the fatty adds used according to the subject invention can be unsubstituted , or substituted , saturated , or unsaturated , acids ( or their salts ), of about c7 to about c20 . specifically exemplified are fatty acids of length c7 to c11 , as typified by , but not limited to , decanoic acid or nonanoic acid . the fatty acid component of the subject invention may be a single fatty acid or a mixture of two or more fatty acids . a variety of different chemical herbicides can be used alone or in combination according to the subject invention . the specific herbicides which should be used for a given application can be readily ascertained by a person skilled in the art . following is a list of herbicides which may be used according to the subject invention . ______________________________________chemical herbicide families and examplesherbicide example______________________________________1 . phenoxy acids ( acids , esters , salts ) 2 , 4 - d , mcpa , dichlorprop2 . benzoic acid dicamba3 . aryloxy phenoxypropionate ( acids , fluazifop , dichlofop esters , salts ) 4 . sulfonyl ureas ( acids , esters ) chlorimuron , bensulfuron5 . imidazilinones imazethapyr6 . bipyridillium paraquat7 . diphenyl ether ( acids , salts ) acifluorfen , fomesafen8 . cyclohexanedione sethdoxydim , cycloxydim , clethodim9 . methane arsonate msma ( methylarsonic acid ) 10 . triazine atrazine , cyanazine11 . aliphatic carboxylic acids dalapon12 . benzonitrile bromoxynil13 . carbamate barban14 . thiocarbamate benthiocarb , triallate______________________________________ ______________________________________other chemical herbicides______________________________________pyrazon glyphosate pichloram metribuzinglufosinate clopyralid bentazon desmediphamquinclorac amitrole phenmedi - triclopyrethiozin pham______________________________________ herbicides other than those which are specifically listed above may also be used according to the subject invention . in one preferred embodiment of this invention , a fatty acid is combined with one or more systemic foliar herbicides with slow uptake characteristics . specifically , the compositions of the subject invention may advantageously comprise a herbicide from one of the following families : phenoxy acids , aryloxy phenoxypropionates , cyclohexanediones , sulfonyl ureas , and imidazilinones . of these families , imidazilinones and sulfonyl ureas are particularly advantageous . a further preferred embodiment is the use of a fatty acid with glyphosate . this combination has shown substantial synergy as described in the examples below . specific examples of the chemical herbicides which can be used together with the fatty acid in the composition of the subject invention include , but are not limited to , glyphosate ( n - phosphonomethyl ! glycine , isopropylamine salt ), imazapyr ( ±!,- 2 - 4 , 5 - dihydro - 4 - methyl - 4 - 1 - methylethyl !- 5 - oxo - 1h - imidazol - 2 - yl !- 3 - pyridinecarboxylic acid ), sethoxydim ( 2 - 1 - ethoxyimino ! butyl !- 5 - 2 - ethyl - thio ! propyl !- 3 - hydroxy - 2 - cyclohexen - 1 - one ), or paraquat ( 1 , 1 &# 39 ;- dimethyl - 4 , 4 &# 39 ;- bipyridinium dichloride ), used alone or optionally with agricultural adjuvants with which the herbicides are normally admixed . one embodiment of the present invention consists of the application of a tankmix of a fatty acid and chemical herbicide . a further embodiment contemplates sequential application of a fatty acid and a chemical herbicide . the process of the subject invention is illustrated in the examples which follow . these examples demonstrate the enhanced synergistic effects achieved through the use of sub - herbicidally effective application rates of the herbicide glyphosate in combination with the fatty acid , nonanoic acid . following are examples which illustrate procedures , including the best mode , for practicing the invention . these examples should not be construed as limiting . all percentages are by weight and all solvent mixture proportions are by volume unless otherwise noted . a greenhouse trial was carried out to demonstrate the enhanced herbicidal activity obtained following application of a combination of a fatty acid and a chemical herbicide . purple nutsedge was planted in 4 inch pots in soil - less potting mix ( promix ) and were cultivated in greenhouses that were maintained at daytime temperatures of 70 °- 90 ° f ., and which were watered by sub - irrigation every other day , until the plants attained the 8 true leaf stage . the fatty acid herbicide , nonanoic acid , was prepared by diluting the requisite amount of sharpshooter 80 % formulation with sufficient water to provide spray mixes which , when applied by a track sprayer at an application rate of 25 gallons per acre ( gpa ) would deliver the field equivalent of , respectively , 0 . 024 , 0 . 488 , 0 . 976 , and 1 . 952 pounds per acre ( lb / acre ) of the active ingredient . the herbicide glyphosate , was prepared by diluting the requisite amount of commercial roundup 4 l formulation with sufficient water to provide a spray mix which , when applied at an application rate of 25 gpa by a track sprayer , would deliver the field equivalent of 1 . 0 ( lb / acre ) of the active isopropyl amine salt . additional spray mixes were made up accordingly containing the respective fatty acid in descending order of concentration as set forth above , thus providing a series of dilutions of compositions containing both types of active ingredients in combination . purple nutsedge plants were treated with the aforedescribed spray mixes and appropriate untreated cheeks in treatment groups consisting of 12 plants each , with a total of 4 replications of a treatment within the test . following application of the spray mixes at a rate of 25 gpa , the plants were removed to the greenhouse and maintained under good growing conditions for the duration of the test period . herbicidal effects were assessed at the indicated days after treatment ( dat ) over a time period of 6 - 27 dat . the weed control ratings ascertained the extent of control , i . e . reduction in growth , obtained and scored on the basis of 0 to 100 where 100 represents kill of the plants and 0 represents no reduction in growth , as compared to the untreated check . the individual ratings on the four treatment replications were averaged to obtain the average percent control for each particular treatment . the results of these tests , indicating evaluations at 6 , 14 and 27 dat are indicated in table 1 . also shown in table 1 is the extent of control expected by a combination of herbicides , as based on their respective activities individually . this expected level of control was calculated according to the well known equation : ## equ1 ## where x =% control by the fatty acid alone and y =% control by the glyphosate alone ( colby , s . r . ( 1966 ) &# 34 ; calculating synergistic and antagonistic responses of herbicide combinations ,&# 34 ; weeds 15 : 20 - 22 ). table 1__________________________________________________________________________ control of 8 leaf nutsedge in a greenhouse trial days after treatment 6 14 27 percent incre - precent in - percent in - nonanoicglypho - approx wt . ratio , no - expect - actual ase over ex - expected actual crease over expect - actual crease overacid sate nanoic acid to glyph - ed con - control pected con - control control expected ed con - control expectedlb / acrelb / acre osate trol % % trol % % control trol % % control__________________________________________________________________________0 . 244 -- -- -- 0 -- -- 0 -- -- 0 -- 0 . 488 -- -- -- 0 -- -- 0 -- -- 0 -- 0 . 976 -- -- -- 0 -- -- 0 -- -- 5 -- 1 . 952 -- -- -- 0 -- -- 4 -- -- 8 ---- 1 . 0 -- -- 25 -- -- 83 -- -- 82 -- 0 . 2441 . 0 0 . 244 : 1 25 64 156 83 88 6 82 100 220 . 4881 . 0 0 . 488 : 1 25 56 124 83 93 12 82 100 220 . 9761 . 0 0 . 976 : 1 25 55 120 83 91 10 83 100 211 . 9521 . 0 1 . 952 : 1 25 74 196 84 96 15 83 100 20__________________________________________________________________________ additional greenhouse tests were performed to evaluate mixtures of fatty acids and herbicides on mature weeds and at reduced herbicidal rates . purple nutsedge was grown as described in example 1 except that it was allowed to reach the 11 leaf stage . spray mixes of sharpshooter 80 % were prepared to the same concentrations and by the same methods as described in example 1 . spray mixes of roundup 4 l were prepared by the methods described above , but at such a concentration that , when sprayed at an application rate of 25 gpa by a track sprayer , they would deliver the field equivalent of 0 . 5 ( lb / acre ) of the active isopropyl amine salt . additional spray mixes were made up accordingly containing the respective fatty acid in descending order of concentration as set forth above together with glyphosate at the concentration set forth above , thus providing a series of dilutions of compositions containing both types of active ingredients in combination . purple nutsedge plants were treated with the aforedescribed spray mixes and appropriate untreated checks in treatment groups consisting of 12 plants each , with a total of 3 replications of a treatment within the test . following application of the spray mixes at a rate of 25 gpa , the plants were removed to the greenhouse and maintained under good growing conditions for the duration of the test period . herbicidal effects were assessed as percent control in the manner described above at 21 and 56 dat . the individual ratings on the three treatment replications were averaged to obtain the average percent control for each particular treatment . the results of these tests are indicated in table 2 . also shown in table 2 is the extent of control expected by a combination of herbicides , as calculated in the manner described above . table 2__________________________________________________________________________ control of 11 leaf nutsedge in a greenhouse trial days after treatment 21 56 percent in - percent in - nonanoicglypho - approx wt . ratio , expect - actual crease over expected actual crease overacid sate nonanoic acid ed con - control expected control control expectedlb / acrelb / ac to glyphosate trol % % control % % control__________________________________________________________________________0 . 244 -- -- -- 1 -- -- 9 -- 0 . 488 -- -- -- 0 -- -- 10 -- 0 . 976 -- -- -- 1 -- -- 13 -- 1 . 952 -- -- -- 3 -- -- 9 ---- 0 . 5 -- -- 38 -- -- 85 -- 0 . 2440 . 5 0 . 488 : 1 39 71 84 86 100 160 . 4880 . 5 0 . 976 : 1 38 76 100 87 96 110 . 9760 . 5 1 . 952 : 1 39 73 89 87 98 131 . 9520 . 5 3 . 904 : 1 40 60 51 86 90 4__________________________________________________________________________ a series of field tests were performed to show the effect of fatty acids in combination with chemical herbicides on mature purple nutsedge and sicklepod . purple nutsedge and sicklepod were grown to the 8 leaf and 6 leaf stage , respectively , in field plots approximately 16 . 5 square feet in area . spray mixes of the fatty acid herbicide , nonanoic acid , was prepared by diluting the requisite amount of sharpshooter 80 % formulation with sufficient water to provide spray mixes which , when applied by a gas - pressurized backpack sprayer at an application rate of 10 gallons per acre ( gpa ) would deliver to the field 0 . 975 , 1 . 950 and 2 . 925 pounds per acre ( lb / acre ) of the active ingredient . the herbicide glyphosate was prepared by diluting the requisite amount of commercial rodeo ( 5 . 4 l ) formulation with sufficient water to provide a spray mix which , when applied at an application rate of 10 gpa , would deliver to the field 0 . 5 , 1 . 0 and 1 . 5 lb / acre of the active isopropyl amine salt . to all glyphosate spray mixes was admixed the surfactant x - 77 ( union carbide ) at a final concentration of 0 . 25 % ( v / v ) in the solutions , as recommended by the manufacturer . additional spray takes were made up accordingly containing the respective fatty acid in descending order of concentration as set forth above , thus providing a series of dilutions of compositions containing both types of active ingredients in combination . the spray mixes , and appropriate checks , were applied to the field plots in a randomized complete block design with 3 replications per treatment . the plants received overhead irrigation every other day during the duration of the experiment . the herbicidal effect of the spray mixes on purple nutsedge , measured as described in example 1 above , including the expected control of the combinations , 17 dat are recorded in table 3 . also recorded are the effects on sicklepod 10 dat . table 3__________________________________________________________________________ control of nutsedge and sicklepod in a field trial 8 leaf nutsedge 6 leaf sicklepod 17 days after treatment 10 days after treatment percent in - percent in - nonanoicglypho - approx wt . ratio , expect - actual crease over expected actual crease overacid sate nonanoic acid ed con - control expected control control expectedlb / aclb / ac to glyphosate trol % % control % % control__________________________________________________________________________0 . 975 -- -- -- 0 -- -- 0 -- 1 . 950 -- -- -- 0 -- -- 3 -- 2 . 925 -- -- -- 0 -- -- 5 ---- 0 . 5 -- -- 57 -- -- 23 ---- 1 . 0 -- -- 70 -- -- 37 ---- 1 . 5 -- -- 77 -- -- 40 -- 0 . 9750 . 5 1 . 95 : 1 57 67 18 23 37 850 . 9751 . 0 0 . 975 : 1 70 85 21 37 77 1080 . 9751 . 5 0 . 65 : 1 77 85 10 40 93 1511 . 9500 . 5 3 . 9 : 1 57 67 18 37 27 211 . 9501 . 0 1 . 95 : 1 70 85 21 39 77 981 . 9501 . 5 1 . 3 : 1 77 88 14 40 98 1522 . 9250 . 5 5 . 85 : 1 57 57 0 40 33 neg . 2 . 9251 . 0 2 . 925 : 1 70 87 24 42 83 982 . 9251 . 5 1 . 95 : 1 77 83 8 43 98 128__________________________________________________________________________ the effect of a combination of nonanoic acid and glyphosate on 5 species of plants grown under field conditions was determined . the five plant species , and their growth stage at the time of treatment , were : velvetleaf ( 3 leaf ), corn ( 4 leaf ), barnyardgrass ( 4 leaf ), sicklepod ( 3 leaf ), and nutsedge ( 2 - 3 leaf ). spray mixes of nonanoic acid were prepared by diluting the requisite amount of sharpshooter 80 % formulation with sufficient water to provide spray mixes which , when applied by a pressurized backpack sprayer at an application rate of 25 gpa would deliver to the field 1 . 95 lb / acre of the active ingredient . the herbicide glyphosate was prepared by diluting the requisite amount of commercial rodeo ( 5 . 4 l ) formulation with sufficient water to provide a spray mix which , when applied at an application rate of 25 gpa , would deliver to the field 0 . 169 , 0 . 338 and 0 . 675 lb / acre of the active isopropyl amine salt . additional spray mixes were made up accordingly containing the glyphosate in descending order of concentration as set forth above together with nonanoic acid at the concentration set forth above , thus providing a series of dilutions of composition containing both types of active ingredients in combination . the spray solutions were applied to a field plot approximately 16 . 5 square feet in area ; there were 2 replications per treatment . herbicidal effect was assessed as described in example 1 . the results on purple nutsedge and sicklepod at 14 and 28 dat are tabulated in tables 4 and 5 , respectively , along with expected values of the combinations calculated according to the method described in example 1 . the results on velvetleaf , corn and barnyardgrass at one rate of the combination are tabulated in table 6 . table 4__________________________________________________________________________ control of nutsedge in a field trial 14 days after treatment 28 days after treatment percent in - percent in - glypho - nonanoic approx wt . ratio , expect - actual crease over expected actual crease oversate acid nonanoic acid ed con - control expected control control expectedlb / aclb / ac to glyphosate trol % % control % % control__________________________________________________________________________0 . 169 -- -- -- 0 -- -- 0 -- 0 . 338 -- -- -- 13 -- -- 0 -- 0 . 675 -- -- -- 28 -- -- 0 ---- 1 . 95 -- -- 0 -- 0 0 -- 0 . 1691 . 95 0 . 087 : 1 0 20 ∞ 0 35 ∞ 0 . 3381 . 95 0 . 173 : 1 13 33 154 0 45 ∞ 0 . 6751 . 95 0 . 346 : 1 28 50 79 0 70 ∞ __________________________________________________________________________ table 5__________________________________________________________________________ control of sicklepod in a field trial 14 days after treatment 28 days after treatment percent in - percent in - glypho - nonanoic approx wt . ratio , expect - actual crease over expected actual crease oversate acid nonanoic acid ed con - control expected control control expectedlb / aclb / ac to glyphosate trol % % control % % control__________________________________________________________________________0 . 169 -- -- -- 0 -- -- 5 -- 0 . 338 -- -- -- 13 -- -- 12 -- 0 . 675 -- -- -- 18 -- -- 15 ---- 1 . 95 -- -- 10 -- -- 10 -- 0 . 1691 . 95 0 . 087 : 1 10 30 200 15 30 1070 . 3381 . 95 0 . 173 : 1 22 30 38 21 45 1160 . 6751 . 95 0 . 346 : 1 26 45 72 24 55 134__________________________________________________________________________ table 6__________________________________________________________________________ control of velvetleaf , corn & amp ; barnyardgrass in a field trial 14 days after treatment velvetleaf corn barnyardgrass approx . wt . percent in - percent in - percent in - ratio , nonanoic expect - actual crease over expected actual crease over expect - actual crease overglyphosate nonanoic acid to glyph - ed con - control expected con - control control expected ed con - control expectedlb / ac acid lb / ac osate trol % % trol % % control trol % % control__________________________________________________________________________0 . 169 -- -- -- 3 -- -- 10 -- -- 13 ---- 1 . 95 -- -- 20 -- -- 25 -- -- 18 -- 0 . 169 1 . 95 0 . 087 : 1 22 85 279 33 80 146 29 70 144__________________________________________________________________________ a field study examined the effect of application of a mixture of nonanoic acid and glyphosate on control of common oats . common oats were grown to the 5 leaf stage in field plots of approximately 80 square feet area . nonanoic acid was prepared in a similar manner as described above to yield spray mixes that would deliver to the field , when applied at a rate of 20 gpa , 0 . 975 , 1 . 95 and 3 . 9 lb / acre of the active ingredient . glyphosate was prepared by diluting the requisite amount of the lawn and garden ( 1 . 6 l ) formulation with water to obtain a spray mix which , when applied at a rate of 20 gpa , would deliver to the field 0 . 10 and 0 . 20 lb / acre of isopropylamine salt of the active ingredient . additional spray mixes were made up accordingly containing the glyphosate in descending order of concentration as set forth above together with nonanoic acid at the concentration set forth above , thus providing a series of dilutions of compositions containing both types of active ingredients in combination . the spray mixes , along with the appropriate checks , were applied to the plants with 3 replications of each treatment . the herbicidal effects 14 dat were determined as described in example 1 and are recorded in table 7 . table 7______________________________________ control of common oats 14 dat approx . wt . percentnon - ratio , increaseanoic glypho - nonanoic overacid lb / sate acid to expected % actual % expectedacre lb / acre glyphosate control control control______________________________________0 . 975 -- -- -- 0 -- 1 . 95 -- -- -- 0 -- 3 . 90 -- -- -- 0 ---- 0 . 10 -- -- 60 -- 0 . 975 0 . 10 9 . 75 : 1 60 78 301 . 95 0 . 10 19 . 5 : 1 60 85 423 . 90 0 . 10 39 . 0 : 1 60 94 57______________________________________ a field trial showing the effect of a mixture of nonanoic acid and glyphosate on control of quackgrass and vetch was performed . the field grown quackgrass and vetch were at 9 and 8 inches tall , respectively , at the time of application . nonanoic acid spray solutions were prepared as described previously to yield solutions which , when applied at a rate of 30 gpa , would deliver to the field 1 . 95 , 4 . 90 , 5 . 85 , and 7 . 80 lb / acre of the active ingredient . glyphosate spray solutions were prepared as in example 5 from the lawn and garden ( 1 . 6 l ) formulation to yield spray solutions which , when applied at a rate of 30 gpa , would deliver to the field 0 . 125 , 0 . 25 , and 0 . 50 lb / acre of the isopropylamine salt of the active ingredient . additional spray mixes were made up accordingly containing the glyphosate in descending order concentration as set forth above together with nonanoic acid at the concentration set forth above , thus providing a series of dilutions of compositions containing both types of active ingredients in combination . the spray mixtures were applied to field plots of approximately 80 square feet total area and each treatment was replicated 3 times . the herbicidal effects of the mixtures 20 dat on vetch , measured as described in example 1 , are recorded in table 8 . the herbicidal effect of the mixture at one combination of rates on quackgrass at times from 5 - 34 dat are recorded in table 9 . table 8______________________________________ control of vetch 20 dat approx . wt . percentnon - ratio , increaseanoic glypho - nonanoic overacid lb / sate acid to expected % actual % expectedacre lb / acre glyphosate control control control______________________________________1 . 95 -- -- -- 2 -- 3 . 90 -- -- -- 7 -- 5 . 85 -- -- -- 25 -- 7 . 80 -- -- -- 30 ---- 0 . 125 -- -- 10 ---- 0 . 25 -- -- 35 ---- 0 . 50 -- -- 47 -- 1 . 95 0 . 125 15 . 6 : 1 12 13 103 . 90 0 . 125 31 . 2 : 1 16 32 965 . 85 0 . 125 46 . 8 : 1 33 73 1257 . 80 0 . 125 62 . 4 : 1 37 83 1241 . 95 0 . 25 7 . 8 : 1 36 32 neg . 3 . 90 0 . 25 15 . 6 : 1 40 58 475 . 85 0 . 25 23 . 4 : 1 51 80 567 . 80 0 . 25 31 . 2 : 1 55 80 471 . 95 0 . 50 3 . 9 : 1 48 72 503 . 90 0 . 50 7 . 8 : 1 51 77 525 . 85 0 . 50 11 . 7 : 1 60 83 387 . 80 0 . 50 15 . 6 : 1 63 92 46______________________________________ table 9__________________________________________________________________________ control of quackgrass a field trial days after trestment 5 20 34 approx . wt . percent in - percent in - percent in - nonanoic ratio , nonanoic expect - actual crease over expected actual crease over expect - actual crease overacid lb / glyphosate acid to glyph - ed con - control expected con - control control expected ed con - control expectedacre lb / acre osate trol % % trol % % control trol % % control__________________________________________________________________________7 . 80 -- -- -- 17 -- -- 20 -- -- 0 ---- 0 . 125 -- -- 0 -- -- 10 -- -- 13 ---- 0 . 25 -- -- 0 -- -- 33 -- -- 60 ---- 0 . 50 -- -- 0 -- -- 87 -- -- 77 -- 7 . 80 0 . 125 62 . 4 : 1 17 38 124 28 82 193 13 57 3387 . 80 0 . 25 31 . 2 : 1 17 27 59 46 85 83 60 78 307 . 80 0 . 50 15 . 6 : 1 17 35 100 90 93 4 77 90 17__________________________________________________________________________ it should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and the scope of the appended claims .
described and claimed are methods and compositions for the control of unwanted vegetation . according to the subject invention , a fatty acid or mixture of fatty acids can be combined with one or more chemical herbicides to achieve synergistic control of a broad range of plants .