GB1583546A

GB1583546A - Method of combating weeds

Info

Publication number: GB1583546A
Application number: GB3371476A
Authority: GB
Original assignee: Fisons Ltd
Current assignee: Fisons Ltd
Priority date: 1977-08-04
Filing date: 1977-08-04
Publication date: 1981-01-28

Description

(54) METHOD OF COMBATTING WEEDS (71) We, FISONS LIMITED, a British Company, Fison House, 9 Grosvenor Street, London WIX 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: This invention concerns a method of combating weeds.

2-Ethoxy-2 ,3-dihydro-3 ,3 -dimethylbenzofuran-5-yl methane-sulphonate, methyl 3 m-tolylcarbamoyloxyphenylcarbamate and ethyl 3-phenylcarbamoyloxyphenylcarbamate are known herbicides. It has now been found that they may be employed in certain particular ways, whereby surprisingly good weed control and crop safety are achieved.

Accordingly, in one aspect, this invention provides a method of combating weeds in a crop, which comprises applying to the crop at a time from the cotyledon leaves stage to the stage at which four true leaves have appeared, a first amount of 2 ethoxy-2,3-dihydro-3,3-dimethylbenzofuran -5-yl methanesulphonate and one or both of methyl 3-m-tolyl-carbamoyloxyphenyl carbamate and ethyl 3-phenylcarbamoyloxyphenylcarbamate, followed 3 to 7 days later by a second amount of 2-ethoxy-2,3-dihydro-3,3 -dimethylbenzofuran-5-yl methanesulphonate and one or both of methyl 3-m-tolylcarbamoyloxyphenyl carbamate and ethyl 3-phenylcarbamoyloxyphenylcarbamate, the first and second amounts added together making a herbicidally effective amount of the said compounds.

The first amount of the said compounds may be applied to the crop either as a mixture thereof or as a sequence thereof, the applications of the compounds being separated by only a short time, for example by one day or less. Similarly, the second amount of the said compounds may be applied to the crop either as a mixture thereof or as a similar sequence.

Preferably, both the first amount and the second amount of the said compounds are applied as admixtures thereof.

Desirably, from 0.2 to 2 kg, especially from 0.25 to 1 kg, e.g. about 0.5 kg, of 2-ethoxy-2,3dihydro-3,3-dimethylbenzofuran -5-yl methanesulphonate are applied per hectare in each of the first and second amounts applied.

Desirably, from 0.2 to 2 kg, especially from 0.2 to 0.8 kg, e.g. about 0.4 kg, of methyl 3-m-tolylcarbamoyloxyphenylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbamate or both in toto are applied per hectare in each of the first and second amounts applied.

Preferably, the first and second amounts of each of the compounds applied are the same.

If desired, an initial amount of methyl 3-m-tolylcarbamoyloxyphenylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbamate or both may be applied to the crop before the first and second amounts of the said compounds. We have found improved weed control to be obtainable if such an initial application is made. If made, it is preferably made at the cotyledon leaves stage of the crop. The amount of methyl 3 m-tolylcarbamoyloxyphenylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbamate or both in toto which is applied in such an initial treatment is from 0.2 to 2 kg, especially from 0.2 to 0.8 kg, e.g. about 0.5 kg per hectare. Advantageously, a non-phytotoxic oil, e.g. Agri-Oil Plus or Sun Oil 11E may also be applied as part of the initial treatment.

The crop may be for example a beet crop (especially sugar beet), spinach, beans or groundnuts.

The treatments may be carried out in conventional ways. Thus, the 2ethoxy-2,3-dihydro-3,3 -dimethylbenzofuran-5-yl methanesulphonate and the methyl 3-m-tolylcarbamoyloxyphenylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbamate or both may be applied individually or in admixture in a composition containing, for example, 0.05 to 4% by weight of the active ingredient(s), though the content thereof may be up to 10% when the composition is to be sprayed from aircraft.

The compositions applied may be solutions, suspensions, granules or dusts.

The liquid compositions which are applied are generally obtained by diluting a concentrate containing, for example 0.5 to 85 by weight of the active ingredient(s), usually with water or a hydrocarbon.

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). If water is employed as carrier in a concentrate, an organic solvent may also be present as carrier, though this is not usually employed. A concentrate containing water as carrier may advantageously also contain a surface active agent.

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 active ingredients) 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 or admixture with water.

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

Wettable powders soluble or dispersable in water may be formed by admixing the methanesulphonate with or without a carrier with a surface active agent.

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 sulphonated phenolformaldehyde 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.

The compositions applied may, if desired, contain fertilizers or other pesticides, e.g.

insecticides or fungicides.

The present method affords outstanding weed control of most annual broad-leaved weeds such as Polygonum spp, Chenopodium spp, Amaranthus spp, Sinapis arvensis, Raphanus raphanstrum, Urtica urens, Stellaria media and Mercurialis annua. In addition, control may be observed of annual grasses, for example Avena spp, Alopecurus myosuroides, Poa spp, Eclzinochloa crits-galli and Setaria spp, especially if treated before the 3-leaf stage.

The invention is illustrated in the following Examples.

Examples 1-4 Compositions containing 2-ethoxy-2,3-dihydro-3,3 -dimethylbenzofuran-5-yl methancsulphonate and methyl 3-m-tolylcarbamoyloxylphenylcarbamate as a tank mix were sprayed on to sugar beet at four sites in April-May under differing conditions of soil and climate at a total spray volume of 200 I/ha.

Three spray programmes were employed: A. 2-Ethoxy-2,3-dihydro-3.3 -dimethylbenzofuran-5-yl methanesulphonate (1 kg/ha) plus methyl 3-m-tolyl-carbamoyloxyphenylcarbamate (0.8 kg/ha) applied at the 2-4 leaf stage of the beet (control).

B. 2-Ethoxy-2,3-dihydro-3,3 -dimethylbenzofuran-5-yl methanesulphonate (0.5 kg/ha) plus methyl 3-m-tolyl-carbamoyloxyphenylcarbamate (0.4 kg/ha) applied at the 2 leaf stage and again 4 days later.

C. Methyl 3-m-tolylcarbamoyloxyphenylcarbamate (0.5 kg/ha) plus Sun Oil 11E (3 1/ha) applied at the cotyledon leaves stage followed by 2-ethoxy-2,3-dihydro-3,3 -dimethylbenzofuran-5-yl methanesulphonate (0.5 kg/ha) plus methyl 3m-tolylcarbamoyloxyphenylcarbamate (0.4 kg/ha) at the 2 leaf stage and again 4 days later.

Crop effects One week after the final application in each programme the percentage leaf area of the beet scorched was assessed in comparison with untreated plots. One week later the percentage vigour of the crop in comparison with untreated plots was assessed. The results are tabulated below.

Leaf area scorched (%) Crop vigour (% of untreated) Spray programme A B C A B C Example 1 10 5 5 92 97 89 Example 2 4 2 4 86 86 82 Example 3 5 3 5 89 90 87 Example 4 10 7 9 89 94 93 Mean 7 4 6 89 92 88 All crop effects had grown out within 4 weeks of the final application.

Weed control Two weeks after the final application in each programme the control of weeds was assessed in comparison with unsprayed plots.

The results are tabulated below.

% Weed control Spray programme A B C Overall Example 1 83 89 98 2 80 94 95 3 84 92 97 4 85 94 93 Mean 83 92 96 Chenopodium album Example 2 100 100 100 3 99 100 100 Mean 100 100 100 Chenopodium ficifolium Example 2 100 100 100 3 100 100 100 Mean 100 100 100 Euphorbia helioscopia Example 3 100 100 100 % Weed Control Spray programme A B C Polygon urn aviculare Example 1 79 85 97 3 83 91 96 4 90 95 98 Mean 84 90 97 P. Convolvulus Example 1 99 100 99 3 98 99 99 4 85 95 94 Mean 94 98 97 P. lapathifolium Example 2 80 96 97 P. persicaria Example 3 98 100 100 % Weed Control Spray programme A B C Sinapsis arvensis Example 1 66 71 81 4 93 97 97 Mean 80 84 89 Urtica urens Example 2 80 94 98 4 95 100 100 Mean 88 97 99 WHAT WE CLAIM IS: 1. A method of combating weeds in a crop, which comprises applying to the crop at a time from the cotyledon leaves stage to the stage at which four true leaves have appeared a first amount of 2-ethoxy-2,3-dihydro-3.3-dimethylbenzofuran-5-yl methanesulphonate and one or both of methyl 3-m-tolylcarbamoyloxyphenylcarbamate and ethyl 3-phenylcarbamoyloxyphenylcarbamate. followed 3 to 7 days later by a second amount of 2-ethoxy-2.3-dihydro-3. -dimethyl-benzofuran-5-yl methanesulphonate and one or both of methyl 3-m-tolylcarbamoyloxyphenylcarbamate and ethyl 3-phenylcarbamoyloxyphenylcarbamate the first and second amounts added together making a herbicidally effective amount of the said compounds.

2. A method according to claim l wherein both the first amount and the second amount of the said compounds are applied as admixtures thereof.

3. A method according to claim 1 or claim 2 wherein from 0.2 to 2 kg of 2 ethoxy-2,3-dihydro-3.3 -dimethylbenzofuran-5-yl methanesulphonate is applied per hectare in each of the first and second amounts applied.

4. A method according to claim 3 wherein from 0.25 to 1 kg of 2-ethoxy-2,3-dihydro-3,3 -dimethylbenzofuran-5-yl methanesulphonate is applied per hectare in each of the first and second amounts applied.

5. A method according to any of claims I to 4 wherein from 0.2 to 2 kg of methyl 3-m-tolylcarbamoyloxyphcnylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbonate or both in toto is applied per hectare in each of the first and second amounts applied.

6. A method according to claim 5 wherein from 0.2 to 0.8 kg of methyl 3 m-tolylcarbamoyloxyphenylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbamate or both in toto is applied per hectare in each of the first and second amounts applied.

7. A method according to any of claims I to 6 wherein the first and second amounts of the compounds applied are the same.

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

Claims

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

Example 3 100 100 100 % Weed Control Spray programme A B C Polygon urn aviculare Example 1 79 85 97

3 83 91 96

4 90 95 98 Mean 84 90 97 P. Convolvulus Example 1 99 100 99

3 98 99 99

4 85 95 94 Mean 94 98 97 P. lapathifolium Example 2 80 96 97 P. persicaria Example 3 98 100 100 % Weed Control Spray programme A B C Sinapsis arvensis Example 1 66 71 81

4 93 97 97 Mean 80 84 89 Urtica urens Example 2 80 94 98

4 95 100 100 Mean 88 97 99 WHAT WE CLAIM IS: 1. A method of combating weeds in a crop, which comprises applying to the crop at a time from the cotyledon leaves stage to the stage at which four true leaves have appeared a first amount of 2-ethoxy-2,3-dihydro-3.3-dimethylbenzofuran-5-yl methanesulphonate and one or both of methyl 3-m-tolylcarbamoyloxyphenylcarbamate and ethyl 3-phenylcarbamoyloxyphenylcarbamate. followed 3 to 7 days later by a second amount of 2-ethoxy-2.3-dihydro-3. -dimethyl-benzofuran-5-yl methanesulphonate and one or both of methyl 3-m-tolylcarbamoyloxyphenylcarbamate and ethyl 3-phenylcarbamoyloxyphenylcarbamate the first and second amounts added together making a herbicidally effective amount of the said compounds.
2. A method according to claim l wherein both the first amount and the second amount of the said compounds are applied as admixtures thereof.
3. A method according to claim 1 or claim 2 wherein from 0.2 to 2 kg of 2 ethoxy-2,3-dihydro-3.3 -dimethylbenzofuran-5-yl methanesulphonate is applied per hectare in each of the first and second amounts applied.
4. A method according to claim 3 wherein from 0.25 to 1 kg of 2-ethoxy-2,3-dihydro-3,3 -dimethylbenzofuran-5-yl methanesulphonate is applied per hectare in each of the first and second amounts applied.
5. A method according to any of claims I to 4 wherein from 0.2 to 2 kg of methyl 3-m-tolylcarbamoyloxyphcnylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbonate or both in toto is applied per hectare in each of the first and second amounts applied.
6. A method according to claim 5 wherein from 0.2 to 0.8 kg of methyl 3 m-tolylcarbamoyloxyphenylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbamate or both in toto is applied per hectare in each of the first and second amounts applied.
7. A method according to any of claims I to 6 wherein the first and second amounts of the compounds applied are the same.
8. A method according to any of claims 1 to 7 wherein an initial amount of methyl

3-m-tolylcarbamoyloxyphenylcarbamate or 3-phenylcarbamoyloxyphenylcarbamate or both is applied to.the crop before the first and second amounts of the said two compounds.
9. A method according to claim 8 wherein the initial amount of methyl 3m -tolylcarbamoyloxyphenylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbamate or both applied is from 0.2 to 2 kg per hectare.
10. A method according to claim 9 wherein the initial amount of methyl 3 m-tolylcarbamoyloxyphenylcarbamate or ethyl 3-phenylcarbamoyloxyphenylcarbamate or both applied is from 0.2 to 0.8 kg per hectare.
11. A method according to any of claims 1 to 10 wherein the crop to which the said compounds are applied is a beet crop, spinach, beans or groundnuts.
12. A method according to claim 11 wherein the crop to which the said compounds is applied is sugar beet.
13. A method according to claim 1 wherein said first and second amounts each comprise 2-ethoxy-2,3-dihydro-3,3 -dimethylbenzofuran-5-yl methanesulphonate and methyl 3 m-tolycarbamoyloxyphenylcarbamate.
14. A method according to any of claims 1 to 13 and substantially as described hereinbefore in the Examples.
15. A crop treated by the method of any of claims 1 to 14.