Abstract:
Cereal crops can be protected from damage caused by certain sulfonylurea herbicides by application of an antidotal compound selected from 1,8-naphthalic anhydride, α-(cyanomethoxyimino)benzacetonitrile, and N,N-diallyl-2,2-dichloroacetamide.

Description:
BACKGROUND OF THE INVENTION 
     The compounds 2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide, 2,5-dichloro-N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]benzenesulfonamide and 2-carbomethoxy-N-[(4,6-dimethylpyrimidin-2-yl)aminocarbonyl]benzenesulfonamide are known to be potent herbicides. These compounds and their herbicidal utility are disclosed, respectively, in U.S. Pat. No. 4,127,405, dated Nov. 28, 1978, U.S. Pat. No. 4,169,719, dated Oct. 2, 1979, and unexamined European Patent Application No. 7687, published Feb. 6, 1980. The disclosure of these two patents and of the patent application are hereby incorporated by reference. 
     It is often difficult to find herbicidal compounds which exhibit sufficient selectivity, that is, which will control weeds but which will not damage useful crop plants. In many cases, antidotes have been found which, when applied in combination with a particular herbicide, act to protect the useful crop plant from damage caused by the herbicide but which do not adversely affect the action of the herbicide on weeds. 
     U.S. Pat. No. 3,564,768, dated Feb. 23, 1971, discloses that 1,8-naphthalic anhydride can be applied to corn seeds to protect corn plants from damage caused by N,N-dialkylthiocarbamate ester preemergent herbicides. According to U.S. Pat. No. 3,749,566, dated July 31, 1973, 1,8-naphthalic anhydride is also useful for protecting rice from N,N-dialkylthiocarbamate ester herbicide damage. 
     U.S. Pat. No. 4,070,389, dated Jan. 24, 1978, discloses that α-(cyanomethoxyimino)benzacetonitrile protects crops from damage caused by triazine, phenylurea, carbamate, benzoic acid derivative and halogenphenoxyacetic acid herbicides. 
     U.S. Pat. No. 4,021,224, dated May 3, 1977, U.S. Pat. No. 4,124,376, dated Nov. 7, 1978, and U.S. Pat. No. 4,137,070, dated Jan. 30, 1979, disclose the use of N,N-diallyl-2,2-dichloroacetamide as an antidote for thiocarbamate and halo acetanilide herbicides. 
     SUMMARY OF THE INVENTION 
     It has now been found that cereal crops can be protected from injury due to an herbicidal compound selected from 2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide, 2,5-dichloro-N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-benzenesulfonamide and 2-carbomethoxy-N-[(4,6-dimethylpyrimidin-2-yl)aminocarbonyl]benzenesulfonamide by combining application of said herbicide to the locus of said crop plant with application of a non-phytotoxic antidotally effective amount of an antidotal compound selected from 1,8-naphthalic anhydride, N,N-diallyl-2,2-dichloroacetamide, and α-(cyanomethoxyimino)benzacetonitrile to the crop seed, to the crop plant or to the locus of the crop plant. Also included in this invention are herbicidal compositions comprising an herbicidally effective amount of one of the aforementioned herbicides and a non-phytotoxic antidotally effective amount of one of the aforementioned antidotes. 
     DETAILED DESCRIPTION 
     Crops which can be protected from injury as described herein include, cereal crops, for example, corn, wheat, rice and sorghum. Application of a non-phytotoxic antidotally effective amount of the antidotes described herein to the crop seed, to the crop plant or to the locus of the crop plant serves to protect the crop plant from damage caused by the herbicides described herein while not adversely affecting the action of the herbicide on desired weeds. 
     A number of methods are available for combining application of the herbicidal and antidotal compounds described herein. The herbicide and antidote may be applied preemergence (applied to the soil after planting, but before crop plants emerge), by preplant soil incorporation (applied to the soil and mixed into the soil before planting), or postemergence (applied to the emerged crop and/or weeds and on the exposed soil surface). Postemergence treatments may be directed so that the herbicide and/or antidote is applied primarily to the weeds or crop. The antidotes and herbicides may be applied either simultaneously or sequentially, with the antidote application either preceding or following the herbicide application. In addition, the antidote may be applied directly to the crop seed. The seeds may be uniformly coated with the antidote according to standard seed treating procedures prior to planting. Alternatively, the antidote may be applied over the exposed seed in open furrow at planting, just prior to covering the seed with soil (in-the-row treatment). 
     The ratio of antidote to herbicide used will vary, depending upon the specific antidote and herbicide used and on the method of application used. The crop species and cultural practices may also have an effect. For example, when the antidote is applied as a seed coating, it may be applied at a rate of about 0.1 to 0.5% of the seed weight. When the seeds are planted at from 10 to 150 kg/ha, the antidote would be distributed at from 0.01 to 0.75 kg/ha. In preemergence, preplant soil incorporation and postemergence treatments, the antidote may be applied at about 0.1 to 10 kg/ha. Similar rates may be used for in-the-row treatments; however, since only the furrow is treated, the lower per hectare rate would be diminished to as low as about 0.01 kg/ha, depending upon the row spacing. Since the herbicides may be used at rates of about 0.001 to 2 kg/ha, the ratio of antidote to herbicide may vary between 1:200 and 10,000:1. One skilled in the art could determine the proper ratio to use in a given situation. 
     In Examples 1 through 11, the crops were typically planted in a silt loam soil at a depth of about 1.5 cm. Spray treatments were applied in an acetone-water-surfactant carrier or, where the component was suitably formulated, in water at a volume rate of about 560 kg/ha. Seed treatments were dissolved or suspended in a carrier consisting of a dimethylformamide-acetone mixture (DMF:acetone, 1:10) which was then added to the seed in a glass container at 2.5 ml per grams of seed. The mixture was tumbled until seeds were uniformly covered and the side of the glass container was clear. Seeds were then aerated thoroughly before planting. Immediately after planting and treating in all but postemergence treatments, the test containers were given simulated rainfall of about 3 mm of water over a 90 minute period to activate the chemical treatments and to initiate crop germination. The tests were then held in the greenhouse under standard greenhouse care until evaluation after from three to seven weeks, depending on the test. Herbicide injury was rated on a scale of 0 to 10 in which 0 indicated no injury, 1 minimal injury and 10 indicated that the plants were dead. 
    
    
     In the following examples, the herbicidal and antidotal compounds are referred to by number as follows: 
     Ia--1,8-naphthalic anhydride 
     Ib--α-(cyanomethoxyimino)benzacetonitrile 
     Ic--N,N-diallyl-2,2-dichloroacetamide 
     IIa--2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzene sulfonamide 
     IIb--2,5-dichloro-N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]benzenesulfonamide 
     IIc--2-carbomethoxy-N-[(4,6-dimethylpyrimidin-2-yl)aminocarbonyl]benzenesulfonamide. 
     The following abbreviations are also used to indicate the various methods of treatment discussed above: 
     PRE--preemergence 
     PPI--preplant soil incorporation 
     POST--postemergence 
     SEED--seed coating 
     ROW--in-the-row treatment. 
     EXAMPLE 1 
     
         ______________________________________Corn Injury Rating(After 4 weeks)            Antidote            Herbicide        IaHerbicide   kg/ha    Application                      None   SEED-0.5% SW*______________________________________None    --       --        0      0IIa     .002     PRE       7      2   .004     PRE       7      3IIb     .25      PRE       5      2   .5       PRE       6      2EPTAM** 6        PPI       10     7.5______________________________________ *% SW = percent seed weight **EPTAM = Sethyl dipropylthiocarbamate 
    
     EXAMPLE 2 
     
         ______________________________________Wheat Injury Rating(After 7 Weeks)   Conc.    Antidote     in soil             IaHerbicide ppb        None     SEED-0.5% SW______________________________________None      --         0        0IIc       .25        0        0     .5         2        0     1.0        4**      0     1.5        6**      4*     2          6.5**    4**     3          6.5**    4.5**______________________________________ *partially headed out **not headed out (all other treatments headed out) 
    
     EXAMPLE 3 
     
         ______________________________________Crop Injury Rating(After 5 Weeks)      AntidotesHerbicide        Ia(2 kg/ha) Ic(0.5 kg/ha)PRE     kg/ha    None    ROW   PPI   ROW   PPI______________________________________CornNone    --       0       0     0     0     0IIa     0.062    9.5     8.5   8.2   8.0   8.2IIb     0.5      8.5     3.0   4.3   3.0   3.0SoybeansNone             0       0     0     0     0IIa     0.062    9       9     9     9     9IIb     0.5      9       9     9     9     9RiceNone             0       0     0     0     0IIa     0.062    9.5     9.5   8.8   8.0   7.5IIb     0.5      5       4.5   5     5.5   6.2______________________________________ 
    
     EXAMPLE 4 
     
         ______________________________________Corn Injury Rating(After 4 Weeks)  Antidotes        SEED      ROW        POSTkg/          (.5% SW)  (2 kg/ha)  (2 kg/ha)Herb. ha     None    Ia  IaK.sup.+                          Ia   IaK.sup.+                                     Ia   IaK.sup.+______________________________________PRENone  --     0       0   0     0    0     0    0IIa   0.031  10      7   7     8    10    10   10 0.125  10      7   7     9    10    10   10 0.5    10      8   8     10   10    10   10IIb   0.031  0       0   0     0    0     0    0 0.125  5       2   0     3    0     4    4 0.5    7       3   2     4    6     7    5POSTNone  --     0       0   0     0    0     0    0IIa   0.031  10      5   5     10   10    8    4 0.125  10      8   7     10   10    10   8 0.5    10      9   8     10   10    10   10IIb   0.031  0       0   0     0    0     0    0 0.125  2       0   0     3    3     0    0 0.5    5       2   2     4    4     2    0______________________________________ IaK.sup.+ = potassium salt of Ia 
    
     EXAMPLE 5 
     
         __________________________________________________________________________Corn Injury Rating(After 4 Weeks)        Antidotes            Ia          Ib            PPI SEED                    PRE PPI SEED                                PRE            2   0.5%                    2   0.5 0.25                                0.5Herb.   kg/ha        None            kg/ha                SW  kg/ha                        kg/ha                            SW  kg/ha__________________________________________________________________________PPINone    --   0   0   0   --  0   2   --IIb     0.125        3   2   2   --  3   4   --   0.25 4   3   2   --  2.5 3   --   0.5  4   4.5 3   --  3   3   --PRENone    --   0   0   0   0   0   0   0IIb     0.125        2   0   0   2   0   3   2   0.25 4   2.5 2.5 3   3   3   3   0.5  3.5 3   2.5 5   3   3   3EARLY POSTNone    --   0   0   0   --  0   0   --IIb     0.125        0   2   0   --  0   0   --   0.25 2   3   2   --  2   2   --   0.5  5   4   3   --  2   3   --LATE POSTNone    --   0   --  0   --  --  0   --IIb     0.125        0   --  0   --  --  3   --   0.25 5.5 --  0   --  --  0   --   0.5  0   --  0   --  --  0   --__________________________________________________________________________ 
    
     EXAMPLE 6 
     
         __________________________________________________________________________Corn Injury RatingAntidote Ia(After 3 Weeks)    Corn            Nutsedge        SEED            ROW POST    ROW POST        0.5%            2   2       2   2Herb.    kg/ha    None        SW  kg/ha                kg/ha                    None                        kg/ha                            kg/ha__________________________________________________________________________PRENone    --   0   0   0   0   0   0   0IIb .062 3.5 2.5 2   3.5 10  10  10    .25  8   4   5.5 7.5 10  10  10    1    8   5.5 6.5 8   10  10  10POSTNone    --   0   --  0   0   0   0   0IIb .016 0   --  0   0   6.5 7.5 8.5    .062 1   --  0   0   9   9   8    .25  2.5 --  2   2   9.5 9   9    1    7   --  5   5.5 10  10  10__________________________________________________________________________ 
    
     EXAMPLE 7 
     
         __________________________________________________________________________Corn Injury RatingAntidote Ic(After 3 Weeks)    Corn            Nutsedge        SEED            ROW POST    ROW POST        0.25%            0.5 0.5     0.5 0.5Herb.    kg/ha    None        SW  kg/ha                kg/ha                    None                        kg/ha                            kg/ha__________________________________________________________________________PRENone    --   0   0   0   0   0   0   0IIb .062 3.5 0   1   3.5 10  10  10    .25  8   2.5 3.5 7   10  10  10    1    8   5   4   7.5 10  10  10POSTNone    --   0   --  0   0   0   0   0IIb .016 0   --  0   0   6.5 6.5 7    .062 1   --  0   1   9   8   8.5    .25  2.5 --  2   2   9.5 8.5 10    1    7   --  3.5 4.5 10  10  10__________________________________________________________________________ 
    
     EXAMPLE 8 
     
         ______________________________________Corn Injury Rating(After 3 Weeks)Antidote-Post at Spike StageHerbicide                    Ia       IcPost-Spike Stage      kg/ha     None    2 kg/ha  0.5 kg/ha______________________________________None       --        0       0        0IIb        0.25      6       4.2      3      0.5       6.8     4.5      4.2      1.0       7.8     6.2      5.5______________________________________ 
    
     EXAMPLE 9 
     
         ______________________________________Crop Injury Rating(After 5 Weeks)      Antidote Ib                    Seed      Row   Post                    0.125%    2     0.5Herbicide    kg/ha   None    SW        kg/ha kg/ha______________________________________PRE                      (CORN)None     --      0       3         0     --IIa      0.062   9       7.5       8     --IIb      0.125   4       1         0     --                    (SORGHUM)None     --      0       0         0     --IIa      0.062   9.5     5.5       5.5   --IIb      0.125   0       0         0     --                    (SOYBEANS)None     --      0       0         0     --IIa      0.062   9       9         9     --IIb      0.125   9       9         9     --POST                     (WHEAT)None     --      0       0         0     0IIb      0.125   2.5     0         0     0                    (CORN)None     --      --      0         0     0IIb      0.125   2       0         0     2                    (SORGHUM)None     --      0       0         0     0IIb      0.125   2       0         1     2                    (SOYBEANS)None     --      0       0         0     0IIb      0.125   7       7         7     7______________________________________ 
    
     EXAMPLE 10 
     
         ______________________________________Wheat Injury Rating(After 4 Weeks)    Antidotes          SEED      ROW       POSTHerbi-         .5% SW    2 kg/ha   2 kg/hacide  kg/ha    None    Ia  IaK.sup.+                            Ia  IaK.sup.+                                      Ia  IaK.sup.+______________________________________PRENone  --       0       0   0     0   0     0   0IIa   0.031    0       0   0     0   0     0   0 0.125    3       0   0     0   0     0   0 0.5      7       4   4     5   5     6   7IIb   0.031    0       0   0     0   0     0   0 0.125    0       0   0     0   0     0   0 0.5      0       0   0     0   0     0   0POSTNone  --       0       0   0     0   0     0   0IIa   0.031    0       0   0     0   0     0   0 0.125    5       0   0     4   5     2   0 0.5      7       3   4     6   7     8   6IIb   0.031    0       0   0     0   0     0   0 0.125    0       0   0     0   0     0   0 0.5      0       0   0     0   0     0   0______________________________________ 
    
     EXAMPLE 11 
     Corn, variety Pioneer L3369, was planted in the field on Matapeake silt loam soil in rows about 60 cm apart with 15 cm between plants in the row. Antidotes and herbicides were applied postemergence when the corn was in the three leaf growth stage. For spraying, the treatment components were dissolved in 5% acetone to which 0.2% Tween-20 had been added. The acetone-Tween-20 solvent was sprayed on similar plots for comparison. 
     The response of corn to the treatments was evaluated 5 weeks after spraying by height measurements and by visual observations as recorded in the following table: 
     
         ______________________________________Injury Response(After 5 Weeks)      Antidote - Post           Ia     IaK.sup.+Herbicide                 0.5    0.3Post    kg/ha    None     kg/ha  kg/ha  1 kg/ha______________________________________None    --       0        0      0      0IIa     0.011    6.5      6.5    5.5    2.5IIb     0.2      5        3.5    3      2.5______________________________________ *IaK.sup.+ -- potassium salt of Ia. 
    
     EXAMPLE 12 
     Postemergent Weed Control With Herbicide - Antidote Combinations 
     Corn and common weed seeds were planted together in 7&#34; pots with Jiffy Mix (Jiffy Products of America, West Chicago, Ill.; a peat moss-vermiculite containing pot mix): gravel (sand blast #3) 50:50, in a growth room with 18 hour photo period, 75°-80° F. day and 70° F. night temperatures. The pots were watered with tap water for 1 to 2 weeks after planting and then with a modified Hoagland solution in the morning and water in the evening. Solutions of herbicide IIa and antidote Ia were prepared separately in AGWET-WGT (60:40)*. The postemergence herbicide treatment was made at two weeks after planting; the postemergent antidote treatment was made two days prior to the herbicide application. 
     
         ______________________________________      Rate of     Rate of      Herbicide   Antidote  Injury      IIa (POST)  Ia (POST) RatingPlant      lbs/acre    lbs/acre  (2 weeks)______________________________________Corn       0           0         0Corn       0.01        0         10Corn       0.01        5         3Morningglory      0.01        0         9Morningglory      0.01        5         9Sickle Pod 0.01        0         8Sickle Pod 0.01        5         8Velvetleaf 0.01        0         9Velvetleaf 0.01        5         9Indigo     0.01        0         9Indigo     0.01        5         9Foxtail    0.01        0         5Foxtail    0.01        5         4______________________________________ 
    
     The herbicides and antidotes described herein can be formulated in a number of ways: 
     (a) the antidote can be formulated for application directly to the crop seed; 
     (b) the antidote and herbicide may be formulated separately and applied separately or applied simultaneously in an appropriate weight ratio as a tank mix; or 
     (c) the antidote and herbicide may be formulated together in the proper weight ratio. 
     Procedures useful for formulating the herbicides and antidotes described herein are described in U.S. Pat. Nos. 4,127,405, 4,169,719, 3,564,768, 3,749,566, 4,070,389, 4,021,224, 4,124,376, 4,137,070 and 4,115,099, the disclosures of which are hereby incorporated by reference. The following examples are illustrative of the various formulation techniques which can be used. 
     EXAMPLE 13 
     Oil Suspension 
     1,8-naphthalic anhydride--25% 
     polyoxyethylene sorbitol hexaoleate--5% 
     highly aliphatic hydrocarbon oil--70% 
     The ingredients are ground together in a sand mill until the solid particles have been reduced to under about 5 microns. The resulting suspension may be applied directly, but preferably after being extended with oils or emulsified in water. 
     EXAMPLE 14 
     High Strength Concentrate 
     1,8-naphthalic anhydride--98.5% 
     silica aerogel--0.5% 
     synthetic amorphous fine silica--1.0% 
     The ingredients are blended and ground in a hammer mill to produce a high strength concentrate, essentially all passing a U.S. Ser. No. 50 sieve (0.3 mm openings). This material may then be formulated in a variety of ways. 
     EXAMPLE 15 
     Emulsifiable Concentrate 
     N,N-diallyl-2,2-dichloroacetamide--30% 
     blend of oil soluble sulfonates and polyoxyethylene ethers--4% 
     xylene--66% 
     The ingredients are combined and stirred with gentle warming to speed solution. A fine screen filter is included in the packaging operation to insure the absence of any extraneous undissolved material in the product. 
     EXAMPLE 16 
     Wettable Powder 
     1,8-naphthalic anhydride--40% 
     dioctyl sodium sulfosuccinate--1.5% 
     sodium ligninsulfonate--3% 
     low viscosity methyl cellulose--1.5% 
     attapulgite--54% 
     The ingredients are thoroughly blended, passed through an air mill to produce an average particle size under 15 microns, reblended, and sifted through a U.S. Ser. No. 50 sieve (0.3 mm opening) before packaging. 
     EXAMPLE 17 
     Wettable Powder 
     (a) 2,5-dichloro-N-[(4,6-dimethoxypyrimidin-2-yl)-aminocarbonyl]benzenesulfonamide--3% 
     (b) 1,8-naphthalic anhydride--50% 
     dioctyl sodium sufosuccinate--1.5% 
     sodium ligninsulfonate--3% 
     low viscosity methyl cellulose--1.5% 
     attapulgite--41% 
     The ingredients are thoroughly blended, passed through an air mill to produce an average particle size under 15 microns, reblended, and sifted through a U.S. Ser. No. 50 sieve (0.3 mm opening) before packaging. 
     EXAMPLE 18 
     Wettable Powder 
     (a) 2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide--2% 
     (b) 1,8-naphthalic anhydride--40% 
     sodium alkylnaphthalenesulfonate--2% 
     low viscosity methyl cellulose--2% 
     diatomaceous earth--54% 
     The ingredients are blended, coarsely hammer milled and then air milled to produce particles essentially all below 10 microns in diameter. The product is reblended before packaging. 
     EXAMPLE 19 
     Wettable Powder 
     2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-aminocarbonyl]benzenesulfonamide--80% 
     sodium alkylnaphthalenesulfonate--2% 
     sodium ligninsulfonate--2% 
     synthetic amorphous silica--3% 
     kaolinite--13% 
     The ingredients are blended and coarsely ground in a hammer mill to produce particles essentially all below 100 microns in size. The composition is then reblended, sifted through a U.S. Ser. No. 50 sieve (0.3 mm opening) and packaged. 
     EXAMPLE 20 
     Solution 
     N,N-diallyl-2,2-dichloroacetamide--20% 
     octylphenoxypolyethoxyethanol--5% 
     high boiling petroleum distillate--75% 
     The ingredients are combined and stirred to produce a solution which can be applied directly or after dilution with additional water. 
     EXAMPLE 21 
     Wettable Powder 
     2,5-dichloro-N-[(4,6-dimethoxypyrimidin-2-yl)-aminocarbonyl]benzenesulfonamide--50% 
     sodium alkylnaphthalenesulfonate--2% 
     low viscosity methyl cellulose--2% 
     diatomaceous earth--46% 
     The ingredients are blended, coarsely hammer milled and then air milled to produce particles essentially all below 10 microns in diameter. The product is reblended before packaging. 
     EXAMPLE 22 
     Wettable Powder of Example 16--40 parts 
     Wettable Powder of Example 19--1 part 
     A tank mix is made by adding these formulations in the proportions given to a stirred mixing tank containing enough water to give a convenient concentration for field application. The mixture can be sprayed using conventional spraying techniques. 
     EXAMPLE 23 
     Concentrate of Example 15--50 parts 
     Wettable Powder of Example 21--1 part 
     A tank mix is made by adding these formulations in the proportions given to a stirred mixing tank containing sufficient water to give a convenient tank concentration for the use intended. The mixture can be sprayed using conventional spraying techniques. 
     EXAMPLE 24 
     Slurry Seed Coat 
     α-(cyanomethoxyimino)benzacetonitrile--25% 
     calcium ligninsulfonate--4% 
     trimethyl nonyl polyethylene glycol ether--4% 
     Rhodamine B--1% 
     permanent red 2 B, calcium salt, extended on Blanc Fixe--1% 
     diatomaceous earth--65% 
     The liquid surfactant and active ingredient are sprayed on the diatomaceous earth, the other ingredients are then added and thoroughly mixed together in an efficient blender. The mixture is then coarsely hammer milled and passed through a fluid mill to produce particles of active ingredient that are less than 10 microns in diameter. The product is reblended before packaging. (Product is used by making about a 30-40% slurry in water and applying the slurry to seed in a commercial seed treater.) 
     EXAMPLE 25 
     Dust Seed Coat 
     1,8-naphthalic anhydride--75% 
     permanent red 2 B, calcium salt, extended on Blanc Fixe--5% 
     diatomaceous earth--20% 
     The ingredients are blended, coarsely hammer milled and passed through a fluid mill to produce particles of active ingredient that are all below 10 microns in diameter. The product is reblended before packaging. (Product is used by dusting on seed at rates of 1-800 gms/100 kg.)