US3255075A - Methane-thiol containing nematocides - Google Patents

Description

dollars.

3,255,075 METHANE-THIOL CONTAINING NEMATOCIDES Max J. Fielding, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed Mar. 29, 1963, Ser. No. 269,143 3 Claims. (Cl. 16722) This invention relates to nematocidal compositions and methods.

More specifically, this invention refers to a method of killing plant pathogenic nematodes by applying to said nematodes a mercapto-terminated thiomethylene compound.

Plant nematodes are found in virtually all soils in which plants will grow. Consequently, every major crop is a potential victim of this pest. The annual toll on crops in the United States is well over several hundred million A practical commercial chemical is needed to stop this unnecessary loss. However, in order to be commercially practicable a chemical must be non-toxic to animals and plants and kill a broad spectrum of nematodes at low rates.

I have discovered that the following compounds qualify as effective commercial nematocides:

Methanedithiol,

Thiodi (methanethiol) Methylenedithiobis(methanethiol) and Thiodimethylenedithiobis (methanethiol) Although all of the above compounds kill nematodes, particularly outstanding results are obtained from thiodi- (methanethiol), methylenedithiobis(methanethiol) and thiodimethylenedithiobis (methanethiol) The most highly preferred compound because of its outstanding activity at low rates is thiodi(methanethiol).

Acceptable nematocidal treatments are obtained from a mixture of two or more of all the above compounds.

PREPARATION Methanedithiol is prepared in the manner described by Cairns et al., J. Am. Chem. Soc., 74, 3982 (1952). Thiodimethanethiol is formed along with methanedithiol in the reaction between hydrogen sulfide and formaldehyde and may be separated by distillation. Methylenedithiolbis(methanethiol) and thiodimethylenedithiobis (methanethiol) are prepared by the process described in Saegebarth, US. Patent 3,056,841.

COMPOSITION Compositions of this invention comprise one or more of the compounds described above together with one or more surface-active agents.

The surface-active agents used in this invention can be a wetting, dispersing or an emulsifying agent which will assist dispersion of the compound. Surface-active agents or surfactants can include such anionic, cationic and nonionic agents as have heretofore been generally employed in plant control compositions of similar type. Suitable surface-active agents are set out, for example, in Searle US. Patent 2,426,417; Todd US. Patent 2,655,417; Jones 3,255,075 Patented June 7, 1966 ethylene thioethers and long chain quaternary ammonium chloride compounds.

Surface-active dispersing agents such as sodium lignin sulfonates, low viscosity methyl cellulose and polymerized sodium salts of alkyl naphthalene sulfonic acids are also suitable in the nematocidal compositions of this invention. Among the more preferred surfactants are the anionic and non-ionic types. Among the anionic surface-active agents, preferred ones are alkali metal or amine salts of alkyl benzene sulfonic acids, such as dodecylbenzenesulfonic acid, sodium lauryl sulfate, alkyl naphthalene sulfonates, sodium N-methyl-N-oleoyltaurate, oleic acid ester.

of sodium isethionate, dioctyl sodium sulfosuccinate and sodium dodecyldiphenyloxide disulfonate. Among the non-ionic compounds, preferred members are alkyl phenoxy poly(ethyleneoxy)ethanols such as nonyl phenol adducts with ethylene oxide; also preferred are trimethyl nonyl polyethylene glycol ethers, polyethylene oxide adducts of fatty and rosin acids, long chain alkyl mercaptan adducts with ethylene oxide and polyethylene oxide adducts with sorbitan fatty acid esters.

In general, less than 10% by weight of the surfaceactive agent will be used in compositions of this invention and ordinarily the amount of surface-active agents will range from 0.5 to 5% by weight.

Nematocidal compositions of this invention can also contain finely divided inert diluents, such as talcs, natural clays, including attapulgite clay and kaolinite clay, pyrophyllite, diatomaceous earths, synthetic fine silicas, calcium silicate, carbonates, calcium phosphates, lime, and such flours as walnutshell, wheat, redwood, soybean and cottonseed flour. i

The amount of the finely divided inert solid diluent can vary widely but will generally range from 1 to 50% by weight of the nematocidal composition. Compositions of from 2 to 30% active ingredient are preferred. The particle size can vary considerably but will ordinarily be somewhat under 50 microns in the finished formulation.

A preferred formulation contains from about 10 to 50% by weight of a mercapto-terminated thiomethylene, a total of 45 to 89% by weight of solid diluents and 1 to 5% by weight of one or more surfactants.

Although the compounds used in this invention are normally liquids, it is possible to formulate them into dusts for direct application or into wettable powders which are applied in a slurry. In the case of wettable powders, surfactants and diluents are usually both present in the nematocidal composition.

It [is sometimes also advantageous to formulate the nematocidal compound of this invention as granules or pellets, for example by applying the active ingredient to preformed clay granules, such as granular attapulgite, or to'granular vermiculite. Usually, such granules will contain 1 to 10% by weight of the active ingredient, although for special uses as much as 15 to 20% by weight can be applied.

Emulsifiable oil solutions can be employed with one or more of the mercapto-terminated thiomethylenes used in this invention. In these nematocidal compositions, the surface-active agent and the oil form a liquid which can be conveniently poured and measured. Such solutions can be mixed with water at the point of application to form an emulsion containing the nematocide and the solvent. Such compositions have the advantage that the oil will often act as a foam inhibitor and thus reduce the tendency for large amounts of surfactants to form objectionable foam. The oil used such as toluene,'kerosene, stoddard solvent, xylene, alkylated naphthalene, diesel oil and the like should be preferably water immiscible and be of a type in' which the active agent will be soluble in the amounts used in particular formulations. Other solvents, such as chlorinated hydrocarbons like tetrachloroethylene,

- 4 to 8 inches.

ketones like cyclohexanones, cellosolves, N,N-dialkylamides, carbitols, and the like can also be used, either alone or in admixture with the hydrocarbon solvents shown above.

In the above emulsifiable oil concentrates, the mercapto-terminated thiomethylenes will be present in amounts ranging from 5 to 80% by weight, to 35% by weight being a preferred range. Precise concentrations of active agent, of course, will depend on the intended use of the composition. When mixed with water at the point of application the oil concentrate will be diluted so that in the final spray emulsion the active agent will be present in amounts ranging from 0.5 to 2% by weight.

A formulation that I have found to be especially advantageous in the application of mercapto-terminated thiomethylenes to nematode infested soil is a composition containing from about 20 to 80% by weight of mercaptoterminated thiomethylenes, from about 17 to 75% by weight of one or more inert liquid diluents and from about 0.5 to 8% by weight of one or more surface-active agents.

APPLICATION As a practical matter application rates of from 2 to 100 pounds of active mercapto-terminated thiomethylenes per treated acre of soil are satisfactory for nematode control, although higher rates can be used. The active mercapto-terminated thiomethylene, preferably in a suitable formulation as described above is applied to the soil by any conventional method such as spraying or dusting by hand or mechanical equipment. After application, the composition is worked into the ground to a depth of about Spot shanking into an open furrow is a particularly advantageous method of application.

The compounds used in this invention are also applied to nematode infested plant material, such as bulbs, tubers, or roots of ornamental plants and nursery stock. Disinfection is carried out by. dipping the bulb, tuber or plant root into a solution or suspension containing 5 to 50,000 p.p.m. of one or more active mercapto-terminated thiomethylene compounds.

An application to a locus of infestation includes the treatment of soil, plant material, before or after planting, and other sites infected with adult nematodes, their eggs or larvae.

The active compounds used in the invention can be advantageously mixed with soil fungicides such as p-Dimethylaminobenzenediazosodium sulfonate;

Quinone oxyaminobenzooxohydrazone;

Tetraalkyl thiuram sulfides such as tetramethyl thiuram monosulfide or disulfide and tetraethyl thiuram monosulfide or disulfide;

Metal salts of ethylene bisdithiocarbamic acid, e.g.

Manganese, zinc, iron and sodium salts;

Pentachloronitrobenzene;

Dodecylguanidine acetate;

N-trichloromethylthio tetrahydrophthalimide (captan);

Phenylmercury acetate;

2,4-dichloro-6-(o-chloroanilino)-s-triazine N-methylmercury p-toluenesulfonanilide;

Chlorophenol mercuri hydroxide;

Nitrophenol mercuri hydroxides;

Ethel mercury acetate;

Ethyl mercury 2,3-dihydroxypropyl mercaptide;

Methyl mercury acetate;

Methyl mercury 2,3-dihydroxypropyl mercaptide;

3,3'-ethylenebis(tetrahydro-4,6-dimethyl-2H-1,3,5-thiadiazine-2-thione) Methyl mercury dicyandiamide;

N-ethyl mercury-p-toluenesulfonanilide;

Metal (e.g. iron, sodium, and zinc), ammonium and amine salts of dialkyldithiocarbamic acids;

Tetrachloronitroanisole;

Hexachlorobenzene;

The above fungicides are added to compositions containing a mercapto-terminated thiomethylene at the rate of 1 to 400 pounds to each 20 pounds of a compound Within the scope of this invention. Illustrative of fungicides used at low rates with the mercapto-terminated thiomethylenes are the above-described organo mercurials. Illustrative of fungicides used at high rates with the mercapto-terminated thiomethylenes are thiuram sulfides and captan. Of course, more or less of the above-listed fungicides can be added to a composition of this invention depending on the fungi present in the area to be protected.

Compositions of this invention can additionally contain soil insecticides such as chlordane, DDT, dieldrin, endrin, aldrin, methoxychlor and others for simultaneous application of nematocide, fungicide and insecticide to the soil.

In addition compositions can contain special additives such as corrosion inhibitors, pigments, antifoam agents and the like.

The compounds used in this invention can also be applied, mixed or in common solution with other chemicals which are used in agronomic and horticultural management and are compatible with the compounds used in this invention. Such chemicals can be but are not restricted to the classes of chemicals commonly known as plant nutrients,fertilizers, herbicides and other nematocides.

The following additional examples in which all percents unless otherwise indicated are by weight are provided to more clearly explain this invention.

Example 1.-Pre.parati0n of methanedithiol and thi0di(methanerhi0l) A rocker bomb is charged with 120 parts by Weight of paraformaldehyde and 544 parts of hydrogen sulfide. The bomb is closed and heated with agitation at 8090 C. for 12 hours. The bomb is cooled, excess hydrogen sulfide vented and the two phases'separated.

The upper aqueous phase is extracted with ether. The ether extract and the lower organic phase are combined, dried with magnesium sulfate and distilled through a column. This distillation produces 90 parts of methanedithiol, boiling point 43 C. at 44 mm., and 104 parts of thiodi(methanethiol), boiling point 57 C. at 0.85 mm. The nuclear magnetic resonance spectrum of thiodi(methanethiol) on Varian A-6O NMR Spectrometer using tetramethylsilane as an external reference shows three bands at delta =-2.57, 2.70 and 2.84 p.p.m. assigned to the two thiol hydrogens and two bands at delt-a=4.23 and Example 2.Preparati0n 0 methylenedithiobis(methanethiol) and lhiodimethylenedithiobis(methanethiol) A steel bomb is charged with 284 parts by weight of 37% formalin solution. About 225 parts of hydrogen sulfide is distilled into the bomb after it is chilled and evacuated. The bomb is then sealed and heated at 60 C. for 4 hours. The reaction vessel is cooled, the excess hydrogen sulfide vented, and the lower organic phase of the two phase reaction mixture is separated. This liquid intermediate (220 parts) is stirred under nitrogen with .150 parts concentrated hydrochloric acid and 300 parts water at C. for 6 hours. The lower organic layer is separated, washed with water and dried over magnesium sulfate. The largest constituent of the resulting oil is methylenedithiobis(methanethiol). A lesser constituent is thiodimethylenedithiobis(methanethiol). Thiodi(methanethiol) is also present in variable amounts. This crude mixture is satisfactory for the nematocidal compositions and methods of this invention.

Ifdesired, the active components of the reaction mixture can be separated by distillation. Thiodi(methanethiol) distills off first, boiling point 57 C. at 0.85 mm., followed by methylenedithiobis(methanethiol), boiling point approximately 110 C. at 0.1 mm.

- Example 3 Percent Thiodi(methanethiol) 25 Dioctyl sodium sulfosuccinate 1 Sodium lignin sulfonate 2 Attapulgite clay 45 Synthetic fine silica 25 These materials are thoroughly blended to prepare a uniform mixture. The mixture is then ground in a micropulverizer until the particle size is substantially less than 50 microns.

This 25% wettable powder formulation, when dispersed in water, is applied with conventional spray' equipment at a concentration of about lO'pounds wettable powder to gallons of water at a rate between to 100 pounds active ingredient per acre to land infested with plant pathogenic nematodes. After spraying onto the surface of the soil, the chemical is mixed in the soil to a "depth of 4 to 6 inches with a rotovator.

When soil infested with root-knot nematode, Meloidogyne, is treated in this way, cotton plants grown show normal development free from nematode infection. Plants grown in similar non-treated soil show stunting, and reduced yields due to nematode infection.

Example 4 Percent The crude reaction product of Example 2, containing methylenedithiobis(methanethiol), thiodi(meth- These materials are thoroughly blended in a ribbon blender, and ground in a micropulverizer until the particle size is substantially less than 50 microns. The resulting wettable powder formulation can be diluted with water to the desired spray concentration.

This formulation is suspended in water, and drenched about the roots of boxwood plants infected with the spiral nematode (Helicotylenchus buxophilus) at rates of 50 to 200 pounds active agent per acre, using enough water to wash the active agent down about the plant roots. Substantially all spiral nematodes are killed by this treatment, allowing the boxwood plant to develop in a normal manner.

Example 5 Percent The crude reaction product of Example 1 30 Blend of poly-alcohol carboxylic esters and oilsoluble sulfonates 6 Alkylated naphthalenes 64 The above ingredients are blended until a completely homogeneous mixture is obtained. The resulting emul sifiable composition can be extended with water to the required concentration for spraying.

The above emulsifiable concentrate is diluted with water and sprayed at the rate of 60 pounds per acre of active ingredient in 120 gallons of water on a field infested with sugar beet nematode (Heteradera schachtii) and the chemical is worked into the soil to a depth of 6 inches. Sugar beets grown in this field develop normally and are substantially free from infestation by nematodes. In an untreated area in the same field, beets are distorted and yields reduced.

Example 6 Percent Methylenedithio-bis(methanethiol) 75 Nonyl phenol polyethoxy ethanol) 10 Xylene--- '15 The mixture is prepared in the same manner as Example 5. v This emulsifiable concentrate is diluted with sufiicient water to drench the soil to the root zone of the plants and applied to roses at a rate of 20 to 100 pounds active agent per acre. Excellent control is obtained of the dagger nematode (Xiphinema diversicaudatum) allowing the roses to grow in a normal manner.

Example 7 Percent Thiodi(methanethiol) 5 Granular attapulgite clay 95 The active ingredient is warmed to about 40 C. .and is sprayed over the surface of the granular clay while the mass is kept agitated and is being tumbled in order to obtain a uniformly impregnated dry granular product. The granular product is applied to soil infested with pathogenic nematodes at rates of 20 to 100 pounds active agent per acre using a conventional fertilizer spreader. The active agent is then worked into the soil by disking. This treatment gives substantially complete control of the sting nematode (Belonolaimus sp.) as shown by a nematode count 15 days after treatment.

Example 8 Percent Methanedithiol 25 Blend of polyalcohol carboxylic esters and oil-soluble sulfonates Alkylated naphthalenes 69 The above ingredients are blended until a completely homogeneous mixture is obtained. The resulting emulsifiable composition is extended with water and sprayed at the rate of 75 pounds per acre of active ingredient in 120 gallons of water on a field infested with sugar beet nematode (Heterodem schachtii') and the chemical is worked into the soil to a depth of 6 inches. Sugar beets grown in this field are substantially free from nematode infestation.

Example 9 The wettable powder of Example 3 is diluted with micaceous tale to obtain a dust containing 2.5. active ingredient:

Percent Powder of Example 3 10 Micaceous talc The ingredients are thoroughly blended and deagglomerated until a uniform product is obtained. The mixture I is applied to the soil at the rate of 20 to pounds of active ingredient per acre and is disked or rototilled into the soil to obtain mixing into the zone of nematode infestation.

Example 10 7 Example 11 For the simultaneous control of root knot nematode and Pythium spp. and Rhizoctonia sppz, the mixture of Example 3 plus commercial formulations of dimethylaminobenzenediazo sodium sulfonate and pentachloronitrobenzene are prepared in a tank mix. For this mixture 40 pounds of the formulation of Example 3 is mixed with 80 gallons of water. To this is added 7 /2 pounds of 70% pentachloronitrobenzene wettable powder and 10 pounds of 60% p-dirnethylaminobenzenediazo sodium sulfonate. This mixture is'applied as a soil spray by application to bandsof soil with conventional spray equipment. The application rate is 5. pounds per acre total active ingredient (equivalent to 100 pounds per acre in the treated band). The soil is rotovated immediately thereafter to mix the chemicals thoroughly with the soil. Following this, cotton seed is planted in the treated band. The cotton seedlings which develop are protected against root .knot nematode (Meloidogyne spp.) and the fungi Pythium spp. and Rhizoctonia spp. A healthy stand of cotton plants is obtained and at harvest time an increased yield of cotton.

Example 12 Percent p-Dimethylaminobenzenediazo sodium sulfonate 15 Thiocli(methanethiol) 20 Sodium lignin sulfonate 2 Dioctyl sodium sulfosuccinate 1 Synthetic fine silica 20 Attapulgite clay 42 The above materials are thoroughly blended to prepare a uniform mixture. The mixture is then ground in a micropulverizer until the particle size is substantially less than 0 microns.

This 35% wettable powder formulation is dispersed in water at the rate of pounds wettable powder per 10 gallons of water. This mixture is now applied as a soil spray by application to bands of soil with conventional spray equipment. The application rate is 3 /2 pounds total active ingredient per acre (equivalent to 70 pounds per acre in the treated band). The soil is rotovated immediately after application of the spray, thoroughly mixing the chemicals with the soil. Immediately thereafter, cotton seed is planted in the treated band. The cotton seedlings which develop are protected against root knot nematode (Meloidogyne spp.) and the fungi Pythium spp. resulting in a healthy stand of cotton plants and an increased yield of cotton at harvest time.

The above ingredients are thoroughly mixed in a ribbon blender and the mixture ground in a micropulverizer until the particle size is substantially less than 50 microns.

This 30% wettable powder formulation is dispersed in water at the rate of 10 pounds wettable powder per 10 gallons of water. This mixture is now applied as a soil spray by application to bands of soil with conventional spray equipment. The application rate is 3 pounds total active ingredient per acre (equivalent to pounds per acre. in the treated band). The soil is rotovated immediately after application of the spray, thoroughly mixing the chemicals with the soil. Immediately thereafter cotton seed is planted in the treated band. The developing cotton seedlings are protected against root knot nematode and the fungi Rhizoctonia spp. A healthy stand of cotton plants is obtained and the yield of cotton at harvest time is increased.

The invention claimed is:

1. A method of controlling nematodes comprising applying to soil a nem'atocidally effective amount of thiodi- (methanethiol) 2. A method of controlling nematodes comprising applying to soil a nematocidally effective amount of methylenedithiobis (methanethiol) 3. A method of controlling nematodes comprising ap plying to soil a nematocidally effective amount of thiodimethylene dithiobis (methanethiol) References Cited by the Examiner UNITED STATES PATENTS 2,864,739 12/1958 Scott l6722 2,882,197 4/ 1959 Webb 167--22 2,938,827 5/1960 Wadsworth l6722 2,966,521 12/1960 Webb 167--13 2,998,346 8/ 1961 Scott l6722 3,103,464 9/1963 Larson l6722 3,137,615 6/ 1964 Ichikawa et al 167-22 JULIAN S. LEVITT, Primary Examiner.

S. J. FRIEDMAN, Assistant Examiner.

Claims (1)

1. A METHOD OF CONTROLLING NEMATODES COMPRISING APPLYING TO SOIL A NEMATOCIDALLY EFFECTIVE AMUNT OF THIODI(METHANETHIOL).