GB1562626A

GB1562626A - Benzofuranyl sulphonate herbicides

Info

Publication number: GB1562626A
Application number: GB4870276A
Authority: GB
Original assignee: Fisons Ltd
Current assignee: Fisons Ltd
Priority date: 1976-11-23
Filing date: 1976-11-23
Publication date: 1980-03-12

Description

(54) BENZOFURANYL SULPHONATE HERBICIDES (71) We, FISONS LIMITED, a British Company of Fison House, 9 Grosvenor Street, London W1X OAH do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a method of combating weeds, herbicidal compositions and their preparation.

The invention provides a method of combating weeds at a locus infested or liable to be infested with them, which method comprises applying to the locus an effective amount of: (a) 2-ethoxy-2,3-dihydro-3 ,3-dimethylbenzofuran-5-yl methanesulphonate (ethofumesate); and (b) one or both of 3-[4-(4-chlorophenoxy)phenyl]1,1-dimethylurea (chloroxuron) and 2,4-dichlorophenyl 4-nitrophenyl ether (nitrofen).

In addition, the invention provides a herbicidal composition comprising (a) and (b) in association with a suitable carrier and/or a surface active agent.

The invention also provides a two-container pack in which (a) and (b) are provided in separate containers, especially in relative proportions as described hereinafter. Desirably, the two-container pack bears or contains directions, either separate or in conjunction with one of the containers, for mixing the contents of the containers or for separately applying the contents thereof.

It has been found that (a) and (b) seem to render weeds more susceptible to the action of the other, so that the present method and composition are unexpectedly advantageous, especially when used in the control of weeds in crops. Mixtures of (a) and (b) are synergistic, being surprisingly effective against weeds, especially broad-leaved weeds and certain weed grasses, e.g. mayweed, knotgrass, barley grass, blackgrass, annual meadow grass, fat hen and speedwell. Components (a) and (b) are also effective at lower dosage rates in combination than those at which (a) or (b) alone is effective. In addition they are safe to crops such as onions, strawberries, leeks, celery, palatable grasses, e.g. Ryegrass and Timothy grass, and ornamentals. Component (b) preferably comprises one only of the two specified compounds.

Each of the 2 essential components (a) and (b) should be employed as 1 to 99% by weight of the total amount of (a) and (b) applied. Preferably, component (a) is employed in an amount of from 10 to 90%, and more preferably 20 to 60% by weight of the total amount of (a) and (b) applied.

The essential herbicides (a) and (b) can be applied together in a composition comprising (a) and (b), and such compositions may be prepared by admixing the ingredients. Usually the compositions are initially produced in the form of concentrates, e.g. containing 0.5-85% in toto of the essential components, and these are diluted with water or a hydrocarbon, usually water, for application, generally such that the concentration in toto of the essential components is 0.05-4%, though it may be up to 50% or more when sprayed from aircraft.

Thus, the present compositions usually contain 0.05-85% in toto of the essential components.

The compositions normally contain a surface active agent and/or a carrier.

The carrier may be a liquid, e.g. water (e.g. water used to dilute a concentrate for application). A concentrate containing water as carrier may advantageously also contain a surface active agent. In one embodiment, (a) and (b) are ground with water, a wetting agent and a suspending agent, usually in an agitated ball mill containing grinding media e.g.

steatite balls to a particle size for both (a) and (b) of preferably less than 5 microns, to form a flowable suspension concentrate.

The carrier may be a liquid other than water, for example an organic solvent, usually a water-immiscible solvent, e.g. a hydrocarbon which boils within the range 130-270"C, in which the essential components are dissolved or suspended. A concentrate containing an organic solvent suitably also contains a surface active agent so that the concentrate acts as a self-emulsifiable oil on admixture with water. In a particular method, an emulsifiable concentrate is produced by stirring together, preferably with warming to aid dissolution, components (a) and (b), one or more emulsifiers and a water-immiscible solvent desirably comprising mainly isophorone to form a solution, and usually filtering or centrifuging to remove insoluble impurities.

The carrier may be a solid, which may be finely divided. Examples of suitable solids are days, sand, mica, chalk, attapulgite, diatomite, perlite and sepiolite, synthetic solid carriers, e.g. silicas, silicates and lignosulphonates, and solid fertilizers.

Wettable powders rapidly dispersible in water can be formed by admixing (a) and (b) in particulate form with a carrier or spraying molten (a) and (b) on to the carrier, admixing a wetting agent and a dispersing agent therewith, and fluid energy milling or pulverising the whole powder mixture to a particulate size sufficiently small that the wettable powder in use can form the desired suspension.

The term 'surface active agent' is used in the broad sense to include materials variously called emulsifying agents, dispersing agents and wetting agents. Such agents are well known in the herbicide art.

The surface active agents used may comprise anionic surface active agents, for example mono- or di-esters of phosphoric acid with fatty alcohol ethoxylates or salts of such esters, fatty alcohol sulphates such as sodium dodecyl sulphate, ethoxylated fatty alcohol sulphates, ethoxylated alkylphenol sulphates, lignin sulphonates, petroleum sulphonates, alkylaryl sulphonates such as alkyl-benzene sulphonates or lower alkyl-naphthalene sulphonates, salts of sulphonated naphthalene-formaldehyde condensates, salts of sulphon ated phenol-formaldehyde condensates, or more complex sulphonates such as the amide sulphonates, e.g. the sulphonated condensation product of oleic acid and N-methyl taurine or the dialkyl sulphosuccinates e.g. the sodium sulphonate of dioctyl succinate.

The surface active agents may also comprise non-ionic agents, for example condensation products of fatty acid esters, fatty alcohols, fatty acid amides or alkyl-substituted phenols with ethylene oxide, fatty esters of polyhydric alcohol ethers e.g. sorbitan fatty acid esters, condensation products of such esters with ethylene oxide e.g. polyoxyethylene sorbitan fatty acid esters, block copolymers of ethylene oxide and propylene oxide, acetylenic glycols such as 2,4,7,9-tetramethyl-5-decyn-4,7-diol, or ethoxylated acetylenic glycols.

The surface active agents may also comprise cationic agents, for example alkyl- and/or aryl-substituted quarternary ammonium compounds such as cetyl trimethylammonium bromide, or ethoxylated tertiary fatty amines.

Preferred surface active agents include ethoxylated fatty alcohol sulphates, lignin sulphonates, alkyl-aryl sulphonates, salts of sulphonated naphthalene-formaldehyde condensates, salts of sulphonated phenol-formaldehyde condensates, sodium oleoyl N-methyltauride, dialkyl sulphosuccinates, alkyl phenol ethoxylates, and fatty alkyl ethoxylates.

Components (a) and (b) may be mixed immediately before use. Desirably, however, they are supplied pre-mixed.

When employed in a crop, for example onions, the composition is usually employed post-emergence of the crop, and is preferably applied after the 1-leaf stage. When employed post-emergence, it is preferred that a pre-emergence treatment of the crop is made with a suitable pre-emergence herbicide, for example propachlor.

Instead of applying (a) and (b) together in a composition such as is discussed above, they can be applied separately in analogous compositions containing just (a) or (b), particularly as a chemical weed control programme or part of a chemical weed control programme in a crop season. Sequential application of (a) and (b) is of particular advantage, particularly when component (a) is applied before component (b), and especially when component (a) is applied pre-emergence and component (b) is applied post-emergence.

A further herbicide, provided it is safe to any crop being treated, can be used in the present method besides (a) and (b). Thus, (a) and (b) can be applied separately and a further herbicide applied with (a) and/or (b). Alternatively, a composition comprising a mixture of (a), (b) and the further herbicide can be applied. Usually the proportions of (a) to the further herbicide are from 1:10 to 10:1 by weight, preferably from 1:3 to 3:1 by weight. Examples of such further herbicides include substituted ureas (e.g. monuron, monolinuron, linuron, fenuron and benzthiazuron), triazines (e.g. trietazine, prometryne and metamitron), DNOC, PCP, ioxynil, bromoxynil, dichlobenil, diquat or paraquat (for pre-emergence use only), endothal, chlorpropham, barban, diallate, propachlor, maleic hydrazide, 3-(l4ethoxyamino/propylidene)-6-ethyl-2H-yran-2,4(3H)-dione, triallate, metobromuron, N-(chloroacetyl)-N-(2,6-diethylphenyl) glycine ethyl ester or N (phosphonomethyl)glycine, methazole, oxadiazon, chlorthal-methyl, and, especially, pyrazon.

Fertilizers or pesticides other than herbicides can also be employed with the present essential herbicides.

Plants, the soil, land or aquatic areas can be treated by the present method. The method and composition may be used for selectively combating weeds, especially at a locus at which a crop, e.g. onions or grass, is growing.

In the present method, usually 0.3-12 kg, preferably 0.5-4 kg, especially 1-4 kg, in toto of (a) and (b) are applied per hectare. Usually 0.1-5.3 kg, preferably 0.3-2.7 kg, especially 0.7-2.7 kg, of (a) are applied per hectare. Usually 0.1-8 kg, preferably 1-3 kg of (b) are applied per hectare when (b) is chloroxuron. Usually 0.1-5.0 kg, preferably 0.5-4.0 kg, especially 1.0-3.0 kg, of (b) are applied per hectare when (b) is nitrofen.

The following Examples are now given, though only by way of illustration.

Example 1 A mixture of ethofumesate and chloroxuron was applied to a growing crop of spring-sown onions at the 1-leaf stage at the rate of 1.0 kg of ethofumesate and 2.0 kg of chloroxuron per hectare. For comparison, similar plots were treated at the same stage with 4 kg per hectare of chloroxuron alone, and similar plots were left untreated as a control.

Weed control as a percentage based on the control plots was as follows: Weed ethofumesate (1.0 kglha) chloroxuron + chloroxuron (2.0 kglha) (4.0 kglha) Mayweed 48 26 Fat Hen 100 71 Knotgrass 88 13 Annual meadow grass 50 Field speedwell 100 Chickweed 100 100 Black bindweed 96 92 Spurrey 100 100 Shepherds Purse 100 Black Nightshade 100 Wild oats 50 Example 2 A mixture of ethofumesate and nitrofen was applied to a growing crop of onions at the 1-leaf stage. Untreated similar plots acted as control. Weed control as a percentage relative to the control was as follows, evaluation being made 2-4 weeks after treatment: ethofumesate (1.0 Kglha) + nitrofen (1.5 kglha) nitrofen (3.0 kglha) Overall Weed control 62 48 Mayweed 31 31 Fat Hen 88 65 Knotgrass 62 55 Chickweed 87 27 Black bindweed 72 78 Spurrey 85 48 Field pansy, forget-me-not, Speedwell, ivy-leaved speedwell, fumitory, parsley and charlock were also well controlled by the mixture of ethofumesate and nitrofen, although corresponding trials with nitrofen alone were not carried out.

Example 3 A mixture of ethofumesate and nitrofen was applied to a growing crop of onions to the 2-leaf stage. Untreated similar plots acted as control. Weed control as a percentage relative to the control was as follows, evaluation being made 2-4 weeks after treatment.

ethofumesate (1.5 kglha) + nitrofen (1.5 kglha) nitrofen (2.0 kglha) Pigweed 80 50 Fat Hen 85 70 No crop injury was observed.

WHAT WE CLAIM IS: 1. A herbicidal composition which comprises: (a) 2-ethoxy-2,3-dihydro-3 ,3-dimethylbenzofuran-5-yl methanesulphonate, and (b) one or both of 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea and 2,4dichlorophenyl-4-nitrophenyl ether, in association with a suitable carrier and/or a surface active agent.

2. A composition according to claim 1, wherein each of components (a) and (b) is present in an amount of from 1 to 99% by weight of the total amount of those compounds which is present.

3. A composition according to claim 2, wherein component (a) is present in an amount of from 10 to 90% by weight of the total amount of components (a) and (b) which is present.

4. A composition according to claim 3, wherein component (a) is present in an amount of from 20 to 60% by weight of the total amount of components (a) and (b) which is present.

5. A composition according to any of claims 1 to 4, wherein one only of 3-[4-(4chlorophenoxy)phenyl]-1,1-dimethylurea and and 2,4-dichlorophenyl 4-nitrophenyl ether is present.

6. A composition according to any of claims 1 to 5, which contains from 0.05-85% by weight in toto of components (a) and (b).

7. A composition according to any of claims 1 to 6 and substantially as described herein with reference to Example 1 or Example 2.

8. A method of combating weeds at a locus infested or liable to be infested with them, which comprises applying to the locus an effective amount of: (a) 2-ethoxy-2,3-dihydro-3 ,3-dimethylbenzofuran-5-yl methanesulphonate, and (b) one or both of 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea and 2,4dichlorophenyl 4-nitrophenyl ether.

9. A method according to claim 8, wherein from 0.3-12 kg in toto of components (a) and (b) are applied per hectare.

10. A method according to claim 9 wherein from 0.5-4 kg in toto of components (a) and (b) are applied per hectare.

11. A method according to claim 10, wherein from 1-4 kg in toto of components (a) and (b) are applied per hectare.

12. A method according to any of claims 8 to 11 wherein from 0.1-5.3 kg of component (a) are applied per hectare.

13. A method according to claim 12, wherein from 0.3-2.7 kg of component (a) are applied per hectare.

14. A method according to claim 13, wherein from 0.7-2.7 kg of component (a) are applied per hectare.

15. A method according to any of claims 8 to 14 wherein component (b) is 3-[4-(4-chlorophenoxy)phenyl]-1 ,1-dimethylurea and is applied at a rate of from 0.1-8 kg per hectare.

16. A method according to claim 15, wherein component (b) is applied at a rate of from 1-3 kg per hectare.

17. A method according to any of claims 8 to 14 wherein component (b) is 2,4-dichlorophenyl-4-nitrophenyl ether and is applied at a rate of from 0.1-5.0 kg per hectare.

18. A method according to claim 17 wherein component (b) is applied at a rate of from 0.5-4.0 kg per hectare.

19. A method according to claim 18 wherein component (b) is applied at a rate of from 1.0-3.0 kg per hectare.

20. A method according to any of claims 8 to 19 wherein components (a) and (b) are applied at the same time.

21. A method according to claim 20 wherein components (a) and (b) are applied in a composition according to any of claims 1 to 7.

22. A method according to any of claims 8 to 21 wherein the locus treated is a growing

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. to the control was as follows, evaluation being made 2-4 weeks after treatment. ethofumesate (1.5 kglha) + nitrofen (1.5 kglha) nitrofen (2.0 kglha) Pigweed 80 50 Fat Hen 85 70 No crop injury was observed. WHAT WE CLAIM IS:

1. A herbicidal composition which comprises: (a) 2-ethoxy-2,3-dihydro-3 ,3-dimethylbenzofuran-5-yl methanesulphonate, and (b) one or both of 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea and 2,4dichlorophenyl-4-nitrophenyl ether, in association with a suitable carrier and/or a surface active agent.

crop. A

23. A method according to claim 22, wherein the growing crop treated is onions, grass, leeks, celery, strawberries or ornamentals.

24. A method according to claim 22 or claim 23, wherein the crop is treated post-emergence thereof.

25. A method according to any of claims 8 to 24 and substantially as described herein with reference to the Examples.