the present invention also relates to an emulsifiable suspension concentrate composition of a herbicidal agent comprising an amino acid or imidazolinylpyridine carboxylic acid ( alone or in combination ) in a solid state suspended in a water immiscible liquid containing an anionic surfactant and an ethoxylated fatty acid surfactant and optionally containing an antifoam agent and a thickening or suspending agent . the herbicidal agent is usually sold in a concentrated form either as a solid or a liquid and , just prior to application , the concentrate is diluted with water , or water containing adjuvants , and sprayed on fields of soil and / or actively growing plants . solid concentrate formulations , such as granulars , wettable powders and dusts , may also be used . since not all solid concentrate formulations of the free acid form of herbicidal agents , such as n - phosphonomethylglycine , exhibit the same high magnitude of efficacy and further since certain highly effective herbicidal compounds , such as n - phosphonomethylglycine and imidazolinylnicotinic acids , are relatively insoluble in water and conventional organic solvents , they are not readily amenable to commercial formulation . chemical modification of said compounds to give the corresponding salts is required to improve their solubility characteristics . surprisingly , it has been found that compounds , such as amino acids and imidazolinylnicotinic acids , may be formulated as liquid concentrates without further chemical modifications of said compounds and with a high degree of retention of efficacy . the emulsifiable suspension concentrate compositions of the present invention are comprised of about 10 % to 50 % of a herbicidal agent , such as n - phosphonomethylglycine or an imidazolinylnicotinic acid , alone or in combination , suspended in about 29 % to 84 % of a non - paraffinic aromatic solvent mixture having a distillation range of 118 ° to 305 ° c . containing about 3 % to 10 % of an anionic surfactant , about 3 % to 10 % of an ethoxylated fatty acid surfactant , 0 to about 0 . 10 % of an antifoam agent and 0 to about 2 . 0 % of a suspending or thickening agent . one preferred composition comprises about 30 % to 50 % of an active herbicidal agent or combination of agents , about 40 % to 57 % of a non - paraffinic aromatic solvent mixture having a distillation range of 118 ° to 305 ° c ., about 5 . 0 % to 7 . 0 % of an anionic surfacant , about 5 . 0 % to 7 . 0 % of an ethoxylated fatty acid surfactant , about 0 . 02 % to 0 . 15 % of an antifoam agent and 0 . 5 to 2 % of a suspending agent . among the herbicidal agents suitable for use in the compositions of the invention are amino acids such as glyphosate and imidazolinylpyridine carboxylic acids such as imazapyr and combinations thereof . a preferred herbicidal agent is glyphosate , alone or in combination with an imidazolinylnicotinic acid . solvents suitable for use in the compositions of the invention include heavy aromatic solvent mixtures having a distillation range of 118 ° to 305 ° c . preferred solvents include those mixtures of aromatics having a distillation range of about 183 ° to 285 ° c ., and the most preferred aromatic solvent mixtures is that which distills in a range of about 225 ° to 280 ° c . anionic surfactants suitable for use in the present invention include alkylarylsulfonic acids such as c 8 - c 18 alkylbenzenesulfonic acid , with dodecylbenzenesulfonic acid being the preferred anionic surfactant . among the ethoxylated fatty acid surfactants which may be employed are ethoxylated castor oils with about 15 - 60 ethylene oxide units per molecule . preferred ethoxylated castor oils are those which have about 36 - 40 ethylene oxide units per molecule . suitable antifoam agents include silicone polymers containing silica such as dimethylsilicone polymer plus silica , and suitable suspending or thickening agents include hydrated fumed silica or attapulgite clays or amine treated attapulgite clays . the herbicidal emulsifiable suspension concentrate compositions may be prepared by dissolving an anionic surfactant in an aromatic solvent and adding a solid herbicidal agent or combination of agents , with vigorous agitation to form a suspension . this suspension is milled to the required particle size distribution . a median particle diameter of 1 - 2 microns provides suitable physical properties . the milled suspension is treated with an ethoxylated fatty acid surfactant and , optionally , an antifoam agent and a suspending or thickening agent and mixed thoroughly . alternatively , the herbicidal agent is milled as a dry powder and is added to a solution of the anionic surfactant in the aromatic solvent with vigorous agitation to ensure complete dispersion and the remaining components are added with stirring . the above - prepared emulsifiable suspension concentrate compositions are physically stable and demonstrate excellent dilution properties in hard and soft waters to produce a sprayable herbicidal emulsion . in practice , it is generally preferable to dilute the compositions of the invention in water containing about 0 . 25 % of an adjuvant such as a polyoxyethylene sorbitan laurate surfactant to obtain an especially high degree of herbicidal activity . in order to facilitate a further understanding of the invention , the following examples are presented primarily for the purpose of illustrating certain more specific details thereof . the invention is not to be deemed limited thereby except as defined in the claims . unless otherwise noted , all parts are by weight . ______________________________________component % ______________________________________n - phosphonomethylglycine 41 . 90dodecylbenzenesulfonic acid 6 . 00ethoxylated castor oil , 36 c .. sup . 1 6 . 00dimethylsilicone polymer with silica . sup . 2 0 . 10mixture of aromatic hydrocarbons with 46 . 00a distillation range of 226 °- 279 ° c .. sup . 3 100 . 00______________________________________ . sup . 1 36 units of ethylene oxide per molecule flomo ® 36 c ., manufactured by desoto . sup . 2 th 100ind ® antifoam , manufactured by thompsonhayward . sup . 3 aromatic 200 °, manufactured by exxon an anionic surfactant , dodecylbenzenesulfonic acid , is dissolved in a water immiscible solvent , aromatic 200 ®, with stirring . this solution is treated with the herbicidal agent , n - phosphonomethylglycine , in a crystalline or powder state with vigorous stirring to give a dispersion . the resultant dispersion is milled until a median particle size of 1 - 2 microns is obtained . the milled dispersion is treated with an ethoxylated fatty acid surfactant , castor oil , 36c 1 , and an antifoam agent , dimethylsilicone polymer with silica 2 and mixed thoroughly . the herbicidal agent , n - phosphonomethylglycine , is milled to give a median particle size of 1 - 2 microns and then added to a solution of an anionic surfactant , dodecylbenzenesulfonic acid in a water immiscible solvent , aromatic 200 ®, with vigorous agitation . the resultant dispersion is treated with an ethoxylated fatty acid surfactant , castor oil , 36c 1 , and an antifoam agent , dimethylsilicone polymer plus silica 2 , and mixed thoroughly . the physical characteristics of the above - described n - phosphonomethylglycine emulsifiable concentrate composition are shown below . ______________________________________viscosity ( brookfield lvt at 22 ° c . 500 - 600 cpspindle # 2 , speed 30 rpm ) density at 20 ° c . 1 . 41 g / mlparticle size ( horiba capa 700 ) 1 . 21 microns ( median ) ph , 2 % diluted in deionized water 2 . 0 - 2 . 4dispersibility in water ( in both good emulsifica - standard hard and soft waters ), tion , no oil sep - 2 . 5 g in 100 ml total volume . aration after 24 hours . ______________________________________ ______________________________________components a b______________________________________imazethapyr -- 33 . 3imazapyr 33 . 33 -- dodecylbenzenesulfonic acid 5 . 00 5 . 00ethoxylated castor oil , 36 c .. sup . 1 5 . 00 5 . 00dimethylsilicone polymer with 0 . 03 0 . 03silica . sup . 2mixture of aromatic hydrocarbons 56 . 64 56 . 64with a distillation range of226 °- 279 ° c . 100 . 00 100 . 00______________________________________ . sup . 1 36 units of ethylene oxide per molecule flomo ® 36 c ., manufactured by desoto . sup . 2 th ind30 ® antifoam , manufactured by thompsonhayward . sup . 3 aromatic 200 ®, manufactured by exxon the herbicidal agent , as a finely divided powder , is added to a rapidly stirred solution of the anionic surfactant , dodecylbenzenesulfonic acid , in the aromatic solvent , aromatic 200 ®. the resultant dispersion is treated with the remaining components and placed on a high shear mixer for 3 minutes . optionally the solid herbicidal agent is milled to a median particle size of 1 - 2 microns prior to use in the above - described preparation . ______________________________________physical properties a b______________________________________dispersibility in water , good emulsi - good emulsi - 4 . 0 g in 100 ml total fication , fication , volume . slight settl - slight settl - ing after 24 ing after 24 hours , easily hours , easily resuspended resuspended______________________________________ ______________________________________preparation of combination emulsifiable suspension con - centrate compositionscomponents c d______________________________________glyphosate 37 . 69 32 . 89imazapyr 4 . 20 9 . 00dodecylbenezenesulfonic acid 6 . 00 6 . 00flomo ® 36 c .. sup . 1 6 . 00 6 . 00th 100ind ® antifoam . sup . 1 0 . 10 0 . 10aromatic 200 ®. sup . 1 46 . 01 46 . 01 100 . 00 100 . 00______________________________________ . sup . 1 as described in example 1 . a solution of dodecylbenzene in aromatic 200 ® is treated with glyphosate with rapid stirring . the resultant dispersion is treated with the remaining components and placed on a high shear mixer for 3 minutes . optionally , a dispersion of glyphosate and the imidazolinylnicotinic acid solid in a solution of dodecylbenzenesulfonic acid in aromatic 200 ® is milled to give a median particle size of 1 - 2 microns prior to the addition of the remaining components . ______________________________________physical properties c d______________________________________dispersibility in water , good emulsi - good emulsi - 4 . 0 g in 100 ml total fication , fication , volume . slight oil slight oil separation separation after 24 after 24 hours , easily hours , easily resuspended resuspended______________________________________ this is an evaluation of the postemergent herbicidal activity of the emulsifiable suspension concentrate composition of n - phosphonomethylglycine as compared to a commercial aqueous solution composition of the isopropylammonium salt of n - phosphonomethylglycine . the test compositions used for this evaluation are the emulsifiable suspension concentrate composition of n - phosphonomethylglycine which is described in example 1 and referred to herein as glyphosate 40 esc and an aqueous soluble composition of the isopropylammonium salt of n - phosphonomethylglycine which is commercially sold by monsanto under the trademark roundup ® and referred to herein as glyphosate salt . seedling plants are grown in jiffy flats for about 2 weeks . the glyphosate 40 esc composition is dispersed in water containing 0 . 25 % tween - 20 ®, a polyoxyethylene sorbitan monolaurate surfactant manufactured by atlas chemical industries in sufficient quantity to provide the equivalent of about 0 . 063 kg to 0 . 500 kg per hectare of n - phosphonomethylglycine to the plants when applied through a spray nozzle operating at 40 psi for a predetermined time . the glysphosate salt is dispersed in water according to the label directions and applied to the plants as described above . after spraying , the plants are placed on greenhouse benches and cared for in the usual manner commensurate with conventional greenhouse practices . the plants are evaluated at 7 and 14 days after treatment and rated according to the rating system shown below . ______________________________________rating system % control______________________________________no effect 0possible effect 1 - 10slight effect 11 - 25moderate effect 26 - 40definite injury 41 - 60herbicidal effect 61 - 75good herbicidal effect 76 - 90approaching complete kill 91 - 99complete kill 100______________________________________ ______________________________________plant species usedcommon name scientific name______________________________________mustard wild brassica kabercotton gossypium hirsustumcorn zea maysmorningglory ipomoea purpureasoybean glycine maxbarnyard grass echinochloa crus - gallilambsquaters chenopidium albumragweed ambrosia artemisifoliagreen foxtail setaria veridis______________________________________ the data obtained at 14 days after treatment are reported in table i below . table i__________________________________________________________________________postemergence herbicidal evaluation grn rate must cot field morn soy barn lambs rag foxcomposition ( ka / ha ) ard ton corn glry bean yardg quart weed tail__________________________________________________________________________glyphosate salt 0 . 500 80 . 0 80 . 0 90 . 0 66 . 7 78 . 3 98 . 7 99 . 3 38 . 3 100 . 0glyphosate esc 0 . 500 60 . 0 50 . 0 95 . 0 71 . 7 80 . 0 94 . 3 96 . 3 40 . 0 91 . 7glyphosate salt 0 . 250 38 . 3 35 . 0 58 . 3 63 . 3 63 . 3 71 . 0 83 . 3 33 . 3 85 . 0glyphosate esc 0 . 250 33 . 3 40 . 0 85 . 3 75 . 3 71 . 7 78 . 3 100 . 0 53 . 3 93 . 3glyphosate salt 0 . 125 13 . 3 20 . 0 18 . 3 30 . 0 20 . 0 23 . 3 61 . 7 6 . 7 46 . 7glyphosate esc 0 . 125 26 . 7 3 . 3 71 . 7 30 . 0 50 . 0 48 . 3 83 . 3 23 . 3 81 . 7glyphosate salt 0 . 063 0 . 0 3 . 3 3 . 3 15 . 0 6 . 7 16 . 7 36 . 7 0 . 0 20 . 0glyphosate esc 0 . 063 6 . 7 0 . 0 61 . 7 10 . 0 20 . 0 35 . 0 70 . 0 13 . 3 40 . 0__________________________________________________________________________ the test compositions used are glyphosate 40 esc and glyphosate salt , and are as described in example 4 . a field containing established , actively growing plants is divided into plots of 10 meters × 30 meters and is sprayed with a tractor mounted compressed air sprayer with a delivery of 200 liters per hectare . the glyphosate 40 esc composition is dispersed in water containing 0 . 25 % tween - 20 ® in sufficient quantity to provide the equivalent of 2 . 0 kg to 0 . 5 kg per hectare to the plants . glyphosate salt is dispersed in water according to the label directions and applied to the plants as described hereinabove . the plots are evaluated at 7 and 14 days after treatment . each treatment is replicated once . the data obtained for 14 days after treatment is reported in table ii . ______________________________________plant speciescommon name scientific name______________________________________redroot pigweed amoranthus retroflexuscommon lambsquarters chenopodium albumcommon purslore portulara oleraceacommon ragweed ambrosia artemisiifolalarge crabgrass digitaria sanguiralisfall panicum panicum diclotomiflorumbarnyard grass echirochloa curs - gallifoxtail millet setaria italica______________________________________ table ii__________________________________________________________________________postemergence field evaluation red root fox rate pig lambs rag crab fall bard tailcomposition kg / ha weed quart weed gras pani yardq millet__________________________________________________________________________glyphosate salt 0 . 5 100 80 98 100 95 100 100glyphosate esc 0 . 5 100 100 85 100 98 100 100glyphosate salt 1 . 0 100 100 100 100 100 100 100glyphosate esc 1 . 0 100 100 100 100 100 100 100glyphosate salt 2 . 0 100 100 100 100 100 100 100glyphosate esc 2 . 0 100 100 100 100 100 100 100__________________________________________________________________________
there are provided compositions comprising a concentrated amount of an herbicidally active agent , or combination of agents , in a solid state suspended in a water immiscible solvent containing an anionic surfactant and a nonionic surfactant and optionally containing an antifoam agent and a suspending or thickening agent . upon dilution with hard or soft water , said compositions readily form sprayable herbicidal emulsions .