AU2019203764A1

AU2019203764A1 - Method and composition for weed control

Info

Publication number: AU2019203764A1
Application number: AU2019203764A
Authority: AU
Inventors: Anthony Flynn; Philip Pentland
Original assignee: Farmalinx Pty Ltd
Current assignee: Farmalinx Pty Ltd
Priority date: 2019-05-29
Filing date: 2019-05-29
Publication date: 2020-12-17

Abstract

A method of controlling seed-set of wild oats in a crop of kabuli chickpea comprising applying flamprop-m-methyl to the crop by crop-topping.

Description

METHOD AND COMPOSITION FOR WEED CONTROL

Field

[0001] This invention relates to a method and composition for the control of wild oats (Avena spp) in kabuli chickpea crops, particularly, seed-set of wild oats in a kabuli chickpea crop.

Background

[0002] Chickpea (Cicer arietinum) is a broadleaf winter crop well suited to some areas of Australia. Chickpea growth during winter months is very slow but accelerates in spring as the weather warms. There are two groups of chickpea - desi and kabuli - mainly distinguished by seed size, shape and colour. The two types have different production requirements, markets and end-uses. Australia is one of the world's largest producers of chickpea, particularly desi chickpea.

[0003] Chickpea is less competitive against weeds than some other crops and control of weeds in chickpea crops is problematic leading to very significant crop reduction unless long term strategies for weed control are adopted.

[0004] Broadleaf weeds and grass weeds, particularly wild oats, cause major problems and a careful management strategy must be worked out well in advance. Industry bodies generally recommend control of weeds in the year prior to sowing chickpea or to avoid paddocks with specific weeds that cannot be controlled by the available herbicides.

[0005] Chickpeas are poor competitors with wild oats because these they have relatively slow germination rates and relatively slow early growth. Weed control is essential if the chickpea crops are to make full use of rainfall, stored soil moisture and nutrients, and to prevent weed seeds from contaminating the grain at harvest. It is desirable that chickpeas should be planted into planned paddocks that have low weed populations. An important part of paddock planning is to reduce the number of weed seeds that are carried over from the previous year.

[0006] A weed control strategy for growing a successful chickpea crop may be based on substantially reducing the viable weed seedbank in the soil before the chickpea crop emerges.

[0007] Trials in northern New South Wales and central Queensland have shown that populations of ten wild oats per square metre can cut yields by as much as 40 % (D White 2000 and J Whish 1998).

[0008] The weed control strategy for growing a successful chickpea crop depends on substantially reducing the viable weed seed bank in the soil before the crop emerges. The currently used strategy for weed control, including wild oats control, in chickpea crops includes control of the majority of weeds before seeding of the chickpea crop, either by cultivation or the use of broad spectrum knockdown herbicides such as glyphosate, paraquat and diquat and their mixtures.

[0009] The use of herbicide in control of wild oats has led to the development of herbicide resistant biotypes of wild oats including resistance to some broad spectrum herbicides used in reducing weeds in land proposed for chickpea cultivation. Group A herbicide-resistant wild oats are becoming a key threat to sustainable farming systems in Australia and around the world. The threat is significant in the production of chickpea crops, because for these crops, farmers in Australia only have Group A herbicides available for post-emergent control. Improved methods for controlling Group A-herbicide resistant wild oats in chickpeas would be very useful.

[0010] Group A herbicides (inhibitors of fat synthesis/AACase inhibitors) include aryloxyphenoxypropionates (FOPs) e.g. diclofop, cyclohexanediones (DIMs) e.g. clethodim, and phenylpyrazoles e.g. pinoxaden.

[0011] Crop-topping, also referred to as spray-topping, is an option used in some crops such as wheat to prevent weed seed-set. The terms "crop-topping" and "spray topping" refer to the application of herbicide at a sub-lethal rate of when grassy weeds are coming into head and flowering. The aim is to reduce the production of viable seed and of seedlings in the following year. Trials using this weed control technique have shown it is not an option in chickpea crops. For example the Western Australian Department of Primary Industries "Mingenew 2017 trial report" (18 January 2018) shows that the yield of chickpea crop-topped at the right time to control weed seed set was 59% of the unsprayed control. The report states that even with the earliest maturing lines of chickpea available crop-topping is not a viable option for use in chickpea crops in the northern agricultural region.

[0012] Australian Pulse Bulletin November 2018 also advises that crop-topping of chickpea usually leads to unacceptable yield and quality problems as the grain will be too immature at the correct weed maturity stage.

[0013] There is a need for an improvement in weed control in chickpea crops, particularly in control of wild oats in chickpea crops.

Summary

[0014] We have now found that the seed-set of wild oats in kabuli chickpea is effectively controlled by applying by crop-topping the crop with the herbicide flamprop-m-methyl [IUPAC name methyl (2R)-2-(N-benzoyl-3-chloro-4-fluoroanilino) propanoate]. The control of seed-set of wild oats in kabuli chickpea is particularly effective with minimal crop damage if flamprop-m-methyl is applied at a certain growth stages of the kabuli chickpea. The control of wild oat seed set is particularly effective for the PBA Monarch variety of kabuli chickpea.

[0015] Accordingly, there is provided a method of controlling seed-set of wild oats in a crop of kabuli chickpea comprising applying flamprop-m-methyl to the crop by crop-topping.

[0016] The method of any one of the previous claims, wherein the flamprop-m methyl is applied to the chickpea crop when it has at least commenced its reproductive phase characterised by the formation of flowerbuds on the lower-most node of the chickpea plant. In a preferred embodiment the herbicide is applied by crop-topping at a growth stage of at least BBCH 51 such as at least BBCH 55. In one embodiment the herbicide is applied by crop-topping at a growth stage of at most BBCH 64.

[0017] In a preferred set of embodiments the method comprises applying flamprop-m-methyl to kabuli chickpea crop at a crop growth stage of BBCH 63 or less, more preferably BBCH 62 or less, even more preferably BBCH 61 or less, and yet more preferably BBCH 60 or less. Accordingly the flamprop-m-methyl is typically applied within the kabuli chickpea growth stage of BBCH 51 to BBCH 64, preferably BBCH 51 to BBCH 63, more preferably BBCH 51 to BBCH 62, even more preferably BBCH 51 to BBCH 61, and yet more preferably BBCH 51 to BBCH 60 such as BBCH 55 to 60.

[0018] The growth stages of chickpea may also be distinguished according to reproductive stages referred to as "R-"stages which are widely used in the Australian chickpea industry. In one set of embodiments the flamprop-m-methyl is applied to the crop by crop-topping when the crop has at least reached chickpea R-stage R1. In a further embodiment the flamprop-m-methyl is applied to the kabuli chickpea crop no later than the middle of flowering, characterised by the opening of about 40% of flowerbuds to form open flowers.

[0019] In one set embodiments the spray topping occurs at a growth sage of the chickpea no later than R-5 and preferably no later than R-4.

[0020] The flamprop-m-methyl is preferably applied to the crop by spraying a spray-mixture comprising a flamprop-m-methyl composition in a liquid diluent, typically water, suitable for spray application. The composition may, and preferably will be applied by spraying the spray-mixture over the Kabuli chickpea crop containing the wild oats weeds. Such a method may be referred to as "crop-topping" and "spray-topping". The spray-mixture may be prepared from a range of types of herbicide concentrates of flamprop-m-methyl such as concentrated emulsions (CE), emulsifiable concentrates(EC), water dispersible granules (WG) and suspension concentrates (SC). The method preferably comprises forming the spray-mixture from an emulsifiable concentrate (EC).

[0021] The flamprop-m-methyl may be applied to the chickpea crop at a range of rates depending on the specific stage of the crop development and the presence of any adjuvants in the applied composition of flamprop-m-methyl. In one set of embodiments the flamprop-m-methyl is applied to Monarch chickpea crop at a rate grams/hectare to 600 grams/hectare, preferably 100 grams/hectare to 450 grams/hectare such as130 grams/hectare to 300 grams/hectare.

[0022] It is generally preferred that the flamprop-m-methyl is applied to the crop of chickpea, such as PBA Monarch variety, in a spray-mixture comprising a spray-oil such as a paraffin or vegetable derived spray-oil.

[0023] In one set of embodiments, the wild oat weeds in the chickpea crop are resistant biotypes of wild oats, for example biotypes which are resistant to at least one herbicide having a Group A mode of action. Examples of Group A herbicides include Clethodim, Haloxyfop, Quizalofop, Butroxydim.

Detailed Description

[0024] Throughout the description and the claims of this specification the word "comprise" and variations of the word, such as "comprising" and "comprises" is not intended to exclude other additives, components, integers or steps.

[0025] The term "emulsifiable concentrate" (EC) refers to a formulation in which a water-insoluble active, such as flamprop-m-methyl, is dissolved a water-immiscible solvent and contains an emulsifier including one or more surfactants, so that the solution will form an oil-in-water emulsion, when diluted with water, for example in forming a spray-mixture of flamprop-m-methyl.

[0026] Herbicide resistance is the ability of a weed biotype to survive an herbicide application, where under normal circumstances that herbicide applied at the recommended rate would kill the weed. Herbicide resistance is generally an inherited trait governing the ability of the plant to survive and reproduce following a dose of herbicide normally lethal to the wild type. In contrast, plant tolerance to a particular herbicide is the inherent ability of that plant species to survive and reproduce after treatment with that herbicide [Weed Technology Volume 12, Issue 4 (October-December) 1998, p789]. There is no selection involved (through herbicide application) because the species is naturally tolerant. A weed population is defined as resistant when a herbicide that once controlled the population is no longer effective (sometimes an arbitrary figure of 20% survival is used). The proportion of herbicide resistant individuals will rise due to selection pressure in situations where one herbicide mode of action (MOA) group is applied repeatedly. In Australia all herbicides are classified into groups based on their MOA. MOA group classifications can be found on all herbicide labels, to identify the group to which a herbicide belongs.

[0027] The term "adjuvant" as used herein is a broad term, and is to be given its ordinary and customary meaning to a person of ordinary skill in the art (and is not to be limited to a special or customized meaning), and refers without limitation to an agent that modifies the effect of other agents and more particularly used to enhance the effectiveness of the herbicide, particularly the flamprop-m-methyl or modify the physical characteristics of the mixture.

[0028] The term "spray-mixture" refers to the active herbicide and other components of the herbicide concentrate composition in a liquid diluent, particularly water, suitable for spray application. The spray-mixture may contain adjuvants such as surfactant and spray-oils which are either part of the herbicide concentrate, added during preparation of the spray-mixture or both.

[0029] Flamprop-m-methyl (IPUAC name methyl (2R)-2-(N-benzoy-3-chloro-4 fluoroanilino) propanoate) is a selective translocated post-emergence herbicide variously allocated to the Group Z category of herbicide modes of action (MOA) and the Group K category of herbicide MOA. Flamprop-m-methyl is commercially available from a number of suppliers throughout Australia, including Farmoz (Farmoz Judgement Herbicide), TGAC Australia Pty Ltd (Macphersons Mavro 90 EC Selective Herbicide), Titan (Titan Flamprop 90 Herbicide), and Nufarm (Mataven 90 Herbicide).

[0030] The terms "crop-topping" and "spray-topping" refer to the spray application of herbicide spray-mixture over the crop to inhibit weed seed set. In the present method the herbicide flamprop -m-methyl may be applied by crop-topping of the kabuli chickpea crop, such as PBA Monarch chickpea crop, when grassy weeds, particularly wild oats, are coming into head and flowering. The method reduces grain contamination of the chickpea crop and the impact of wild oats seed set on future crops at the site of the crop-topping. As a result the effect of wild oats seed set on future crops is significantly reduced, particularly for future crops of kabuli chickpea such as kabuli chickpea of PBA Monarch variety.

[0031] Crop-topping is usually applied by ground application such as boom spray but can be applied by aerial applications, particularly for example when the ground is wet.

[0032] Ground application may involve a process of calculating the area to be sprayed with the tank load and adding the correct amount of product to the water in the spray tank. Flamprop-m-methyl EC may be applied, for example, at spray volumes of 30-100 litres per hectare with spray equipment producing MEDIUM spray droplets according to the ASAE S572 for standard nozzles.

[0033] Aerial application may be carried out using any fixed-wing aircraft, properly calibrated, may be used to apply flamprop-m-methyl EC. Flamprop-m methyl spray volumes of 20-30 litres per hectare preferably 30 litres per hectare with spray equipment producing MEDIUM spray droplets according to the ASAE S572 for standard nozzles.

[0034] Labels governing the use of flamprop-m-methyl in broadacre agriculture in Australia instruct the end user that the composition is for the control of wild oats (black oats) in wheat and triticale and crop-topping of wild oats in wheat only. Wheat and triticale are grasses (as is wild oats) and are considerably different from broadleaf plants such as chickpeas including kabuli chickpea of PBA Monarch variety. These differences have a bearing on the weed management programs understood to be required for weed control in these different crops. Flamprop-m methyl while effective as a crop-topping application in wheat is not effective in triticale and indeed commercial labels of flamprop-m-methyl warn users not to apply the herbicide to triticale by crop-topping (spray-topping). In contrast with wheat and triticale chickpeas are weak competitors with grassy weeds such as wild oats. As a consequence different weed management practices have been required for chickpea crops and the use of crop-topping (or spray-topping) on chickpea with the herbicides tested to date has led industry bodies to provide strong warnings against this practice in chickpea crops.

[0035] The finding that crop-topping using the herbicide flamprop-m-methyl at a certain stage of the chickpea variety's development would allow effective control of seed set of wild oats without significant crop damage was therefore unexpected.

[0036] The method may involve applying flamprop-m-methyl at a rate sufficient to effectively control seed set of the wild oats present in the crop of kabuli chickpea, such as PBA Monarch variety, without substantial damage to the kabuli chickpea.

[0037] The method involves application of flamprop-m-methyl to the crop of kabuli chickpea. The optimum application rate of the formulation will depend on the specific formulation of flamprop and any adjuvants present which may influence the efficacy of the herbicide. In one set of embodiments the method comprises applying flamprop-m-methyl, preferably in the form of a spray-mixture at a rate of application per hectare of flamprop-m-methyl in the range 40 grams/hectare to 600 grams/hectare, preferably 100 grams/hectare to 450 grams/hectare, even more preferably 130 grams/hectare to 300 grams/hectare.

[0038] The effectiveness of the crop-topping is particularly evident when carried out by applying flamprop-m-methyl within the growth stage of kabuli chickpea of BBCH 51 to BBCH 64, preferably BBCH 51 to BBCH 63, more preferably BBCH 51 to BBCH 62, even more preferably BBCH 51 to BBCH 61, and yet more preferably BBCH 51 to BBCH 60. During this growth stage damage to the crop and contamination of seed is minimised.

[0039] In one set of embodiments the method comprises at least two applications of flamprop-m-methyl including an application of flamprop-m-methyl within the growth stage of kabuli chickpea, such as PBA Monarch variety, of BBCH 51 to BBCH 64, preferably BBCH 51 to BBCH 63, more preferably BBCH 51 to BBCH 62, even more preferably BBCH 51 to BBCH 61, and yet more preferably BBCH 51 to BBCH 60 and a second application of flamprop-m-methyl takes place at a later time within the crop growth stage window of BBCH 51 to BBCH 64.

[0040] In one set of embodiments a flamprop-m-methyl application rate of about 170 +/- 40 g/hectare is used for crop areas with a relatively modest infestation of wild oats and an application rate of about 340 +/- 70 g/hectare is used for crop areas with a relatively high infestation of wild oats. Wild oats generally grow in patches of low to moderate densities of up to 100 plants per square metre. Accordingly the term high infestation of wild oats refers to wild oats densities of over 100 plants per square metre.

[0041] The composition of the flamprop-m-methyl may be in a range of formulation types such as concentrate emulsion (CE), emulsifiable concentrate (EC), water dispersible granules (WG) or powders. In a preferred embodiment the flamprop-m-methyl is provided in the form of an emulsifiable concentrate (EC).

[0042] In one set of embodiments the method comprises applying the flamprop m-methyl to the crop from a spray mixture formed from an EC that comprises a concentration of flamprop-m-methyl, of 4 wt% to 20 wt% preferably 7 wt% to 11 wt%, even more preferably about 9 wt%.

[0043] The method may comprise applying the flamprop-m-methyl to the crop by crop-topping from a spray-mixture formed from an EC that comprises a concentration of flamprop-m-methyl of 50 g/L to 150 g/L of flamprop-m-methy. Particularly useful EC concentrates contain 70 g/L to 120 g/L of flamprop-m-methyl such as about 90 g/L of flamprop-m-methyl.

[0044] In one set of embodiments the method comprises a step of forming a spray-mixture of the herbicide by mixing the flamprop-m-methyl composition, preferably an EC composition with a spray adjuvant, particularly spray oil, which may be added by tank-mixing. Examples of spray oils include paraffinic spray oils, vegetable oil derived oils such as vegetable oils and esters of vegetable oils such as methyl and ethyl esters of vegetable oils. In one embodiment the spray oil contains an oil such as paraffin oil naphtha-based petroleum oil, vegetable based oil in an amount such as 50% to 98% oil and, one or more surfactants such as 1 wt% to 40 wt% functioning as emulsifiers and/or wetting agents. In another embodiment the spray oil may contain 60 to 85% of emulsifiable oil such as paraffin oil naphtha based petroleum oil, vegetable based oil and 15 to 40% of nonionic surfactants. In one embodiment, the spray oil comprises a paraffinic oil.

Products correctly identified as "vegetable oil concentrates" typically consist of 60 to % of vegetable oil (i.e. seed or fruit oil, most commonly from cotton, linseed, soybean or sunflower) and 15 to 40% of nonionic surfactants. Adjuvant performance can be improved by replacing the vegetable oil with esters such as methyl or ethyl esters of fatty acids that are typically derived from vegetable oils. The amount of oil based adjuvants added to the spray-mixture generally does not exceed about 2.5% by volume, and more typically the amount is from about 0.1 to about 1% by volume. The application rate of oil-based adjuvants to the spray mixture are in the range 0.1 3 litres/100 litres, preferably in the range 0.3 - 1 litres/100 litres, more preferably about 0.5 litres/100 litres which corresponds to 0.5 % on a v/v basis. Such adjuvants are usually dosed to achieve a target concentration in the spray water rather than a target application rate per hectare.

[0045] Spray adjuvants containing oils, with or without emulsifiers, particularly methylated seed oils or ethylated seed oils, are particularly compatible in spray mixtures.. Therefore one embodiment of the present invention relates to a mixture or method for controlling wild oat seed set, further comprising forming the spray mixture. The step of forming of the spray mixture may involve mixing the flamprop-m methyl composition, preferably in the form of an EC with water and optionally an adjuvant. In a preferred aspect an adjuvant such as a spray oil, which may be a crop oil concentrate or vegetable oil concentrate such as an esterified seed oil such as methylated or ethylated seed oil is used. The method may involve adding an adjuvant (in any order of addition or mixing) to the spray-mixture, and contacting the crop with an amount of the spray-mixture effective to control wild oats seed-set.

[0046] The ratio of the volume of flamprop-m-methyl (as an EC formulation) to the volume of spray water varies with such parameters as:

(1) the loading of flamprop in the EC;

(2) the application rate of flamprop on a per-hectare basis, and

(3) The spray rate (litres/hectare).

[0047] For example if the target application rate of a particular EC formulation of flamprop is 2 litres of EC per hectare, and the application spray rate is 30L/ha (eg in an aerial application scenario, then the ratio of EC (liquid) to spray water (liquid) is 2/30.

[0048] Alternatively if the target application rate is 2 litres of EC per hectare and target spray rate is 1001/ha (eg from a boom spray), then the ratio of EC (liquid) to spray water (liquid) is 2/100.

[0049] These conditions can be determined by calculation and simple experimentation by one skilled in the art.

[0050] In one set of embodiments the spray oil comprises a fatty acid or fatty acid derivative such as a methyl of ethyl ester derivative that enhances the penetration of herbicide into the weed. The spray oil may comprise a surfactant that is non-ionic, anionic or cationic in nature. In one embodiment the spray oil includes a non-ionic surfactant such as an alkoxylated alkyl alcohol surfactant. In one preference, the concentration of the spray oil in spray water is in the range 200 ml to 1000 ml spray oil per 100 L of water, preferably in the range 300 ml to 700 ml/1OOL water, still more preferably about 500 m/1OOL water.

[0051] The concentration of the flamprop-m-methyl in the spray mixture may be determined having regard to the spray equipment and the desired rate of spray volume per area of land.

[0052] The method may utilise flamprop-m-methyl in the form of an emulsifiable concentrate (EC). A rance of EC formulations are available which may be used. Typically flamprop EC composition comprises 50 g/L to 150 g/L of flamprop-m methyl, preferably 70 g/L to 120 g/L of flamprop-m-methyl, more preferably about 90 g/L of flamprop-m-methyl.

[0053] The EC compositions will typically comprise a water-immiscible diluent in which flamprop-m-methyl is soluble. In one preference, the flamprop-m-methyl EC comprises about 300 - 850 g/L of aromatic hydrocarbon solvent, preferably 600-750 g/L, more preferably about 670 g/L.

[0054] In one embodiment the flamprop-m-methyl EC comprises about 30 200g/L of paraffinic oil, preferably about 50-120 g/L, more preferably about 75g/L.

[0055] In one preference the flamprop-m-methyl EC comprises about 20-150 g/L of propylene carbonate, preferably 40-80 g/L, more preferably about 50 g/L.

[0056] Where the method uses a composition of flamprop-m-methyl in EC form the composition will include an emulsifier component which may include a mixture of a non-ionic and anionic surfactant. The surfactants include an emulsifier component which may include an alkylarylsulfonate anionic surfactant and a non- ionic surfactant. Suitable alkylarylsulfonate anionic surfactants include alkyl benzene sulfonates, for example, the sodium, calcium or triethyl ammonium salts of alkyl benzene sulfonic acid. Suitably, the alkyl moiety of the calcium alkylbenzene sulfonate salt, which may be straight or branched, is C-C 16 alkyl. Preferably the alkyl moiety is C 10 -C 14 alkyl. Most preferred alkyl benzene sulfonates are the sodium, calcium or triethyl ammonium salts of dodecyl benzene sulfonic acid.

[0057] The preferred non-ionic emulsifers are nonionic emulsifiers comprising a polyalkylene oxide derivative. The emulsion concentrate composition preferably does not give rise to crystalline precipitates upon storage for at least 48 hours at O°C. Preferred non-ionic surfactants include the condensation products of alkylene oxide with components forming nonpolar groups such as the condensation products of ethylene oxide with fatty alcohols such as oleyl alcohol and cetyl alcohol; the condensation products of ethylene oxide with phenols and alkylphenols such as isooctylphenol, octylphenol and nonylphenol; the condensation products of ethylene oxide with castor oil; the partial esters derived from long chain fatty acids and hexitol anhydrides, for example sorbitan monolaurate, and their condensation products with ethylene oxide; ethylene oxide/propylene oxide block copolymers; lauryl alcohol polyglycol ether acetal.

[0058] Examples of nonionic surfactants which may be used alone or in combination in the emulsifier component are listed below, in which EO=ethylene oxide units, such as PO=propylene oxide units and BO=butylene oxide units: C10 C 24-alcohols which may be alkoxylated, e.g. with 1-60 alkylene oxide units, preferably 1-60 EO and/or 1-30 PO and/or 1-15 BO in any order. The terminal hydroxyl groups of these compounds can be terminally capped by an alkyl, cycloalkyl or acyl radical having 1-24 carbon atoms.

[0059] Preferred are non-ionic surfactants are ethoxylated oils such a castor or canola oil ethoxylates having at least 25, preferably at least 27 or more preferably at least 37 ethoxy units.

[0060] Another group of preferred nonionic surfactants are alcohol alkoxylates, which are based on ethoxylate or a mixed mixed ethoxylate/propoxylate. In a preferred aliphatic alcohol alkoxylate, the alkoxylate chain may have at least 5 alkoxy moieties, suitably from 5 to 25 alkoxy moieties, preferably 5 to 15, in particular 5 to 11. The alcohol moiety is as a rule derived from a C9.81 aliphatic alcohol.

[0061] In one aspect the spray-mixture is prepared from an EC composition of flamprop-m-methyl comprising:

flamprop-m-methyl in an amount of 50 g/L to 150 g/L, preferably 70 g/L to 120 g/L, more preferably about 90 g/L;

water-immiscible solvent preferably selected from aromatic and aliphatic hydrocarbons, preferably in an amount of from 400 g/L to 800 g/L and preferably selected from naphtha, paraffinic hydrocarbons and mixtures thereof;

[0062] co-solvent, preferably water soluble co-solvent selected from alcohols, carbonates and ketones and more preferably propylene carbonate, preferably in an amount of 5 g/L to 100 g/L;

[0063] a non-ionic emulsifier selected from the group consisting of alkoxylated alcohol, ethoxylated tristyryl phenol, a castor oil ethoxylate, an alkoxylated (C8 9 alkyl)phenol, preferably, selected from the group consisting of an alkoxylated polypropyleneglycol (e.g., Termul 203), an alkyl polyoxyalkylene ether, an ethylene oxide-propylene oxide block co-polymer (e.g., Termul 203), an alkoxylated nonylphenol (e.g., Termul 200), a castor oil ethoxylate, such as a castor oil-54-EO (e.g., Termul 1285), more preferably a castor oil ethoxylate, preferably in an amount of 15 g/L to 100 g/L, preferably 30 g/L to 80 g/L; and

[0064] a calcium alkylbenzene sulfonate such as dodecylbenzene sulfonate, preferably in an amount of 5 g/L to 100 g/L, preferably 30 g/L to 80 g/L.

[0065] In one embodiment, the flamprop-m-methyl EC comprises about 30 g/L to 120 g/L of surfactant having poly-alkoxylate functionality such as the non-ionic surfactants referred to above.

[0066] In one set of embodiments the flamprop-m-methyl EC comprises vegetable oil alkoxylate in an amount in the range 30 g/L to 120 g/L, preferably 50 g/L to 90 g/L, more preferably about 68 g/L.

[0067] In set of embodiments the flamprop-m-methyl EC comprises an anionic surfactant which is an alkylbenzene sulfonate surfactant, preferably a calcium salt.

[0068] The calcium salt of alkylbenzene sulfonate may be presented as a concentrate (eg 70%) in a solvent (eg 2-ethyl hexanol). In one preference the calcium salt of alkylbenzene sulfonate is present in the EC at a concentration in the range 25-80 g/L, preferably in the range 30-50 g/L more preferably about 46 g/L based on the quantity of calcium alkyl benzene sulfonate (ie net of solvent in the concentrate).

[0069] The flamprop-m-methyl may be applied to the crop from a spray-mixture using overhead spraying equipment such as spray boom equipment.

[0070] The herbicidal spray-mixture composition containing flamprop-M-methyl may contain a minor amount of another herbicide such as up to 10 wt% of the herbicide component. Preferably the composition contains no more than 5wt% of other herbicide based on the total weight of herbicides Generally it is preferred that the spray mix composition contain flamprop-M-methyl as the sole herbicide.

[0071] In one embodiment, the flamprop-m-methyl is applied to a chickpea crop infested with wild oats when the wild oats is at growth stage Z30 or later on the Zadok scale.

[0072] In one preference, the flamprop-m-methyl is applied when wild oats are at growth stage Z40 or earlier on the Zadok scale.

[0073] In one preference, the flamprop-m-methyl is applied when wild oats are at growth stage of about Z31.

[0074] In one preference the method of reducing the seed set of wild oats in a kabuli chickpea crop comprises a preliminary step (prior to seeding with kabuli chickpea seed) of applying one or more applications of knock-down herbicides such as paraquat or glyphosate or both.

[0075] Plant Growth Stages

[0076] Plant growth stages (phenotypes) have been systematised in the BBCH scale, and for peas the broad growth stage categories in BBCH are as follows:

- germination 1 - leaf development 3 - stem elongation (main shoot) - inflorescence emergence 6 - flowering 7 - development of fruit 8 - ripening of fruit and seed 9- senescence.

[0077] More detailed subdivisions of the broad growth stage categories include:

51 - first flower buds visible outside leaves - first separated flower buds visible outside leaves but still closed 59 - First petals visible, flowers still closed - First flowers open (sporadically within the population) 61 - Beginning of flowering: 10% of flowers open 62 - 20% of flowers open 63 - 30% Of flowers open 64 - 40% of flowers open - Full flowering: 50% of flowers open 67 - Flowering declining 69 - End of flowering

[0078] An alternative notation for the later growth stages (reproductive or r stages) of kabuli chickpeas is as follows:

RO- False flowering. False flowers lack fully developed petals R1- Start flowering. One flower bud at any node on the mainstem R2- Calyx opening. Bud grows but is still sterile, sepals begin to form R3- Anthesis. Pollination occurs before the bud opens R4- Wings extend. Flower petals extend to form a flower

R5 - Corolla collapses. Flower collapses and petals senesce and peduncle reflexes so that the developing pod usually hangs below the subtending leaf R6- Pod initiation. One pod is found on any node on the main stem R7- Full pod. One fully expanded pod is present that the dimensions characteristic of the cultivar R8-Beginning seed. One fully expanded pod is present in which seed cotyledon growth is visible when the fruit is cut in cross-section with a razor blade (following the liquid endosperm stage R9- Full seed. One pod with cavity apparently filled by the seeds when fresh R10-Beginning maturity. One pod on the main stem turns to a light golden-yellow in colour R11-50% golden pod. %0% of pods on the plant mature R12-90% golden pod. 90% of pods physiologically mature (golden yellow), usually about 140-200 days after planting depending on season and cultivar.

[0079] When using flamprop-m-methyl to control wild oats in wheat, it is known that application later than flag leaf stage of the crop is potentially damaging to the crop. By contrast, when using flamprop-m-methyl to control wild oats in chickpeas, the inventors have found that application later than the middle of flowering is potentially damaging to the crop.

[0080] An alternative growth scale (for weeds such as wild oats) is the Zadok growth scale, and the broad growth stage categories are:

ZO - Germination Z1 - Seedling growth Z2 - Tillering Z3 - Stem elongation Z4 - Booting Z5 - Ear emergence from boot Z6 - Anthesis (flowering) Z7 - Milk development Z8 - Dough development Z9 - Ripening

[0081] Z3 and Z4 of the Zardok scale may be expanded into sub-categories as follows:

[0082] Z3 - A more detailed Zadok growth scale counts swollen nodes that can be felt on the main stem.

• •30 - Pseudostem (youngest leaf sheath erection) • •31 - First node detectable • •32 - Second node detectable • •33 - Third node detectable • •34 - Fouth node detectable • •35 - Fifth node detectable • •36 - Sixth node detectable • •37 - Flag leaf just visible • •39 - Flag leaf ligule just visible

[0083] Z4 - Booting

Score the appearance of the sheath of the flag leaf. • •41 - Flag leaf sheath extending • •43 - Boots just visible swollen • •45 - Boots swollen • •47 - Flag leaf sheath opening • •49 - First awns visible

[0084] The invention will now be described with reference to the following examples. It is to be understood that the examples are provided by way of illustration of the invention and that they are in no way limiting to the scope of the invention.

Examples

Example 1

[0085] Composition of Flamprop-m-methyl EC (90g/L)

[0086] Table 1. The composition of a 90g/L flamprop-m-methyl EC

Component Cas. No Chemical name Concentration Function (g/L) Flamprop-m-methyl 63729-98-6 Flamprop-m-methyl 93.3 Active (96.4%) Solvent Naphtha Solvesso 200 64742-94-5 (petroleum) heavy 670.0 Solvent aromatic Paraffin Oil 100SN 8012-95-1 Paraffin, liquid 75.0 Adjuvant Jeffsol PC 108-32-7 Propylene Carbonate 50.0 Co-solvent Termul1285 61791-12-6 Castor oil ethoxylate 68.2 Emulsifier Benzenesulphonic Nansa EVM 70/2E 90194-26-6 dervis,4-Cl0-u4-als 63.5 Emulsifier in 2-Ethylhexanol TOTAL 1020

Example 2

[0087] Formulation Process for 90g/L flamprop-m-methyl EC composed according to table 1.

[0088] The manufacturing method described here has been used make a 1000L batch.

[0089] Step 1: Fill a 1,200-1,500L stainless steel mixing vessel with all of the required solvents (Jeffsol PC and Solvesso 200) for a 1,000L batch. Begin mixing with a high shear mixer on low speed (Dispermat was used in the pilot plant).

[0090] Step 2: Gradually add flamprop-m-methyl to the mixing vessel and mix on a medium speed.

[0091] Step 3: Continue mixing until all the flamprop-m-methyl tech is dissolved.

[0092] Step 4: Gradually add in the Termul 1285, Paraffin oil and Nansa EVM /2E. Mix on moderate speed until clear and homogenous.

Example 3

[0093] Quality control

[0094] Complete dissolution

A sample should be taken at the completion of the batch. The sample is checked for any remaining undissolved active. If the sample contains any undissolved active, the batch must be mixed for a longer period of time until active is completely dissolved.

Foaming

[0095] Excessive foaming may result from high shear speeds. Avoid using high shear speeds and make sure that the mixing head is completely immersed in the product

Final Product Testing

[0096] A number of tests were undertaken on the final product candidate (Table 2).

[0097] Table 2. Test to be undertaken on the final product

Test method Specification

Appearance Light amber clear liquid pH (1% w/w solution) 6- 7 Specific gravity (g/ml) 1.01- 1.04 Active ingredient concentration 81g/L - 99g/L (g/L)

[0098] Physical and Chemical Properties of the Product

[0099] The physical and chemical properties of the product candidate are provided (Table 3).

Table 3. Properties of product candidate 8341-1 Test Method Data Appearance (physical state, colour, odour) Clear light amber liquid pH (MT 75.3) (1%w/w solution) 6-7

Specific Gravity 1.01-1.04

Viscosity (MT 192) (After 1 min, Spindle 2, 20RPM) N/A Pourability (MT 148.1) N/A Suspensibility on Dilution with Water (MT 184) N/A

Spontaneity of Dispersions (MT 160) N/A Wet Sieve Test (MT 185) N/A

Persistent foam (MT 47.2) 30 - 40mL

Packaging Stability (FLUORINATED HDPE) Stable

Flash Point (MT 12.1) 870C)

Flammability N/A Explosive properties N/A Oxidising properties N/A Corrosive hazard N/A

Example 4

[0100] Method studies: Monarch variety of kabuli Chickpea Yields

[0101] Formulation F1 (described in above examples 1,2,3) was an EC containing 90g/L of flamprop-m-methyl.

[0102] Spray oil SO comprised paraffinic oil (520g/L) and alkoxylated alcohol non-ionic surfactant (240g/L).

[0103] The following treatments were used (Table 4).

[0104] Table 4 (Treatments)

(spray volume 1O0L/ha)

Number Product Rate Rate (g Application applied ai/ha) schedule 1 Untreated nil nil n/a control 2 F1 +SO 1.875 L/ha 168.8 Single foliar + 0.5% v/v application at of spray- BBCH 59 (18 Sept water 3 F1 +SO 3.75 L/ha + 337.5 Single foliar 0.5% v/v of application at spray-water BBCH 59 (18 Sept) 4 F1 +SO 1.875 L/ha 168.8 Single foliar + 0.5% v/v application at of spray- BBCH 65 (1 water October) F1 +SO 3.75 L/ha + 337.5 Single foliar 0.5% v/v of application at spray-water BBCH 65 (1 October Note: foliar Note: foliar application application at BBCH 59 at BBCH 65 is is designated designated treatment A treatment B

[0105] Table 5 (Chronology)

Days after Crop stage Event application timing (DAA)

-113DAAA BBCH 00 Crop sown ODAAA BBCH 59 Application A of treatments 2 & 3 13DAAA BBCH 65 Application B of treatments 4 & 5 Crop vigour, phytotoxicity and GreenSeeker@ assessments 6DAAB BBCH 69 Crop vigour, phytotoxicity and GreenSeeker@ assessments 13DAAB BBCH 72 Crop vigour, phytotoxicity and GreenSeeker@ assessments 29DAAB BBCH 78 Crop vigour, phytotoxicity and GreenSeeker@ assessments 57DAAB BBCH 89 Crop harvested Grain yield assessed

[0106] Table 6: Grain Yield of Monarch chickpea with 5 treatments shown in Table 4

Treatment timing Rate Grain yield number flampropr ( (kq/ha) ai/ha) 57 DAAB

1 Nil Nil 1117 ab 2 A (BBCH 59) 168.8 1077 abc 3 A (BBCH 59) 337.5 1198 a 4 B (BBCH 65) 168.8 952 c B (BBCH 65). 337.5 1025 bc

[0107] Note to Table 6: yield means followed by the same letter are not significantly different (P=0.05).

[0108] From Table 5, 6 application timing had a significant effect on grain yield, with formulation F1 applied at BBCH 65 (outside the instant invention) recording significantly lower grain yield than when applied at BBCH 59 (within the instant invention). Both application rates of formulation F1 applied at BBCH 59 recorded equivalent grain yield to the intreated control, with the 337.5 g ai/ha application rate recording significantly higher grain yield than both rates applied at BBCH 65.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method of controlling seed-set of wild oats in a crop of kabuli chickpea comprising applying flamprop-m-methyl to the crop by crop-topping.

2. The method of claim 1 wherein the kabuli chickpea is of the PBA Monarch variety.

3. The method of any one of the previous claims, wherein the flamprop-m methyl is applied to the chickpea crop when it has at least commenced its reproductive phase characterised by the formation of flowerbuds on the lower-most node of the chickpea plant in at least some plants of the crop.

4. The method of any one of the previous claims, wherein the flamprop-m methyl is applied to the crop when it has reached at least BBCH growth stage 51, preferably at least BBCH growth stage 55.

5. The method of any one of the previous claims, wherein the flamprop-m methyl is applied at a growth stage of at least BBCH 51 and at most BBCH 64.

6. The method of any one of the previous claims, wherein the flamprop-m methyl is applied at a growth stage of BBCH 55 to BBCH 63.

7. The method of any one of the previous claims, wherein the flamprop-m methyl is applied at a growth stage of BBCH 55 to BBCH 61.

8. The method of any one of the previous claims, wherein the flamprop-m methyl is applied at a growth stage of BBCH 55 to BBCH 60.

9. The method of any one of the previous claims, wherein the flamprop-m methyl is applied to the crop when it has at least reached chickpea R stage R1.

10. The method of any one of the previous claims, wherein the flamprop-m methyl is applied to the chickpea crop no later than when it has reached the middle of flowering, characterised by the opening of at least about 40% of flowerbuds to form open flowers.

11. The method of any one of the previous claims, wherein the flamprop-m methyl is applied no later than when the chickpea crop has reached R stage R5, preferably no later than when the chickpea crop has reached R stage R4.

12. The method of any one of the previous claims, wherein the flamprop-m methyl is applied no later than the development of pods on the lower nodes of the chickpea plants in at least some plants of the crop.

13. The method of any one of the previous claims, wherein the flamprop-m methyl is applied no later than when the first flowers on the lowermost nodes of the chickpea plants have fallen in at least some plants of the crop.

14.The method of any one of the previous claims, wherein the flamprop-m methyl is applied to the crop by crop-topping a spray-mixture formed by dilution of an emulsifiable concentrate (EC) of flamprop-m-methyl.

15.The method of any one of the previous claims, wherein method comprises applying the flamprop-m-methyl to the crop from a spray-mixture formed from an EC that comprises a concentration of flamprop-m-methyl of 50 g/L to 150 g/L of flamprop-m-methyl.

16.The method of any one of the previous claims, wherein method comprises applying the flamprop-m-methyl to the crop from a spray mixture formed from an EC that comprises a concentration of flamprop-m-methyl of 70 g/L to 120 g/L, more preferably about 90 g/L of flamprop-m-methyl.

17. The method of any one of the previous claims, wherein the flamprop-m methyl is applied to kabuli chickpea crop at a rate 40 grams/hectare to 600 grams/hectare.

18. The method of any one of the previous claims, wherein the kabuli chickpea crop includes wild oats resistant to one of more Group A herbicides.

19. The method of claim 18 wherein the wild oats is resistant to at least one Group A herbicide selected from the group consisting of Clethodim, Haloxyfop, Quizalofop and Butroxydim The method of any one of the previous claims, wherein the flamprop-m-methyl is applied to a crop of PBS Monarch variety of kabuli chickpea at a rate of 100 grams/hectare to 450 grams/hectare.

20. The method of any one of the previous claims, wherein the flamprop-m methyl is applied to Monarch chickpea crop at a rate of 130 grams/hectare to 300 grams/hectare.

21. The method of any one of the previous claims, comprising applying flamprop-m-methyl by spraying a spray-mixture comprising flamprop-m methyl water diluent and a spray oil selected from the group consisting of paraffinic spray oils, vegetable oils and esters of vegetable oils.

22. The method of claim 21, wherein the amount of spray oil in the spray mixture does not exceed about 2.5% by volume.

23. The method of claim 21, wherein the amount of spray oil in the spray-mix is from 0.1% to 1% by volume.

24. The method of any one of claims 21 to 23, wherein the spray oil comprises 60 Vol% to 85 Vol% of emulsifiable petroleum-based oil or vegetable based oil and 1Vol % to 40 Vol% of nonionic surfactant.

25. The method of any one of claims 21 to 23, wherein the concentration of spray oil in the spray-mix is 100 ml to 1000 ml spray oil per 100 L of water.

26. The method of any one of the previous claims wherein the flamprop-m methyl is applied from a spray-mix formed form an emulsifiable concentrate (EC) of flamprop-m-methyl comprising 300 g/L to 850 g/L of aromatic hydrocarbon solvent.

27. The method of any one of the previous claims wherein the flamprop-m methyl is applied from a spray-mix formed form an emulsifiable concentrate (EC) of flamprop-m-methyl comprising 30-200g/L of paraffinic oil.

28. The method of any one of the previous claims wherein the flamprop-m methyl is applied from a spray-mix formed form an emulsifiable concentrate (EC) of flamprop-m-methyl comprising 20 g/L to 150 g/L of propylene carbonate.

29. The method of any one of the previous claims wherein the flamprop-m methyl is applied from a spray-mix formed from an emulsifiable concentrate (EC) of flamprop-m-methyl comprising an emulsifier component including a mixture of a non-ionic and anionic surfactant.

30. The method of any one of the previous claims wherein the flamprop-m methyl is applied from a spray-mix formed from an emulsifiable concentrate (EC) of flamprop-m-methyl comprising an emulsifier component comprising about 30 g/L to 120 g/L of surfactant having poly alkoxylate functionality.