CS212282B2 - Herbicidal agent - Google Patents

Abstract

The invention relates to a herbicidal composition comprising a combination of a herbicidally active thiocarbamate, a chlorinated N,N-substituted acetamide as an antidote for the thiocarbamate, and a certain organophosphorothioate which is used to prevent the degradation of the thiocarbamate in soil. The organophosphorothioate significantly prolongs the life of the herbicide in soil.

Description

(54) Herbicide

The invention relates to a herbicidal composition comprising a combination of a herbicidally active thiocarbamate, a chlorinated N,N-substituted acetamide as an antidote for the thiocarbamate, and a certain organophosphorothioate which is used to prevent the degradation of the thiocarbamate in soil. The organophosphorothioate significantly prolongs the life of the herbicide in soil.

The invention relates to herbicidal compositions and their use, in particular to herbicidal compositions comprising a herbicidally active thiocarbamate in combination with a certain acetoamide as an antidote and an organic phosphorus compound which serves to prolong the effectiveness of a single application of the thiocarbamate herbicide in suppressing the growth of undesirable plants.

Thiocarbamates are well known in agricultural practice as herbicides useful for controlling weeds in crops such as corn, potatoes, beans, beets, spinach, tobacco, tomatoes, alfalfa, etc. Thiocarbamates are mainly applied pre-emergence. They have been found to be particularly effective when incorporated into the soil before the crops are planted. The concentration of thiocarbamate herbicide in the soil is highest immediately after application. The length of time that the initial concentration is maintained depends largely on the specific soil treated. The rate at which the concentration of thiocarbamate herbicide decreases after application varies with the type of soil.

This is evident both from the observable extent of actual weed control and from the detectable presence of undegraded thiocarbamate remaining in the soil after a significant period of time.

It has now been found that the persistence in soil of certain herbicidally active thiocarbamates combined with antidotally active acetamides is substantially prolonged by incorporating into the herbicidal composition certain organophosphorus compounds which have no herbicidal activity of their own. The improved persistence of the thiocarbamates in soil is manifested in various ways.

For example, it can be shown that the rate of decline of thiocarbamates in soil is significantly reduced by the use of an organophosphorus compound. This can be demonstrated by analyzing soil samples taken at regular intervals after application of the thiocarbamate herbicide.

Improved persistence in soil is also evident from herbicidal activity tests in which the degree of weed damage is determined after a certain period of time after application of the herbicide. These tests demonstrate that organophosphorus compounds, which have no herbicidal activity of their own, enhance the herbicidal activity of thiocarbamates by increasing their persistence in soil and thus extending their effective life. Other manifestations of the increased persistence of thiocarbamate herbicides are apparent from the following description.

The subject of the invention is a new herbicidal composition, characterized in that it contains

a) a herbicidally effective amount of a thiocarbamate of the general formula r'-s-c-n where.

each of R ² and R ³ is C 1 -C 8 alkyl, C 1 -C 8 alkenyl, phenylalkyl, or phenyl and each of these groups is optionally substituted with one, two, or three halogen atoms and is independently C 1 -C 8 alkyl or C 1 -C 8 cycloalkyl or both together are alkylene together with a non-phytotoxic antidotally effective amount of a compound of the general formula ^{R C 1} n ^GH (3-n)- ^C - ^N ^ _Q where n

represents 1 or 2 and each of the symbols

R ⁸ and R 9 independently represent C 1 -C ₁₂ alkyl or C ₂ -C ₁₂ alkenyl or a group

-N

represents a group of the general formula

R ¹ ' where each of the symbols β'θ and r' ¹ independently represents hydrogen or methyl and 1 2

R represents hydrogen, C 1-4 alkyl or phenyl

b) an organophosphorus compound of the general formula

R

WITH

II

P-X-R where

^R4 represents C1-C8 alkyl, C1-C8 alkenyl, C8-C8 alkynyl or C8-C8 cycloalkyl, each of which is optionally substituted with up to three substituents selected from the group consisting of halogens, cyano,

C 1 -C 8 alkoxy and C 1 -C ₃ alkylthio,

R^ represents Cj-Cj alkyl Cj-Cj alkoxy or Cj-Cj alkylthio,

R ⁸ represents C 1 -C ₂₀ alkyl, C 8 -C ₂₀ alkenyl or C 8 -C 20 alkynyl, each of which is optionally substituted with up to three substituents selected from the group consisting of halogens, nitro, cyano, C 1 -C 20 alkoxy and C 1 -C 20 alkylthio, C 1 -C 20 cycloalkyl or a residue of the formula

-<R ⁷ ) _m -0 where

R represents 0,-C^ alkyl, Cg-C^ ^a:Lk enyl or Cg-C^ alkynyl, each of these groups being optionally substituted with up to three substituents selected from the group consisting of halogens and cyano, m represents the number 0 or 1 and represents phenyl, optionally substituted with up to three substituents selected from the group consisting of halogens, trifluoromethyl, nitro, cyano, Cj-C^ alkoxy, Cj-Cg carbalkoxy and C,-Cg alkylsulfinyl,

X represents oxygen or sulfur and

Y represents oxygen or sulfur, wherein the weight ratio of thiocarbamate to organophosphorus compound is 1:1 to 15:1.

The individual substituents in the above compounds preferably have the following meaning:

R

R

R

Rj

are as defined above, represent C1-C4 alkyl, represent C1-C4 alkyl, C1- _C4 alkoxy or C1-C4 alkylthio, represent phenyl, chlorophenyl, nitrophenyl, C1-C4 alkylsulfinylphenyl, C1-C4 phenylalkyl, or C1-C4 alkylthioalkyl, represent oxygen or sulfur and represent oxygen.

It is even more advantageous if the individual symbols in the above compounds have the following meaning:

R ² and R ³ have the above meanings, represent alkyl, represent C 1 -C 4 alkyl, C 1 -C 4 alkoxy or C 1 -C 4 alkylthio, represent phenyl, chlorophenyl, nitrophenyl, Ογ -C 8 alkylsulfinylphenyl or C ₂ -C 8 alkyl thiophenyl, represent oxygen or sulfur and represent oxygen.

The most preferred compounds are those in which

R ¹ represents C 1 -C 4 alkyl,

3°

R and R independently represent C1-C8 alkyls, r4 represents C1-C8 alkyl,

^S3 represents C1-C4 alkyl, C ₍ -C4 alkoxy or C)-C4 alkylthio,

R^ represents phenyl, chlorophenyl, nitrophenyl, C^-Cg alkylsulfinylphenyl, or Cj-Cg alkylthiophenyl,

X represents oxygen or sulfur and

Y represents oxygen.'

The terms alkyl, alkenyl, alkynyl and alkylene are intended to include both straight-chain and branched-chain radicals. All ranges of carbon number include both upper and lower limits.

The term halogen atom refers to a fluorine, chlorine, bromine or iodine atom and combinations thereof.

The term herbicide means a compound that suppresses or modifies plant growth. The term herbicidally effective amount means that amount of a compound that has a modifying effect on plant growth. The term plant means germinating seeds, emerging seedlings and mature vegetation, both roots and above-ground parts of plants. Suppressive or modifying effects include all deviations from natural development, for example killing, retardation, defoliation, desiccation, regulation, stunting, tillering, stimulation, leaf scorching, dwarfing, etc.

By extending the soil life of said thiocarbamate is meant the effect of maintaining the molecular structure and/or herbicidal activity of the thiocarbamate substantially the same as when first applied to the site. Extended soil life is manifested by a slower rate of decline in weed killing ability or by an increase in the half-life of the effective concentration of the thiocarbamate in the soil. Other methods of determining the soil life of compounds will be apparent to those skilled in the art.

Thus, according to the invention, the organophosphorus compound described above is added to thiocarbamates in order to prolong their molecular integrity and herbicidal efficacy.

As the examples below show, there is no critical range for the ratio of these two components. The effect of extending the life in soil occurs over a wide range of ratios. However, it is most preferred to apply the compounds in a ratio of thiocarbamate to organophosphorus compound of from about 0.1:1 to about 50:1. The preferred range for this ratio is from about 1:1 to about 25:1, and the most preferred range is from about 1:1 to about 15:1.

Thiocarbamates suitable for use in the compositions of the invention include S-ethyldi-n-propylthiocarbamate, S-ethylhexahydro-1H-azepine-1-carbothioate, S-ethyldiisobutylthiocarbamate, S-n-propyldi-n-propylthiocarbamate, S-ethylethylcyclohexylthiocarbamate, S-n-propylethyl-n-butylthiocarbamate, S-p-chlorobenzyldiethylthiocarbamate, S-2,3,3-trichloroallyl5 diisopropylthiocarbamate, S-2,3-dichloroallyldxisopropylthiocarbamate and S-benzyldisec.butylthiocarbamate.

Organophosphorus compounds suitable for the compositions of the invention include O-ethyl-S-phenylethylphosphonodithioate, O-ethyl-S-p-chlorophenylethylphosphonodithioate, O,0-diethyl-S-ethylthioethylphosphorodithioate, O,0-diethyl-O-p-methylsulfinylphenylphosphorodithioate, O,0-diethyl-S-ethylthiomethylphosphorodithioate, O,0-dimethyl-O-p-nitrophenylphosphorothioate, O,0-dimethyl-O-phenylphosphorothioate, O,0-diethyl-O-phenylphosphorothioate, O,0-diisopropyl-O-phenylphosphorothioate, O,0-dimethyl-O-benzylphosphorothioate, O,0-diethyl-O-(2-phenylethyl)phosphorothioate, O,0-di-n-propyl-O-phenylphosphorothioate, O-ethyl-S-ethyl-O-phenylphosphorothioate, O,O-di-n-propyl-O-phenylphosphorothioate and O-methyl-S-phenylmethylphosphonodithioate. Further examples are given in the tests given below.

The utility of many thiocarbamates as herbicides can be substantially extended to a wider range of crop species by adding an antidote to the herbicide composition. The antidote protects the crop from damage by the herbicide and increases the tolerance of the crop to the herbicide. This increases the selectivity of the herbicide, i.e., it retains efficacy against undesirable weeds while reducing herbicidal activity against desired crop species.

Examples of antidotes and methods of their use are disclosed in U.S. Patent No. 3,959,304, issued to E. G. Teach on May 25, 1976; U.S. Patent No. 3,989,503, issued to F. M. Pallos et al. on November 2, 1976; U.S. Patent No. 4,021,224, issued to F. M. Pallos et al. on May 3, 1977; U.S. Patent No. 3,133,509, issued to O. L. Hoffman on May 5, 1964; and U.S. Patent No. 3,564,768, issued to O. L. Hoffman on February 3, 1971.

Examples of antidotes falling within the scope of the above general formula include N,N-diallyldichloroacetamide and N,N-diallylchloroacetamide. Examples of substances not falling within the scope of this formula include 1,8-naphthalic anhydride.

The antidote is applied in conjunction with the thiocarbamate and the organophosphorus compound in a non-phytotoxic amount at which the antidote effect occurs. The term non-phytotoxic amount is understood to mean the amount of antidote that causes only minor damage to the target crops at most. The term antidote effect amount is understood to mean the amount of antidote that substantially reduces the extent of damage to the target crops caused by the thiocarbamate.

The preferred ratio of herbicide to antidote is from about 0.1:1 to about 30:1. A particularly preferred amount is from about 3:1 to about 20:1.

The following examples further illustrate the means, methods and effect of the invention. The examples are for illustrative purposes only and do not limit the scope of the invention in any way.

Example 1

Soil persistence tests

This example demonstrates, based on periodic chemical analyses of soil composition, the effectiveness of organophosphorus compounds of the invention in extending the life of thiocarbamate herbicides in soil.

For each test, a half-liter glass jar containing 250 g of soil (dry matter) is used. Three types of soil with different structures are used: loamy sandy soil, silt soil and clay soil. The relative amounts of sand, silt and clay in these soils are determined mechanically and the amount of organic matter and acidity (pH) are determined chemically. The results of the analyses are given below.

Table I

Soil analysis

Soil Composition (% by weight) Organic matter sand sputum clay mass·) pH loamy sandy soil 64 29 7 4 6.8 alluvial soil 32 56 12 3 7.2 clay soil 50 30 20 4.7 6.1

The test compounds or combinations thereof are dissolved in water in such concentrations that 5 ml of the sample contains such an amount of active ingredients that is equivalent to the desired level of treatment after addition to the preserving jars. Thiocarbamates are used in these tests in the form of emulsifiable liquid concentrates containing an antidote to prevent damage to the crops. The concentrates are diluted accordingly to a value corresponding to a level of treatment of 6.72 kg/ha of active ingredient. Of the organophosphorus compounds tested, O,0-diethyl-O-phenylphosphorodithioate is applied as a technical liquid diluted to an application concentration of 0.56 kg/ha or 1.12 kg/ha and O-ethyl-S-phenylethylphosphonodithioate is applied in the form of an emulsifiable liquid concentrate diluted to an application concentration of 4.48 kg/ha of active ingredient.

An aliquot sample of the aqueous mixture containing the thiocarbamate, antidote and organophosphate additive at the appropriate concentration (5 ml) is pipetted into a preserving bottle and mixed into the soil with a spatula. The bottle is then capped and shaken by hand for approximately 30 seconds.

After this treatment, about 50 seeds of Echinochloa crusgalli and two seeds of D-Kalb XL-45A maize are sown in the soil. The soil is then moistened to a level corresponding to field conditions and the unsealed bottle is placed in a greenhouse where the temperature is maintained at about 21 to 27 °C. Water is introduced into the soil regularly.

The tests are always carried out twice, and separate bottles are used for each test. After a specified interval, two bottles are removed from the greenhouse, the above-ground parts of the plants are removed, the bottles are tightly closed and left to freeze until chemical analysis is carried out. After another interval, another pair of bottles are removed and subjected to the same treatment. For each stage of application, 6 preserving bottles are prepared for analysis (2 of these 6 bottles are controls, i.e. bottles treated immediately after treatment with the test chemicals).

Each of the samples thus prepared is macerated with 2 liters of water in a Waring Blender and the extract is transferred to a 4-liter container. About 10.0 ml of antifoaming agent is added and the mixture is rapidly distilled. About 400 ml of distillate is collected. 5 drops of concentrated hydrochloric acid are added to the distillate to prevent the formation of an emulsion. The thiocarbamate is extracted from the distillate with two 2.0 ml portions of isooctane. The extracts are then combined. Analysis for thiocarbamate content is carried out by gas chromatography.

In Tables II and III, the chromatographic analysis data are converted to equivalent soil concentrations expressed in ppm by weight of thiocarbamates. These tables present the results as average values from each pair of duplicate samples.

The tables clearly show that the thiocarbamate content decreases with time in each type of soil. It is further evident that this decrease is considerably slower in the presence of the organophosphorus compound. The effect of the organophosphorus compound on the aluminous sandy soil is particularly evident from the data corresponding to 21 days in Table II and three weeks in Table III. compared with the experimental data obtained for the control samples. The higher values obtained in the experimental data are a clear confirmation of the fact that the rate of decrease is considerably reduced due to the presence of the organophosphorus compounds. A similar effect is evident in the alluvial soil from the data corresponding to 3 days in Table II and one week in Table XII. A similar effect is finally evident in the clayey soil and from the data corresponding to 7 days in Table II and two weeks in Table III.

Table II

Results of soil persistence tests

Herbicide: S-ethyldi-n-propylthiocarbamate (active ingredient) mixed in a weight ratio of 12:1 with N,N-diallyldichloroacetamide (antidote)

Application rate: 6.72 kg/ha

Amount of herbicide present in soil (ppm active ingredient)

Grade Number of days after application

Organophosphorus additive applications 0 3 7 14 21 283

Sandy loam soil

- (control experiment) - 11.71 9.97 7.88 6.12 0.76 0.71 0,O-diethyl-O-phenylphosphorothioate 0.56 11.43 10.25 8.41 6.88 5.38 2.28 0,0-diethyl-O-phenylphosphorothioate 1,121 12.10 13.23 10.91 6.79 5.74 3.95 O-ethyl-S-phenylethylphosphonodithioate 4.48 10.36 11.70 8.05 5.17 3.18 1.04

Alluvial sawmill

-(control experiment) - 10.59 2.58 0.24 0.12 0.00 - ^(b) 0,Q-diethyl-O-phenylphosphorothioate 0.56 12.05 9.05 7.26 0.82 0.41 0,O-diethyl-O-phenylphosphorothioate 1,121 12.02 10.04 7.58 1.23 0.38 - O-ethyl-S-phenylethylphosphonodithioate 4.48 10.24 9.54 1.48 0.30 0.00 Clay soil - (control experiment) - 15.79 8.75 0.40 0.27 0.22 - 0,O-diethyl-O-phenylphosphorothioate 0.56 12.24 9.38 5.87 0.51 0.43 - 0,O-diethyl-O-phenylphosphorothioate 1,121 12.68 10.88 9.26 0.55 0.39 - O-ethyl-S-phenylethylphosphonodithioate 4.48 1-1.47 8.88 4.29 0.24 0.18 - (a! each number represents an average value of two samples.

(b) - means that the sample was not analyzed.

Table III

Results of soil persistence tests

Herbicide: 3-ethyldiisobutylthiocarbamate (active ingredient) mixed in a weight ratio of 24:1 with Ν,Ν-diallyldichloroacetamide (antidote)

Application rate: 6.72 kg/ha

Degree Amount of herbicide present in soil (ppm active ingredient) Number of weeks after application Organophosphorus additive application (kg/ha) 0 1 2 3 4 5

Sandy loam soil

- (control experiment) - 9.00 7.30 6.15 3.35 0.68 0.30 0,0-diethyl-0-phenylphosphorothioate 1,121 9.40 9.14 6.55 5.25 5.18 3.65 Alluvial soil - (control experiment) - 8.05 1.25 0.13 0.17 0.07 0.03 0,0-diethyl-0-phenylphosphorothioate 1,121 7.95 7.45 6.05 5.65 4.84 0.66 Clay soil - (control experiment) - 8.35 7.00 0.16 0.11 0.07 0.07 0,Q-diethyl-O-phenylphosphorothioate 1,121 8.35 7.10 4.90 2.11 1.18 0.37 (a) Each number is an average value of two measurement.

Example 2

Herbicide efficacy improvement trials

This example provides herbicidal efficacy data showing that organophosphorus additives enhance the herbicidal efficacy of thiocarbamates. The effect is monitored by comparing the extent of weed control in test dishes treated with thiocarbamate compared to similar dishes treated with both thiocarbamate and an organophosphorus compound.

As in Example 1, the thiocarbamates are used in the form of an emulsifiable liquid concentrate containing 0.72 kg/l of active ingredient. As indicated below, in several tests, an antidote is also included in the composition to prevent damage to crops. The organophosphorus compounds are used primarily in technical form, although in some cases, as indicated, they are used in the form of emulsifiable liquids, granules, and microcapsules.

Stock solutions are prepared by adding the appropriate amounts of the test chemicals to 100 ml of a mixture containing equal volumes of water and acetone. 5 ml of the stock solution is then added to 13.62 kg of soil containing approximately 5% moisture in a 18.9 L rotary mixer. The soil is mixed with the stock solution in the mixer for 10 to 20 seconds.

The soil is then placed in aluminum trays measuring 6.4 cm deep, 8.9 cm wide, and 19.0 cm long. The soil is tamped down and six furrows are marked along its length. Different plants are used as test weed plants in each test. In total, the following plants are used:

birch hedgehog chicken leg sorghum

Setaria lutescens (Wigel) Houbb, Echinochloa crusgalli (L.) Beauv, Sorghum bicolor (L.) Moench (milo) Barley Hordeum vulgare (L.) Barley Setaria faberi Herrm gi _ro ]t Sorghum bieolor (L.) Moench (wild cane)

In some of these trials, corn is also sown. The corn used is Zea mays CL.) De Kelb XL-45A.

Sufficient seeds are sown to produce several seedlings 2.5 cm long in each row. The trays are placed in a greenhouse maintained at 21 to 29.5°C. The trays are watered daily.

Three weeks after treatment, the degree of weed control and maize damage is estimated and recorded as a percentage control compared to the growth of the same species of plants of the same age in the control untreated dish. A scale of 0 to 100% is used, where 0% means no effect, i.e. plant growth is the same as that of the control plants in the untreated dish, and 100% means complete killing.

The results of the tests are summarized in the following tables. Each table contains a control comparative experiment. It is clear from all the tables that at all levels of application of the organophosphorus additive there is a significant improvement in the average percentage of weed control compared to the control experiment. All the experiments shown in each individual table are experiments carried out at the same time under the same conditions. However, there are variations between the individual tables because it is difficult to reproduce the same environmental conditions at different times of the year. Variations also occur because different combinations of weeds and/or soils were used. Overall, however, it is clear that the herbicidal effect of thiocarbamates three weeks after application is significantly better when organophosphorus compounds are used.

Table IV

Herbicidal effect on Hordeum Vulgare, Echinochloa orusgalli, Sorghum bieolor (milo) and í .«:,!··· ria faberi

Herbicide: S-ethyldi-n-propylthiocarbamate in the form of an emulsifiable liquid at a concentration of 0.72 kg/l containing, where indicated, Ν,Ν-diallyldichloroacetamide (p.nti·’' in a weight ratio of 12:1

Application rate: 3.36 kg/ha

Soil: clay

Evaluation period: 3 weeks after treatment Degree Without an antidote Organophosphorus application Average grade Damage Average grade Damage ingredient (kg/ha) weed control- corn suppression of the cuckoo? í. O very (%) (%) very (%) («)

- (control experiment) O-ethyl-S-phenylethyl- 0.56 65 92 0 60 58 95 0 0 phosphonodithioate 1.12 100 100 1 00 20 (4E) ^ís) 2.24 100 80 100 0 4.48 100 i 00 99 0 0-ethyl-S-phenylethyl- 0.56 97 90 78 0 phosphonodithioate 1.12 100 80 81 0 (100) ^(b) 2.24 100 30 88 0 4.48 100 90 99 10

continuation of table IV

Organophosphorus Application level Without an antidote Average grade Damage Average grade Damage ingredient (kg/ha) suppression of the corn suppression of the corn very (%) (%) very (%) (%)

O-ethyl-S-p-chloro- 0.56 8, 0 phenylethylphosphonodi- 1.12 90 20 thioate (4E) 2.24 100 75 4.48 100 80 O-ethyl-S-p-chlorofe- 0.56 66 0 nylethylphosphonodi- 1.12 84 0 thioate (10G) 2.24 82 30 4.48 96 60 0,O-diethyl-S-ethyl- 1.12 80 20 thioethylphosphorodi- 2.24 85 40 thioate (technical) 4.48 87 50 0,0-diethyl-0-p-me- ’.12 96 60 thylsulfnylfepylphos- 2.24 100 95 phorodithioate (those- 4.48 100 90 nicky) 0,0-diethyl-S-ethyl- 1.12 97 75 thioMethylphosphorodi- 2.24 98 90 thioate (technical) 4.48 98 80 0,0-dimethyl-0-p-ni- 1.12 98 70 triphenylphosphorodi- 2.24 95 70 thioate (technical) 4.48 100 90

(a) 4E: emulsifiable liquid containing 0.48 kg/l of active ingredient (b) 10G: granular formulation containing 10% by weight of active ingredient.

Application methods

The herbicidal compositions of the invention are suitable for suppressing the growth of undesirable vegetation and are applied pre-emergence or post-emergence to the site where suppression is to be achieved. Application can be made before sowing, after sowing into the soil or to the surface. The compositions are usually similar to conventional standard compositions that are easy to handle. Typical standard compositions contain additional additives or diluents and a carrier which are either inert or active. Examples of such additives or carriers include water, organic solvents, carriers for dusts, carriers for granulates, surfactants, oil-water mixtures, water-oil emulsions, wetting agents, dispersants and emulsifiers. Herbicidal compositions are usually in the form of dusts, emulsifiable concentrates, granules, pellets or microcapsules.

A. Poprae

Sprays are heavy, powdery products that are used in dry form. They are loose and settle quickly, so they are not blown by the wind to places where their presence is not desired. They contain primarily an active ingredient and a heavy, loose powdery carrier.

Their effect is sometimes increased by adding wetting agents and, for easier production, inert absorbent grinding aids are also added to them. For the dusts according to the invention, an inert carrier of either vegetable or mineral origin can be used. Anionic or nonionic substances are preferably used as wetting agents. Suitable absorbent grinding aids are substances of mineral origin.

Suitable inert solid carriers suitable for dusts are organic or inorganic powders which have a high bulk density and are very free-flowing. They are also characterised by a low specific surface area and low absorption capacity for liquids. Suitable grinding aids are natural clays, diatomaceous earth and synthetic mineral fillers derived from silica or silicates. Of the ionic and non-ionic wetting agents, the most suitable are those which are commonly referred to as wetting agents or emulsifiers.

Although solid surfactants are preferred due to their ease of handling, some liquid nonionic agents can also be used in the preparation of dusts.

Preferred carriers for dusts are micaceous talcs, pyrophyllite, heavy kaolin clays, tobacco powder, and ground calcium phosphate (mineral).

Preferred grinding additives are attapulgite, diatomaceous earth, synthetic fine silica, and synthetic calcium and magnesium silicates.

The most preferred wetting agents are alkylbenzene and alkylnaphthalene sulfonates, sulfated fatty alcohols, acid amines or amides, long chain sodium isothionate acid esters, sodium sulfosuccinate esters, sulfated or sulfonated fatty acid esters, petroleum sulfonates, sulfonated vegetable oils, and ditertiary acetylene glycols. Preferred dispersants are methylcellulose, polyvinyl alcohol, lignin sulfonates, polymeric alkylnaphthalene sulfonates, sodium naphthalene sulfonate, polymethylene naphthalene sulfonate, and sodium long chain alkanoyl N-methyl-N-alkanoyl taurate.

Inert solid carriers in the powders of the present invention are typically present in concentrations of from about 30 to 90% by weight, based on the total mixture. The grinding aid typically comprises from 5 to 50% by weight of the composition and the wetting agent typically comprises from about 0 to 1.0% by weight of the composition. The powders may also contain other surfactants such as dispersants in concentrations of up to about 0.5% by weight and minor amounts of anti-caking agents and antistatic agents. The particle size of the carrier is typically in the range of from 30 to 50 µm.

B. Emulsifiable concentrates

Emulsifiable concentrates are usually solutions of active ingredients in water-immiscible solvents mixed with an emulsifying agent. Before use, the concentrate is diluted with water to form an emulsion of solvent droplets.

Typical solvents for use in emulsifiable concentrates are oils, chlorinated hydrocarbons, and water-immiscible ethers, esters, and ketones.

Typical emulsifiers are anionic or nonionic surfactants or mixtures of the two. Examples include alkyl (long chain) or mercaptopolyethoxy alcohols, alkylarylpolyethoxy alcohols, fatty acid esters of sorbitan, polyoxyethylene ethers of fatty acid esters of sorbitan, polyoxyethylene glycol esters of fatty or resin acids, fatty alkylamide condensates, calcium and amine salts of fatty alcohol sulfates, oil-soluble petroleum sulfonates or preferably mixtures of these emulsifiers. These emulsifiers constitute about 1 to 10% by weight of the total mixture.

The emulsifiable concentrates of the invention contain about 15 to about 50% by weight of active ingredient, about 40 to 82% by weight of solvent and about 1 to 10% by weight of emulsifier. Other additives such as flow agents and adhesion promoters may also be present.

C. Granules and pellets

Granules and pellets are physically stable particulate formulations containing active ingredients that are attached to or dispersed in a matrix. The matrix consists of a coherent inert carrier of macroscopic dimensions. Typical particles are about 1 to 2 mm in diameter. Granules and pellets also often contain surfactants to facilitate the leaching of the active ingredients from the granules or pellets.

The carrier is preferably of mineral origin and usually one of the following two types of carriers is present. Carriers of the first type are porous spun granules with high absorption capacity, such as preformed attapulgite from which a suitable fraction has been separated on sieves or thermally expanded granular vermiculite from which a suitable fraction has been separated on sieves. A solution of the active ingredient can be sprayed onto each of these substances and the solution is absorbed into the carrier in an amount of up to 25% by weight, based on the total weight.

A second type of carrier, which is also suitable for pellets, is initially powdered kaolin clays, hydrated attapulgite or bentonite clays in the form of sodium, calcium or magnesium bentonites. Water-soluble salts, such as sodium salts, may also be present, which facilitate the disintegration of the granules or pellets in the presence of moisture. These components are mixed with the active ingredients to form mixtures which are granulated or pelletized and dried. The resulting compositions contain the active ingredient uniformly distributed throughout the mass. Such granules and pellets can also be produced with up to 25 to 30% by weight of the active ingredient, but more often a concentration of about 10% by weight is required for optimum distribution. The most preferred granulates according to the invention have a particle size in the range of 15 to 30 mesh.

The surfactant is usually a conventional surfactant of the anionic or nonionic type. Which surfactant is most suitable depends on the type of granules used. When the granulate is produced by spraying the active ingredient in liquid form onto pre-formed granules, the most suitable surfactants are nonionic liquid surfactants which are miscible with the solvent.

Such substances are commonly known as emulsifiers and include alkylaryl polyether alcohols, alkyl polyether alcohols, polyoxyethylene sorbitan fatty acid esters, polyethylene glycol fatty or resin acid esters, fatty alcohol amide condensates, oil-soluble petroleum or vegetable oil sulfonates or mixtures thereof. These substances usually constitute up to about 5% by weight of the total composition.

When the active ingredient is first mixed with a powdered carrier and then granulated or pelletized, liquid nonionic wetting agents may also be used, but it is usually preferred to add some of the solid powdered anionic wetting agents, such as those mentioned above in connection with wettable powders, at the time of mixing. These agents constitute about 0 to 2% by weight of the total composition.

Preferred granules or pellets according to the invention therefore contain 5 to 30% by weight of active ingredient, about 0 to 5% by weight of wetting agent and about 65 to 95% by weight of inert carrier.

D. Microcapsules

Microcapsules are formed by completely enclosed droplets or granules containing active substances. The capsule shell material forms an inert porous membrane which allows the release of the encapsulated substances into the surrounding environment at a controlled rate over a predetermined period of time. Microcapsules are a particularly suitable composition according to the invention because the organophosphorus compounds which form a component of the compositions according to the invention are liquid.

The encapsulated droplets typically have a diameter of about 1 to 50 µm. The encapsulated liquid typically

2J2282 constitutes about 50 to 95% by weight of the entire capsule and may contain a small amount of solvent in addition to the active ingredients.

Encapsulated granules are characterized by the fact that a porous membrane closes the pore openings of the granule carrier and thus seals the liquid containing the active ingredients inside the capsule. Its release then occurs in a controlled manner. The typical size of encapsulated granules is in the range of 1 mm to 1 cm. In agricultural practice, granules of about 1 to 2 mm in size are usually used.

Granules may be made by extrusion, agglomeration or granular materials in their natural form. Examples of carriers include vermiculite, sintered clay granules, kaolin, attapulgite, wood chips and granulated coal.

Suitable encapsulating materials include natural and synthetic rubbers, cellulosic materials, styrene-butadiene copolymers, polyacrylonitriles, polyacrylates, polyesters, polyamides, polyurethanes and starch xanthates.

E. General

Each of the compositions can be produced as a package containing both the thiocarbamate herbicide and the antidote and the organophosphorus additive together with other additives (diluents, emulsifiers, surfactants, etc.). The compositions can also be prepared directly at the application site. In this case, the components are transported to the application site in separate tanks. The herbicide, antidote and organophosphorus component can be in the form of compositions of the same type or of different types before the final mixing. For example, the herbicide and antidote can be in the form of microcapsules and the organophosphorus component in the form of an emulsifiable concentrate or vice versa.

Another alternative is to apply the herbicide, the antidote, and the organophosphate sequentially, with any one of these compounds being applied first. This method is less suitable, as better results are achieved with simultaneous application.

In general, any conventional method of application may be used. The site of application may be soil, seeds, seedlings or mature plants as well as an irrigated field. Soil application is preferred. Dusts and liquid compositions may be applied using dusting equipment, hand sprayers and aerosol generating devices. The compositions may also be applied from aircraft as dusts or sprays, as they are effective at very low rates. Dusts and liquid compositions are typically applied to the soil to modify or suppress the growth of germinating seeds or emerging seedlings.

After application by conventional methods, the compositions are distributed in the soil to a depth of at least 1.25 om below the surface. Phytotoxic compositions do not need to be pre-mixed with soil particles. Instead, the compositions may be applied to the soil surface directly by spraying or sprinkling. Phytotoxic compositions of the invention may also be applied by mixing them with irrigation water supplied to the field to be treated. This method allows the compositions to penetrate into the soil along with the absorbed water. Dusts, granules or liquid compositions applied to the soil surface may be introduced below the soil surface by conventional methods such as disking, shearing or mixing.

The herbicide, antidote and organophosphate adjuvant compositions of the invention can be applied to the soil via irrigation systems. In this method, the compositions are directly added to the irrigation water immediately prior to irrigating the field. This method can be used in all geographical areas regardless of rainfall, as it allows for the supplementation of natural precipitation during the critical period of plant growth. Typically, the concentration of the herbicide/adjuvant system composition in the irrigation water is in the range of about 10 to about 150 ppm by weight. The irrigation water can be applied via sprinkler systems, furrow irrigation or flooding. Such application is most effective prior to weed emergence, in early spring before emergence or within two days after field cultivation.

The compositions of the invention may also contain other additives, such as fertilizers, insecticides or other herbicides. Suitable pesticides are 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid and their salts, esters and amides, triazine derivatives such as 2,4-bis-(3-methoxypropylamino)-6-methylthio-s-triazine, 2-chloro-4-ethylamino-6-isopropylamino-s-triazine-2-ethylamino-4-isopropylamino-6-methylmercapto-s-triazine, urea derivatives such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea, acetamides such as N,N-diallyl-alpha-chloroacetaniide, N-(slfB-o,chloroacetyl)hexamethyleneimine and N,N-diethyl-alpha-bromoacetamide, and benzoic acids such as 3-amino-2,5-dichlorobenzoic acid.

Suitable fertilizers which can be used in conjunction with the active ingredients of the invention are ammonium nitrate, urea and superphosphate. Other useful additives are substances in which plant organisms take root and grow, such as compost, manure, humus, sand, etc.

The amount of the composition of the invention which constitutes a herbicidally effective amount depends on the type of seed or plant to be controlled. The rate of application of the active ingredient varies from about 0.01 to about 56 kg/ha, preferably from about 0.11 to about 28 kg/ha, the actual amount used depending on the overall cost and the desired results. It will be apparent to those skilled in the art that compositions which exhibit lower herbicidal activity must be used at higher rates than more effective compounds to achieve the same degree of control.

Claims (7)

SUBJECT OF THE INVENTION What is claimed is: 1. A herbicidal composition comprising a) a herbicidally effective amount of a thiokerbamate of the formula O ¹¹ rscn; Where R ¹ represents C 1 -C 6 alkyl, C 1 -C 6 alkenyl, C 1 -C 6 phenylalkyl, or phenyl, and each of these groups is optionally substituted with one, two or three halogen atoms and each of the symbols oi R 1 and R 2 are independently C 1 -C 6 alkyl or C 1 -C 6 cycloalkyl, or both together represent C 1 -C 6 alkyl; alkylene together with a non-phytotoxic antidotally effective amount of a compound of formula ^{G 1} n ^CH (3-n) O-R ° -ft-A where χχ represents 1 or 2 and each of the symbols R ⁸ and R ⁸ independently represent alkyl or C ₂ -C ₁₂ alkenyl or a group R ⁸ represents a group of the general formula R 1 1 wherein each of R ^G and R ¹ 'independently represent hydrogen or methyl and R ¹² represents hydrogen, C, -C ₄ alkyl or phenyl and (b) an organophosphoric compound of the general formula wherein R ⁴ represents C 8 -C 8 alkyl, C 8 -C 8 alkenyl, C 8 -C 8 alkynyl or C 8 -C 8 alkyl; cycloalkyl, each of which is optionally substituted with up to three substituents selected from the group consisting of halogens, cyano, C 1 -C 8 alkoxy and C 1 -C 8 alkylthio, R 1 represents C 1 -C ₄ alkyl, C 1 -C ₄ alkoxy or C 1 -C ₄ alkylthio, R 6 represents C 1 ^-C 6 alkyl, C 1 ^-C 6 or ^C 2 ^-C 4, each of which is optionally substituted with up to three substituents selected from the group consisting of halogens, nitro, cyano, Ο, -C 8 alkoxy and C 1-6 alkyl; -C 8 alkylthio, C 8 -C 8 alkylthio; cycloalkyl or a radical of formula - (R ⁷ ) _ffl -0 where R ⁷ represents a C, -C 4 alkyl, C 2 ^-C 4 ^{ell £ en-yl} or _C2-C4 alkynyl, each of those groups being optionally substituted with up to three substituents selected from halo and cyano, m. represents 0 or 1; and O represents phenyl optionally substituted with up to three substituents selected from the group consisting of halogens, trifluoromethyl, nitro, cyano, C 1 -C 8 alkoxy, C 1 -C 8 carbaloxy and C 1 -C 8 alkylsulfinyl, X represents oxygen or sulfur; and Y represents oxygen or sulfur, wherein the weight ratio of thiocarbamate to organophosphorus compound is 1: 1 to 15: 1. 2. A composition according to claim 1, characterized in that the thiocarbamate containing a thiocarbamate of the formula R · ^ ³ where R 'is a C, -Cg alkyl, Cg-Cg alkenyl, Cy-Cg phenylalkyl, or phenyl, each of these groups are optionally substituted with one, two or three halogen atoms and each of the symbols R ² and R ³ are independently C 1 -C 8 alkyl and C 8 -C 8 alkyl; cycloalkyl, or both together form a C 1-6 alkyl alkylene, and as organophosphorus compound it contains an organophosphorus compound of formula. R ⁴ C> S ^{x L 2} → ⁶ where R ⁴ represents C 1 -C 4 alkyl, R ^ is C ^ -C ^ alkyl, O, alkoxy or C -C alkylthio, R6 is phenyl, chlorophenyl, nitrophenyl, C ^ Cy-alkylsulfinylfenyl, Cy-C ^ Cg-phenylalkyl or -C ^{ell £ £} yl ^thioall .yl ^a X represents oxygen or sulfur. 3. The herbicidal composition of claim 1, wherein the thiocarhamate comprises a thiocarbamate of the formula R ¹ represents C 1 -C 8 alkyl, C 1 -C 8 alkenyl, C 1 -C 6 phenylalkyl, or phenyl, each of which is optionally substituted with one, two or three halogen atoms and each of the symbols 2 3 R and R independently represent C 1 -C 8 alkyl or C 8 -C 8 alkyl; cycloalkyl, or both together form C 1 -C 6 alkyl; alkylene and contains as organophosphorous compound O, O-diethyl O-phenylphosphorothioate. 4. The herbicidal composition of claim 1, wherein the thiocarbamate is S-ethyldi-n-propylthiocarbamate and the organophosphoric compound is O, O-phenylphosphorothioate. and 5. The herbicidal composition of claim 1, wherein the thiocarbamate is 5-ethyldiisobutylthiocarbamate and the organophosphorus compound is O, O-phenylphosphorothioate. 6. The herbicidal composition of claim 1, 2, 3, 4 or 5 wherein the weight ratio of thiocarbamate to organophosphoric compound is from 1: 1 to 15: 1. ' 7. The herbicidal composition of claims 1 to 6, wherein the antidote is N, N-diallyldiehlorecetamide.