg n.sub.D.sup.20 1.546051 b.p. 160 - 164.degree. C./0.2mmHg n.sub.D.sup.20 1.528952 b.p. 160 - 164.degree. C./0.15mmHg n.sub.D.sup.20 1.521653 b.p. 173 - 176.degree. C./0.15mmHg n.sub.D.sup.20 1.546254 2-CH.sub.3, b.p. 156 - 160.degree. C./0.05mmHg n.sub.D.sup.20 1.5509 4-CH.sub.3 S55 n.sub.D.sup.20 1.548956 2,4,5-Cl.sub. 3 b.p. 142 - 148.degree. C./0.15mmHg n.sub.D.sup.20 1.548057 2,5-Cl.sub.2, 4-Br b.p. 161 - 165.degree. C./0.15mmHg n.sub.D.sup.20 1,567458 2,4,6-Cl.sub.3 b.p. 143 - 145.degree. C./0.08mmHg n.sub.D.sup.20 1.549659 3,5-(CH.sub.3).sub.2, b.p. 144 - 148.degree. C./0.1mmHg n.sub.D.sup.20 1.5690 4-Cl60 2,4-Cl.sub.2, 6-CH.sub.3 b.p. 138 - 140.degree. C./0.1mmHg n.sub.D.sup.20 1.540861 2,6-Cl.sub.2, b.p. 181 - 185.degree. C./0.12mmHg n.sub.D.sup.20 1.5660 4-NO.sub.262 2-Cn, 4,6-Cl.sub.2 b.p. 172 - 175.degree. C./0.15mmHg n.sub.D.sup.20 1.556963 b.p. 176 - 180.degree. C./0.1mmHg n.sub.D.sup.20 1.534764 b.p. 169 - 171.degree. C./0.15mmHg n.sub.D.sup.20 1.534165 4-CH.sub.3 S-, b.p. 148 - 150.degree. C./0.05mmHg n.sub.D.sup.20 1.5470 3,5-(CH.sub.3).sub.266 n.sub.D.sup.20 1.552467 2-Cl, 4-CH.sub.3 S b.p. 153 - 158.degree. C./0.1mmHg n.sub.D.sup.20 1.5650______________________________________

EXAMPLE 7

Wettable powder:

15 parts by weight of compound No. 26, 80 parts by weight of a mixture of diatomaceous earth and clay (1:5) and 5 parts by weight of the emulsifier "Runnox" (polyoxyethylene alkylaryl ether) are mixed and crushed to give a wettable powder. This formulation may be diluted with water to a concentration of 0.05% and may be applied by spraying on insects and/or their habitat.

EXAMPLE 8

Emulsifiable concentrate:

30 parts by weight of compound No. 13, 30 parts by weight of xylene, 30 parts by weight of "Kawakasol" (aliphatic hydrocarbons with a high boiling point) and 10 parts by weight of the emulsifier "Sorpol" (polyoxyethylene alkylaryl ether) are mixed and stirred to give an emulsifiable concentrate. This formulation may be diluted with water to a concentration of 0.05% and may be applied by spraying on insects and/or their habitat.

EXAMPLE 9

Dust:

2 parts by weight of compound No. 21 and 98 parts by weight of a mixture of talc and clay (1:3) are mixed and crushed to give a dust. This formulation may be applied by dusting on insects and/or their habitat.

EXAMPLE 10

Dust:

1.5 parts by weight of compound No. 5, 2 parts by weight of isopropyl hydrogen phosphate (PAP) and 96.5 parts by weight of a mixture of talc and clay (1:3) are mixed and crushed to give a dust. This formulation may be applied by dusting on insects and/or their habitat.

EXAMPLE 11

Granule:

10 parts by weight of compound No. 16, 10 parts by weight of bentonite, 78 parts by weight of a mixture of talc and clay (1:3) and 2 parts by weight of lignin sulphite are mixed. To this mixture 25 parts by weight of water are added and then the mixture is kneaded. It is cut into granules of about 20 to 40 mesh by means of a granulating machine. The granules are then dried at a temperature of 40.degree. to 50.degree. C. to give a granular formulation. This formulation may be applied by scattering on insects and/or their habitat.

EXAMPLE 12

Oil:

0.5 part by weight of compound No. 40, 20 parts by weight of Versicoal AR-50 (aromatic hydrocarbons with a high boiling point) and 79.5 parts by weight of Deobase (deodorized kerosene) are mixed and stirred to give an oily formulation. This formulation may be applied by spraying on insects and/or their habitat.

EXAMPLE 13

Tobacco cutworm or cotton leaf worm (Prodenia litura) larvae test

Solvent: 3 parts by weight of dimethyl formamide Emulsifier: 1 part by weight of alkylaryl polyglycol ether

To prepare a suitable preparation of the active compound, 1 part by weight of the active compound was thoroughly mixed with the stated amount of solvent and the emulsifier. The emulsifiable concentrate obtained was then diluted with water to the prescribed concentration.

Testing method:

Sweet potato leaves were dipped in the preparation of the active compound diluted to the prescribed concentration and were dried and put in a Petri dish of 9 cm diameter. 10 tobacco cutworm larvae were then placed in the dish. The dish was kept in a constant temperature chamber at 28.degree. C. After 24 hours, the number of dead insects was counted and the killing ratio was calculated. The results are shown in Table 2.

Table 2______________________________________Test results against Prodenia litura larvae______________________________________ Killing Ratio (%)Compound Active Ingredient ConcentrationNo. 1000ppm 300ppm 100ppm______________________________________ 1 100 100 100 2 100 100 80 3 100 100 100 4 100 100 90 5 100 100 100 6 100 100 100 7 100 100 60 8 100 90 -- 9 100 100 --10 100 100 6011 100 100 5012 100 100 --13 100 100 10014 100 100 10015 100 100 10016 100 100 10017 100 100 10018 100 100 --19 100 100 10020 100 100 --21 100 100 9022 100 100 10023 100 100 9024 100 100 --25 100 100 6026 100 100 10027 100 100 10028 100 100 10029 100 100 8030 100 100 9031 100 90 --32 100 100 10033 100 100 10034 100 100 10035 100 100 8036 100 100 8037 100 100 10038 100 100 10039 100 100 10040 100 100 10041 100 80 5042 100 100 9043 100 100 9044 100 90 --45 100 100 6046 100 100 --47 100 100 8048 100 100 6049 100 100 10050 100 100 10051 100 100 6052 100 100 9053 100 100 8054 100 100 --55 100 100 --56 100 100 10057 100 100 10058 100 100 10059 100 100 8060 100 100 10061 100 100 8062 100 100 8063 100 100 5064 100 90 --65 100 100 --66 100 100 --67 100 100 90______________________________________DEP*(commerciallyavailablecomparison) 100 25 0MPP**(commerciallyavailablecomparison) 30 0 0Untreated control 0______________________________________ *DEP: O,O-dimethyl-1-hydroxy-2,2,2-trichloroethyl-phosphonate **MPP: O,O-dimethyl-O-[(4-methylmercapto-3-methyl)phenyl] phosphorothioat

EXAMPLE 14

Fall webworm (Hyphantria cunea) larvae test

Testing method:

Mulberry leaves were dipped in the preparation of the active compound diluted to the prescribed concentration prepared in the same manner as in Example 13, and after drying in air, were placed in a Petri dish of 9 cm diameter. 10 fall webworms were then placed in the dish and the dish was kept in a constant temperature chamber at 25.degree. C. After 24 hours, the number of dead insects was counted and the killing ratio was calculated. The results are shown in Table 3.

Table 3______________________________________Test results against Hyphantria cunea larvae______________________________________ Killing Ratio (%)Compound Active ingredient concentrationNo. 1000ppm 300ppm 100ppm______________________________________ 1 100 100 100 3 100 100 100 5 100 80 6010 100 90 --11 100 100 8013 100 100 9016 100 100 9017 100 100 --18 100 64 6019 100 90 4020 100 100 9021 100 90 5023 100 100 6024 100 100 6026 100 100 10027 100 100 6028 100 80 5030 100 100 --32 100 100 10036 100 100 --37 100 100 9038 100 100 8039 100 100 9040 100 100 10044 100 70 6047 100 100 --54 100 100 10055 100 100 10056 100 100 7058 100 100 --60 100 100 8065 100 100 10066 100 100 10067 100 90 80______________________________________MPP(commerciallyavailablecomparison) 90 0 0Untreated control 0______________________________________

EXAMPLE 15

Rice stem borer (Chilo suppressalis) larvae test

Testing method:

Egg masses of the rice stem borer were attached to rice, at the tillering stage, planted in a pot of 12 cm diameter, and on the 7th day from the hatching, 40 ml of the preparation of the active compound diluted to the prescribed concentration (prepared in the same manner as in Example 13) were sprayed on to the rice. The rice was kept in a greenhouse. Three days later, the treated stem was examined by breaking it and the killing ratio was calculated from the surviving borers and killed borers. The results are shown in Table 4.

Table 4______________________________________Test results against Chilo suppressalis larvae______________________________________ Killing ratio (%) Killing Ratio (%)Com- Active Ingredient Com- Active Ingredientpound Concentration pound ConcentrationNo. 250ppm No. 250ppm______________________________________ 1 100 41 100 3 100 44 100 5 100 47 100 6 100 50 10011 87.7 51 10013 100 52 10015 100 53 10016 98.6 54 10018 100 55 10019 100 56 10020 100 58 94.721 100 60 10023 95.5 65 10024 100 66 10026 10027 100 DEP28 100 (commercially30 95.4 available 9532 100 comparison)37 100 Untreated 038 100 control39 9940 96.4______________________________________

EXAMPLE 16

By the methods of Examples 13 to 15, and as reported in Table 5 below, the compounds of this invention are shown to exhibit excellent activity against insects belonging to the Lepidoptera such as tobacco cutworm (Prodenia litura), rice stem borer (Chilo suppressalis), fall webworm (Hyphantria cunea) and the like, as compared with compounds of similar structure, identified by letters of the alphabet.

Table 5__________________________________________________________________________Results of tests on harmful Lepidoptera insects__________________________________________________________________________ Killing Ratio (%) Tobacco cutworm Rice-stem Fall webworm (Prodenia litura) borer (Hyphantria cunea) 1000 300 100 250 1000 300 100 Compounds ppm ppm ppm ppm ppm ppm ppm__________________________________________________________________________ ##STR33##30 10 0 0 0 0 0 ##STR34##100 100 100 100 100 100 100 ##STR35##0 0 0 0 40 0 0 ##STR36##30 5 0 0 0 0 0 ##STR37##100 100 100 100 100 100 100 ##STR38##10 0 0 0 50 0 0 ##STR39##0 0 0 0 0 0 0 ##STR40##10 0 0 0 20 0 0 ##STR41##100 100 100 100 100 100 100 ##STR42##10 0 0 0 0 0 0 ##STR43##40 0 0 0 30 0 0 ##STR44##100 100 100 100 100 100 90 ##STR45##50 0 0 0 40 0 0 ##STR46##50 0 0 0 40 0 0 ##STR47##100 100 100 96.4 100 100 100 ##STR48##50 0 0 0 50 0 0 ##STR49##30 0 0 10 10 0 0 ##STR50##100 100 100 100 100 80 60 ##STR51##10 0 0 0 20 0 0 ##STR52##0 0 0 0 0 0 0 ##STR53##0 0 0 0 0 0 0 ##STR54##10 0 0 0 0 0 0 ##STR55##100 100 100 99 100 100 90 ##STR56##10 0 0 0 10 0 0 ##STR57##20 0 0 0 10 0 0 ##STR58##60 20 0 12.3 30 0 0 ##STR59##100 100 100 98.6 100 100 90 ##STR60##20 0 0 0 0 0 0 ##STR61##20 0 0 0 0 0 0 ##STR62##100 100 100 100 100 90 40__________________________________________________________________________

EXAMPLE 17

Test against Green peach aphids (Myzus persicae) and Hop aphid (Phorodon humuli) (contact action)

Solvent: 3 parts by weight of aceotn Emulsifier: 1 part by weight of alkyl aryl polyglycol ether

To prepare a suitable preparation of active compound, 1 part by weight of the active compound is mixed with the stated amount of solvent containing the stated amount of emulsifier and the concentrate is diluted with water to the desired concentration.

Cabbage plant infested with each aphids are sprayed with the preparation of the active compound until dripping wet. After 24 hours, the degree of destruction is determined as a percentage: 100% means that all the aphids are killed whereas 0% means that none are killed.

The results are shown in Table 6.

Table 6__________________________________________________________________________Results of tests on Green peach aphid and Hop aphid__________________________________________________________________________ Concen tration Green peach of a.i. aphid Hop aphid (%) A B A B__________________________________________________________________________ ##STR63##0.1 0.02 0.004 0.0008 0.00016 100% 100 100 90 5 -- 100 100 100 93 100% 100 100 90 25 -- 100% 100 100 100Compound No. 13 of the 0.000032 -- 0 -- 93present invention ##STR64##0.1 0.02 0.004 0.0008 0.00016 100% 100 100 80 30 -- 100% 100 75 50 100% 100 80 50 25 -- 100% 100 100 93Compound No. 26 of the 0.000032 -- 5 -- 70present invention ##STR65##0.1 0.02 0.004 0.0008 0.00016 85% 80 70 15 5 -- 100% 98 70 40 85% 70 40 25 10 -- 100% 100 98 80Commercial control: 0.000032 -- 10 -- 30lebaycid (D)__________________________________________________________________________ *A: Resistance-acquired Green peach aphid and Hop aphid **B: Green peach aphid and Hop aphid without resistance

EXAMPLE 18

Carmine mite or two-spotted spider mite (Tetranychus telarius test) Testing method:

A haricot bean having two developing leaves planted in a 6 cm diameter pot was infected with 50-100 imagines and nymphs of carmine mite. Two days after the infection, 40 ml of the preparation of the active compound diluted to the prescribed concentration prepared in the same manner as in Example 13 were sprayed on to the pot. The pot was kept in a greenhouse for 10 days, and the control effect was evaluated. The evaluation is expressed by an index of the following scale:

Control Effect Index 3: No living imago or nymph 2: Less than 5% of living imagines and nymphs based on the untreated control 1: 6-50% of living imagines and nymphs based on the untreated control 0: more than 51% of living imagines and nymphs based on the untreated control

The results are shown in Table 7.

Table 7______________________________________Test results against Tetranychus telarius larvae______________________________________ Control EffectCompound Active Ingredient ConcentrationNo. 1000 ppm 300 ppm 100 ppm______________________________________13 3 3 316 3 3 217 3 3 220 3 3 321 3 3 323 3 3 224 3 3 244 3 3 249 3 3 3CPCBS*(comparison) 3 2 0CMP**(comparison) 3 1 0Untreated Control 0 0 0______________________________________ *CPCBS (Wettable Powder): p-chlorophenyl-p'chlorobenzenesulfonate 36%: bis(4-chlorophenoxy)metan 14% **CMP: O,O-diethyl-S-(2,5-dichlorophenylmercaptomethyl) dithiophosphate

EXAMPLE 19

House fly (Musca domestica) test Testing method:

1 ml of an emulsion of the active compound diluted to the prescribed concentration prepared in the same manner as in Example 13 was applied on to a filter paper placed in a Petri dish of 9 cm diameter. 10 mature female adult house flies were then placed in the dish and the dish was kept in a constant temperature chamber at 28.degree. C. After 24 hours, the number of dead insects was counted and the killing ratio was calculated.

The results are shown in Table 8.

Table 8______________________________________Test results against Musca domestica adults______________________________________ Killing Ratio (%) Active Ingredient ConcentrationCompound 1000 100 10No. ppm ppm ppm______________________________________13 100 100 8014 100 100 --15 100 100 --16 100 100 --18 100 100 --19 100 100 --20 100 100 --21 100 100 --40 100 100 --41 100 100 --49 100 100 7050 100 100 8062 100 100 --DEP (comparison) 100 100 --Untreated Control 0 0 0______________________________________

It will be appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.

Claims

1. A method of combatting insects, acarids, or nematodes which comprises applying to the insects, acarids or nematodes or to an insect, acarid or nematode habitat an insecticidally, acaricidally or nematocidally effective amount of a phosphoric acid ester of the formula ##STR66## wherein at least one X is nitro, cyano, lower alkylmercapto, lower alkylsulfinyl, lower alkoxycarbonyl, or lower alkylcarbonyl, and the others if present may also be halogen or lower alkyl, and

m is 1, 2 or 3.

2. The method according to claim 1, wherein such compound is O-ethyl-O-(4-methylmercaptophenyl)-S-n-propyl phosphorothiolate of the formula ##STR67##

3. The method according to claim 1, wherein such compound is O-ethyl-O-(4-nitrophenyl)-S-n-propyl phosphorothiolate of the formula ##STR68##

4. The method according to claim 1, wherein such compound is O-ethyl-O-(4-cyanophenyl)-S-n-propyl phosphorothiolate of the formula ##STR69##

5. The method according to claim 1, wherein such compound is O-ethyl-O-(3-methyl-4-methylmercaptophenyl)-S-n-propyl phosphorothiolate of the formula ##STR70##

6. The method according to claim 1, wherein such compound is O-ethyl-O-(3-methyl-4-nitrophenyl)-S-n-propyl phosphorothiolate of the formula ##STR71##

7. The method according to claim 1, wherein such compound is O-ethyl-O-(2-methyl-4-methylmercaptophenyl)-S-n-propyl phosphorothiolate of the formula ##STR72##

8. The method according to claim 1, wherein such compound is O-ethyl-O-(3,5-dimethyl-4-methylmercaptophenyl)-S-n-propyl phosphorothiolate of the formula ##STR73##

9. An insecticidal, acaricidal or nematocidal composition containing as active ingredient an insecticidally, acaricidally or nematocidally effective amount of a phosphoric acid ester of the formula ##STR74## wherein at least one X is nitro, cyano, lower alkylmercapto, lower alkylsulfinyl, lower alkoxycarbonyl, or lower alkylcarbonyl, and the others if present may also be halogen or lower alkyl, and

m is 1, 2 or 3,

in admixture with a pesticide diluent.

10. A composition according to claim 9 in which said compound is:

O-ethyl-O-(4-methylmercaptophenyl)-S-n-propyl phosphorothiolate,

O-ethyl-O-(4-nitrophenyl)-S-n-propyl phosphorothiolate,

O-ethyl-O-(4-cyanophenyl)-S-n-propyl phosphorothiolate,

O-ethyl-O-(3-methyl-4-methylmercaptophenyl)-S-n-propyl phosphorothiolate,

O-ethyl-O-(3-methyl-4-nitrophenyl)-S-n-propyl phosphorothiolate,

O-ethyl-O-(2-methyl-4-methylmercaptophenyl)-S-n-propyl phosphorothiolate,

O-ethyl-O-(3,5-dimethyl-4-methylmercaptophenyl)-S-n-propyl phosphorothiolate.