US3373010A - Herbicidal composition and method - Google Patents

Description

United States Patent Ofilice 3,373,010 Patented Mar. 12, 1968 3,373,010 HERBICIDAL COMPOSITION AND METHOD Harold C. Olson, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed Oct. 8, 1964, Ser. No. 402,608 4 Claims. (Cl. 71-120) ABSTRACT OF THE DISCLOSURE Compositions containing an herbicidally effective amount of 1-(p-chlorophenyl)-3,3-dimethylurea, 1-(3,4- dichlorophenyl) 3,3 dimethylurea or 1-(3,4-dichlorophenyl)-3-n-butyl-3-methylurea in combination with an herbicidally effective amount of alpha,alpha,alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine and method of using same for synergistic herbicidal response.

This invention relates to herbicidal compositions. It is more particularly directed to compositions containing herbicidally effective amounts of:

A substituted urea selected from the group consisting of l-(p-chloropheny)-3,3-dimethylurea, hereinafter referred to as monuron, 1-(3,4-dichlorophenyl)-3,3-dimethylurea, hereinafter referred to as diuron, and 3-(3,4- dichlorophenyl)-1-n-butyl-1-methylurea, hereinafter referred to as neburon; and

Alpha,alpha,alpha-trifluoro 2,6 dinitro-N,N-dipropyl-p-toluidine, hereinafter referred to as trifluralin.

I have found it is characteristic of mixtures of the above named substituted ureas with trifluralin to produce combinations which are more effective as weed killers than either herbicide used alone. The result is that the combination has enhanced herbicidal effectiveness in the destruction and prevention of weeds.

The ratio of substituted urea: trifiuralin can range from about 1:2 to 5:1. Preferably the ratio is from 1:2 to 2: 1.

It is much preferred to formulate the active components of the invention, comprising trifiuralin and one of the herbicidal substituted phenyl ureas, with conventional pest control adjuvants, modifiers or diluents, hereinafter called inert carriers. Formulation with such inert carriers is preferred because handling is facilitated and herbicidal action is thereby frequently enhanced.

These compositions, whether solutions, emulsions, dispersions of the active components in a liquid solvent or wettable powders, contain as a conditioning agent one or more surface-active agents in an amount suflicient to render a given composition containing the active component readily dispersible in water or in oil. By the term surfaceactive agent it is understood that wetting agents, dispersing agents, suspending agents and emulsifying agents are included.

Suitable surface-active agents can be anionic, cationic, and non-ionic, such as are set out, for example, in Detergents and Emulsifiers-1964 Annual by J. W. Mc- Cutcheon, Inc.

Suitable surface-active agents for use in compositions of the present invention are: polyethylene glycol esters with fatty acids or ethers with fatty alcohols and fatty alkylol amide condensates, alkylaryl sulfonates, fatty alcohol sulfates, dialkyl esters of sodium sulfosuccinate, fatty acid esters of sodium isethionate, polyoxyethylene ethers and thioethers and long chain quaternary ammonium chlorides.

Among the more preferred surfactants are the anionic and non-ionic type. Among the anionic surface-active agents, preferred ones are alkali metal or amine salts of alkylbenzene sulfonic acids such as dodecylbenzene sulthe form of a spray will contain fonic acid, sodium lauryl sulfate, alkylnaphthalene sulfonates, sodium N-methyl-N-oleoyltaurate, oleic acid ester of sodium isethionate, dioctyl sodium sulfosuccinate, sodium dodecyldiphenoloxide disulfonate. Among the non-ionic compounds, preferred members are alkylphenoxy poly(ethyleneoxy) ethanols such as octyl, nonyl or dodecylphenol adducts with ethylene: oxide; trimethylnonyl polyethylene glycol ethers, polyethylene oxide adducts of fatty and rosin acids, long chain alkyl mercaptan adducts with ethylene oxide.

Other preferred surfactants include lignin sulfonates, sodium and calcium salts of polymerized alkylnaphthalene sulfonates and alkylarylsulfonates, methyl cellulose, and polyvinyl acetate.

In preparing these herbicidal compositions, surface active agents will generally be employed at concentrations of from about 1% to 10%, by Weight. Levels as high as 0.25 to 6 parts for each part of the total herbicides present, however, give unusual and unexpected beneficial results. Such compositions have a greater herbicidal effectiveness than can be expected from a consideration of the activity of the components used separately.

Powdered or dust compositions of the invention, whether or not also modified with a surface-active agent, are prepared by mixing the active compounds of the invention with finely-divided inert carriers. Such carriers are preferably talc, natural clays, synthetic fine silica or calcium silicate, pyrophyllite, diatomaceous earth and flours such as walnut shell, wheat, soya bean, redwood and cotton seed iiours. Other inert solids which can be used are sulfur, calcium sulfate, and the like, either in powder or granular form. The percentage, by Weight, of active components in the solid compositions will vary according to the manner in which the compositions are to be applied, but in general, will be from about 0.1 to percent, by weight.

Herbicidal compositions can also be prepared by dispersing or dissolving the active components in an inert non-aqueous carrier. Aliphatic and aromatic hydrocarbons, for example, hydrocarbons of petroleum origin, are preferred as carriers.

Other carriers, used alone or in admixture with petroleum hydrocarbons, may be alcohols, glycols, aliphatic or aromatic ketones such as cyclohexanone, acetophenone, or methylisobutyl ketones, or amides such as dimethylformamide. Carriers such as dimethyl sulfoxide, Cellosolve, and carbitol may be used. The amount of herbicide in such compositions can range from 10 percent or less to 40 or even 50 percent by weight.

Adhesives such as gelatin and albumin, and resins such as rosin, alkyd resins and the like, can also be used in the compositions to increase the tenacity of deposits following application.

In general, the herbicidal compositions as applied in from about 0.2 percent to 95 percent by Weight of the combined herbicidally active components.

Compositions of this invention various ways as follows:

Wettable powders are prepared by combining in a blender the two active components in the desired ratio, adding a diluent together with a wetting agent to :assure easy preparation of an aqueous suspension and also a dispersing agent to prevent flocculation in water. These components are blended together, then passed through a hammer mill or other suitable grinding device until the particle size is substantially below 50 microns. The product is then reblended until homogenous.

Aqueous dispersions are prepared by mixing the active components, a dispersing agent and a suspending agent with water and grinding in a pebble mill or sand mill can be prepared in 3 until the individual particles are substantially all below 5 microns.

Oil dispersions are prepared in substantially the same Way as aqueous dispersions, but in this case the dispersing agent chosen can also be an emulsifier for the oil so that the final product can be diluted with water to form a spray emulsion. In these dispersions the trifluralin may be partially or completely soluble. Emulsifiable oil solutions, in which both the substituted urea and trifluralin are soluble, are prepared by mixing the active components with solvents such as xylene, heavy aromatic naphtha or water insoluble ketones such as isophorone. The addition of an emulsifying agent to the solvent completes the formulation and also aid in the solution process. Such solutions may contain -50% of active ingredient, 2l5% of emulsifier and 3588% solvent.

Pellets are prepared by blending the ground active ingredients with a binding clay, and if rapid disintegration in water is desired, also a readily soluble salt. The blend is then moistened with 10 to percent water, and then extruded from a die under high pressure to yield a compact pellet. Such pellets may contain 3 to 50% by weight of active ingredient, and up to about 15% by weight of a soluble salt.

Granules are prepared by spraying an aqueous suspension of the herbicidal urea and an oil solution of trifluralin upon a granular diluent such as granular attapulgite, while tumbling the latter to obtain uniform deposition. Alternatively, granules may also be prepared from mixtures such as described for pellets above, by mixing with larger amounts of water and forming in a commercial granulator such as the Stokes granulator and drying the product.

Dusts are most frequently prepared by diluting wettable powders with a dense, rapid settling diluent such as micaceous talc by blending the two together in a ribbon or cone blender. Alternatively, where wetting or dispersing agents are undesirable, the active components are first mixed with a minor amount of a fluffing diluent and a grinding aid, micropulverized and then blended with the dense major diluent.

The herbicidal composition can be applied as a spray, dust or granule to the locus or area to be protected from weeds. Such application can be made directly upon the locus or area and the weeds thereon during the period of weed infestation in order to destroy the weeds, or alternatively, the application can be made in advance of an anticipated weed infestation to prevent such infestation. Thus, the compositions can be applied as foliar sprays, but can also be applied as sprays or as granules or pellets directly to the soil. Alternatively, the dry powdered compositions can be dusted directly on the plants or on the soil. For some purposes, as in the treatment of ponds or lake bottoms, it will be convenient to use the pellet formof the compositions.

The compositions of the invention are, of course, :ap' plied in amount sufficient to exert the desired herbicidal action. The rate of application for destroying or preventing weeds will vary with the particular weed pest involved, the formulation used, the herbicidal activity of the active ingredients, the purposes for which the application is being made (such :as for either short-term or long-term control), the manner of application, plant density, prevailing weather conditions and like variables. Since many variables play a role, it is not possible to indicate one rate of application suitable for all situations.

In general, however, the rate of application of active components of the invention when mixed with each other in the proportions above-indicated and formulated with inert carriers will range from about 0.5 to 6 pounds per acre of active components. When the compositions are used for pre-emergence purposes the amount of urea used will range from about 0.3 to 3.0 pounds per acre and the amount of trifluralin applied will range from about 0.3 to 1.5 pounds per acre.

For some specific uses, specific combinations of this invention demonstrate greatly enhanced herbicidal effectiveness. Rates of application that are generally found effective in these situations can be indicated, but it must be remembered that the determination of the proper rate in any given instance is conventional procedure to those skilled in the art. Thus, for example, the combination of diuron with trifluralin is outstandingly useful in controlling a wide variety of weeds in cotton. For instance, weeds such as crabgrass, Digitaria spp.; foxtail, Setaria spp.; barnyardgrass, Ec/rs'nochloa crusgalli; seedling Johnsongrass, Sorghum halepense; pigweed, Amaranthus spp.; goosegrass, Eleusine indica; ragweed, Ambrosia spp.; annual morningglory Ipomoea spp.; and cocklebur, Xanthium spp.; are controlled in cotton when sprayed with the combination of diuron and trifluralin.

Combinations of monuron and trifluralin are suitable for use in controlling weeds in cotton, sugar cane, and citrus orchards and neburon-trifiuralin combinations are particularly suited for controlling weeds in nursery stock.

These combinations can be applied to the weed-infested area such as by spraying. Immediately after application, the soil can be disked as with a rototiller. The crop can be planted at that time or two to three weeks later, depending on application rates, and the control of weeds is excellent.

Pre-emergence application and directed post-emergence treatments other than by spraying, using these compositions, are also useful to kill weeds in agricultural crop fields. Rates of application in pre-emergence use depend upon the desired effect. For example, rates of application ranging from about 0.3 to 3.0 pounds per acre of herbicidal urea and about 0.3 to 1.5 pounds per acre of trifiuralin are generally sufficient for pre-emergence application.

In order that the invention can be better understood the following examples are given in addition to the ex- 21 .iples already given above. The examples illustrate typical herbicidal compositions of the invention, methods for their preparation, herbicidal applications and results obtained. The numbers following the tabulated ingredients represent parts by weight of the ingredients within the respective compositions.

Example I A tank mix in gallons of water is applied at the rate of 0.75 pound of active ingredient per acre of both 3-(3,4-dichlorop henyl)-l,ldimethylurea as K armex wettable powder diuron) and a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine as Treflan EC 44.5% trifluralin, to a cotton field which has not yet been planted. The soil is a clay loam. Immediately after spraying, the chemical treatment is incorporated into the soil to a depth of 1 to 2 inches by means of a rototiller. The cotton seed is planted within two weeks at a depth of 1% inches. For 7 to 12 weeks, and sometimes longer, the herbicide application provides effective control of crabgrass, goosegrass, foxtail, ragweed, pigweed and annual morningglory.

Example 11 A tank mixture of the two compounds of Example I in 40 gallons of water is utilized at the rate of 0.4 to 0.6 pound of active ingredient per acre, of each of the two active ingredients along with 2.0 pounds of trimethylnonyl polyethylene glycol ether, on a cotton field which is in the process of being planted. Application is made by means of tractor-mounted equipment in such a manner that the herbicidal mixture is immediately disced into the soil to a depth of l to 2 inches. The cotton is planted at a depth of 1%. inches. The treatment provides excellent control for an extended period on such weed species as crabgrass, Johnsongrass seedlings, harnyardgrass, foxtail, cocklebur, velvetleaf and annual morningglory.

Example III The tank mixture of Example 2 is used at the same rates for pre-emergence control of the annual weeds, listed in Example 2 in soybeans. The soybeans are planted 1% inches deep. Shortly thereafter the mixture is applied at the rates of Example 2. Within a few minutes the compounds are incorporated to a depth of /2 to 1 inch. Excellent 'weed control is observed.

Example IV Example V Percent Diuron 20 Trifluralin 20 Dioctyl sodium sulfosuccinate 2 Sodium lignin sulfonate 3 Attapulgite clay 55 A wettable powder is prepared in the following manner. The above ingredients are blended and ground to a particle size smaller than 30 mesh. This product is then micropulverized in an air mill to a particle size below 50 microns. The mixture is reblended and is then ready for use as a wettable powder.

Example VI Percent Monuron 50 Trifluralin 1O Alkylaryl sodium sulfonate 2 Methyl cellulose 1 Attapulgite clay 37 The above ingredients are formulated as a wettable powder by blending and micropulverizing to a particle size below 50 microns, followed by reblending.

Example VII Percent Neburon Trifluralin 20 Alkylaryl calcium sulfonate 30 Trimethylnonyl polyethylene glycol ether 3 Xylenes 46 An emulsifiable solution is prepared by stirring the above components in a tank until a homogenous solution is obtained.

Example VIII Percent 50% active neburon wetta-ble powder 10 44.5% active trifluralin emulsifiable 1O Granular attaclay (IS-30 mesh) 80 The granular attaclay is tumbled in a mixer to which the neburon wettable powder is added. This agitated mix is sprayed with the trifiuralin diluted 1:1 with xylene. After the spraying is complete, excess solvent is removed by drying and the granules are ready for application.

Example IX Percent Diuron Trifluralin 5 Hydrated attapulgite clay 79 Nonylphenylpolyethylene glycol ether 1 The above components are blended, micropulverized to pass a 30 mesh screen and moist granulated in a Stoker granulator by addition of 15-20% of water. The granules are dried and are then ready for application.

The above components are blended, micropulverized to pass a 30 mesh screen, moistened with 15-20% of water acid extruded under pressure through a die. The extrusions are cut into pellets and dried prior to application.

Example XI Percent Diuron 15 Trifluralin n 10 Hydrated attapulgite clay 2 Disodium hydrogen phosphate anhydrous 1 Calcium magnesium lignin sulfonate 15 Sodium pentachlorophenate 1 Water 56 An aqueous dispersion is prepared by grinding the above dry components to pass a 30 mesh screen. The water is then added and the aqueous suspension is ground in a sand mill with external cooling to a particle size essentially less than 5 microns.

Example XII Percent Monuron l 20 'Iln'fluralin 10 White mineral oil 60 Polyoxyethylene sorbital hexa-oleate 10 An oil dispersion is prepared by grinding the above dry Example XIII A tank mix in 75 gallons of water is applied at a rate of 0.75 pound of active ingredient per acre of both 1-(pchlorophenyl)-3,3-dimethylurea as Telvar wettable powder, monuron and a,a,a-trifiuoro-2,6-dinitro-N,

-dipropyl-p-toluidine as Treflan EC 44.5% trifluralin, to a cotton field which has not yet been planted. The manner and depth of application are the same as in Example I, and similar outstanding results are obtained.

The embodiments of the invention in which an exclusive property or privilege is claimed are:

1. A herbicidal composition comprising a herbicidally effective amount of a mixture of:

a substituted urea selected from the group consisting of 1 (3,4 dichlorophenyl)-3,3-dimethylurea, l-(pchlorophenyl)-3,3-dimethylurea and 1-(3,4-dichlorophenyl)-3-n-butyl-3-methylurea; and

a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine; the ratio of 11,,06 trifluoro 2,6-dinitro-N,N-dipropyl-ptoluidine: substituted urea being from 1:0.5 to 122.0.

2. A herbicidal composition comprising a herbicidally effective amount of a mixture of one part by Weight of ot,ot,ot trifluoro 2,6-dinitro-N,N-dipropyl-p-toluidine and 0.5 to 2.0 parts by weight of 1-(3,4-dichlorophenyl)-3,3- dirnethylurea.

3. A method for the control of weeds which comprises applying to a locus to be protected a herbicidal composition comprising a herbicidally efifective amount of a mixture of:

a substituted urea selected from the group consisting of 1 (3,4dich1oropheny1)-3,3-dimethylurea, l-(p-chloropheny1)-3,3 dimethylurea and 1 (3,4 dichlorophenyl)-3-n-=buty1-3-methyl*urea; and a,a,a-trifiuoro2,G-dinitro-N,N-dipropyl-p-toluidine, the ratio of a,u,oc trifl'uoro 2,6-dinitro-N,N-dipropylptoluidine: substituted urea being from 1:05 to 1:2.0.

4. A method for the control of Weeds which comprises applying to a locus to be protected a herbicidal composition comprising a herbicidally effective amount of a mixture of one part by weight of 0c,a,oc-tl'iflllOrO-2,6-di11itl0 8 N,N-dipropyi-p-toluidine and 0.5 to 2.0 parts by weight of 1-(3,4-di:hloropheny1) -3,3-dimethy1urea.

References Cited 5 UNITED STATES PATENTS 2,709,648 5/1955 Ryker et a1. 712.6 3,257,190 6/1966 Soper 71 2.3

10 JAMES O. THOMAS, 111., Primary Examiner.