AU8193298A - New herbicidal compositions - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Rhone-Poulenc Agro ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: New herbicidal compositions The following statement is a full description of this invention, including the best method of performing it known to me/us:- 4 9 3 9 188EP 98 la 25 35 S* 40

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The present invention relates to new herbicidal compositions comprising a mixture of methyl 2-[(4-ethoxy-6-methylamino-1,3,5triazin-2-yl)carbamoylsulfamoyl]benzoate, i.e. ethametsulfuron methyl and N-(2,4-difluorophenyl)-2-[3-(trifluoromethyl)phenoxy]-3pyridinecarboxamide, i.e. diflufenican. It also relates to the use of the mixture and to a method of controlling weeds.

Ethametsulfuron methyl is a well known selective herbicide disclosed in European Patent No. 136,061 and The Pesticide Manual page 475-476, 11th edition (British Crop Protection Council) recommended for the post-emergence control of wild mustard, hempnettle and other broad-leaved weeds in oilseed rape.

Diflufenican is a well known selective herbicide disclosed in European Patent No. 53011 and Australian Patent No. 557053 and The Pesticide Manual page 397-398, 1 th edition (British Crop Protection Council), recommended for the control of grass and broad-leaved weed species in autumn sown wheat and barley, applied pre- or early postemergence.

The use of certain sulfonylurea herbicides (chlorsulfuron, metsulfuron methyl and ethametsulfuron methyl) to control Emex australis (doublegee) is described in Plant Protection Quarterly Vol 11(4), 1996 pp 160 and 161. A number of compatible products are named including, for Muster, (the tested product containing ethametsulfuron methyl) the post-emergent products difluferican, metosulam, metribuzin and clopyralid. A single test result for doublegee control at the 5-7 true leaf stage in lupins (Gungurru) using Muster Brodal (30g 100 ml) with 0.2% BS1000 (a biodegradable wetter) is described. 85% doublegee control is reported using this mixture. 80% control is reported using the same amounts of Muster and BS1000 in the absence of Brodal which, according to the figures, adds only 5% control. Brodal contains 50g of diflufenican per 100 ml.

There is no disclosure or suggestion of synergism between ethametsulfuron methyl and diflufenican. 50g/ha of diflufenican (used as Brodal) is reported to contribute only an additional 5% of weed kill when used with 30g/ha of ethametsulfuron methyl (as Muster).

This literature reference therefore does nothing to direct attention to mixtures of diflufenican and ethametsulfuron methyl as possibly O T *-<vjL 23 possessing utility in the control of other weeds nor of the possibility of the mixure being synergistic on other weeds.

Certain individual weed species constitute a serious problem and are insufficiently controlled by either ethametsulfuron methyl or diflufenican alone. Thus more effective control of (for example) wild radish (Raphanus raphanistrum) and shepherd's purse (Capsella bursapastoris) is required.

As a result of research and experimentation it has been found that the use of ethametsulfuron methyl in combination with diflufenican improves the control of wild radish Raphanus raphanistrum. Therefore the said combination represents an important technological advance.

The term "combination" as used in this specification refers to the "combination" of ethametsulfuron methyl and diflufenican.

Surprisingly, it has been found that the combined herbicidal activity of ethametsulfuron methyl with diflufenican, for the control of certain weed species is greater than expected, without an unacceptable increase in crop phytotoxicity, when applied post- emergence (especially early post-emergence) of the weed species, i.e. the herbicidal activity of ethametsulfuron methyl with diflufenican showed an unexpected degree of synergism, as defined by Limpel, P.H.

Schuldt and D. Lamont, 1962, 1. Proc. NEWCC 16, 48-53, using the 25 formula:- E=X+Y- X.Y 100 where E the expected percent inhibition of growth by a mixture of two herbicides A and B at defined doses.

X the percent inhibition of growth by herbicide A at a defined dose.

S* Y the percent inhibition of growth by herbicide B at a defined dose.

When the observed percentage of inhibition by the mixture is greater than the expected value E using the formula above the combination is synergistic.

S 40 The unexpected synergism on Raphanus raphanistrum gives improved reliability in controlling serious competitive weeds of many crop species, leading to a considerable reduction in the amount of active ingredient required for weed control.

A high level of control of this weed is desirable to prevent:- 1) yield loss, through competition and/or difficulties with harvest, 2) crop contamination leading to storage and cleaning difficulties, 3) unacceptable weed seed return to the soil, Accordingly, the present invention provides a new herbicidal composition comprising: ethametsulfuron methyl (methyl 2-[(4-ethoxy-6methylamino-1,3,5-triazin-2-yl)carbamoylsulfamoyl]benzoate); and diflufenican (N-(2,4-difluorophenyl)-2-[3- (trifluoromethyl)phenoxy]-3-pyridinecarboxamide); in association with a herbicidally acceptable diluent or carrier and/or surface active agent. It will be understood that the amount of ethametsulfuron methyl and diflufenican will be a herbicidally effective amount a synergistic herbicidally effective amount).

These compositions may be used as herbicides in a broad range of dose rates depending on the crop to be treated, the weeds present and their population, the compositions used, the timing of the treatment, the climatic and edaphic conditions, and the dose ratio of(a) required to obtain a satisfactory level of weed control but not necessarily total control. When applied to a crop-growing area, the rate of application should be sufficient to control the growth of weeds without causing substantial permanent damage to the crop.

25 Generally a composition in which the ratio is from about 1:5 to about 2.85:1 wt/wt is used, preferably from about 1:5 to about 1.33:1 wt/wt; with the exclusion of the weight ratio of of 1:1.67 in an aqueous composition containing 0.2% BS1000.

Unless otherwise stated, the percentages and ratios appearing in this specification are by weight.

Generally the active ingredients are homogeneously dispersed in other components cited hereinafter, such as a diluent or carrier and/or 35 surface-active agents.

The term "herbicidal compositions" is used in a broad sense, to include not only compositions which are ready for use as herbicides but also concentrates which must be diluted before use. Preferably, the 40 compositions contain from 0.05 to 90% by weight of ethametsulfuron methyl and diflufenican.

The herbicidal composition may contain solid and liquid carriers and surface-active agents wetters, dispersants or emulsifiers alone or in combination). Surface-active agents that may be present in the herbicidal compositions of the present invention may be of the ionic or non-ionic types, for example sulphoricinoleates, quaternary ammonium derivatives, products based on condensates of ethylene oxide with nonyl- or octyl-phenols, or carboxylic acid esters of anhydrosorbitols which have been rendered soluble by etherification of the free hydroxy groups by condensation with ethylene oxide, alkali and alkaline earth metal salts of sulphuric acid esters and sulphonic acids such as dinonyland dioctyl-sodium sulphono-succinates and alkali and alkaline earth metal salts of high molecular weight sulphonic acid derivatives such as sodium and calcium lignosulphonates. Examples of suitable solid diluents or carriers are aluminium silicate, talc, calcined magnesia, kieselguhr, tricalcium phosphate, powdered cork, absorbent carbon black and clays such as kaolin and bentonite. Examples of suitable liquid diluents include water, acetophenone, cyclohexanone, isophorone, toluene, xylene, and mineral, animal, and vegetable oils (these diluents may be used alone or in combination).

Herbicidal compositions according to the present invention may also contain, if desired, one or more conventional adjuvants such as adhesives, protective colloids, thickeners, penetrating agents, stabilisers, sequestering agents, anti-caking agents, colouring agents and corrosion S inhibitors. These adjuvants may also serve as carriers or diluents.

The preferred herbicidal compositions according to the present invention are water dispersible granules. Water Dispersible Granules (WG or WDG) formulations comprise small granules which disintegrate and disperse in water prior to application. Granules can be formed either by agglomeration or through the use of elevated pressure, for example, extrusion. Surface active agents, such as dispersants and wetting agents, are essential ingredients of the formulation. Clays, silicas and starch, among others, can be used as carriers.

35 Herbicidal compositions according to the present invention may also comprise ethametsulfuron methyl and diflufenican in association with, and preferably homogeneously dispersed in, one or more other pesticidally active compounds and, if desired, one or more compatible pesticidally acceptable diluents or carriers.

Preferred herbicidal compositions according to the present invention which comprise ethametsulfuron methyl and diflufenican in association with other pesticides, e.g. herbicides, are those wherein the other herbicide is for example terbutryn, metosulam, flumetsulam, imazethapyr, MCPA and sulfentrazone (which are particularly useful where the composition is to be applied to a lupin or canola crop locus).

The compositions of the invention may be made up as an article of manufacture comprising ethametsulfuron methyl and diflufenican and optionally other pesticidally active compounds as hereinbefore described, and as is preferred, a herbicidal composition as hereinibefore described and preferably a herbicidal concentrate which must be diluted before use, comprising the ethametsulfuron methyl and diflufenican within a container for the aforesaid ethametsulfuron methyl and diflufenican or a said herbicidal composition and instructions physically associated with the aforesaid container, setting out the manner in which the aforesaid ethametsulfuron methyl and diflufenican or herbicidal composition contained therein, is to be used to control the growth of weeds. The containers will normally be of the types conventionally used for the storage of chemical substances and concentrated herbicidal compositions, which are solids or liquids at normal ambient temperatures, for example cans and drums of plastics materials or metal (which may be internally-lacquered), bottles of glass and plastics materials; and when the contents of the container is a solid, for example a granular herbicidal composition, boxes, for example of cardboard, plastics material, metal or sacks. The containers will normally be of sufficient capacity, to contain amounts of the active ingredients or herbicidal compositions sufficient to treat at least one hectare of ground, to control the growth of weeds therein but will not exceed a size which is convenient for conventional methods of handling. Instructions will be physically associated with the container, for example by being printed directly thereon or on a label or tag affixed thereto. The directions will normally indicate that the contents of the container, after dilution if necessary, are to be applied to control the growth of weeds at rates of application from about 20g to about I100g of ethametsulfuron methyl and from about 35g to about I100g of diflufenican per hectare in the manner and for the purpose hereinbefore described.

According to a further feature of the present invention there is provided a method for controlling the growth of weeds at a locus which comprises applying to said locus:ethametsulfir on methyl, and diflufenican; with the exclusion of the method of controlling Emex australis at a lupin crop locus, which consists of applying ethametsulfutron methyl at a dose rate of 30g/ha, and diftufenican at a dose rate of in the presence of of 0.2% BSI000.

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They are generally applied at application rates of about 20g to about 100g/ha of(a) and from about 35g to about 100g/ha of(b), preferably from about 20g to about 50g/ha of and about 37.5g to about 100g/ha of(b). The method of the invention may be used to control a very wide spectrum of broadleaf weeds in crops, for example pulse crops (such as lupins, field peas, chick peas) and oil seed crops (such as canola), without significant permanent damage to the crop.

The combined use described above offers both foliar and residual activity and consequently can be employed over a long period of crop development, generally from pre-weed post-crop emergence to postweed post-crop emergence. Preferably the combination is applied postemergence, more preferably early post-emergence (of crops) By the term 'post-emergence application' is meant application to the aerial or exposed portions of the weeds which have emerged above the surface of the soil. By the term' early post-emergence application' is meant application to the aerial or exposed portions of the weeds which have emerged above the surface of the soil and are between the cotyledonous stage and the second to third leaf stage (or third and fourth whorl stage) of growth. By the term 'foliar activity' is meant herbicidal activity produced by application to the aerial or exposed portions of the weeds which have emerged above the surface of the soil. By the term 'residual activity' is meant herbicidal activity produced by application to the soil in which weed seeds or seedlings are present before emergence of the weeds above the surface of the soil, whereby seedlings present at the time of application or which germinate subsequent to application from seeds present in the soil, are controlled. Weeds that may be controlled by this method are generally broad leaved weeds and include, for example, Abutilon theophrasti, Adonis microcarpa, Ageratum conyzoides, Amaranthus retroflexus, Bidens pilosa, Brassica toumefortii, Capsella bursa-pastoris, Chenopodium album, Commelina nudiflora, Emex australis, Descurainia sophia, Galinsoga parviflora, Galeopsis tetrahit, Galium aparine, Lactuca serriola, Lamium amplexicaule, Polygonum spp, Portulaca spp, Raphanus raphanistrum, Rapistrum rugosum, Sida spp, Sinapis arvensis, Sisymbrium officinale, Sisymbrium orientale, Solanum nigrum and Stinkweed spp.

The pattern of persistence of ethametsulfuron methyl and diflufenican allows the method of the present invention to be practised by the time-separated application of separate formulations.

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-7- In accordance with the usual practice, a tank mix may be prepared prior to use by combining separate formulations of the individual herbicidal components.

The following Experiment illustrates the present invention.

EXPERIMENTAL PROCEDURE Ethametsulfuron methyl and Diflufenican The experiments were carried out post planting of the crop and post-emergence of the weed species at a research farm in York, Western Australia. A tank mix comprising ethametsulfuron methyl and diflufenican (referred to as DFF) was dissolved in water to give a solution containing the appropriate concentration of active ingredients.

Ethametsulfuron methyl (as the commercial formulation "Muster", trade mark, a soluble concentrate containing 75% and diflufenican (as the commercial formulation "Brodal", trade mark, an aqueous suspension concentrate) were also weighed out individually and dissolved in water to give a solution containing the appropriate concentration of active ingredient. Each solution was mixed and applied at a spray volume of 50 litres/hectare to a plot 3 metres by 20 metres comprising the weed population, which was naturally occurring, and crop species (lupin). A control plot was sprayed with a solution not containing test compound.

Visual assessment of phytotoxicity was made 20, 34 and 52 days after crop emergence for each weed species, and is shown as a percentage reduction in growth, based on a comparison with the control plot.

The table below shows the observed control of the weed species obtained by each herbicide alone and as a combination, with the figure in brackets representing the predicted value using the Colby formula where it is possible to calculate such values.

RESULTS

A. Weed Population: Wild Radish 52 Days after Treatment Table 1 Ethametsulfuron methyl Dose g/ha 0 22.5 DFF 0 14.25 45.75 77.25(53.7) Note that both herbicides and the mixture were formulated with the addition of a biodegradable wetter (BS1000).

According to a further feature of the present invention, there is provided a product comprising a synergistic herbicidally effective amount of ethametsulfuron methyl and diflufenican as a

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combined preparation for simultaneous, separate or sequential use in controlling the growth of weeds at a locus.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

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Claims (12)

1. A herbicidal composition comprising:- ethametsulfuron methyl, which is methyl 2-[(4-ethoxy-6- methylamino-1,3,5-triazin-2-yl)carbamoylsulfamoyl]benzoate; and diflufenican, which is N-(2,4-difluorophenyl)-

2-[3-(trifluoromethyl)phenoxy]-3-pyridinecarboxamide; in association with a herbicidally acceptable diluent or carrier and/or surface active agent. 2. A composition according to claim 1 with the exclusion of the weight ratio of of 1:1.67 in an aqueous composition containing 0.2% BS1000 which is an anionic wetting agent.

3. A composition according to claim 1 or 2 in which the weight ratio of(a) is from about 1:5 to about 2.85:1

4. A composition according to claim 1 or 2 in which the weight ratio of is from about 1:5 to about 1.33:1.

5. A method for controlling the growth of weeds at a locus which comprises applying to said locus:- ethametsulfuron methyl, which is methyl 2-[(4-ethoxy-6- methylamino-1,3,5-triazin-2-yl)carbamoylsulfamoyl]benzoate; and diflufenican, which is N-(2,4-difluorophenyl)- 2-[3-(trifluoromethyl)phenoxy]-3-pyridinecarboxamide; with the exclusion of the method of controlling Emex australis at a lupin crop locus, which consists of applying ethametsulfuron methyl at a dose rate of 30g/ha, and diflufenican at a dose rate of 50g/ha in the presence of 0.2% BS1000 which is an anionic wetting agent..

6. A method according to claim 5 using from about 20g/ha to about 100g/ha of ethametsulfuron methyl and from about 35g/ha to about 100g/ha of diflufenican.

7. A method according to claim 5 or 6 using from about to about 50g/ha of ethametsulfuron methyl and from about 37.5g/ha to about 100g/ha of diflufenican.

8. A method according to claim 5, 6 or 7 in which the weed species controlled include broadleaf weeds. 25 35 S. S *9S*55

9. A method according to claim 8 in which the broadleaf weed is wild mustard (Raphanus raphanistrum) or shepherd's purse (Capsella bursa-pastoris A method according to any one of claims 5 to 9 in which ethametsulfuron methyl and diflufenican are applied early post- emergence.

11. A product comprising:- ethametsulfuron methyl, which is methyl 2-[(4-ethoxy-6- methylamino-1,3,5-triazin-2-yl)carbamoylsulfamoyl]benzoate; and diflufenican, which is N-(2,4-difluorophenyl)-2-[3- (trifluoromethyl)phenoxy]-3-pyridinecarboxamide. as a combined preparation for simultaneous, separate or sequential use in controlling the growth of weeds at a locus.

12. A composition according to claim 1 substantially as hereinbefore described.

13. A method according to claim 5 substantially as hereinbefore described. 25 14. A product according to claim 11 substantially as hereinbefore described. S S S* *s 11 The steps, features, compositions and compounds disclosed herein or referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more of said steps or features. DATED this EIGHTEENTH day of SEPTEMBER 1998 Rhone-Poulenc Agro by DAVIES COLLISON CAVE Patent Attorneys for the applicant(s) S *S we S S.. S C *5 r°