Sulfonylurea herbicidal antidotes

Abstract

Sulfonylurea compounds have the formula ##STR1## in which R is selected from the group consisting of 1-4 carbon alkyl, phenyl, and methyl substituted phenyl;R.sub.1 is selected from the group consisting of hydrogen and 1-4 carbon alkyl; andR.sub.2 is selected from the group consisting of mono- and polyhalosubstituted phenyl, 3-6 carbon alkynyl, and 2-6 carbon alkoxyalkyl.

Description

BACKGROUND OF THE INVENTION

Uses of Herbicides

An herbicide is a compound which controls or modifies plant growth, e.g., killing, retarding, defoliating, desiccating, regulating, stunting, tillering, stimulating, and dwarfing. "Plant" refers to all physical parts, including seeds, seedlings, saplings, roots, tubers, stems, stalks, foliage, and fruits. "Plant growth" is meant to include all phases of development from seed germination to natural or induced cessation of life.

Herbicides are generally used to control or eradicate weed pests. They have gained a high degree of commercial success because it has been shown that such control can increase crop yield and reduce harvesting costs.

Herbicidal effectiveness is dependent upon several variables. One of these is the time or growth related method of application. The most popular methods of application include: pre-plant incorporation into the soil; pre-emergence surface treatment of seeded soil; and post-emergence treatment of the plant and soil.

The most important determinant of herbicidal effectiveness is the susceptibility of the target weed. Certain herbicidal compounds are phytotoxic to some weed species but not to others.

The manufacturer of the herbicide recommends range of rates and concentrations calculated to maximize weed control. The range of rates varies from approximately 0.01 to 50 pounds per acre (0.0112 to 56 kilograms/hectare (k/ha)), usually from 0.1 to 25 pounds per acre (0.112 to 28 k/ha). The actual amount used depends upon several considerations, including particular weed susceptibility and overall cost limitations.

Need for Herbicidal Antidotes

Unfortunately, few herbicides are selective exclusively of weed species. Many are toxic to both weeds and the intended crop beneficiary. Therefore, a particular herbicide's use may be proscribed by its injurious effect on the cultivated crop even though it may otherwise provide excellent control of weeds plaguing that crop.

To preserve the beneficial aspects of herbicide use and to mitigate crop damage, many herbicidal antidotes have been prepared. These antidotes reduce or eliminate damage to the crop without substantially impairing the ameliorative effect of the herbicide. See U.S. Pat. Nos. 4,021,224 and 4,021,229 and Belgian Pat. No. 846,894.

Although several explanatory theories have been advanced, the precise mechanism by which an antidote reduces herbicidal crop injury while retaining weed injury has not been conclusively established. An antidote compound may in fact be a remedy, interferent, protectant, or antagonist. As used herein, "antidote" describes the effect of establishing herbicidal selectivity.

Thiocarbamate herbicides are particularly effective in the control of grassy type weeds which interfere with the cultivation of a wide variety of crops, e.g., barley, corn, lentils, peanuts, peas, potatoes, soybeans, spinach, tobacco and tomatoes. Frequently, their beneficial use requires the addition of an antidotal compound.

DESCRIPTION OF THE INVENTION

It has been discovered that sulfonylurea compounds are effective antidotes for the protection of cultivated crops from thiocarbamate herbicidal injuries. Sulfonylurea compounds have the following formula ##STR2## in which

R is selected from the group consisting of 1-4 carbon alkyl (preferably methyl), phenyl, and methyl substituted phenyl;

R.sub.1 is selected from the group consisting of hydrogen and 1-4 carbon alkyl; and

R.sub.2 is selected from the group consisting of mono- and polyhalosubstituted phenyl (wherein the substituents are preferably chloro and bromo), 3-6 carbon alkynyl, and 2-6 carbon alkoxyalkyl.

One embodiment of this invention is a two-part herbicidal system comprised of

(a) an antidotally effective amount of a compound of the formula ##STR3## in which

R is selected from the group consisting of 1-4 carbon alkyl (preferably methyl), phenyl, and methyl substituted phenyl;

R.sub.1 is selected from the group consisting of hydrogen and 1-4 carbon alkyl; and

R.sub.2 is selected from the group consisting of mono- and polyhalosubstituted phenyl (wherein the substituents are preferably chloro and bromo), 3-6 carbon alkynyl, and 2-6 carbon alkoxyalkyl; and

(b) an herbicidally effective amount of a thiocarbamate of the formula ##STR4## in which

R.sub.3 is selected from the group consisting of 1-6 carbon alkyl and 2-6 carbon alkenyl;

R.sub.4 is selected from the group consisting of 1-6 carbon alkyl, 2-6 carbon alkenyl, cyclohexyl and phenyl; or

R.sub.3 and R.sub.4 together form a 5-10 carbon alkylene ring; and

R.sub.5 is selected from the group consisting of 1-6 carbon alkyl, 1-4 carbon haloalkyl, 5-10 carbon alkylene ring, phenyl, substituted phenyl, wherein the substituents are 1-4 carbon alkyl, 1-4 carbon haloalkyl, and halo, benzyl, and substituted benzyl, wherein the substituents are 1-4 carbon alkyl, 1-4 carbon haloalkyl, and halo.

The terms "alkyl" and "alkenyl", as used herein, are intended to include both straight and branched-chain groups. All carbon atom ranges are intended to be inclusive of both upper and lower limits.

This invention also includes the method of protecting crops from herbicidal injury which comprises applying to the locus where protection is desired an antidotally effective amount of a sulfonylurea of the formula ##STR5## in which

R is selected from the group consisting of 1-4 carbon alkyl, preferably methyl, phenyl, and methyl substituted phenyl;

R.sub.1 is selected from the group consisting of hydrogen and 1-4 carbon alkyl; and

R.sub.2 is selected from the group consisting of mono- and polyhalosubstituted phenyl, wherein the substituents are preferably chloro and bromo, 3-6 carbon alkynyl, and 2-6 carbon alkoxyalkyl.

Preparation

The thiocarbamates of the present compositions can be prepared by the procedures described in U.S. Pat. Nos. 2,913,327 and 3,185,720.

The compounds of this invention an be prepared in the manner described in the following examples. (Compound numbers in the examples correspond to those in Tables IV and V.)

EXAMPLE 1

(Compound No. 1)

Preparation of 1-(4-chlorophenyl)-3-methanesulfonylurea

A solution was prepared containing 3.8 grams (g) (0.03 mole) of 4-chloroaniline in 30 milliliters (ml) of benzene containing one drop each of the catalysts triethyl-amine and dibutyltin dilaurate. A solution of 3.6 g (0.03 mole) methanesulfonylisocyanate in 6 ml of benzene was added to the first solution. The mixture was allowed to stand overnight at room temperature.

The product was filtered, washed, and dried, yielding 6.6 g (89% theoretical yield) of 1-(4-chlorophenyl)-3-methanesulfonylurea (m.p. 225.degree.-235.degree./decomposed). Structure was confirmed by infrared spectraphotometric analysis (IR).

EXAMPLE 2

(Compound No. 2)

Preparation of 1-(2,6-dichlorophenyl)-3-methanesulfonylurea

A solution was prepared containing 3.2 g (0.02 mole) of 2,6-dichloroaniline in 30 ml benzene, and one drop each of triethylamine and dibutyltin dilaurate. A second solution of 2.4 g (0.02 mole) of methanesulfonylisocyanate in 6 ml of benzene was added to the first solution. The temperature of the reaction mixture was allowed to rise to 35.degree. C. The mixture was then allowed to stand for three days.

The precipitate was filtered, washed with a small amount of benzene and hexane, and dried. The product was 5.3 g (94.6% theoretical yield) of 1-(2,6-dichlorophenyl)-3-methanesulfonylurea (m.p. 232.degree.-235.degree./decomposed). Structure was confirmed by IR.

EXAMPLE 3

(Compound No. 3)

Preparation of 1-(4-chlorophenyl)-1-ethyl-3-benzenesulfonylurea

A solution was prepared containing 3.1 g (0.02 mole) of 4-chloro-N-ethylaniline in 25 ml benzene and one drop each of triethylamine and dibutyltin dilaurate. A second solution of 3.7 g (0.02 mole) of benzenesulfonylisocyanate in 25 ml benzene was added to the first solution. The temperature was allowed to rise to 35.degree. C. The mixture was stirred for 2 hours at room temperature and for one-half hour at 40.degree.-45.degree. C.

The solvent was removed by vacuum evaporation and the residue was triturated with hexane and dried. The product was 6.1 g (89.7% theoretical yield) of 1-(4-chlorophenyl-1-ethyl-3-benzenesulfonylurea (m.p. 145.degree.-146.degree. C.). Structure was confirmed by IR.

EXAMPLE 4

(Compound No. 4)

Preparation of 1-(4-bromophenyl)-1-ethyl-3-benzenesulfonylurea

A solution was prepared containing 4.0 g (0.02 mole) of 4-bromo-N-ethylaniline in 25 ml of benzene and one drop each of triethylamine and dibutyltin dilaurate. A solution of 3.7 g (0.02 mole) of benzenesulfonylisocyanate was added to the first solution. The temperature was allowed to rise to 35.degree. C. The mixture was stirred for 2 hours at room temperature and for one-half hour at 40.degree.-45.degree. C.

The solvent was removed by vacuum evaporation and the residue was triturated with hexane and dried. The product was 7.5 g (97% theoretical yield) of 1-(4-bromophenyl)-1-ethyl-3-benzenesulfonylurea (m.p. 146.degree.-148.degree. C.). Structure was confirmed by IR.

EXAMPLE 5

(Compound No. 7)

Preparation of 1-(2,2-dimethoxyethyl)-3-(p-toluenesulfonylurea)

2,2-dimethoxyethylamine (2.2 g of 0.021 mole) and 3.9 g (0.02 mole) of p-toluenesulfonyl isocyanate were reacted in 25 ml of benzene with one drop each of triethylamine and dibutyltin dilaurate. The temperature was allowed to rise to 35.degree. C. The mixture was stirred for 1 hour at room temperature and one-half hour at 50.degree.-55.degree. C.

The solvent was removed by vacuum evaporation. The product was 7.6 g of a semi-solid 1-(2,2-dimethoxyethyl)-3-(p-toluenesulfonylurea). Structure was confirmed by IR.

These and other compounds prepared in a similar manner appear in Table I.

TABLE I__________________________________________________________________________SULFONYLUREA HERBICIDAL ANTIDOTES ##STR6##Cmpd. PhysicalNo. R R.sub.1 R.sub.2 Chemical Name Constant__________________________________________________________________________1 CH.sub.3 H ##STR7## 1-(p-chlorophenyl)-3-methanesulfonylurea m.p. 225-235.degree. C.2 CH.sub.3 H ##STR8## 1-(2,6-dichlorophenyl)-3-methanesulfonyl- urea m.p. 232-235.degree. C. ##STR9## C.sub.2 H.sub.5 ##STR10## 1-p-chlorophenyl-1-ethyl-3-(benzene- sulfonyl)urea m.p. 145-146.degree. C.4 ##STR11## C.sub.2 H.sub.5 ##STR12## 1-p-bromophenyl-1-ethyl-3-(benzene- sulfonyl)urea m.p. 146-148.degree. C.5 ##STR13## CH.sub.3 ##STR14## 1-(.alpha.-methylpropargyl)-1-methyl-3- (p-toluenesulf onyl)urea m.p. 144-145.degree. C.6 ##STR15## H ##STR16## 1-(.alpha., .alpha.-dimethylpropargyl)-3- (p-toluenesu lfonyl)urea m.p. 143-145.degree. C.7 ##STR17## H ##STR18## 1-(2,2-dimethoxyethyl)-3-(p-toluene- sulfonyl)urea semi-solid__________________________________________________________________________

Testing

Stock solutions of the herbicides were prepared by diluting the requisite amount of each herbicide in water. The solution concentrations and application rates are summarized in Table II.

TABLE II______________________________________Herbicide Stock Solutions Composition Herbicide Water ApplicationHerbicide Name (mg) (ml) ml/flat.about. lb/acre______________________________________VERNAM.RTM. 413 400 4 0.75S-propyl N,N-dipropyl 300 300 5 1.00thiocarbamate 625 500 5 1.25 1950 400 5 5.00 3000 500 5 6.00EPTAM.RTM. 2667 500 5 5.00S-ethyl N,N-dipropyl 2560 400 5 6.00thiocarbamateSUTAN.RTM.S-ethyl diisobutyl 1300 250 5 5.00thiocarbamateRO-NEET.RTM.S-ethyl N-cyclohexyl 390 125 5 3.00thiocarbamate______________________________________

Stock solutions of each antidote compound were prepared at the desired concentrations by diluting the requisite amounts of each antidote in acetone. The concentrations and rates for each method of application are summarized in Table III.

TABLE III______________________________________Antidote Stock SolutionsAntidote: SulfonylureasComposition ApplicationAntidote (mg) Acetone (ml) ml/flat lb/acre Method*______________________________________95 15 0.30 1.00 IF95 15 1.50 5.00 IF16 40 2.50 0.25 PPI20 50 5.00 0.50 PPI40 50 5.00 1.00 PPI40 10 5.00 2.00 PPI40 10 5.00 5.00 PPIDilutionsStock Solution A:20 50Stock Solution B:5 ml of A 45 5.00 0.05 PPIStock Solution C:10 ml of B 45 5.00 1/80 PPI______________________________________ *IF = Infurrow surface application. PPI = Preplant incorporation of herbicide and antidote as a tank mix.

All of the soil used in the tests described herein was loamy sand soil treated with 50 parts per million (ppm) each of a commercially available fungicide cis-N[(trichloromethyl)-thio]-4-cyclohexene-1,2-dicarboximide, and 18-18-18 fertilizer, which contains 18% by weight equivalent each of nitrogen, phosphorus pentoxide, and potassium oxide.

The herbicides were applied to the soil by pre-plant incorporation (PPI). The antidotes were also applied by this method and in-furrow.

For in-furrow (IF) antidote application a one pint (473 cubic centimeter) sample of soil from each planting flat was removed and retained. After leveling and furrowing the soil, seeds of the crop or weed species were planted 1/2 inch deep (1.27 centimeter (cm)). Each flat was divided in half by a wooden barrier. A stock solution of the antidote was atomized directly onto the exposed seeds and soil in the open furrow on one side of the barrier. The seeds in the entire flat were then covered with the previously removed soil. The antidotally untreated sections of flats were compared for observed differences which would indicate lateral movement of the antidote through the soil.

All flats were placed on greenhouse benches where temperature was maintained between 70.degree. and 90.degree. C. (21.1.degree. to 32.2.degree. C.). The flats were watered by sprinkling as needed to assure good plant growth.

Control flats contained crops treated with herbicides only at the various rates and methods of application.

Injury ratings were taken four weeks after application of the antidote. The effectiveness of the antidote was determined by visual comparison of injuries to crops and weeds in the control and test flats to those in untreated flats.

The treated crops initially screened for diminution of herbicidal injury were milo, wheat, cotton, rice, barley, corn and soybeans. Those compounds which showed substantial crop injury reduction were further tested at reduced rates. The herbicides and the most active antidote compositions were then screened on two weed species. The weed species tested for control included watergrass (Echinochloa crusgalli), foxtail (Setaria viridis), wild oat (Avena fatua), Johnsongrass (Sorghum halepense), and shattercane (Sorghum bicolor).

KEY TO TABLES IV AND V

Antidotes

Compound numbers in these tables correspond to the numbers and their chemical description in Table I.

Application times: IF=In-furrow surface application PPI=Pre-plant incorporation

Herbicides

VERNAM.RTM.=S-propyl N,N-dipropylthiocarbamate. EPTAM.RTM.=S-ethyl N,N-dipropyl thiocarbamate. SUTAN.RTM.=S-ethyl diisobutyl thiocarbamate. VERNAM, EPTAM, and SUTAN are described in U.S. Pat. No. 2,913,327. RO-NEET.RTM.=S-ethyl N-cyclohexyl thiocarbamate, is described in U.S. Pat. No. 3,185,720. Rates: All rates are shown in pounds per acre. Injury Ratings: U=Antidotally untreated; % injury 4 weeks after herbicide application. T=Antidotally treated; % injury 4 weeks after treatment with herbicide plus antidote compound. -=Indicates no change. TABLE IV__________________________________________________________________________SulfonylureaAntidotal Effectiveness % Crop InjuryCmpd. Antidote Herbicide Milo Wheat Cotton Rice Barley Corn SoybeanNo. Rate Time Name Rate U T U T U T U T U T U T U T__________________________________________________________________________1 5.00 IF VERNAM 1.00 100 60 75 100 95 100 98 100 5.00 IF VERNAM 5.00 85 100 50 0 60 100 1.00 IF VERNAM 1.00 100 80 5.00 IF VERNAM 1.00 100 70 1.00 PPI VERNAM 1.00 95 -- 5.00 PPI VERNAM 1.00 95 -- 0.25 PPI VERNAM 1.25 90 -- 0.50 PPI VERNAM 1.25 90 -- 1.00 PPI VERNAM 1.25 90 -- 1.00 PPI VERNAM 1.25 70 90 5.00 PPI VERNAM 1.25 70 100 1.00 PPI VERNAM 6.00 60 -- 5.00 PPI VERNAM 6.00 60 -- 1.00 IF VERNAM 1.00 95 -- 95 -- 5.00 IF VERNAM 1.00 95 -- 95 30 0.50 PPI VERNAM 1.00 95 -- 1.00 PPI VERNAM 1.00 95 -- 5.00 PPI VERNAM 1.00 95 -- 1.00 PPI VERNAM 1.25 90 -- 2.00 PPI VERNAM 1.25 90 -- 5.00 PPI VERNAM 1.25 90 -- 1.00 PPI VERNAM 6.00 60 30 5.00 PPI VERNAM 6.00 60 -- 0.50 PPI EPTAM 6.00 80 -- 5.00 PPI EPTAM 6.00 80 60 0.50 PPI EPTAM 6.00 90 80 5.00 PPI EPTAM 6.00 90 501 1.00 PPI SUTAN 5.00 35 30 5.00 PPI SUTAN 5.00 35 65 1.00 IF RONEET 3.00 90 -- 5.00 IF RONEET 3.00 90 -- 1.00 IF RONEET 3.00 75 -- 5.00 IF RONEET 3.00 75 552 5.00 IF VERNAM 1.00 100 -- 75 -- 95 -- 98 -- 5.00 IF VERNAM 5.00 85 -- 50 20 60 80 0.50 PPI EPTAM 6.00 80 -- 5.00 PPI EPTAM 6.00 80 -- 0.50 PPI EPTAM 6.00 90 85 5.00 PPI EPTAM 6.00 90 603 5.00 IF VERNAM 1.00 100 -- 97 -- 100 -- 97 -- 5.00 IF VERNAM 5.00 80 -- 65 -- 5 -- 1.00 IF VERNAM 6.00 40 30 5.00 IF VERNAM 6.00 55 -- 5.00 IF VERNAM 6.00 55 65 1.00 IF VERNAM 6.00 60 -- 5.00 IF VERNAM 6.00 60 --4 5.00 IF VERNAM 1.00 100 -- 97 -- 100 -- 97 -- 5.00 IF VERNAM 5.00 80 100 65 90 5 40 1.00 PPI VERNAM 6.00 60 -- 5.00 PPI VERNAM 6.00 60 -- 1.00 PPI VERNAM 6.00 60 20 5.00 PPI VERNAM 6.00 60 104 5.00 PPI EPTAM 5.00 85 65 0.50 PPI EPTAM 6.00 90 75 5.00 PPI EPTAM 6.00 90 855 5.00 IF VERNAM 0.75 95 -- 60 -- 60 -- 40 -- 5.00 IF VERNAM 5.00 60 -- 70 20 30 --6 5.00 IF VERNAM 0.75 95 60 60 -- -- -- 60 -- 40 -- 5.00 IF VERNAM 5.00 70 10 30 -- 1.00 IF VERNAM 1.00 90 -- 5.00 IF VERNAM 1.00 90 70 1.00 IF RO-NEET 3.00 65 50 5.00 IF RO-NEET 3.00 65 407 5.00 IF VERNAM 0.75 95 50 60 -- -- -- 60 -- 40 -- 5.00 IF VERNAM 5.00 70 0 30 -- 1.00 IF VERNAM 1.00 90 -- 5.00 IF VERNAM 1.00 90 -- 0.05 PPI EPTAM 5.00 80 -- 0.50 PPI EPTAM 6.00 85 -- 0.05 PPI EPTAM 6.00 85 -- 1/80 PPI EPTAM 6.00 85 -- 1.00 IF RO-NEET 3.00 65 50 5.00 IF RO-NEET 3.00 65 30__________________________________________________________________________ TABLE V__________________________________________________________________________SulfonylureaHerbicidal Effectiveness % Weed InjuryCmpd. Antidote Herbicide Watergrass Foxtail Wild Oat Johnsongrass ShattercaneNo. Rate Time Name Rate U T U T U T U T U T__________________________________________________________________________1 1.00 IF VERNAM 1.00 95 70 100 -- 5.00 IF VERNAM 1.00 95 60 100 70 1.00 PPI VERNAM 1.00 95 -- 100 -- 5.00 PPI VERNAM 1.00 95 -- 100 -- 0.25 PPI VERNAM 1.25 70 -- 100 -- 0.50 PPI VERNAM 1.25 70 -- 100 -- 1.00 PPI VERNAM 1.25 70 -- 100 -- 1.00 PPI VERNAM 1.25 95 -- 100 -- 5.00 PPI VERNAM 1.25 95 -- 100 -- 1.00 PPI VERNAM 6.00 100 -- 100 -- 5.00 PPI VERNAM 6.00 100 -- 100 -- 1.00 IF VERNAM 1.00 95 -- 95 -- 5.00 IF VERNAM 1.00 95 85 95 -- 0.50 PPI VERNAM 1.00 95 -- 95 -- 1.00 PPI VERNAM 1.00 95 -- 95 -- 5.00 PPI VERNAM 1.00 95 -- 95 -- 1.00 PPI VERNAM 1.25 97 -- 97 -- 2.00 PPI VERNAM 1.25 97 -- 97 -- 5.00 PPI VERNAM 1.25 97 -- 97 -- 1.00 PPI VERNAM 6.00 85 -- 90 -- 5.00 PPI VERNAM 6.00 95 -- 90 -- 0.50 PPI EPTAM 6.00 100 -- 100 -- 5.00 PPI EPTAM 6.00 100 -- 100 -- 0.50 PPI EPTAM 6.00 100 -- 100 -- 5.00 PPI EPTAM 6.00 100 -- 100 --1 1.00 PPI SUTAN 5.00 100 -- 100 -- 5.00 PPI SUTAN 5.00 100 -- 100 -- 1.00 IF RONEET 3.00 95 -- 100 -- 5.00 IF RONEET 3.00 95 -- 100 -- 1.00 IF RONEET 3.00 95 -- 95 -- 5.00 IF RONEET 3.00 95 -- 95 --2 0.50 PPI EPTAM 6.00 100 -- 100 -- 5.00 PPI EPTAM 6.00 100 -- 100 -- 0.50 PPI EPTAM 6.00 100 -- 100 -- 5.00 PPI EPTAM 6.00 100 -- 100 --3 1.00 IF VERNAM 6.00 100 -- 100 -- 5.00 IF VERNAM 6.00 100 -- 100 -- 5.00 IF VERNAM 6.00 1.00 IF VERNAM 6.00 100 -- 100 -- 5.00 IF VERNAM 6.00 100 -- 100 --4 1.00 PPI VERNAM 6.00 100 -- 100 -- 5.00 PPI VERNAM 6.00 100 -- 100 -- 1.00 PPI VERNAM 6.00 85 -- 90 -- 5.00 PPI VERNAM 6.00 95 -- 90 -- 5.00 PPI EPTAM 5.00 100 -- 0.50 PPI EPTAM 6.00 100 -- 100 -- 5.00 PPI EPTAM 6.00 100 -- 100 --6 1.00 IF RO-NEET 3.00 95 -- 95 -- 5.00 IF RO-NEET 3.00 95 -- 95 --7 0.05 PPI EPTAM 5.00 100 -- 100 -- 0.50 PPI EPTAM 6.00 100 -- 100 -- 0.05 PPI EPTAM 6.00 100 -- 100 -- 1/80 PPI EPTAM 6.00 100 -- 100 -- 1.00 IF RO-NEET 3.00 95 -- 95 -- 5.00 IF RO-NEET 3.00 95 -- 95 --__________________________________________________________________________

Formulations

The object of the formulation is to apply the compounds and compositions to the locus where control is desired by a convenient method. The "locus" may include soil, seeds, seedlings, and vegetation.

The amount of antidote compound which comprises part of an herbicidal composition will generally range from approximately 0.001 to 30 parts by weight per weight of the active herbicidal compound.

Formulations will generally contain several additives. Among these are some inert ingredients, diluent carriers, organic solvents, water, oil and water, water in oil emulsions, carriers of dusts and granules, and surface active wetting, dispersing, and emulsifying agents.

Fertilizers, e.g., ammonium nitrate, urea and superphosphate, may also be included.

Aids to rooting and growth, e.g., compost, manure, humus, sand, etc., may likewise be included.

The formulations are commonly dusts, wettable powders, granules, solutions or emulsifiable concentrates.

Dusts are free-flowing powder compositions containing the herbicidal compound impregnated on a particulate carrier. The particle size of the carriers is usually in the approximate range of 30 to 50 microns. Examples of suitable carriers are talc, bentonite, diatomaceous earth, and pyrophyllite. Anti-caking and anti-static agents can be added, if desired. The composition generally contains up to 50% of active ingredient. Dusts, like liquid compositions, can be applied by spraying from boom and hand sprayers or airplanes.

Wettable powders are finely divided compositions comprising a particulate carrier impregnated with the herbicidal compound and additionally containing one or more surface active agents. The surface active agent promotes rapid dispersion of the powder in aqueous medium to form stable, sprayable suspensions. A wide variety of surface active agents can be used, for example, long chain fatty alcohols and alkali metal salts of the sulfated fatty alcohols; salts of sulfonic acid; esters of long chain fatty acids; and polyhydric alcohols; in which the alcohol groups are free, omega-substituted polyethylene glycols of relatively long chain length. A list of surface active agents suitable for use in agriculture formulations can be found in Wade Van Valkenburg, Pesticide Formulations (Marcel Dekker, Inc., N.Y., 1973) at pages 79-84.

Granules comprise the herbicidal composition impregnated on a particulate inert carrier having a particle size of about 1 to 2 millimeters in diameter. The granules can be made by spraying a solution of the active ingredient in a volatile solvent onto the granular carrier. Suitable carriers in preparation of granules include clay, vermiculite, sawdust, granular carbon, etc.

The herbicidal compositions can also be applied to the soil in the form of a solution in a suitable solvent. Solvents frequently used in herbicidal formulations include kerosene, fuel oil, xylene, petroleum fractions with boiling ranges above xylene, and aromatic petroleum fractions rich in methylated naphthalenes.

Emulsifiable concentrates consist of an oil solution of the herbicide along with an emulsifying agent. Prior to use the concentrate is diluted with water to form a suspended emulsion of oil droplets. The emulsifiers used are usually a mixture of anionic and nonionic surfactants. Other additives such as spreading agents and stickers can be included in the emulsifiable concentrate.

The compounds and compositions of this invention can also be applied by addition to irrigation water supplied to the field to be treated. This method of application permits the penetration of the compositions into the soil as the water is absorbed therein.

It is not necessary that the compounds and compositions be admixed with the soil particles. After application by the above discussed methods, they may be distributed below the surface to a depth of at least one-half inch by conventional means such as discing, dragging, or mixing.

Claims

1. A compound of the formula ##STR19## in which R is selected from the group consisting of 1-4 carbon alkyl, phenyl, and methyl substituted phenyl;

R.sub.1 is selected from the group consisting of hydrogen and 1-4 carbon alkyl; and

R.sub.2 is 3-6 carbon alkynyl.

2. A compound according to claim 1 in which R is p-tolyl, R.sub.1 is methyl, and R.sub.2 is .alpha.-methylpropargyl.

3. A compound according to claim 1 in which R is p-tolyl, R.sub.1 is hydrogen, and R.sub.2 is .alpha.,.alpha.-dimethylpropargyl.