HERBICIDE COMPOSITION

The present invention relates to a new approach to the protection of wheat crops from unwanted weeds, and to new compositions for this purpose utilising ethofumesate.

The control of unwanted weeds in wheat crops has been an problem in agriculture for decades. Many different herbicides have been used over the years to control and kill such weeds. However, problems have more recently been experienced with the use of many of these herbicides, as the weeds have developed a significant resistance against them over time. Problems include a present day standard pendimethalin and enhanced metabolism resistance. In some locations the conventional herbicides are therefore no longer sufficiently effective. In addition, other herbicides which were still effective are no longer allowed to be used in the concentrations required due to environmental considerations.

There is therefore a need for a herbicide which can be both effective at controlling or inhibiting the growth of unwanted weeds in wheat crops, and which is not damaging to the environment.

Ethofumesate (2-ethoxy-3,3-dimethyl-5-methylsulfonyloxy-2H-benzofuran) has been known as a herbicide since the 1970s. It was used for the control of cereal and other vegetation in sugar beet, but not for the control of weeds in wheat and other cereal crops. Weeds treated include knotgrass, redshank, black bindweed, cleavers, chickweed and annual meadow grass. The ethofumesate was conventionally used in large amounts, up to about 2000 grams of the active ingredient per hectare of grassland.

EP 113169 A (FBC Limited) discloses herbicidal formulations optionally containing ethofumesate. Ethofumesate is shown to be used as a foliar spray as a herbicide to control a wide range of weeds (including, in this case, wheat) in crops such as grassland and beet crops.

However, contrary to previous technical thinking in the field, it has now surprisingly been found that ethofumesate can in fact be effective as a herbicide for the

protection of wheat crops while controlling or inhibiting the growth of unwanted weeds, and for killing the weeds. It was found that ethofumesate was useful in, for example, post emergence winter wheat programmes, and for most present day varieties except Soissons.

Furthermore, in contrast to many of the existing herbicides which are used against grass weeds, ethofumesate is not known to have had any resistance shown against it by weeds.

Therefore, in accordance with the present invention, there is provided a use of, and/or a method of using, a composition comprising ethofumesate as a herbicide in the protection of wheat crops, with the proviso that the wheat crop is preferably not Soissons.

The use and method allows wheat to be grown whilst controlling or inhibiting the growth of surrounding weeds.

The composition is preferably applied to the crop via a hydraulic sprayer, post crop emergence, and acts primarily via root uptake.

Wheat, genus Triticum, exists as a number of types. Durum wheat (T. durum) and emmer wheat are tetraploid wheats. Hexaploid wheats include spelt wheat, compact wheat and bread wheat.

Preferably, the wheat is bread, or common, wheat, T. aestivum.

Preferably, the wheat is a winter wheat. Winter wheat is a wheat that is usually planted in autumn (such as September to December for the northern hemisphere), and typically harvested around August the following year. Most commercially available varieties of winter wheat may be treated with the compositions of the invention. Other wheat, such as autumn drilled spring wheat which has hardened off, may also be treated.

Soissons is preferably not used as the variety has been shown to have susceptibility to being killed by ethofumesate. Soissons is a variety bred by Maison Florimund Desprez (France) and has Jena x HN35 parentage. It is available from www.Elsoms.com.

The timing of the application of the ethofumesate is an important factor in the protection of the wheat crops. While ethofumesate may be herbicidally effective against wheat plants at very early stages of growth, once the wheat plant reaches a certain stage of growth, the ethofumesate is no longer significantly herbicidally effective against it. It is therefore preferred that a composition comprising ethofumesate is applied to the wheat either pre emergence or not before ZCK 12 or 13. While there is no definitive latest cut-off point for applying the ethofumesate, it is often not applied after ZCK 25 as the weed can be too large for the ethofumesate to be sufficiently effective, hi some seasons, the cut-off point can be later still, up to ZCK 30 or 31 if the weeds are small or if the ethofumesate is being used as a soil residual.

ZCK refers to the Zadoks scale, which quantifies the development and growth of cereal grains. The scale is based on ten principal plant development stages, which are divided into secondary stages. A new leaf is counted as fully emerged when 50 percent of the leaf blade has unfolded. Two or more codes may be used to describe a plant using the Zadoks scale. For example, wheat that has six leaves unfolded (16), three tillers (23) and one node on the main stem (31) would be staged as 16,23,31. A full tabulated explanation of the various stages is given below.

This table and its explanation of the various stages can be found at e.g. http://weeds.rnontana.edu/crop/Growth_stages_book/p22_23.htm .

More preferably, the composition is applied pre emergence or post emergence to the wheat after ZCK 12 or 13 at the earliest, most preferably between ZCK 13-21, especially if the crop is healthy. In the event that the crop is not considered to be healthy at ZCK 13, the composition can be applied at a later stage when it is considered by the skilled person to be sufficiently healthy.

In contrast to ethofumesate compositions used previously in the control of wheat crops, according to the present invention, the composition may be applied to the wheat such that only an amount of ethofumesate of between about 50 grams active/ha and about 800 grams active/ha, preferably at least 62.5 grams active/ha, or at least 200 grams active/ha is applied. This is equivalent to about 1-4 litres of formulated product (200gramme formulated product) per hectare, as compared with the 10 litres of formulated product (2000 grams active per hectare) which was previously used. This represents a significant reduction in the quantity of ethofumesate required.

Preferably, the composition is applied to the wheat such that an amount of ethofumesate of about 600 grams active/ha is applied to the wheat crops in any formulation.

Ethofumesate may be used alone in the protection of wheat crops, or alternatively may be used in combination with one or more further herbicides. Examples of such further herbicides include phenmedipham, pendimethalin, trifluralin, iodosulfuron, mesosulfuron, isoproturon (IPU), chlorotoluron (CTU), flufenacet, diflufenican (DFF), flurtamone, picolinofen, tribenuron, fenoxaprop, clodinafop, bromoxynil, ioxynil, flupyrsulfuron- methyl, pinoxaden, pyroxsulam and mixtures and combinations thereof.

Other herbicides, such as IPU, CTU and trifluralin are facing opposition to their use due to concerns about their impact upon the environment. The use of ethofumesate of the invention would be a substitute for them.

Additionally, other herbicides, the effectiveness of which has diminished against the weeds, are effective in combination with the ethofumesate.

Optionally, some of the active ingredients may include substances as safeners, such as cloquintocet-methyl with clodinafop and mefenpyr-methyl with fenoxaprop, for example.

Preferably, the one or more further herbicides are selected from iodosulfuron, +/- mesosulfuron, pendimethalin, +/-picolinofen, flufenacet, and +/-DFF.

When more than one further herbicides are combined with ethofumesate, these further herbicides can include mixtures of iodosulfuron with mesosulfuron (marketed by Bayer under the trade name Atlantis), flufenacet with DFF (marketed by Bayer under the trade names Firebird and Liberator), flurtamone with DFF, pendimethalin with picolinofen, clodinafop with trifluralin (marketed by Syngenta under the trade name Hawk), bromoxynil with ioxynil, clodinafop with DFF, clodinafop with pinoxaden, and fenoxaprop with IPU.

As well as ethofumesate itself, sources of ethofumesate which may be used in the invention comprise Leyclene (a mixture ethofumesate, bromoxynil and ioxynil; sold under that trade name by Bayer), or a mixture of phenmedipham and ethofumesate, the latter being useful in later growth stages.

Typical ethofumesate formulations used in the present invention include 200 g/1 EC and 500 g/1 SC (EC = Emulsifiable Concentrate, SC = Suspension Concentrate).

Optionally, the compositions used in the invention can also comprise one or more adjuvants. These can be any adjuvants which are authorised for use in herbicidal formulations, but are preferably selected from oil based adjuvants and mixtures, organosilicone based adjuvants and mixtures, non-ionic based adjuvants and mixtures, polymeric based adjuvants and mixtures, and fatty acid based adjuvants and mixtures, and combinations thereof.

Weeds are usually considered to be plants that grow among cultivated plants, such as wheat crops, and compete with the crop for space, nutrients, water, etc.

In its protection of the wheat crops, the ethofumesate-containing composition is used to control or inhibit the growth of weeds, and also preferably to kill the weeds.

Preferred target weeds are grasses, such as blackgrass (Alopecurus myosurides), annual meadow grass (Poa annua), knotgrass, chickweed, cleavers, redshank and/or black bindweed.

Also provided in accordance with the present invention is a composition comprising ethofumesate and one or more further herbicides. Examples of further herbicides include pendimethalin, trifluralin (sold for example under the trademark "Treflan" by Dow Agrosciences or in combination with diflufenican as Ardent ^tm by Bayer Crop Sciences), iodosulfuron, mesosulfuron, isoproturon (IPU), chlorotoluron (CTU), flufenacet, diflufenican (DFF), flurtamone, picolinofen, tribenuron, fenoxaprop, +/- clodinafop ( for example sold under the trademark Topik by Syngenta), flupyrsulfuron- methyl (for example sold under the trademark Lexus by DuPont), pinoxaden, and combinations thereof.

Preferably, the one or more further herbicides are selected from iodosulfuron, +/- mesosulfuron, pendimethalin, +/-picolinofen, flufenacet, and +/-DFF.

When more than one further herbicides are combined with ethofumesate, these further herbicides can include mixtures of iodosulfuron with mesosulfuron (marketed by

Bayer under the trade name Atlantis), flufenacet with DFF (marketed by Bayer under the trade names Firebird and Liberator), flurtamone with DFF, pendimethalin with picolinofen, clodinafop with trifluralin (marketed by Syngenta under the trade name

Hawk), bromoxynil with ioxym ^' L clodinafop with DFF, clodinafop with pinoxaden, and fenoxaprop with IPU (marketed by Bayer under the trade name Puma). Pendimethalin is marketed under the trademark "Stomp" by BASF.

Optionally, the compositions comprising more than one further herbicides can also comprise one or more adjuvants. These can be any adjuvants which are authorised for use in herbicidal formulations, but they are preferably selected from oil based adjuvants and mixtures, organosilicone based adjuvants and mixtures, non-ionic based adjuvants and mixtures, polymeric based adjuvants and mixtures, and fatty acid based adjuvants and mixtures, and combinations thereof.

Preferably, the composition comprises between about 50 to about 500 g/1 of ethofumesate, and between about 1 to about 1500 g/1 of any further herbicide component. More preferably, the composition comprises between about 75 to about 250 g/1 of ethofumesate, and between about 75 to about 1250 g/1 of any further herbicide component. Still more preferably, the composition comprises between about 90 to about 200 g/1 of ethofumesate, and between about 90 to about 800 g/1 of any further herbicide component.

Also in accordance with the present invention is provided a method of controlling or inhibiting the growth of weeds and of killing weeds associated with wheat crops comprising applying a herbicidally effective amount of ethofumesate alone or a composition containing ethofumesate and one or more further herbicides as described above.

Experimental data shows that ethofumesate is as least as or more efficient in controlling and killing blackgrass as any other residual partners currently used, and that it achieves high activity against annual meadow grass even at low concentrations.

The invention will now be further explained by reference to the following examples, which are intended to be illustrative only, and in no way limiting upon the scope of the invention.

Examples

STANDARD OPERATING PROCEDURES

1 This Standard Operating Procedures describe the equipment most commonly used for application of the test material, its calibration and general maintenance.

2 REQUIREMENTS

2.1 Knapsack Sprayers

Where a knapsack sprayer is used to apply the treatment to the required crop, the propellant source (e.g.CO ₂ /compressed air) is attached to a vessel containing the appropriate treatment. This pressurises the vessel so that when the valves are opened, the spray is forced out of the bottle and through the boom.

The gas bottle is attached to a regulator to control the amount of gas entering the vessel and the pressure is monitored by a gauge attached to the handle of the sprayer.

Each boom is individually numbered.

2.1.1 Nozzles and Filters

The number of nozzles present on the boom are either 4 (2m swath) or 6 (3m swath) at 50 cm spacing or 5 (2m swath) at 40cm spacing.

Low Drift 110° flat fan tips are most commonly used. Occasionally other nozzle types may be used for specialised purposes.

2.1.2 Calibration

The output required from each nozzle per minute is calculated using a typical formula such as :

Output (1/min) =

spray vol (1/ha) x forward speed (km/li) x nozzle spacing (m) 600

for example if spray volume = 200 1/ha forward speed = 3.6 km/h (= lm/sec) nozzle spacing = 0.5 m

output required = 20O x 3.6 x 0.5

600 = 0.6 1/min

Once the required output is determined the boom can then be calibrated. This is done by measuring the output from each nozzle at a specified pressure over a given period of time. The pressure can then be adjusted to give the required output within a 5% tolerance. A check for satisfactory atomisation is also made at this point and any errant nozzles are replaced and the calibration procedure repeated.

If the correct output cannot be achieved within the manufacturers specified pressure range, smaller or larger nozzles will be fitted and the process repeated.

The calibration procedure is carried out at least before commencement of spray season i.e. Autumn and Spring and as soon as possible after any nozzles need to be replaced in the field.

2.1.3 Maintenance

When spraying is finished the canisters and the spray boom are thoroughly cleaned using water and All Clear® Extra. If a pesticide is sprayed that requires a specific cleaner then this cleaner will be used.

2.2 Granule application

Granule applications are normally made by the use of a Pepperpot.

2.3 Seed Treatment

Seed is normally provided pre-treated by an Officially Recognised Efficacy Testing Facility or Organisation.

Tables 1-8 below detail the data obtained from applying compositions comprising ethofumesate onto crops to control the growth of blackgrass over a number of years, 2003-2006.

Materials and Method

AU trials carried out were of a small plot with a randomised block design. Generally plot size was around 20m ² replicated 3-4 times.

The trials were conducted in commercial fields with a known blackgrass problem. Each plot was marked with canes and measures were undertaken to ensure no overspray from the grower.

AU applications were made using a hand held boom. The chemical was applied in an application volume of 200 1/ha.

Assessments of crop selectivity were carried out using the accepted crop visual score and weed control carried out by either quadrant counts or a visual assessment of overall control per plot.

Results - Harvest year 2003: Ethofumesate crop selectivity and activity when used as final residual partner

Table 1

Crop Safety Assessments

Application Date Crop Size Damage

25-Nov ZCK 12 Equivalent to standards

(some effects from pre emergence)

Crop effects equivalent to standards observed.

% Weed Control Table 2

ZCK 12 3 Weeks after ZCK 12 % Control

Untreated Untreated 25% g/c

Standards

Lexus 2Og + Topik 0.125 + Protugan Plus 4.0 100

Galion 0.5

Lexus 2Og + Topik 0.125 + Ethofumesate 200gai 100

Galion 0.5

Lexus 2Og + Topik 0.125 + Ethofumesate 400gai 98.3

Galion 0.5

Lexus 2Og + Topik 0.125 + Ethofumesate 800gai 100

Galion 0.5

Lexus 2Og + Topik 0.125 + Ethofumesate 400gai + Simazine 240gai 99.3 Galion 0.5

Lexus 20g + Topik 0.125 + Ethofumesate 400gai + Simazine 240gai 99

Galion 0.5 + Grounded 0.2

Lexus 2Og + Topik 0.125 + Ethofumesate 400gai + Simazine 240gai 100 Galion 0.5 + Kinetic 0.05%

(The figures 0.5 and 0.125 etc means 0.5 and 0.125 1/ha of the formulated product applied)

AU treatments except untreated for a pre-emergence application of Trooper + Treflan.

Galion is an adjuvant (oxyalkylene glycol)

Conclusions - 2003

Protugan Plus was a mixture of isoproturon and simazine and has been removed from the market due to environmental issues with simazine. The data clearly shows that ethofumesate alone is as effective as this product when used in programmes, with no loss in weed control or effect on crop safety. It is therefore an ideal environmentally friendly replacement for the now unavailable Protugan Plus.

Results - Harvest Year 2004: To confirm crop selectivity by means of harvested yield and activity as the Atlantis/Lexus Partner and final residual

Table 3

Pre emergence October November % Blackgrass Yield Control T/ha

Untreated Untreated Untreated 333 hds/m2 1.1

Atlantis 0.4kg + Stomp 3.3 + 23.33 BioPower 1.0

Atlantis 0.4kg + Ethofumesate 23.33 6.2 400 gai + BioPower 1.0

Trooper 4.0 + Lexus 2Og + Stomp 3.3 + 16.67 5.9

Treflan 2.0 Galion 0.5 Trooper 4.0 + Lexus 2Og + Stomp 3.3 + Ethofumesate 200 gai 40 6.9

Treflan 2.0 Galion 0.5 Trooper 4.0 + Lexus 2Og + Stomp 3.3 + Ethofumesate 400 gai 70 7.1

Treflan 2.0 Galion 0.5 Trooper 4.0 + Lexus 2Og + Stomp 3.3 + Ethofumesate 800 gai 91.67 8.6

Treflan 2.0 Galion 0.5 Trooper 4.0 + Lexus 2Og + Ethofumesate 26.67 6.4

Treflan 2.0 400 gai

Trooper 4.0 + Atlantis 0.4kg + Stomp 3.3 + 75 8.4

Treflan 2.0 BioPower 1.0

Trooper 4.0 + Atlantis 0.4kg + Ethofumesate 78.33 8.6

Treflan 2.0 400 gai + BioPower 1.0

BioPower is an alkylethersulphate sodium salt adjuvant (Bayer Crop Science Ltd)

Conclusions - 2004

1) It can clearly be seen from Table 3 that the presence of ethofumesate has a positive effect upon the percentage of blackgrass control. Treatment with Lexus 2Og + Stomp 3.3 + Galion 0.5 in October with no ethofumesate treatment in November gave a poor degree of control, only 16.67%. However, in comparison, the introduction of ethofumesate in November greatly increases the degree of control, with an approximately 250% increase for 200 gai up to a 550% increase for 800 gai.

2) Also, when ethofumesate replaces Stomp® (a pendimethalin-containing herbicide) in the October treatment, the degree of control of blackgrass again increases.

3) Ethofumesate could replace IPU or Stomp in programmes or as a tank mix partner. There are no issues in crop safety with regard to the standard and this is reflected in the yield of crop per hectare achieved. In non pre-emergence programmes, ethofumesate is as crop safe as Stomp (giving equivalent yields). Clearly, without the ethofumesate programme, the level of weed control was unacceptable. While Stomp has been an effective herbicide, there are serious concerns that the weeds have developed a resistance to it, particularly when it is used post-emergence.

Harvest Year 2005: To demonstrate ethofumesate activity as an Atlantis partner or when used alone as a final residual herbicide.

Table 4

Application Date Crop Size Damage

26-Oct ZCK 13 No

03-Mar ZCK 22-23 No

Table 5

Blackgrass

Mid October (+ BYDV all plots) Spring % Control 16/06/2005

Untreated Untreated

Standard

Atlantis 0.4 + Stomp 2.5 + BioPower 1.0 83

Atlantis 0.4 + Ethofumesate 400 gai + BioPower 1.0 80 Atlantis 0.4 + Ethofumesate 600 gai + BioPower 1.0 83 Atlantis 0.4 + Ethofumesate 800 gai + BioPower 1.0 83 Atlantis 0.4 + Liberator 0.6 + BioPower 1.0 83

Standards

Atlantis 0.4 + Alpha Trifluralin 2.0 + BioPower 1.0 Stomp 2.5 80 Atlantis 0.4 + Alpha Trifluralin 2.0 + BioPower 1.0 IPU 1500 gai 77

Atlantis 0.4 + Alpha Trifluralin 2.0 + BioPower 1.0 Ethofumesate 400 77 gai Atlantis 0.4 + Alpha Trifluralin 2.0 + BioPower 1.0 Ethofumesate 600 80 gai Atlantis 0.4 + Alpha Trifluralin 2.0 + BioPower 1.0 Ethofumesate 800 78 gai

Conclusions - 2005

When used as a tank mix partner with October Atlantis, ethofumesate gave equivalent levels of control as the standards (Stomp and Liberator). When used as a final residual in the spring, following autumn Atlantis applications it was again comparable to the standards. No crop effects were observed at any timing.

Results Harvest Year 2006

Experiment 1: To establish crop safety and selectivity of ethofumesate when used a partner with Firebird

Table 6

Application Date Crop Size Damage

31-Oct ZCK 13-21 No

17-Nov ZCK 21-23 No 03-Mar ZCK 25 No

Table 7

Blackgrass

November Crop (3 leaf Plus) % Control

21/02/2006

Prior to Atlantis

Untreated 58 ρlants/m2

Liberator 0.3 + Treflan 2.0 69

Firebird 0.3 + Treflan 2.0 66.7

Firebird 0.3 + Ardent 1.0 + Treflan 1.0 59.8

Firebird 0.3 + Ardent 1.5 + Treflan 0.75 49.4

Firebird 0.3 + SIP 31529 0.2 55.2

Firebird 0.3 + Ethofumesate 60Og 86.3

Present Standards

Trooper 2.0 + Treflan 2.0 78.2 Stomp 3.3 52.9

All follow the same pre-emergence application (except untreated)

Conclusions - Experiment 1 2006

Ethofumesate mixes again show good crop selectivity. When mixed with Firebird instead of Treflan and Ardent, the ethofumesate gave a degree of weed control which is significantly superior to the herbicides which are presently use as partners for Firebird. Additionally, when mixed with Firebird, the ethofumesate gave a weed control which is significantly superior to the present day standards.

Experiment 2: 2006

Table 8

Autumn Post-em (ZCK 11-12 T2 + 10 days Spring Treatment Blackgrass

Blackgrass) including BYDV % Control

Untreated Untreated Untreated 586 heads/m2

Atlantis 0.4 + Firebird 0.3 + Treflan 2.0 100

Biopower 1.0

Lexus 2Og + Stomp 3.3 PU 150Og + Treflan 2.0 68.9

Atlantis 0.4 + Firebird 0.3 + Ethofumesate 600gms 99.9

Biopower 1.0

IPU 1500g + Treflan 2.0 Atlantis 0.4 + 88.1

Biopower 1.0

Firebird 0.3 + Treflan 2.0 Atlantis 0.4 + 87

Biopower 1.0

Conclusions - Experiment 2 2006

Again Ethofumesate shows good crop selectivity as the final residual herbicide, and gives weed control which is comparable to the Atlantis + Firebird followed by Treflan programme, and which is also significantly better than the other existing programmes. Treflan, however, is in danger of being removed from the market.

Ethofumesate provides a novel opportunity to introduce a new active into blackgrass and annual meadow grass programmes. It can replace present day actives, which are either showing some degree of resistance or are under review from environmental issues.

Chickweed Treatment

The attached table shows that ethofumesate may be used to successfully control chickweed at concentrations as low as 62 grams active ingredient/ha.

Table 9

*Trt No: Treatment Number

2007 Experiment: Pre emergence use of ethofumesate in wheat

To establish the crop safety and weed control from pre-emergence of ethofumesate mixtures in Winter Wheat

Trial and Crop Details

Crop: Winter Wheat

Variety: Cordiale

Drilling Date: 28/9/07

Soil Type: Sandy Clay Loam

Previous Treatment: : None

Previous Crop: Winter Wheat

Application Date: Oct 1 2007

Results

See table below for overall weed control.

Trooper (BASF) contains flufenacet and pendimethalin Firebird (Bayer) contains flufenacet and diflufenican Diflanil contains diflufenican Ethostat contains ethofumesate

At this pre emergence timing, the overall weed control can equal the standard Trooper or even surpass the standard. No adverse crop effects were seen at any assessment timing. This timing has proved very crop safe, even up to eight weeks after application. No crop loss in vigour or establishment was noted.