IL29368A - Synergistic herbicidal compositions containing a 2-methylthio-1,3,5-triazine and a benzimidazole - Google Patents

Description

SynergistiG herbicidal compositions containing a 2«.methylthio-lf3 jS-triazine and a bensimidazole FISGKS PEST CONTROL LIMITED C:27812 The present invention relatee to novel compositions of matter particularly suitable for the selective control of weeds.

It has been found that the selective herbicidal compositions hereinafter described possesses exceptional activity for the selective control of certain¾«eds in certain crops'*" owing to the mutual synergistic effect of its two active ingredients indicated below.

Accordingly the present invention is for synergistic selective herbicidal compositions comprising a mixture of a triazine of the general 1 3 4 where R , R , R and R are hydrogen, alkyl or alkoxyalkyl groups, together with at least one substituted benzimidazole of the formula; where R** is hydrogen, a lower alkyl group or -COOR10 where ^ is optionally halogen-substituted lower alkyl, optionally alkyl-substitute a 6 7^ R8 9 aryl or cycloalkyl group; and R , R and R are the same or different and are each hydrogen, an optionally halogen-, hydroxy-or alkoxy-substituted alkyl, hydroxy, alkoxy, nitro, halogen, cyano, thiocyano, isothiocyanOj azido, carboxy, alkoxyearbonyl, carbamoyl, K-mono or Ν,Ν-disubstituted carbamo¾ amino mono- or disubstituted by alkyl, acyl or halogen-substituted acyi; mercapto, alkylthio, alkyl- - 3a - 29368/2 The substituted benzimidazoles identified above are active herbicides, and have been described for example in Israel Patent Specification ϊίο* 20714. " : Examples of these substituted benzimidazoles which may be mentioned include: 4,5, 6,7-tetrachloro-2-trifluoromethylbenzimidazole, 4.5.6-trichloro-2-trifluoromethylbenzimidazole, 4.5.7-trichloro-2-trifluoromethylbenzimidazole, 4.5-dichloro-2-trifluoromethylbenzimidazole, -iodo-2-trifluoromethylbenzimidazole, -cyano-2-trifluoromethylbenzimidazole, 4.6-dichloro-2-trifluoromethylbenzimidazole, . 4.7-dichloro-2-trifluoromethylbenzimidazole, 4-nitro-6-chloro-2-trifluoromethylbenzimidazole, 4-chloro-6-nitro-2-trif1uoromethylbenzimidazo1e, 4-chloro-2-trifluoromethylbenzimidazole, 4-bromo-5, 6,7-trichloro-2-trifluoromethylbenzimidazole, 4, 6, 7-trichloro-5-methyl-2-trifluoromethylbenzimidazole, 4 , 5, 6-trichloro-2-pentafluoroethylbenzimidazole, l-carboethoxy-4, 5,6-trichloro-2-trifluoromethylbenzimidazole and 4 , 5, 6, 7-tetrachloro-l-methyl-?2~trifluoromethylbenzimidazole.

According to a preferred embodiment of the invention, the substituted benzimidazole is 5-iodo-2-trifluoromethylbenzimidazole or 4,5-dichloro-2-trifluoromethylbenzimidazole. According to a further preferred embodiment, the present invention is for a mixture of 5-iodo-2-trifluoromethylbenzimidazole or 4, 5-dichloro-2-trifluoromethylbenzimidazole and 2-methyl-thio-4-isopropylamino-6-( amma-methoxypropyl )amino-l , 3 ,5-triazine.

It has bee found that the mixtures according to the present invention possess herbicidal activity considerabl in excess of the herbicidal . activity of the components of the mixture; the mixtures thus exhibit synergism.

The salts of the substituted benzimidazoles are water soluble, and 9i - 5 - benzimidazoles may be formulated in any of the usual ways for insoluble compounds, together with wetting agents, solvents, solid diluents etc.

The triazines have very low solubility in all liquids, and therefore require to be formulated as a suspension, for example as an aqueous suspension. In the erbicidal mixture, therefore, this. may comprise for example ah aqueous suspension of. both the benzi idazole and the triazine. Alternatively a physically stable formulation is a wettable powder formulation of a mixture of the finely ground triazine, an inert diluent and a solid salt, for example, the sodium salt, of the substituted benzimidazole.

The proportion of the triazine and the substituted benzimidazole in a composition may vary over a wide range, and comprises from about 1-50 parts of triazine admixed with from about 1-100 parts of the substituted benzimidazole. Suitably the composition contains.0.25 to 75 parts of the substituted benzimidazole to one part of the triazine, and according to a preferred embodiment the composition contains about 2 to 4 parts of the substituted benzimidazole to 1 part of the triazine.

The present invention is also for a process for the selective control of weeds in crops ; the rate of application may vary over a wide range according to the crop species, and generally is of the order of about 2 to 32 ounces per acre (140 g.-2.24 Kg. per hectare) of the active ingredients.

Thus it is preferred to use the composition such that there is applied to the crop from 0.25 to 8 ounces per acre (20 g. -560 g. per Hectare) of the triazine and from 2 to 16 ounces per acre (140g.-1.12 Kg, per hectare) of the substituted benzimidazole.

The compositions according to the present invention may also include one or more other selective herbicides,, and it has been found advantageous in some cases to include in the composition a substituted phenoxy- carboxylic carboxylic carboxyl generally comprises an alkyl and/or halogen substituted phenoxyallphatic/ acids, and their salts, for example alkali metal, amine, alkanolamine salts, and functional derivatives, for example esters and amides. These compounds may be of activity such that they are recognised as commercial herbicides, or may be of only slight herbicidal activity. Examples of carboxylic the substituted phenoxyaliphatic/acids which may be mentioned include 2,4-dichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid; 2,4,5-trichlorophenoxyacetic acid, gamma-2,4-i;dichlorophenoxy-butyric acid, gamma-2-methyl-4-chlorophenoxy-butyrip acid and alpha-2-methyl-4-chlorophenoxypropionic acid. These compounds are preferably used in the form of a salt. , . · carboxylic The amount of substituted phenoxyaliphatic/acid is suitably in the range 0.5 to 4 parts, and preferably 1-2 parts, per part of substituted benzimidazole in the mixture.

The compositions according to the present invention may include any of the usual components such as surface active agents, stickers, diluents and other additives used in the art. The composition might comprise liquids suitable for spraying or powders suitable for dusting. The extent of dilution for spraying does not appear to be critical.

The active ingredients may be dispersed or dissolved in the carrier for application in any suitable way.

Thus for example, the active ingredients may be dissolved in a water immiscible solvent, such as for example a high boiling hydrocarbon, suitably containing dissolved emulsifying agents so as to act as a self-emulsifiable oil on addition to water.

The active ingredients may also be admixed with a wetting agent with or without an inert diluent to form a wettable powder which is soluble or dispersible in water, or may be mixed with the inert diluent to form a solid or powdery product.

Inert diluents with which the aqtive ingredients may be incorporated include solid inert media comprising powdered or divided solid materials, for example, clays, sands, talc, mica, fertilizers and the like, such products either comprising dust or larger particle size materials.

The wetting agents used may comprise anionic compounds such as for example soaps, fatty sulphate esters such as dodecyl sodium sulphate, octadecyl sodium sulphate and cetyl sodium sulphate, fatty aromatic sulphonates such as alkyl-benzene sulphonates or butyl naphthalene sulphonate, more complex fatty sulphonates such as the amide condensation product of oleic acid and N-methyl taurine or the sodium sulphonate of dioctyl succinate.

The wetting agents may also comprise non-ionic wetting agents such as for example condensation products of fatty acids, fatty alcohols or fatty substituted phenols with ethylene oxide, or fatty esters and ethers of sugars or polyhydric alcohols, or the products obtained from the latter by condensation with ethylene oxide, or the products known as block copolymers of ethylene oxide and propylene oxide. The wetting agents may also comprise cationlc agents such as for example cetyl triraethylammonium bromide and the like.

The compositions according to the present invention are of particular value in the control of weeds in cereal crops, and particularly for post emergence treatment of the crop. Crops which may be protected in this way include wheat, barley, maize, oats, rice and sugar cane.

The extent of the control of the weed species using these mixtures is distinctly greater than what would be expected from the herbicldal activity of the individual components.

The following examples are given to illustrate the present invention; parts are by weight.

Example 1 A mixture of 2 parts of 5-iodo-2-trifluororaethylbenzimidazole (compound I) and 1 part of 2-methylthio-4-isopropylamino-6-(gamma- methoxypropyl)amino-l,3,5-triazine (compound II) as an aqueous suspension of a wettable powder was sprayed on to various young weed species at a rate equivalent to 9 ounces per acre (630 g. per hectare) of the 2 ingredients combined. At intervals of 4, 6 arid 8 days after spraying the degree of damage to the plants was assessed on a scale of 0 to 100 by comparison with unsprayed controls. For comparison, compound I at the rate of 12 ounces per acre (840 g. per hectare) and compound II at the rate of 6 ounces per acre (420 g. per hectare) were each sprayed alone.

The table below shows the amount of herbicidal effect on chickweed, mayweed, speedwell and cleavers caused by each composition at intervals of 4, 6 and.8 days after spraying.

Example 2 A mixture of 4 parts of 5-iodo-2-trifluoromethylbenzimidazole and 1 part of 2-methylthio-4-isopropylamino-6r(gamma-methoxypropyl )amino- 1,3,5-triazine, was prepared as an aqueous suspension of a wettable powder and -sprayed at the rate of 10 ounces per acre (700 g,/hectar e) on various oun weeds as described in.Exam le 1. The de ree of dama e to the weeds expressed as % weed control, was measured at 2, 4, 7 and 17 days after spraying and the results obtained are given below.

Example 3 The following compositions were prepared as aqueous suspensions of wettable powders :- A. 4, 5-dichloro-2-trifluoromethylbenzimidazole - 6 parts 2-methylthio-4-isopropylamino-6-(gamma- methoxypropy1)amino-l ,3, 5-triazine - 2 parts 2-methyl-4-chlorophenoxyacetic acid - 12 parts B„ 5-iodo-2-trifluoromethylbenzimidazole - 6 parts 2-methylthio-4-isopropylamino-6-(gamma- methoxypropyl)amino-l ,3, 5-triazine - 2 parts 2-methyl-4-chlorophenoxyacetic acid - 12 parts Solely by way of comparison the following single component compositions were also prepared: - C. 2-methyl-4-chlorophenoxyacetic acid D. 2-methylthio-4~isopropylamind-6-( gammamethoxypropyl)-amirio-l ,3,5- triazine.

These compositions were sprayed on fields of wheat and barley infested with various weed species when the crops were at the 2-3 leaf stage. The rate of application based on combined active ingredients was as follows:- A - 20 ounces per acre (140 g./hectare) B - 20 ounces per acre (140 g. ectare) C - 20 ounces per acre (140 g./hectare) D - 2 ounces per acre ( 14 g./hectare).

The degree of weed control expressed as a percentage of untreated controls was as follows:- Composition A B D Weed Species Black bindweed (P. convolvulus). 92 87 60 28 Redshank (P. persicaria) 100 97 30 7 Chickweed (S. media; 9S> 97 38 44 Knotgrass (f. avieni ^re 83 90 60 25 Field speedwell (V. agrestis) 87 80 35 10 Corn marigold (C. segetum) 79 52 36 30 In the preceding examples, the substituted benzimidazole and phenoxy- carboxylic aliphatic/acid were used in the form of the sodium salt; in accordance with usual practice weights are based on the acid equivalent.

The post-emergence treatment of weed infested crops according to the present invention is suitably applied when the crop is at the 2 to 5 leaf stage, and preferably at the 2 to 3 leaf stage.

Claims (22)

29368/3 ClAIMS

1. Synergistic herbicidal compositions comprising a mixture of a triazine of the formulas SCH, 1 2 3 4 where R , R , R and R are hydrogen, alkyl or alkoxyalkyl groups, together with at least one substituted benzimidazole of the formulas E6 ' where R^ is hydrogen, a lower alkyl group or -COOR where R is optionally halogen-substituted alkyl, optionally alkyl-substituted fi 7 ft Q aryl or cycloalkyl; and R , R , R and R are the same or different and are each hydrogen, an optionally halogen-, hydroxy- or alkoxy-substituted alkyl, hydroxy, alkoxy, nitro, halogen, cyano, thiocyano, isothiocyano, azido, carboxy, alkoxycarbonyl, carbamoyl, N-mono or NpN-disubstituted carbamoyl, amino mono- or disubstiuted by alkyl, acyl or halogen-substituted acyi mercapto, alkylthio, alkylsulphinyl, alkylsulphonyl, sulpho, alkoxysulphonyl, sulphamoyl or a saturated heterocyclic ring attached to the benzimidazole system through a nitrogen atom and X is trifluoromethyl, or pentafluoroethyl, or a salt or functional derivative of said benzimidazole, where such exist.

2. A herbicidal composition as claimed in claim 1 wherein the ratio of the triazine to the substituted benzimidazole is in the range 1-50 , parts of the. former to 1-100 parts of the latter.

3. A herbicidal composition as claimed in claim 2 wherein the ratio of the triazine to the substituted benzimidazole is approximately 1 part of the triazine to 2-4 parts of the substituted benzimidazole.

4. A herbicidal composition as claimed in any of the preceding claims wherein the triazine is 2-methylthlc~4-isopropylamino-6-( gamma-methoxypropyl) amino.- 1 ,3,5-triazine, 2,4-bis-isopropylamino-6-methylthio-s-triazine, 2-ethylamino-4-isopropylamino-6-methylthio-s-triazine, 2,4-bis(monoethylamin< 6~methyl-mercaptp—s-triazine or 2-isopropylamino-4-methylaraino-6-methyl-mercapto-s-triazine.

5. A herbicidal composition as claimed in any of the preceding claims " 1 2 wherein the triazine is one in which at least one of the groups R , R , . 3 4 R ,. and R is alkoxyalkyl „

6. A herbicidal composition as claimed in claim 5 wherein the triazine 1- 2 3 is one in which at least one of the groups R , R ,,R . and R is gamma-methoxyprop l .

7. A herbicidal composition as claimed in any. of the preceding claims wherein the triazine is 2-methylthio-4-isopropylamino-6-( gamma-methoxypropyl) amino-1β,5-triaziiie .

8. A herbicidal composition as claimed in any of the preceding claims wherein the substituted benzimidazole is 4,5,6;7-!-tetrachloro-2-trifluoro-. methylbenzimidazole, 4,5,6-trichlor-2-trifluoromethylbenzimidazole, 4,5,7-trichlorb-2-trifluoromethylbenzimidazole, 4 ,5-dichloro-2-trifluoro-methyl benzimidazole, 5-iodo-2-trifluoromethyl benzimidazole, 5-cyano-2-trifluoromethyl benzimidazole, 4,6-dichloro^2-trifluoromethylbenzimidazole, methyl benzimidazole, 4-chloro-6-nitro-2-trlfluoromethyl benzimidazole. 4-chloro-2-trifluororaethyl benzimidazole, 4-bromo-5,6,7-trlchloro-2-trifluoromethyl benzimidazole, 4, 6, 7-trichloro-5-methyl-2-trifluoromethyl benzimidazole, 4,5,6-trichloro-2-pentafluoroethyl benzimidazole, 5-nitro-2-pentafluoroethyl benzimidazole, morpholino trichloro-2-tri-fluoromethyl benzimidazol , l-carboethoxy- ,5,6-trichloro-2-trifluoromethyl benzimidazole or 4,5, 6, 7-tetrachloro-l-methyl-2-trifluoromethyl benzimidazole.

9. A herbicidal composition as claimed in any of the preceding claims wherein the substituted benzimidazole is 5-iodo-2-trifluoromethyl benzimidazole or 4,5-dichloro-2-trifliioromethyl benzimidazole.

10. A herbicidal composition as claimed in any of the preceding claims which comprises a mixture of 2-methylthlo-4-isopropylamino-6-( gamma methoxypropyl)amino-l,3,5-triazine and 5-iodo-2-trifluoromethyl benzimidazole or 4,5-dichloro-2-trifluoromethyl benzimidazole.

11. A herbicidal composition as claimed in claim 10 which comprises a mixture of 2-methylthio-4-isopropylamino-6-(gamma methoxypropyDamino-1,3,5-triazine and 5-iodo-2-trifluoromethyl benzimidazole in a ratio of approximately 1 part of the former 'to 2 - 4 parts of the latter.

12. A herbicidal composition as claimed in any of the preceding claims wherein the substituted benzimidazole is in the form of a salt.

13. A herbicidal composition as claimed in any; of the preceding claims which contains a surface active agent and/or a sticker and/or a diluent.

14. A herbicidal composition as claimed in any of the preceding claims which contains another selective herbicide.

15. A herbicidal composition as claimed in any of the preceding claims which also contains a substituted phenoxyaliphatic acid or a salt or functional derivative thereof. - 14 29368/2

16. A herbicidal composition as claimed in Claim 15 wherein the substituted phenoxyaliphatic carboxylic acid is 2-methyl-4-chlorophenoxyacetic acid or alpha-2-methyl-4-chloro-phenoxypropionic acid.

17. A herbicidal composition as claimed in Claim 15 or Claim 16 wherein the substituted phenoxyaliphatic carboxylic acid is present in amount comprisin 0.5 to 4 parts per part of substituted benzimidazole .

18. Herbicidal compositions as claimed in Claim 1 substantially as he-sslnbe ore described.

19. Herbicidal compositions as claimed in Claim 1 substantially as .hereinbefore described and illustrated in any of the preceding Examples.

20. A process for the preparation of herbicidal compositions as claimed in any of the preceding claims which comprises mixing together a triazine and a substituted benzimidazole as hereinbefore defined.

21. A process for the control of weeds in crops which comprises applying to the crop area or the soil a mixture of a triazine and a substituted benzimidazole as hereinbefore defined. '

22. A process for the control of weeds in crops as claimed in Claim 21 substantially as hereinbefore described. PC/rb